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  • Organic Chemistry  (7,440)
  • Earth model, also for more shallow analyses !
  • Ecology
  • Industrial Chemistry
  • 1980-1984  (3,489)
  • 1950-1954  (3,393)
  • 1935-1939  (1,972)
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Year
  • 1
    Electronic Resource
    Electronic Resource
    Ideology and wildlands management: The case of Rondeau Provincial Park, Ontario (1980)
    Springer
    Environmental management 4 (1980), S. 111-124 
    Details
    ISSN: 1432-1009
    Keywords: Carolinian ; Ecology ; Ideology ; Policy ; Rondeau ; Technology ; Wildland Management ; Parks
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract This is a critical examination of some of the basic concepts that have guided management of parks and related reserves, often termed wildlands. Study is focussed on Rondeau Provincial Park, Ontario, and on concepts such as wilderness, primeval forest, and the Carolinian forest. Deer culling and other management policies and practices have been based upon the idea that the highly valued sassafras, tulip, and other species of the Carolinian forest are decreasing due to browsing. Field mapping and analysis of historic vegetation records indicate that this trend is not in fact occurring. Historic research also reveals difficulties in defining the Carolinian or other perceived types of forest for management purposes. A major reassessment of ideology and management policy and practice seem to be required in Rondeau and other wildlands. Vague or general concepts such as wilderness or preservation should be strongly complemented and supported by more precise statements of objectives, a learning attitude, and experimentation and research. As a result of the technical uncertainties and value judgments frequently involved, management should also be based upon the expressed preferences and continuing involvement of citizens.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01866508
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  • 2
    Electronic Resource
    Electronic Resource
    Ecological planning: A review (1981)
    Springer
    Environmental management 5 (1981), S. 495-505 
    Details
    ISSN: 1432-1009
    Keywords: Suitability analysis ; Land-use assessment ; Ecology ; Planning ; Human ecology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Beginning with the passage of the National Environmental Policy Act in 1969, the federal government of the United States has enacted numerous pieces of legislation intended to protect or conserve the environment. Other national governments have also enacted environmental legislation during the past two decades. State and local governments have also adopted policies concerned with environmental planning and management. Multiple laws and overlapping governmental agency responsibilities have confused development and resource management efforts. A comprehensive methodology that integrates the legal mandates and the agency missions into a common and unified framework is needed. Ecological planning offers such a method. Application of the method allows planners and resource managers to better understand the nature and character of the land and/or resource and therefore make better decisions about its appropriate use or management. The steps taken in an ecological planning process—1) goal setting, 2) inventory and analysis of data, 3) suitability analysis, 4) developing alternatives, 5) implementation, 6) administration, and 7) evaluation—are outlined and explained. Hand-drawn overlays and computer programs as techniques for handling ecological planning information are compared. Observations and suggestions for further research are offered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01866722
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  • 3
    Electronic Resource
    Electronic Resource
    Photosynthetic metabolism in the cyanophytaOscillatoria rubescens D.C. (1982)
    Springer
    Archives of microbiology 131 (1982), S. 107-111 
    Details
    ISSN: 1432-072X
    Keywords: Cyanophyta ; Cyanobacteria ; Oscillatoria rubescens ; Photosynthetic pathways ; Photosynthetic enzymes ; Ecology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Short term14C labelling experiments and enzymatic activities related to primary pathways of photosynthesis have been studied in the cyanophytaOscillatoria rubescens D.C. from axenic cyclostat cultures. Responses of samples from cultures with different amounts of nitrogen are presented and compared. Variations in photosynthetic pigments are used to quantify the degree of nitrogen starvation at different levels. PEPcarboxylase activity remains low and is not affected by nitrogen starvation. RuBPcarboxylase activity is lowered to nearly two thirds of its normal metabolic rate by starvation but PEPcarboxykinase and aspartate aminotransferase activities are significantly higher in this case. Malate dehydrogenase is slightly altered and malic enzyme is never active. Starved algae replaced in fresh complete media fix rapidly14C in nitrogen compounds such as amino acids. Results are discussed in regard to both physiological and ecological characteristics ofO. rubescens. PEPcarboxykinase can play a role in making efficient use of HCO 3 - .
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01053990
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  • 4
    Electronic Resource
    Electronic Resource
    Aerobic denitrification: a controversy revived (1984)
    Springer
    Archives of microbiology 139 (1984), S. 351-354 
    Details
    ISSN: 1432-072X
    Keywords: Aerobic denitrification ; Thiosphaera pantotropha ; Nitrate reduction ; Bacterial selection ; Ecology ; Oxygen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract During studies on the denitrifying mixotroph, Thiosphaera pantotropha, it has been found that this organism is capable of simultaneously utilizing nitrate and oxygen as terminal electron acceptors in respiration. This phenomenon, termed aerobic denitrification, has been found in cultures maintained at dissolved oxygen concentrations up to 90% of air saturation. The evidence for aerobic denitrification was obtained from a number of independant experiments. Denitrifying enzymes were present even in organisms growing aerobically without nitrate. Aerobic yields on acetate were higher (8.1 g protein/mol) without than with (6.0 g protein/mol) nitrate, while the anaerobic yield with nitrate was even lower (4 g protein/mol). The maximum specific growth rate of Tsa. pantotropha was higher (0.34 h-1) in the presence of both oxygen (〉80% air saturation) and nitrate than in similar cultures not supplied with nitrate (0.27 h-1), indicating that the rate of electron transport to oxygen was limiting. This was confirmed by oxygen uptake experiments which showed that although the rate of respiration on acetate was not affected by nitrate, the total oxygen uptake was reduced in its presence. The original oxygen uptake could be restored by the addition of denitrification inhibitors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00408378
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  • 5
    Electronic Resource
    Electronic Resource
    Bacillus tusciae, a new species of thermoacidophilic, facultatively chemolithoautotrophic hydrogen oxidizing sporeformer from a geothermal area (1984)
    Springer
    Archives of microbiology 139 (1984), S. 397-401 
    Details
    ISSN: 1432-072X
    Keywords: Bacillus tusciae ; New species ; Taxonomy ; Ecology ; Chemolithoautotrophy ; Hydrogen oxidation ; Hydrogenase ; Thermophily ; Geothermal manifestation ; Solfatara
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A thermophilic, chemolithoautotrophic, hydrogen-oxidizing sporeformer has been isolated from ponds in a solfatara in the geothermal area of Tuscany (Italy). Some physicochemical parameters of the habitat were determined. The habitat was characterized by the presence of molecular hydrogen in the escaping gases, a very low content of phosphate and organic matter. Temperature and water level in the ponds varied widely. The organism formed oval, subterminal spores, which swelled distinctly the sporangium. Optimal growth occured between pH 4.2 and 4.8 at 55°C. It grew best under autotrophic conditions, but organic substrates including short chain fatty acids, amino acids and alcohols could also support heterotrophic growth. Sugars were not metabolized. The hydrogenase was soluble but did not reduce pyridine nucleotides. Based on its morphological and biochemical features, the organism belongs to the genus Bacillus, but differs from all the previously described species. It is therefore proposed as constituting a new species, Bacillus tusciae.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00408386
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  • 6
    Electronic Resource
    Electronic Resource
    On optimal intrinsic growth rates for populations in periodically changing environments (1981)
    Springer
    Journal of mathematical biology 12 (1981), S. 343-354 
    Details
    ISSN: 1432-1416
    Keywords: Ecology ; Periodic differential equations ; Optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Summary The theory developed here applies to populations whose size x obeys a differential equation, $$\dot x = r(t)xF(x,t)$$ in which r and F are both periodic in t with period p. It is assumed that the function r, which measures a population's intrinsic rate of growth or intrinsic rate of adjustment to environmental change, is measurable and bounded with a positive lower bound. It is further assumed that the function F, which is determined by the density-dependent environmental influences on growth, is such that there is a closed interval J, with a positive lower bound, in which there lies, for each t, a number K(t) for which $$F(K(t),t) = 0$$ and, as functions on J × ℝ, F is continuous, while ∂F/∂x is continuous, negative, and bounded. Because x(t) = 0, 〉 0, or 〈 0 in accord with whether K(t) = x(t), K(t) 〉 x(t), or K(t) 〈 x(t), the number K(t) is called the “carrying capacity of the environment at time t”. The assumptions about F imply that the number K(t) is unique for each t, depends continuously and periodically on t with period P, and hence attains its extrema, K min and K max. It is, moreover, easily shown that the differential equation for x has precisely one solution x * which has its values in J and is bounded for all t in ℝ; this solution is of period p, is asymptotically stable with all of J in its domain of attraction, and is such that its minimum and maximum values, x min * and x max * , obey $$K_{min} \leqslant x_{min}^* \leqslant x_{max}^* \leqslant K_{max}^* .$$ The following question is discussed: If the function F is given, and the function r can be chosen, which choices of r come close to maximizing, x min * ? The results obtained yield a procedure for constructing, for each F and each ɛ 〉 0, a function r such that x min * 〉 K max − ɛ.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00276921
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  • 7
    Electronic Resource
    Electronic Resource
    Competition for fluctuating nutrient (1983)
    Springer
    Journal of mathematical biology 18 (1983), S. 255-280 
    Details
    ISSN: 1432-1416
    Keywords: Population dyamics ; Ecology ; Periodic solutions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract A model of the competition of n species for a single essential periodically fluctuating nutrient is considered. Instead of the familiar Michaelis-Menten kinetics for nutrient uptake, we assume only that the uptake rate functions are positive, increasing and bounded above. Sufficient conditions for extinction are given. The existence of a nutrient threshold under which the Principle of Competitive Exclusion holds, is proven. For two species systems the following very general result is proven: All solutions of a τ-periodic, dissipative, competitive system are either τ-periodic or approach a τ-periodic solution. A complete description of the geometry of the Poincaré operator of the two species system is given.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00276091
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  • 8
    Electronic Resource
    Electronic Resource
    Fagus silvatica L. und das aceri-fagetum an der alpinen Waldgrenze in Mitteleuropäischen gebirgen (1981)
    Springer
    Plant ecology 44 (1981), S. 13-24 
    Details
    ISSN: 1573-5052
    Keywords: Aceri-Fagetum ; Alpine timberline ; Dynamics of stands ; Ecology ; Fagus silvatica ; Morphogenesis ; Polycormons ; Vegetative regeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In the Central Europaean mountain ranges, the alpine timberline is usually formed by Picea abies or by other conifers (Larix decidua, Pinus mugo, Pinus cembra). Unlike in the East Europaean mountains, the Balkan Peninsula, the Europaean Mediterranean and Les Vosges, Fagus silvatica occurs sporadically on the alpine timberline in this area where it forms very specific woods. This type of the alpine timberline is bound to the association Aceri-Fagetum (Bartsch 1940, Moor 1952). This association is found on the highest sites of the Fagion alliance in the subalpine vegetation zone. Within this zone, the association is bound to localities with heavy snowfall and a submaritime climat. It occupies larger areas in the Swiss Jura and in Les Vosges. In other Central Europaean mountains (the Alps, Schwarzwald, Krkonoše etc.) it occus in isolated areas only. Many trunk deformations and bush forms are found with Fagus on a large scale in the snow impacted localities (steep slopes, periphery of corries, avalanche slopes etc.). Crawling and sliding snow causes these growth deformations in the Fagus seedlings since their first year. The general increase of the vegetative propagation is a remarkable and exceptional response of Fagus in adapting to these extreme growth conditions. Under alpine timberline conditions, the generative propagation is very limited. The vegetative shoots with adventitious root systems are formed mainly from branches layering in the humus. The typical monocormonal tree-form of Fagus from lower altitudes turns in this way into a polycormon. From an evolutionary point of view, it is a suitable substitution; but from the ecological viewpoint, however, it is a sturdy growth form. In its typical form, the polycormon is formed by a number of vegetative shoots, which may be deformed but are very elastic and resistent. The number of shoots in a polycormon varies from 3–5 below, and up to 40–50 at and above the timberline. They are formed by shoots of a number of filial successions. The decay of a polycormon results from decreasing vitality of single shoots or, very often, it is caused by the impact of snow and ice. Considering, however, the fact that single shoots have a sufficient adventitious root system and are thus physiologically independent, the dying of the other shoots does not mean a danger for the existence of the remaining part of the polycormon. The age of a polycormon as a whole is difficult to determine. Fagus polycormons can be considered as a typical growthform of the highest sites of the association Aceri-Fagetum. No other tree species is able to form close stands under these conditions. This phenomenon is of primary importance for the existence of this plant community. The unusual character of the structure and dynamics of the highest Aceri-Fagetum stands gives rise to a special type of the alpine timberline which should be understood not as a ‘line’ but as a transitional zone between the closed stands and the hon-wooded plant communities of the subalpine vegetation zone. The dynamic succession of the Fagus polycormons guarantees the stability of the Fagus stands forming the alpine timberline.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00119797
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  • 9
    Electronic Resource
    Electronic Resource
    Dynamics ofOstrya carpinifolia woods in the Southern Alps (N-Italy) (1982)
    Springer
    Plant ecology 48 (1982), S. 123-131 
    Details
    ISSN: 1573-5052
    Keywords: Ecology ; Fringe communities ; Numerical classification ; Ostrya carpinifolia woods ; Phytogeographic elements ; Phytosociology ; Southern Alps (N-Italy) ; Vegetation dynamics ; Wood edge communities
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Forest regeneration in the vegetation complex of the submontane belt in the Southern Alps involves the active participation ofOstrya carpinifolia woods and their wood edge communities. The corresponding syndynamical processes are described by employing phytosociological, phytogeographical and ecological methods. It is concluded that: (i) The communities of the grassland-wood transition are of major importance in the successional developments in this man-made vegetation complex. (ii) Many species occurring in the region of the deciduous forests of Eurasia find their refuge in such transitional communities and are supposed to play an important part in the succession. (iii) Ostrya carpinifolia is considered as an early successional tree species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00726880
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  • 10
    Electronic Resource
    Electronic Resource
    Some observations on the ecology, metal uptake and nickel tolerance of Alyssum serpyllifolium subspecies from the Iberian peninsula (1981)
    Springer
    Plant ecology 45 (1981), S. 183-188 
    Details
    ISSN: 1573-5052
    Keywords: Alyssum serpyllifolium subspecies ; Nickel accumulation ; Nickel tolerance ; Ecology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Experiments were carried out on the tolerance to, and uptake of, nickel by three iberian subspecies of Alyssum serpylliforium Desf. Two of these subspecies, the serpentine-endemic ssp. lusitanicum from Bragança, Portugal and ssp. malacitanum from Málaga, Spain, are hyperaccumulators (〉 1000 μg/g in dried material) of nickel. Their possible ancestor, ssp. serpyllifolium (from Granada, Spain) was a non-accumulator of this element. Seeds of the two serpentine-endemics germinated extensively in nickel concentrations up to 12 000 μg/g (1.2%) whereas ssp. serpyllifolium only germinated in nickel concentrations below 60 μg/ml. Tolerance tests involving measurement of new root lengths of excised seedlings placed in varying nickel concentrations, again showed much greater tolerance of the two serpentinophytes. In both series of experiments, the order of tolerance was: ssp. lusitanicum 〉 ssp. malacitanum 〉 ssp. serpyllifolium. In pot trials involving seedlings of ssp. malacitanum grown in mixtures containing varying amounts of calcium, magnesium, and nickel, the most important finding was that plants will tolerate higher nickel contents in the soil when excess calcium is added. This is achieved by lowering the uptake of nickel. There appeared to be some concomitant reduction in calcium uptake in the presence of nickel, and some increase in uptake of magnesium. The resultant lower calcium/magnesium ratio in the plant, though not symptomatic of a favourable condition for colonization of serpentine soils, probably results from a mechanism which renders nickel innocuous to the plant at the expense of calcium uptake. It is suggested that the physiological characters of ssp. lusitanicum and ssp malacitanum are sufficiently different to support arguments for promoting the latter to full specific rank as has now been done for ssp. lusitanicum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00054673
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  • 11
    Electronic Resource
    Electronic Resource
    Pflanzenvergesellschaftungen mit Riccia-Arten in Südwestafrika (Namibia) (1984)
    Springer
    Plant ecology 55 (1984), S. 57-64 
    Details
    ISSN: 1573-5052
    Keywords: Ecology ; Hepaticae ; Pioneer vegetation ; Resurrection (poikilohydric) plants ; Riccia ; South West Africa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Three associations of the Nanocyperion teneriffae Lebrun 1947 (Sporoboletalia festivi Lebrun 1947) are described. They are physiognomically and ecologically similar to associations of the Mediterranean Isoeto-Nanojuncetea Br.-Bl. et Tx. 1943 and Helianthemetalia guttati Br.-Bl. 1940. They are rich in very specialized therophytes and resurrection plants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00039982
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  • 12
    Electronic Resource
    Electronic Resource
    Factors affecting growth and nodulation ofHippophaë rhamnoides L. ssp.Rhamnoides in soils from two successional stages of dune formation (1981)
    Springer
    Plant and soil 63 (1981), S. 317-331 
    Details
    ISSN: 1573-5036
    Keywords: Actinorhizas ; Ecology ; Gamma irradiation ; Hippophaë rhamnoides ; Longidorus ; Nematode ; Nodulation ; Root nodules ; Soil sterilization ; Succession
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary To explain the decline of Hippophaë scrub in the vegetation succession in the dunes of The Netherlands, the growth and nodulation of Hippophaë plants grown in pots, using soil from an early stage (site AH) and a post-optimum stage (site HP), were investigated. In HP-soil nodulation, yield, and the nitrogen and phosphorus content of test plants were always lower and the number of necrotic nodules and the dry matter content were always higher than in AH-soil, even after inoculation with crushed nodules and the addition of a nutrient solution. Plants in HP-soil also had darker roots, less root hairs, a higher number of short lateral roots and a higher percentage of dead roots than those in AH-soil. These characteristics of adverse growth conditions disappeared upon ignition or gamma-irradiation of HP-soil. Possible explanations of these results are discussed. The degeneration of Hippophaë scrub cannot be ascribed to the age of the plants, the absence of sufficient infective endophyte particles or to abiotic factors such as unfavourable physical (particle size) or chemical soil conditions but is caused by biotic factors. No indications were obtained that plant-pathogenic fungi and bacteria are involved. HP-soil in contrast to AH-soil, however, contained large numbers of the nematodeLongidorus sp., a species known to cause root deformations. The conclusion was that this nematode is one of the biotic factors involved in the degeneration of the Hippophaë scrub. This degeneration is due to a restriction of the root system resulting in a low phosphate uptake, a low nodulation capacity and, as a consequence, a low nitrogen content. The results demonstrate that biotic soil factors are important in influencing succession in higher plant communities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02370033
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  • 13
    Electronic Resource
    Electronic Resource
    Frankia growth and activity as influenced by water potential (1982)
    Springer
    Plant and soil 69 (1982), S. 293-297 
    Details
    ISSN: 1573-5036
    Keywords: Ecology ; Frankia ; Nitrogen fixation ; Water potential
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Growth responses of Frankia isolates to decreasing water potential were monitored in systems where potentials were controlled by KCl, NaCl and Polyethylene glycol. The highest potential tested was −2 bar (basal medium). The general pattern emerging was that isolates fromAlnus glutinosa, A. viridis andComptonia peregrina showed declining growth at potentials below −2 to −5 bar. AMyrica gale isolate showed declining growth with decreasing potential. All isolates were more sensitive to decreases in potential in a matric controlled than an osmotic controlled system. They all showed approximately 50 percent growth reduction at −5 to −8 bar, and meagre growth at −16 bar after 35 days. The Comptonia isolate was the most vigorous at low potentials. Nitrogen fixation ability was monitored for two isolates. Highest specific activities were observed between −3 and −5 bar for the Myrica isolate and between −5 and −7.5 bar for theA. glutinosa isolate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02374525
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  • 14
    Electronic Resource
    Electronic Resource
    Nematodes (Longidorus sp. andTylenchorhynchus microphasmis loof) in growth and nodulation of sea buckthorn (Hippophaë rhamnoides L.) (1983)
    Springer
    Plant and soil 73 (1983), S. 141-147 
    Details
    ISSN: 1573-5036
    Keywords: Actinorhizas ; (Actinomycetes) ; Ecology ; Hippophaë ; (Mystiflora: Elaeagnaceae) ; Longidorus ; (Nematoda: Longidoridae) ; Nodulation ; Soil ; sterization ; Vegetational succession ; Tylenchorhynchus (Nematoda: Tylenchrohynchidae)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Hippophaë rhamnoides seedlings were grown in sterilized and unsterilized soil from a decliningH. rhamnoides scrub, to which different numbers ofLongidorus sp. andTylenchorhynchus microphasmis were added. In sterilized and unsterilized soil, retardation of growth, content of dry matter in the shoots, and incidence of deformed short lateral roots of test plants were positively correlated with counts of both nematode species. Nitrogen content in the shoots, nodulation on the roots of test plants and increase increase in nematodes were negatively correlated with the initial number of both nematode species in sterilized soil. In unsterilized soil, an unknown biotic factor was present that reduces growth ofH. rhamnoides, nodulation and multiplication of the nematodes. This factor seems to interact with the nematodes in reducing growth ofH. rhamnoides.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02197763
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  • 15
    Electronic Resource
    Electronic Resource
    Effects of crop rotation and fertilization on catalase activity in a soil of the southeastern United States (1982)
    Springer
    Plant and soil 69 (1982), S. 97-104 
    Details
    ISSN: 1573-5036
    Keywords: Catalase ; Ecology ; Fertilizers ; H2O2∶H2O2 oxidoreductase ; Rhizosphere effects ; Soil enzymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Catalase activity of a loamy sand under a 3-year crop rotation in the southeastern U.S.A. was monitored. Corn (Zea mays L.), cotton (Gossypium hirsutum L.), and soybean [Glycine max (L.) Merr.] were the summer crops in the rotation. Winter wheat (Triticum aestivum L.) was planted after corn, and soybean was followed by a winter fallow period. Cotton was followed by a mixture of common vetch (Vicia sativa L.) and crimson clover (Trifolium incarnatum Gibelli & Belli) which was eventually plow-incorporated as a green manure. Highest mean catalase activities were recorded in soil under the wheat, soybean, and winter legume crops; lowest activities were found in soil bearing corn and cotton, and during the winter fallow period. The fertilization regime influenced soil catalase activity independently of the crop. Soil deficient in any of the major elements showed low enzyme activity. Highest activity was found in soil fertilized with P and K, and with N supplied by a winter legume crop. Addition of supplementary mineral nitrogen to this regime reduced catalase activity. Elimination of the winter legume crop from an otherwise complete fertilization regime resulted in a drastic reduction in enzyme activity. In soil receiving a complete fertilization regime there was a close correlation between soil catalase and xylanase activities. A similar correlation between these two enzymes was not found in soil receiving incomplete fertilization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02185708
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  • 16
    Electronic Resource
    Electronic Resource
    The determination of soil chitinase activity: Conditions for assay and ecological studies (1983)
    Springer
    Plant and soil 75 (1983), S. 95-106 
    Details
    ISSN: 1573-5036
    Keywords: Chitin ; Chitinase ; Chitinglycanohydrolase ; E. C. 3.2.1.14 ; Ecology ; Fertilizers ; Rhizosphere effects ; Soil enzymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Chitinase activity was determined by incubating a mixture of toluene-treated soil with 1% (w/w) colloidal chitin suspension for 18 h at 37°C and then, after dilution, assaying the amount of N-acetyl-glucosamine released. Maximal chitinase activity was observed at 45°C and optimal pH for enzymatic reaction was 5.0–5.5. Soil chitinase activity decreased with increasing soil depth and was significantly affected by crop cover and fertilization regime. Chitin added to soil stimulated chitinase activity. Enzyme activity was correlated with the soil fungal population but not with numbers of actinomycetes or bacteria. A specialized mycoflora was associated with chitin decomposition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02178617
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  • 17
    Electronic Resource
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    Production ecology in the Northern Baltic (1981)
    Springer
    Hydrobiologia 76 (1981), S. 87-96 
    Details
    ISSN: 1573-5117
    Keywords: Ecology ; production ; Gulf of Bothnia ; pelagial ; benthos
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Production biology in the Bothnian Bay is discussed and compared to that of the southern parts of the Baltic. Severe ice-conditions, low water temperatures in spring and early summer and a pronounced water-colouring cause a delay of the spring development of phytoplankton and a low annual production in the Bothnian Bay. This delay makes possible a higher efficiency of the pelagic system as the zooplankton fauna can develop in harmony with the food resources. The downward transport of energy and matter to the bottom communities from an efficient pelagial should be small and temporally unpredictable, which is thought to be an adequate explanation of the observed very low benthic fauna biomasses in the Bothnian Bay.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00014038
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    Ecology of sessile rotifers (1980)
    Springer
    Hydrobiologia 73 (1980), S. 181-193 
    Details
    ISSN: 1573-5117
    Keywords: Ecology ; feeding ; invertebrate behavior ; larval biology ; Rotifer ; sessile rotifer ; substrate-dependent survivorship ; substrate selection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00019445
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  • 19
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    Production of brook charr and ouananiche in a large rapid, tributary of the Caniapiscau River, northern Quebec (1980)
    Springer
    Environmental biology of fishes 5 (1980), S. 27-32 
    Details
    ISSN: 1573-5133
    Keywords: Salvelinus fontinalis ; Salmo salar (ouananiche) ; Ecology ; Salmonids ; Atlantic salmon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis The age structures of brook charr (Salvelinus fontinalis) and ouananiche (Salmo salar) stocks inhabiting a large rapid the river Méo, tributary to the Caniapiscau River were used to compare population stability and production of these species in north central Quebec. The brook chart stock was stable whereas ouananiche showed considerable variation in year class strength. Stock estimates were not significantly different for the two species although the brook charr estimate was 1.5 that of the ouananiche. Production estimates differed by a greater margin because of different growth patterns. Brook chair production was estimated at 19.4 kg ha−1 yr−1. Above age 2+ it was 11.4 kg ha−1 yr−1 which compares with 4.8 kg ha−1 yr−1 for the same age groups of ouananiche.
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    URL: http://dx.doi.org/10.1007/BF00000947
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    Analysis of temporal changes in fish assemblages in Serpentine Creek, Queensland (1980)
    Springer
    Environmental biology of fishes 5 (1980), S. 117-133 
    Details
    ISSN: 1573-5133
    Keywords: Cycles ; Communities ; Diversity ; Ecology ; Estuary ; Multiple regressions ; Oceanography ; Salinity ; Seasons ; Time-series analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis From November 1975 to April 1977 nocturnal dermersal fish were sampled fortnightly at ten sites in Serpentine Creek using a three meter beam trawl with a 3.2 cm mesh net. Forty-five species from thirty-four families were obtained totalling 14 518 individuals with the six most abundant species comprising approximately 72% of the catch. Using multiple regression techniques with Fourier transformations, the mean number of species (S) and abundance (N) of all fish were found to conform to a regular annual cyclical pattern with maxima in April and May. A trend toward declining abundances of individuals and species was present. Shannon (H′) and Gleason (G) diversity indices showed no regular seasonal trends and are considered poor indicators of pollution. In comparison with other estuarine studies at different latitudes Serpentine Creek conforms to the theory that more tropical waters have the greatest faunal diversity. Seventeen of the 22 most abundant species demonstrated a regular annual cycle of abundance. The number of species, abundance and diversity measures were greatest about 1 km from the mouth of the creek and gradually declined upstream. This was the region with highest macrobenthos diversity and with the most stable abiotic values. Temperature and/or salinity were positively correlated with the abundance of eleven species. The species were placed in five groups according to their periodic characteristics. The proportion of ‘resident’ species was low and this is consistent with Tyler's (1971) theory of temperature stabilized fish assemblages. The known biology of six species is related to their occurrence. Salinity and temperature values in the creek exhibit an annual cycle which preceeds that of Bramble Bay by approximately one month. Rainfall in the watershed was correlated with observed salinity values. It is postulated that salinity is the common feature between temperate and tropical estuaries in the maintenance of community cycles.
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    URL: http://dx.doi.org/10.1007/BF02391619
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    Reproductive tactics of the Asian cichlids of the genusEtroplus in Sri Lanka (1981)
    Springer
    Environmental biology of fishes 6 (1981), S. 95-103 
    Details
    ISSN: 1573-5133
    Keywords: Behavior ; Ecology ; Parental care ; Reproductive cycles ; Colonial nesting ; Etroplus maculatus ; Etroplus suratensis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis The Asian cichlids,Etroplus maculatus (the orange chromide) and E. suratensis (the green chromide) in Sri Lanka reproduce twice during the year when water conditions are favorable for nest construction and maintaining visual contact with offspring. These are the drier premonsoonal and monsoonal seasons when water turbidity decreased and salinity increased. When breeding in isolation orange chromide pairs selected dense vegetation where nests were camouflaged. During the peak breeding cycle (July) orange chromide pairs selected sparse vegetation for nesting as a compromise between survival of young and availability of adult food. These areas were also occupied by foraging non-breeding conspecifics which increased the threat of cannibalism of offspring. Under these pressures most orange chromides nested in colonies which helped decrease both actual and attempted cannibalism. The sympatric green chromide does not forage during nesting and nest site selection was determined mainly by factors favoring offspring survival. Biparental care is exhibited by both species. One member of an orange chromide pair stands guard over offspring while the other leaves the territory to forage — their roles are reversed every few minutes. The total parental investment is equivalent to the full investment of a single parent. Monogamy appears to be maintained by their metabolic constraints. In the green chromide both parents are vigilant over offspring and neither forages thus spending twice as much time in parental investment.
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    URL: http://dx.doi.org/10.1007/BF00001803
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    Fluctuations in the muskellunge (Esox masquinongy Mitchill) population of Chautauqua Lake, New York (1981)
    Springer
    Environmental biology of fishes 6 (1981), S. 207-211 
    Details
    ISSN: 1573-5133
    Keywords: Fish ; Ecology ; Population density ; Exploitation ; Tagging ; Catch per effort
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Population and exploitation estimates were made from angler recaptures of Chautauqua Lake muskellunge,Esox masquinongy Mitchill. Fish were tagged during Conservation Department studies in 1941–1946, 1961–1965 and 1976–1978. Population estimates of adult fish ranged from one to seven fish per hectare and angler exploitation rates of tagged fish fluctuated from 3.8% to 14.1%. Relative catch indicators suggest a major decline in the lake's muskellunge population during the last decade. Overexploitation, habitat alteration and interspecific competition with recently introduced fish species were cited as probable causes of the decline.
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    URL: http://dx.doi.org/10.1007/BF00002785
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  • 23
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    The lack of changes in nocturnal estuarine fish assemblages between new and full moon phases in Serpentine Creek, Queensland (1981)
    Springer
    Environmental biology of fishes 6 (1981), S. 213-218 
    Details
    ISSN: 1573-5133
    Keywords: Australia ; Communities ; Cycles ; Diversity ; Ecology ; Estuary ; Lunar periodicity ; Migration ; Sub-tropics ; Tides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis A series of 10 sites were sampled at new and full moon phases in a vertically homogenous estuary, Serpentine Creek, Queensland, Australia. Forty-five species (14,518 individuals) were caught and analysed using standardized Shannon & Gleason diversity indices, and total number of species and individuals. The coefficients of variation for these values were greater for times than for sites. There were no significant differences between 14 pairs of new and full moon phases fort,t,t, andt, or between mean number of individuals for the 16 most abundant species. If significant variations do exist within months, then experiments should be done between spring and neap tides as this study found no differences between the spring tides associated with new and full moon phases.
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    URL: http://dx.doi.org/10.1007/BF00002786
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    Progress report on the eel expedition of R.V. ‘Anton Dohrn’ and R.V. ‘Friedrich Heincke’ to the Sargasso Sea 1979 (1981)
    Springer
    Environmental biology of fishes 6 (1981), S. 371-375 
    Details
    ISSN: 1573-5133
    Keywords: Anguilliformes ; Anguillidae ; Leptocephalus ; Fish larvae ; Horizontal distribution ; Vertical distribution ; Spawning area ; Migration ; Ultrasonic tracking ; Hydrography ; Ecology ; North Atlantic ; Anguilla anguilla ; A. rostrata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis This report presents preliminary results of the 1979 Sargasso Sea expedition from February to May 1979. Information is given on horizontal and vertical distribution of eel larvae and adults, adult eel tracking and pelagic trawling. Related matters such as electrophoretic studies on anguilliform larvae, feeding of eel larvae, predation on leptocephali, occurrence of other anguilliform larvae and hydrography are mentioned.
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    Thermoregulatory behavior and diel activity of yearling winter flounder, Pseudopleuronectes americanus (Walbaum) (1982)
    Springer
    Environmental biology of fishes 7 (1982), S. 177-180 
    Details
    ISSN: 1573-5133
    Keywords: Temperature ; Behavior ; Ecology ; Fisheries ; Fish ; Marine juveniles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Sixteen yearling winter flounder, tested individually for 3-day periods in electronic shuttleboxes, voluntarily occupied an 8–27°C range of temperature, with a modal final thermal preferendum of 18.5°C (mean 18.7°C, median 19°C, midpoint 17.5°C, s.d. 1.9°C, S k + 0.33). The locomotor activity pattern of the yearling fish in the laboratory was markedly nocturnal, with mean hourly nocturnal activity exceeding mean hourly diurnal activity by a factor of 3.4. Maximum activity occurred at 0300 EST, minimum activity at 1400 EST. While activity generally increased with temperature, a local activity minimum occurred at 18.7°C, coinciding with the 24-hour mean final thermal preferendum. Comparison of these laboratory data with previously published field data suggest that behavioral responses to temperature and light play significant roles in determining age- and size-specific differences in seasonal depth stratification and onshore-offshore distributions in this species.
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    URL: http://dx.doi.org/10.1007/BF00001789
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    Beta diversity of a Gulf of California rocky-shore fish community (1980)
    Springer
    Environmental biology of fishes 5 (1980), S. 109-116 
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    ISSN: 1573-5133
    Keywords: Bay ; Dispersal ; Ecology ; Egg type ; Fish larvae ; Islands ; Points ; Rocky habitats ; Species turnover
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Reef fish community composition in three segments of a peninsular rocky shoreline in the Gulf of California was estimated over four periods by visual observation. ‘Point’ and ‘bay’ segments had regular and distinct species compositions over most periods while a ‘middle’ segment was least distinct but consistently had the greatest number of species. Compositional change along the peninsula was least regular during the coldest sea temperature period (April). Mean species turnover between segments was highest between point and bay. Within segments, the point had greater compositional predictable composition (lowest species turnover). When species with regular frequency of encounter were classified into ‘point’, ‘middle’, ‘bay’, and ‘no trend’ groups it was found that comparatively more ‘point’ species had pelagic eggs and comparatively more ‘bay’ species had demersal eggs. Beta diversity of rocky-shore fishes along the physical gradient of the Punta Doble peninsula reflects a transition between exposed and protected rocky shoreline communities. The correlated physical environmental characteristics associated with exposed and protected habitats are discussed in relation to diversity regulation and dispersal strategies in reef fishes.
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    Field observation on death feigning: a unique hunting behavior by the predatory cichlid, Haplochromis livingstoni, of Lake Malawi (1981)
    Springer
    Environmental biology of fishes 6 (1981), S. 361-365 
    Details
    ISSN: 1573-5133
    Keywords: Mimicry ; Shamming death ; Africa ; Fish ; Chafing ; Predation ; Ecology ; Cyrtocara
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Haplochromis (=Cyrtocara) livingstoni, one of the predatory cichlids of the sand community of Lake Malawi, Africa, occurs at a density of 1.3 individuals per hectare. They are territorial, defending areas 15 m wide by 40 m long along the interface of sand andVallisneria weed beds. Individuals use a ‘death feigning’ hunting pattern to capture prey. From a position of lying on their sides semiburied in the sand, these fish attack small cichlids. During four hours of SCUBA observations three successful attacks from this position were seen. After an attack the small cichlids scatter and the predator moves on toward a new aggregation of fish where it again plays dead. Individuals feign death an average of seven times per thirty minutes watch. Death feigning behavior is initiated in two ways. The fish either 1) is stationary with its ventral surface on or close to the sand, and then falls onto its side, or 2) drops from the water colum into `lying on side' position. The initial behavioral actions of the latter method are similar to chafing behavior. But instead of chafing the sand and rising again off the bottom, the fish plows into the sand and remains immobile. These data further add to the evidence that cichlids are remarkably flexible in their feeding behavior.
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    Patterns of abundance variation in reef fishes near an artificial reef at Guam (1982)
    Springer
    Environmental biology of fishes 7 (1982), S. 121-136 
    Details
    ISSN: 1573-5133
    Keywords: Seasonality ; Predator-prey ; Predator interference ; Turnoverrate ; Diversity ; Ecology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Development of the fish community on a submerged 16 m barge and variation in fish abundance on nearby transects were surveyed twice monthly for twenty months. A steady increase in abundance was observed for certain fishes on the barge, whereas a few species exhibited distinct seasonal variation on both the barge and transects. Most of the seasonal species settled between March and May. Some seasonal species appeared to be site selective in their settlement and consequently settled juveniles were clumped in their distribution. An abundance of preferred topographical features may be why settlement was relatively high at the study site and indirectly why predators became significantly (r3 = 7.67***, N = 37) more abundant at the study area during the months of maximum prey settlement. Concurrent settlement of several species during the same few months may be important because juveniles become an abundant food source to predators during those few months only. Periodic swamping of predators by abundant juvenile prey may improve the chances for individuals of rarer prey species to be overlooked and therefore be succesfully recruited.
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    Resiliency of reef fish communities in the Florida Keys following a January 1977 hypothermal fish kill (1983)
    Springer
    Environmental biology of fishes 9 (1983), S. 41-53 
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    ISSN: 1573-5133
    Keywords: Artificial reefs ; Competition ; Intermediate disturbance ; Ecology ; Mortality ; Predation ; Recruitment ; Stability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis In January 1977, a record breaking cold spell caused fish kills at Big Pine Key, Florida. Census data collected before and after the cold spell from a series of model reefs constructed in 1975 showed a significant drop in mean number of reef fish species and individuals. Following this disturbance, high recruitment of juveniles occurred, presumably due to reduced competition, predation, or a combination of these. Model and natural patch reef communities examined the summer following the cold spell (1977) were significantly different from those examined the summer before (1976) and the second summer following the cold spell (1978). During the summer of 1977, a significantly smaller mean fish size and a significantly greater mean number of species and individuals were observed. Increased species richness following the cold spell is consistent with the intermediate disturbance hypothesis. Contrary to some theoretical predictions, results suggest reef fish communities are highly resilient to some regional disturbance.
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    Occurrence and infective potential of the endophyte ofHippophaë rhamnoides L. ssp.rhamnoides in coastal sand-dune areas (1980)
    Springer
    Plant and soil 56 (1980), S. 123-139 
    Details
    ISSN: 1573-5036
    Keywords: Actinorhizas ; Ecology ; Endophyte distribution ; Hippophaë rhamnoides ; Infective potential ; Nodulation ; Root nodules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The infective potential (IP) of nodule homogenates from field-grownHippophaë rhamnoides L. ssp.rhamnoides was determined by counting the number of nodules formed on test plants after inoculation with various dilutions of the homogenates. The IP was almost constant,i.e. 105 to 106 per gram of fresh nodule material. Methods to store nodule material without loss of IP were tested. The IP of air-dried nodule powders stored at 6°C hardly decreased during a period of more than a year. Data are presented on the IP of soil samples from sites representing various stages of dune formation. BeforeH. rhamnoides appeared, the IP was low: 1 to 36 nodules were formed on test plants per kg of soil. This low IP was due to low numbers of infective endophyte particles in these soils. During the succession of theH. rhamnoides scrub, the IP of the soil increased, due to the increase in the number of endophyte particles in the soil. Gradually, however, nodulation was limited by other environmental factors. The nature of these factors is discussed.
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    Populations ofRhizobium japonicum associated with the surfaces of soil-grown roots (1981)
    Springer
    Plant and soil 61 (1981), S. 71-80 
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    ISSN: 1573-5036
    Keywords: Ecology ; Fluorescent antibody ; Immunofluorescence ; Rhizobium japonicum ; Rhizosphere ; Root surfaces ; Soybean
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Populations of nativeRhizobium japonicum 123 in the rhizospheres of field and pot grown plants as determined by immunofluorescence were calculated on the basis of root surface area. The density ofR. japonicum 123 on the root fluctuated between a few hundred to over a thousand per square centimeter of root surface. As root volume expanded rapidly, the Rhizobium density fell to less than one hundred per unit area. There was no appreciable effect due to different plant, nitrogen amendment, or addition of another strain ofR. japonicum, on the surface density of the nativeR. japonicum population on roots. Nor did the native population influence the added strain. Direct examination of root surface segments revealed that naturalized rhizobia existed sparsely on root surfaces in the form of short rods. They were observed to be attached sideways or in a polar manner on root hairs, epidermal cells, and at junctions of tap and lateral roots. There was no evidence of specific stimulation of the homologous Rhizobium by the host plant as a prelude to nodulation.
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    Life history of the gulf darter, Etheostoma swaini (Pisces: Percidae) (1984)
    Springer
    Environmental biology of fishes 11 (1984), S. 121-130 
    Details
    ISSN: 1573-5133
    Keywords: Ecology ; Habitat ; Feeding ; Age ; Growth ; Reproduction ; Mississippi
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Etheostoma swaini, the gulf darter, was collected from the Black Creek drainage in southern Mississippi (February 1978 – April 1979). The gulf darter generally inhabits small- to moderate-size creeks and occurs over a sand or sandy mud bottom, often in association with aquatic vegetation or a layer of organic debris. Larval dipterans were the most important food items, both numerically and volumetrically. Chironomids were found in 71–100% of the stomachs in all except the unusual March 16 collection. The length frequency distribution and the scale annuli analysis indicated there were three year-classes present in the population at any one time. Fifty-one percent of the specimens taken were less than 12 months old. During the mid-February to late March spawning season gulf darters were most often collected over clean gravel or gravelsand substrates. Laboratory observations suggest that the female burrows into the gravel where the demersal, adhesive eggs are deposited. Female gulf darters significantly outnumbered males at a ratio of 59:41.
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    Early development of the northern logperch, Percina caprodes semifasciata, according to the theory of saltatory ontogeny (1984)
    Springer
    Environmental biology of fishes 11 (1984), S. 173-190 
    Details
    ISSN: 1573-5133
    Keywords: Percidae ; Etheostomatini ; Darters ; Ecomorphology ; Embryology ; Ecology ; Early life history
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis The early development of northern logperch, Percina caprodes semifasciata, was examined from an ecological perspective and in relation to the theory of saltatory ontogeny. Steps, the intervals of relative homeostasis, separated by thresholds, rapid switches to new form and function resulting from canalization of changes in the preceeding step, are described and related to environmental factors. Adaptive shifts in growth allometries provided further evidence of the saltatory nature of ontogeny. Logperch eggs are small (1.2 mm diameter), demersal, and adhesive. The simple embryonic respiratory system reflects high oxygen availability on the lotic spawning grounds. Hatching occurs early, relative to other darters, and free embryos are pelagic. The small free embryos presumably drift downstream to lentic areas, where small planktonic food is more abundant. Logperch are therefore nonguarding, open substrate spawning lithopelagophils and, along with other Percina species, have not advanced from ancestral percid reproductive styles. Percina species have generally remained in ancestral habitats-rivers and lakes. The close correlation between developmental patterns of logperch and environmental factors is therefore interpreted as a restriction based on retention of ancestral characteristics, not as evidence of novel adaptations to new habitats.
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    Early development of the rainbow darter, Etheostoma caeruleum, according to the theory of saltatory ontogeny (1984)
    Springer
    Environmental biology of fishes 11 (1984), S. 277-299 
    Details
    ISSN: 1573-5133
    Keywords: Percidae ; Etheostomatini ; Ecomorphology ; Embryology ; Ecology ; Early life history ; Heterochrony
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis The early development of rainbow darter, Etheostoma caeruleum, was examined from an ecological perspective. Steps and thresholds of ontogeny to completion of body squammation are defined, and related to environmental factors. Rainbow darter eggs are about 2 mm diameter, considerably larger than those of related logperch (Percina caprodes). The embryonic vitelline respiratory plexus is much more extensive. The pelagic interval characteristic of logperch and ancestral percids is eliminated and onset of exogenous feeding is delayed. The larger larvae of the rainbow darter can begin feeding directly on aquatic insects, and complete their life cycle in streams. Therefore, shifts in the timing of important thresholds (e.g. exogenous feeding) are ecologically important. Furthermore, early maturation and/or delayed bone and scale formation may be responsible for reductions in the lateralis system and scalation in this and other darter species.
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    Seasonality in habitat selection by the gold color morph of Cichlasoma citrinellum and its relevance to sympatric speciation in the family Cichlidae (1980)
    Springer
    Environmental biology of fishes 5 (1980), S. 75-78 
    Details
    ISSN: 1573-5133
    Keywords: Cichlid ; Ecology ; Behavior ; Evolution ; Tropics ; Polymorphism ; Central America ; Lake Malawi ; Africa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Cichlasoma citrinellum is a polymorphic species whose individual coloration varies from the dark grey markings typical of the species to yellow, orange, and red. In Lake Jiloá, Nicaragua the depth distribution of these latter, nongrey, golden morphs shows dramatic seasonal variation. In the height of the dry season in February over 50% of the gold morphs occur above 9 m, but as the breeding season approaches they migrate deeper such that less than 7% of the gold population occurs above 9 m at the onset of the breeding season. During the rainy season when breeding occurs most of the gold morphs occur below 15 m. It appears that gold morphs ‘voluntarily’ move into deeper water to breed rather than being aggressively forced deeper by larger, territorial grey morphs as was implied in an earlier paper (McKaye & Barlow 1976). Since the morphs of this species assortatively mate and select different habitats in which to breed, future sympatric splitting of this species is possible. Likely examples of sympatric speciation and of incipient speciation in the family Cichlidae are discussed.
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    Prevalence and intensity ofCapillaria catostomi (Nematoda: Trichuroidea) in white sucker (Catostomus commersoni) in southern Lake Huron, Canada (1980)
    Springer
    Environmental biology of fishes 5 (1980), S. 267-271 
    Details
    ISSN: 1573-5133
    Keywords: Fish ; Nematode ; Populations ; Life cycle ; Host factors ; Ecology ; Parasites
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis A total of 314 white suckers (Catostomus commersoni) taken monthly during May to December 1975 and in April and May 1976 from southern Lake Huron, Ontario, Canada, were examined forCapillaria catostomi. Prevalence determined from fresh white suckers (66%) was significantly lower than from frozen white suckers (81%). However, there was no significant difference in prevalence ofC. catostomi in samples taken at monthly intervals; in male and female white suckers; or in the age categories. Mean intensity of infection was not significantly different in fresh (9.6 [± 13.41]) or frozen (10.4 [± 13.11]) white suckers. There was no significant difference in intensities between monthly samples in male and female white suckers or in the age categories. Suckers were infected with 1–172 worms. The percentage of male, female and immature worms did not change with sex or age of host or by month. The frequency distribution showed the parasites were overdispersed. A possible life cycle forC. catostomi involving an oligochaete intermediate host is discussed and an attempt made to explain the almost constant levels of prevalence and intensity.
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    Neue Wege zu 1H- und 2H-Pyrrolen (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 658-663 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New Routes to 1H- and 2H-PyrrolesA synthesis of 1H-pyrroles is described starting with pyridine analogues of chalcones and involving the reaction of acetic anhydride with 1-pyrroline-1-oxides. Another route leads from 1-pyrrolines to 2 H-pyrroles via bromination with N-bromosuccinimide and subsequent dehydrobromination in dimethylformamide.
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    Erratum (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 681-681 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    URL: http://dx.doi.org/10.1002/hlca.19800630317
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    Nucleophilic addition to C,C double bonds. IIIFor Part I, see [1]; for Part II, see [2].. Chemical reactivity of 1endo, 4endo: 5exo, 8exo-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalen-10syn-ol and X-ray structure analysis of its p-nitrobenzoate (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 674-681 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: The title compound 1 is a further example of an olefinic alcohol that undergoes ether formation under basic conditions (→ 3) although the double bond is not activated by an electron-attracting group. This unusual reactivity is due to steric compression, which is increased in the 10-methyl analogue 2. This forms the corresponding ether 7 at a much higher rate. - In a deuteriated medium, base-catalysed cyclization of 1 gives the exo-deuteriated ether 6, corresponding to trans-addition. - An X-ray structure analysis of 4, the p-nitrobenzoate of 1, is presented.
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    The Synthesis of β,γ- and α,β-Unsaturated Aldehydes via Polyene EpoxidesDedicated to Dr. O. Isler on the occasion of his 70th birthday (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 1665-1674 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A substitute for the Darzens glycidic ester synthesis for converting unsaturated ketones or aldehydes into the homologated β,γ- or α,β-unsaturated aldehydes employing sulfur ylides is described. The carbonyl group is converted into the unsaturated oxirane which is then rearranged to the new aldehyde. High yields of isomerically pure aldehydes are available by this method and the process is of practical importance in the conversion of β-ionone into the β-C14-aldehyde, a key intermediate in the Isler synthesis of vitamin A. The efficient preparation of α- and β-cyclocitral by the novel process is also described.
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    Globularifolin, A New Acyl Iridoid Glucoside from Globularia cordifoliaPart 3 in the series ‘Glycosides of Globulariaceae’. For parts 1 and 2 see [1] [2]. (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 117-120 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: Six iridoid glucosides have been isolated from Globularia cordifolia by the combination of open column - and high performance liquid chromatography. The structure of the new compound, named globularifolin, and the identity of the others have been established by chemical transformations and spectral evidence of the compounds and their derivatives.
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    Photofragmentation of Dibenzyl Ketone in the Presence of Tetramethylpiperidine Derivatives. Studies on light stabilizer mechanisms [1] (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 132-147 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: The interaction of selected tetramethylpiperidine derivatives with radicals arising from the Norrish-type I cleavage of dibenzyl ketone under oxygen was studied. Product analyses and kinetic studies showed that the investigated sterically hindered piperidine derivatives have a pronounced effect on both the nature and distribution of the products of photolysis of dibenzyl ketone in the presence of oxygen. Observations indicated that the phenylperacetoxyl radical is formed as an intermediate during irradiation and that it interacts with the additives used. Possible mechanisms of the reactions studied are discussed.The observation that oxidation of an isolated double bond by the radicals formed in dibenzyl ketone photolysis under oxygen is strongly inhibited in the presence of the studied sterically hindered amines is discussed in the light of the results presented. The findings are considered in relation to the problem of polymer stabilization.
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    Approaches to the Synthesis of Cytochalasans. Part 2. Pyrrolinone derivatives as basic unitsPart 1: [1].Part of the Ph.D. Thesis of T. Schmidlin, Basel 1979. (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 121-131 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: Several attempts to prepare 3-acetyl-5-benzyl-3-pyrrolin-2-one (7) from phenylalanine are described. This goal was only reached formally, because compound 7 exists in the tautomeric form of (Z)-5-benzyl-3-(1′-hydroxyethylidene)-4-pyrrolin-2-one (17) according to the spectral data. The problem of tautomerism in pyrrolinone systems is discussed.
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    Nucleophile Aminoalkylierung mit ThiopivalamidenVorläufige Mitt. [1]. (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 102-116 
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    Notes: Nucleophilic Aminoalkylation with ThiopivalamidesVorläufige Mitt. [1].Of the twelve thioamides 7a-e and 8a-g, only N,N-dimethylthiopivalamide (7a) could be metallated at the CH-group in a-position to the N-Atom. The reagent 9 thus obtained (Table 1) reacts in high yields with primary haloalkanes, with aldehydes, and with non-enolizable ketones (Table 2). As shown in Scheme 1, the products can be hydrolyzed to pivalamides, cleaved to secondary amines, or reduced to neopentylamines (see 18/19, 15/equation (4) and (5), and 16/20, respectively).
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    Laser Induced Excitation Spectra of the Cations of Some Fluoro-substituted Phenols (B̃2 A″ ↔ X̃2 A″) in the Gaseous Phase (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 1920-1925 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Excitation spectra of the cations of pentafluorophenol, 2,3,4-trifluorophenol, 2,4,5-trifluorophenol, 2,5-difluorophenol and 3,5-difluorophenol have been obtained by pumping the B̃2 A″ ← X̃2A″ transition with a dye laser. The cations were first produced in their ground states by Penning ionisation using argon metastables. Vibrational frequencies of some of the fundamentals have been inferred for these cations in the B̃2 A″ state from the excitation spectra, and in the X̃2 A″ state from the emission spectra. Possible applications of the reported results are suggested.
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    Synthesen von polyhalogenierten Butyrylchloriden, Vorläufern der pyrethroiden Haloketene1. Mitteilung über Cu+-katalysierte Radikaladditionen von Polyhalogenverbindungen an Olefine.Auszugsweise präsentiert am ‘International Symposium on Chemistry of the Pyrethroids’ vom 16.-19. Juli 1979 in Oxford, am ‘1st European Symposium on Organic Chemistry’ vom 20.-23. August 1979 in Köln, am ‘178th ACS National Meeting’ vom 9.-14. September 1979 in Washington, D.C., sowie an der Herbstversammlung der Schweizerischen Chemischen Gesellschaft vom 19.-20. Oktober 1979 in Bern. (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 1947-1957 
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    Keywords: Chemistry ; Organic Chemistry
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    Notes: Synthesis of Polyhalogenated Butyryl Chlorides, Precursors of Pyrethroid HaloketenesThe copper (I)-catalyzed free radical addition of halomethanes to acrylates and the addition of halogenated acetic acid derivatives to fluoro- or chloro-substituted ethylenes affords polyhalogenated butyric acid derivatives. Chlorides of these acids serve as precursors for haloketenes used in efficient syntheses of pyrethroids.
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    High Acceleration and Improved Diastereoselectivity of Intramolecular Ene-Type Reactions by Diethylaluminum Chloride. Preliminary Communication (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2010-2014 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The pyrrolidines 2 and 10 were obtained by thermal ene-reactions at +70° and +180° from the (Z)-4-aza-1, 6-diene 1 and from the (E)-4-aza-1, 6-diene 9 in the ratios of 75:25 and 50:50, respectively. On the other hand, these cyclizations proceeded readily in the presence of diethylaluminum chloride at - 78° and - 35° giving in high yield the trans-pyrrolidine 2 from 1 with 100% and from 9 with 89% diastereoselectivity.
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    Tieftemperatur 13C-NMR.-Spektren von 13C-und 6Li-markierten Chlor-, Brom- und Jod-Lithium-Carbenoiden. Vorläufige Mitteilung (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2046-2053 
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    Keywords: Chemistry ; Organic Chemistry
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    Notes: Low Temperature 13C-NMR. Spectra of 13C- and 6Li-Labelled Chloro-, Bromo-, and Iodo-lithiumcarbenoidsThe 13C-NMR. spectra of tetrahydrofuran solutions of 16 chloro-, bromo-, and iodo-6lithio- and -7lithio-carbenoids with 13C-labelled methane, ethane, ethylene, and cyclopropane C-skeletons have been measured at temperatures around - 100° (for examples see Fig. 1 and 2). Invariably, the exchange of hydrogen or halogen by lithium causes deshielding (Δδ, see Table 1) of the 13C-signal by up to 289 and 434 ppm, respectively, and decrease of 1J (1H, 13C) and 1J(13C,13C) couplings (see Table 2) with the C-atom of up to 104 and 30 Hz, respectively. The 1J(6Li, 13C) and 1J(7Li, 13C) coupling of ca. 17 and 45 Hz, respectively, obtained in ten cases (Table 1) is independant of the substitution pattern of the C-skeleton and of the particular halogen atom.
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    The trans-Influence in Platinum (II) Complexes. 1H- and 13C-NMR. and X-ray structural studies of tridentate Schiff's base complexes of platinum (II) (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2071-2086 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1H- and 13C-NMR. data are reported for the complexes [Pt(1)L] and [Pt(2)L]; 1 = OC6H4CH = NCH2CH2O, 2 = OC6H4CH = NC6H4O; L = PR3, AsR3, C ≡ N (cyclohexyl), DMSO, pyridine, secondary amine. The molecular structures of [Pt (2) (NHEt2)] (I) and [Pt (2) (PPh3)] (II) have been determined by X-ray analysis. Relevant bond distances for I: Pt-N (amine) = 2.076 Å, Pt-N (imine) = 2.017 Å, Pt-O = 1.992 Å and 2.002 Å; for II: Pt-P = 2.248 Å, Pt-N = 2.064 Å, Pt-O = 1.964 and 2.005 Å. Both the solid and solution state data are interpreted in terms of differences in the trans influence of the ligand L. The question of metal-ligand d-p π back bonding to the imine is discussed.
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    A Model for Nicotinamide-Trytophane Charge-Transfer Interactions: The complexation of nicotinamide-ammonium salts by a macrocyclic receptor molecule bearing tryptophane side chains (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2112-2118 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The complexation of primary ammonium salt substrates by macrocyclic polyether receptor molecules provides a general method for studying the nature and stereochemistry of intermolecular interactions. The substrates and receptors are fitted each with one of the interacting units and the resulting effects in the complex are analyzed. The method is used to study the biologically important indole-pyridinium donor-acceptor interaction. The complexes between macrocycles, bearing an indole group in side chains, and pyridinium-ammonium salts display a characteristic charge-transfer band. The absorption coefficients and stability constants have been determined. Competition experiments also provide a new method for measuring the stability constants of macrocycle-ammonium complexes in organic solvents.
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    Aristoserratin, ein neues Indolalkaloid aus Aristotelia serrata W.R.B. OLIVER und A. peduncularis (LABILL.) HOOK. F. 178. Mitteilung über organische Naturstoffe177. Mitt. s. [1].Teil der geplanten Dissertation von R.K., Universität Zürich. (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2130-2134 
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    Notes: Aristoserratine, a New Indole Alkaloid from Aristotelia serrata W.R.B. OLIVER and from A. peduncularis (LABILL.) HOOK. F.The new indole alkaloid aristoserratine (2) has been isolated from Aristotelia. Its structure and absolute configuration were elucidated on the basis of spectroscopic data.
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    Polar Substituent Effects in the Solvolysis of Primary and Tertiary Alkyl Halides. Polar Effect IX (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2152-2158 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: When the Hammett-Taft equation log (k/ko)=ρq · σ1q is applied to the solvolysis of the 3-substituted propyl bromides 6a-6i in ethanol/water 4:1 (v/v) log k correlates linearly with σ1q except in cases where R exerts an anchimeric effect. The reaction constant ρq for 6 is - 0.12 and is typical for a nucleophilic solvent-assisted ks process at a primary C-atom. The tertiary halides 1 and 3, however, which react with little or no nucleophilic solvent assistance, i.e. by kc processes, lead to larger ρq values of -0.71 and -1.14, respectively. The reaction constant pq is therefore a sensitive gauge for charge development in the transition state for solvolysis of saturated compounds.
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    Action du cyanure mercurique sur quelques halogénures de désoxy-3-trifluoroacétamido-3-D-ribofurannosyle. Note de laboratoire (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2258-2263 
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    Keywords: Chemistry ; Organic Chemistry
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    Notes: Reactions of Some 3-Deoxy-3-trifluoroacetamido-D-ribofuranosyl Halides with Mercuric CyanideThe expected 2,5-anhydro-D-allononitrile 11 was obtained when the 2-O-benzoyl-3-deoxy-3-trifluoroacetamido-D-ribofuranosyl bromide reacted with mercuric cyanide, whereas the isomeric 1,2-O (1-cyanoethylidene) derivative was formed from the 2-O-acetylated halide; no reaction occurred when the halide was 2-O-p-nitrobenzoylated.
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    Lipophilic Amides of EDTA, NTA and Iminodiacetic Acid as Ionophores for Alkaline Earth Metal Cations (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2264-2270 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of electrically neutral lipophilic di-, tri-, and tetra-amides containing tertiary-amine N-atoms were prepared in order to investigate their selectivity for alkali and alkaline earth metal cations in solvent polymeric membranes. Considerable selectivity changes were observed for membranes incorporating certain of these ligands as compared with ligand-free membranes. A 1:1 cation/ligand complex was isolated from N, N′, N″-triheptyl-N, N′, N″-trimethyl-nitrilotriacetamid and Mg (SCN)2 whereas with Ca (SCN)2 the corresponding 2:3 cation/ligand complex was formed. N, N′, N″, N‴, N‴-tetramethyl-ethylenediaminetetraacetamide yields a 1:1 cation/ligand complex with Mg (SCN)2.
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    Beitrag zur massenspektrometrischen retro-Diels-Alder-Reaktion: 1,2,3,4-Tetrahydrophenanthren. 35. Mitteilung über massenspektrometrische Untersuchungen34. Mitt.: s. [1]. Auszugsweise vorgetragen an der 13. Diskussionstagung der Arbeitsgemeinschaft Massenspektrometrie, 28.-30. Mai 1980 in Köln. (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2295-2301 
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    Keywords: Chemistry ; Organic Chemistry
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    Notes: Contribution to the Mass Spectral retro-Diels-Alder Reaction: 1,2,3,4-Tetrahydrophenanthrene[1,4-13C]-1,2,3,4-Tetrahydrophenanthrene (1) was synthesized starting from [1,4-13C]-succinic acid. The mass spectral behavior (EI./MS., 70eV) of 1 is very similar to that of tetraline [2] concerning its loss of ethylene from the molecular ion. Similarly the fragmentation reaction of the synthetic precursors, ketones 7 and 8, seems to partly undergo a carbon rearrangement reaction prior to the elimination of ethylene which is unlike to the behavior of α-tetralone.
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    Beiträge zur Kenntnis des chromophoren Systems der Corrine. XIX. Mitt.: [1].. Über die Reaktion von Derivaten des Cobyrinsäure-heptamethylesters mit unterchloriger SäureMeinem verehrten Kollegen Oskar Glemser gewidmet (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2320-2327 
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    Keywords: Chemistry ; Organic Chemistry
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    Notes: Contributions to the Knowledge of the Corrin Chromophore, X. Reaction of Derivatives of Cobyrinic Acid Heptamethyl Ester with Hypochlorous Acid(Cobalt)-dicyano-, chloro-cyano-, and dichloro-cobyrinic acid heptamethylesters (1, 2 and 3), respectively, as well as their 10-chloro derivatives 4, 5 and 6 react with hypochlorous acid. A report on the structure and some properties of the reaction products 8, 9 and 10 is given.
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    Steroids and sex hormons. Part 264Part 263, s. [1].. Lewis acid catalyzed reversible [1,5]-hydride shift in 3,19-epoxy-steroids (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2342-2357 
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    Keywords: Chemistry ; Organic Chemistry
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    Topics: Chemistry and Pharmacology
    Notes: 3β, 19-Epoxy-3 α-methoxy-steroids (e.g. 1, Scheme 1) are converted into the corresponding 3 α-methoxy-19-oxo compounds (e.g. 3) in the presence of boron trifluoride etherate, via an intramolecular hydride ion transfer from C (19) to (3) which is shown to be an equilibrium process. By subjecting the specifically deuteriated (19 S)- and (19 R)-compounds 1b and 1c to this reaction it was shown to be highly stereoselective.
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    Synthesis of Pure Al35Cl3 and Al37Cl3 (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2375-2379 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chemically and isotopically pure Al35Cl3 and Al37Cl3 are synthesized from Al (s) and HCl (g). The yield is quantitative and no measurable decrease in isotopic content from HCl to AlCl3 takes place.
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    A Norrish Type I cleavage in the photolysis of a steroidal α,β-unsaturated δ-lactonePart of the doctoral thesis of A. Cánovas, I.Q.S., Barcelona, 1980.. Photochemical Reactions. XIV [1] (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2390-2392 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The UV. irradiation of 17 β-acetoxy-4-oxa-5 α-androst-1-en-3-one (1) yields A,B-diseco-steroids originating from a Norrish I process of the lactone function.
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    Die Strukturdynamik von Pentadienylmetall-Verbindungen mit endständiger Alkyl-Gruppe: zugleich «stereoselektive» und «stereodefensive» Synthese eines natürlichen RiechstoffesTeil VIII der Reihe «Selektive Synthesen mit Organometallen»; VII. Mitteilung s. [1]. (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2393-2403 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: Structural Dynamics of Pentadienyl Metal-Compounds Bearing a Terminal Alkyl Substituent: Both ‘Stereoselective’ and ‘Stereodefensive’ Synthesis of a Natural Perfume.The (2Z, 4E)-, (2E, 4Z)- and (2E, 4E)-isomers of 2,4-decadien-1-ol (5) have been obtained with high and predictable stereochemical homogeneity starting from both (Z)- and (E)-1, 4-decadiene. These hydrocarbons were hydroxylated in a reaction sequence consisting of metallation (by means of s-butyllithium or butyllithium/potassium-t-butoxide, giving rise to organometallic intermediates of specific conformation), dimethoxyborylation and oxidation. The different decadienols as well as (2E, 4Z)-2, 4-undecadien-1-ol were converted into the isovalerates, the ester derived from (2E, 4Z)-2, 4-decadien-1-ol being a natural flavor component.
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    Regio- and Stereoselective Functionalizations of Tricyclo [3.3.0.02,8]octan-3-one, a Potential Synthon for Polycyclopentanoid Terpenes and Prostacyclin Analogs. Preliminary CommunicationPresented in parts at the ESOC I Conference, Köln 1979 [1], and in full at the VIII IUPAC Symposium on Photochemistry, Seefeld 1980 [2]. (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2440-2445 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chemical transformation of tricyclo [3.3.0.02,8]octan-3-one (1) have been carried out in order to explore its potential utility as a versatile synthon for polycyclopentanoid terpenes and prostacyclin analogs. Various functionalizations of rings A and B and annulation of a third ring C were achieved in generally high yields. The system provides for a large measure of regio- and stereoselective reaction control.
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    Methyl-triisopropoxy-titanium, a highly selective nucleophilic methylating reagentPresented by D.S. at the meeting of the Organic Division of the German Chemical Society, Bad Nauheim, October 16, 1980.. Preliminary Communication (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2451-2454 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: Replacement of lithium or magnesium by titanium can furnish nucleophilic organometallic reagents of high selectivity as exemplified by the title compound 1 (see Tables 1-3).
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    Nucleoside und Nucleotide. Teil 15. Synthese von Desoxyribonucleosid-monophosphaten und -triphosphaten mit 2(1H)-Pyrimidinon, 2(1H)-Pyridinon und 4-Amino-2(1H)-pyridinon als BasenTeil 14 s. [1].Für Einzelheiten vgl. [2][3]. (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2488-2494 
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    Keywords: Chemistry ; Organic Chemistry
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    Notes: Nucleosides and Nucleotide. Part 15. Synthesis of Deoxyribonucleoside Monophosphates and Triphosphates with 2(1H)-Pyrimidinone, 2(1H)-Pyridinone and 4-Amino-2(1H)-pyridinone as the BasesThe phosphorylation of the modified nucleosides 1-(2′-deoxy-β-D-ribofuranosyl)-2(1 H)-pyrimidinone (Md, 4), 4-amino-1-(2′-deoxy-β-D-ribofuranosyl)-2(1 H)-pyridinone (Zd, 6) and the synthesis of 1-2′-deoxy-β-D-ribofuranosyl-2(1 H)-pyrimidinone-5′-O-triphosphate (pppMd, 1), 1-(2′-deoxy-β-Dribofuranosyl)-2(1 H)-pyridinone-5′-O-triphosphate (pppIId, 2), and 4-amino-1-(2′-deoxy-βD-ribofuranosyl)-2(1 H)-pyridinone-5′-O-triphosphate (pppZd, 3) are described. The nucleoside-5′-monophosphates pMd (5) and pZd (7) were obtained by selective phosphorylation of Md (4) and Zd (6), respectively, using phosphorylchloride in triethyl phosphate or in acetonitril. The reaction of pMd (5) pII d (8) or pZd (7) with morpholine in the presence of DCC led to the phosphoric amides 9, 10 and 11, respectively, which were converted with tributylammonium pyrophosphate in dried dimethylsulfoxide to the nucleoside-5′triphosphates 1, 2 and 3, respectively.
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    Synthesis of cannabinoid model compounds. Part 2Part 1: see [1].: (3R, 4R)-Δ1(6)-Tetrahydrocannabinol-5″-oic acid and 4″(R, S)-Methyl-(3R, 4R)-Δ1(6)-tetrahydrocannabinol-5″-oic Acid (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2508-2514 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: Two novel cannabinoid model compounds, (3R, 4R)-Δ1(6)-tetrahydrocannabinol-5″-oic acid (22) and 4″(R, S)-methyl-(3R, 4R)-Δ1(6)-tetrahydrocannabinol-5″-oic acid (23) were synthesized by acid-catalyzed condensation of (+)-trans-p-mentha-2, 8-dien-l-ol (1) with the substituted resorcinols 18 and 19 obtained by a Wittig reaction between 3, 5-bis(benzyloxy)benzaldehyde (7) and methyl 4-bromobutanoate (10) or methyl 4-bromo-2(R, S)-methylbutanoate (11) resp. with subsequent hydrogenation. The resulting methyl esters 20 and 21 were hydrolyzed to give acids 22 and 23.
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    Unambiguous Proof for Alcoxycarbonyl-group Migration in Wagner-Meerwein Rearrangements (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2538-2553 
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    Keywords: Chemistry ; Organic Chemistry
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    Notes: In HSO3F/SO2ClF the β-hydroxy esters Ph-CHOH-CMe2-COOR (1, R=Me, Et) are doubly protonated, then transformed into the fluorosulfates 7 and (partly) into the fluorides 8. At -15°, both 7 and 8 undergo a rearrangement, forming derivatives of Me2C=C(Ph)COOR (2). By labelling 1 with 13C, singly (13C(3)) and doubly (13C(1,3)), it could be shown that exclusively the ROOC groups undergo a 1,2-shift. Compound 2 is also formed in HSO3F/SO2ClF from the isomeric Me2COH-CHPh-COOR (3) by elimination, and less easily from the α-hydroxy ester Ph-CMe2-CHOH-COOR (5) via a phenyl 1,2-shift. Another isomer, Ph-C(OH)Me-CHMe-COOR (4) gives products different from 2.Using more acidic systems containing SbF5, the free carbenium ions 13 (Ph-CH+-CMe2-COOR) can be stabilized; they do not form 2, possibly because of complexation of the ester group with SbF5. The energy profile and the mechanism of the rearrangement 1 → 2 are discussed.
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    Transition metal complexes with bidentate ligand 2, 11-Bis (diphenylphosphinomethyl)benzo[c]phenanthrene (1). XPart IX: see [1].. Preparation and spectroscopic properties of cis-[PtCl2 (1)] trans- and cis-[PtH (PPh3) (1)] [BF4] and crystal and molecular structure of cis-[PtCl2 (1)] · CHCl3 (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2519-2530 
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    Keywords: Chemistry ; Organic Chemistry
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    Notes: It is shown that ligand 1, designed to span trans-positions, under appropriate conditions also gives cis-mononuclear complexes of platinum (II). The structure of cis-[PtCl2 (1)] (2) has been determined by single-crystal X-ray diffraction. The major distortion from square planar coordination is the P-Pt-P angle of 104.8°. Values of valence angles within the bidentate ligand indicate that this part of the molecule is very strained. Two phenyl groups, one on each phosphorus, lie almost parallel to each other separated by ca. 3.2-3.3 Å. The 1H-NMR. data for this compound show that the π-phenyl interactions observed in the solid state occur also in solution. The preparation and NMR.-spectroscopic properties of trans- and cis-[PtH(PPh3) (1)] [BF4] are reported.
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    Masthead (1981)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 64 (1981) 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Über Pterinchemie 76. Mitteilung [1] Eine einfache Synthese von LeucovorinTeil der Dissertation von E. Khalifa, Universität Zürich 1980. (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2554-2558 
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    Notes: A Convenient Synthesis of LeucovorinThe synthesis of leucovorin, a 5-formyl-(6R or S)-5,6,7,8-tetrahydropteroyl-L-glutamic acid (II) is described. The L-folic acid was first reduced to (6R, S)-tetrahy-dro-L-folic acid (I); formylation with methyl-formate in DMSO gave directly leucovorin (as a diastereomeric mixture) in good yields. To demonstrate, that the formylation occurred regiospecifically at N (5) and not at N (10), N (10)-nitroso-(6 R, S)-tetrahydro-L-folic acid was formylated under the same conditions. Reductive elimination of the N (10)-nitrosogroup gave the identical leucovorin as in the previous case. The synthetic leucovorin was biologically as active as the natural product with Streptococcus faecalis ATCC 8043 and Pediococcus cerevisiae ATCC 8081.
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    Synthèse partielle et propriétés oncostatiques des pseudo-tubulosines, analogues de l'émétine et de la tubulosine (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 1335-1346 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Partial Synthesis and Oncostatic Properties of Pseudotubulosines, Analogues of Emetine and TubulosinePseudotubulosines, structural analogues of emetine and tubulosine, have been synthesized by either Pictet-Spengler or Bischler-Napieralski condensation from dihydrocorynantheal or corynantheidal. Spectral data, cytotoxic and oncostatic properties of these new alkaloids are described.
    Additional Material: 3 Tab.
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    Physico-Chemical Properties of Deuterated Compounds. 5th Communication4th Communication, see[1].. The isotope partition coefficient in cyclohexane hydrogen and cycloheptane/hydrogen mixtures (1981)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 64 (1981), S. 176-179 
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    Keywords: Chemistry ; Organic Chemistry
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    Notes: The isotope partition coefficient α between cyclohexane, cycloheptane and hydrogen has been determined between 80 and 180° and pressures around 1 atm. The values decrease with increasing deuterium content y of the hydrogen and can be expressed by the simple equation Ina = Δ S/R + (ΔH + δ · y)/RT with an error of ±1%. However it was not possible to achieve good agreement with theoretical calculations using a unique average value for the partition function of the hydrocarbon.
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    Stoffwechselprodukte von Mikroorganismen. 193. Mitteilung192. Mitt. s. [1].. Ferrithiocin (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 1400-1406 
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    Notes: Metabolites of Microorganisms. FerrithiocinThe strain Tü 1998 from Streptomyces antibioticus produces besides the indicator antibiotics β- and γ-rubromycins a new sulfur containing metabolite. This metabolite, called ferrithiocin, has been isolated in the form of a iron complex. The structure 1 of the iron-free compound was elucidated by spectroscopic studies and chemical degradation.
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    Dediazoniation of Arenediazonium Ions in Homogeneous Solutions. Part XVI. Kinetics and mechanisms of dediazoniation of p-chlorobenzenediazonium tetrafluoroborate in weakly alkaline aqueous solutions under nitrogen gasPart XV: s. [1]. (1981)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 64 (1981), S. 513-528 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: The kinetics of reactions of p-chlorobenzenediazonium ions in aqueous buffer solutions (pH 9.0-10.6) under N2 (〈 5 ppb of O2) have been measured between 20 and 50°C. The formation of trans-diazotate is first-order with respect to the concentration of hydroxyl ions and to the equilibrium concentration of diazonium ions, if the diazonium ion⇄cis-diazotate equilibrium is considered as a fast prior equilibrium. This indicates that the p-chlorobenzenediazonium ion, in contrast to all previous investigations with the p-nitrobenzenediazonium ion and benzenediazonium ions carrying similar substituents with a -M effect, rearranges from the cis- to the trans-configuration as diazohydroxide and not as diazotate. The formation of trans-diazotate is catalyzed by carbonate and inhibited by hydrogen carbonate ions; mechanisms of these catalyses are discussed, and the solvent isotope effect KH2O/KD2O measured by an 1H-NMR. technique reported. The kinetics of the dediazoniations can be analyzed as a mixture of two reactions, a relatively fast first reaction, reaction A, which is responsible for about 5% of the total reaction, and a second reaction F. Both are first-order with respect to diazonium ion; reaction A is also first-order in hydroxyl ions. There are some indications that reaction A corresponds to the hydrolysis of the diazonium ion to give eventually amine and nitrite ions. Reaction F shows a complex dependence on hydroxyl ions; it is related to the homolytic dediazoniation.
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    Preferential Solvation of the Sodium Cation in Binary Mixtures of Tetrahydrofuran with Unidentate Nitrogen Ligands (1981)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 64 (1981), S. 547-555 
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    Notes: 23Na-chemical shifts for the NaClO4 solute depend markedly upon the composition of binary solvent mixtures of THF with amines (pyridine, piperidine, pyrrolidine, aniline, propylamine, and isopropylamine). These changes, analyzed in a novel application of the Hill formalism, show equality of the intrinsic equilibrium constant K for the successive steps, upon displacement of THF from sodium coordination by one of these amines. The results, which are entirely consistent with tetracoordination of the sodium cation by these solvents, also indicate proportionality of the K values to the amine chemical shifts.
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    The Reaction of Pyruvic Acid with Amines and Aminoesters Reexamined. Preliminary communication (1981)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 64 (1981), S. 568-571 
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    Keywords: Chemistry ; Organic Chemistry
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    Notes: Phenylglycine esters react with pyruvic acid to give α-methylsuccinic amides 9 instead of the expected Schiff bases 8, analogously to p-anisidine but unlike aniline.
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    Propellanes. LXII. The endo- and exo-adducts of 11-cyano-1,6-methano[10] annulene with 4-methyl-1,2,4-triazoline-3,5-dionePart LXI: see [1].Dedicated to the memory of Professor Frantisek Šorm (1981)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 64 (1981), S. 579-581 
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    Notes: The title compounds have been isolated and their structures determined by X-ray crystallography. Their relative stability is discussed in terms of theory and experiment. The endo-adduct is the thermodynamically more stable one.
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    Notizen zur Synthese sulfonierter Derivate von 5,6,7,8-Tetrahydro-1-naphthylamin und 5,6,7,8-Tetrahydro-2-naphthylamin (1981)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 64 (1981), S. 572-578 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: Notes on the Synthesis of Sulfonated Derivatives of 5,6,7,8-Tetrahydro-1-naphthylamine and 5,6,7,8-Tetrahydro-2-naphthylamineSulfonation of 5,6,7,8-tetrahydro-1-naphthylamine (1) with sulfuric acid gave a mixture of 1-amino-5,6,7,8-tetrahydronaphthalene-2-sulfonic acid (2), 4-amino-5,6,7,8-tetrahydronaphthalene-2-sulfonic acid (13) and 4-amino-5,6,7,8-tetrahydronaphthalene-1-sulfonic acid (3). The same reaction with 5,6,7,8-tetrahydro-2-naphthylamine (20) yielded 3-amino-5,6,7,8-tetrahydronaphthalene-2-sulfonic acid (21); formation of 2-amino-5,6,7,8-tetrahydronaphthalene-1-sulfonic acid (16) or of 3-amino-5,6,7,8-tetrahydronaphthalene-1-sulfonic acid (24) was not observed. Treatment of 4-bromo-5,6,7,8-tetrahydro-1-naphthylamine (4) or of its 4-chloro analogue 5 with amidosulfuric acid gave 1-amino-4-bromo-5,6,7,8-tetrahydronaphthalene-2-sulfonic acid (9) and its 4-chloro analogue 10, respectively, which were dehalogenated to 2. Preparations of 13 and 24 were achieved by sulfonation of 5-nitro-1,2,3,4-tetrahydronaphthalene (14) and 6-nitro-1,2,3,4-tetrahydronaphthalene (22) to 4-nitro-5,6,7,8-tetrahydronaphthalene-2-sulfonic acid (15) and 3-nitro-5,6,7,8-tetrahydronaphthalene-1-sulfonic acid (23), respectively, followed by Béchamp reductions. The sulfonic acid 13 was also obtained by hydrogenolysis of 4-amino-1-bromo-5,6,7,8-tetrahydronaphthalene-2-sulfonic acid (11) or of its 1-chloro analogue 12; compounds 11 and 12 were synthesized from N-(4-bromo-5,6,7,8-tetrahydro-1-naphthyl)acetamide (7) and from its 4-chloro analogue 8, respectively, by sulfonation with oleum and subsequent hydrolysis. By ‘baking’ the hydrogensulfate salt of 1 or 20 compounds 3 and 21 were obtained, respectively. Synthesis of 16 was achieved by sulfur dioxide treatment of the diazonium chloride derived from 2-nitro-5,6,7,8-tetrahydro-1-naphthylamine (17) giving 2-nitro-5,6,7,8-tetrahydronaphthalene-1-sulfonyl chloride (18), followed by hydrolysis of 18 to the corresponding sulfonic acid 19 and final reduction.
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    Die Hydrolyse von 6exo-substituierten 2exo- und 2endo-Norbornylestern der p-Toluolsulfonsäure. Norbornanreihe. 3. Mitteilung (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 928-937 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Hydrolysis of 6exo-Substituted 2exo- and 2endo-Norbornyl p-Toluenesulfonates. Norbornane Series. Part 3Hydrolysis of the 6exo-substituted 2exo- and 2endo-norbornyl p-toluenesulfonates 1b-1 and 2b-1, respectively, in 70% dioxane led to different amounts of the following products: Unrearranged 2exo-norbornanols 3 and norbornenes 5, accompanied in somes cases by small amounts of the rearranged Rendo-epimers 4 and 6 and by norticyclenes 7. When the 6exo-substituent was a nucleophilic group as in 1e-1 and 2e-1, various amounts of tricyclic products were also formed by endo-cyclization. These results show that the 2exo- and 2endo-esters 1 and 2, respectively, react by way of different intermediates. In cases where the 6exo-substituent was an n-electron donor, as in 1m-r and 2m-r, quantitative fragmentation to (3-cyclopentenyl)acetaldehyde (13) occurred.
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    The Radical Ions of Naphtho [1,8-cd]-[1,2,6]thiadiazine and Some of Its Derivatives (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2144-2151 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The radical cations and anions of naphtho [1,8-cd]-[1,2,6]thiadiazine (1) and 6,7-dihydroacenaphtho [5, 6-cd]-[1,2,6]thiadiazine (2), as well as the radical anion of acenaphtho [5, 6-cd]-[1,2,6]thiadiazine (3) have been characterized by ESR. spectroscopy. The π-spin distributions in the radical cations \documentclass{article}\pagestyle{empty}\begin{document}$ 1^{\oplus \atop \dot{}}$\end{document} and \documentclass{article}\pagestyle{empty}\begin{document}$ 2^{\oplus \atop \dot{}}$\end{document} strongly resemble those in the iso-π-electronic phenalenyl radical. A prominent feature of the radical anions \documentclass{article}\pagestyle{empty}\begin{document}$ 1^{\ominus \atop \dot{}}$\end{document}, \documentclass{article}\pagestyle{empty}\begin{document}$ 2^{\ominus \atop \dot{}}$\end{document} and \documentclass{article}\pagestyle{empty}\begin{document}$ 3^{\ominus \atop \dot{}}$\end{document} is the substantial localization of the π-spin population on the thiadiazine fragment. These findings are satisfactorily accounted for by HMO models using conventional heteroatom parameters.
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    Two Furanosesquiterpene Marine Metabolites with Antifeedant PropertiesA preliminary account of this work was presented at the International Colloquium CNRSORSTOM on Natural Products of Biological Interest of the Pacific, in Noumea, New Caledonia, September 1979. (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2159-2167 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Two new sesquiterpenoids, nakafuran-8 (1) and -9 (8), have been isolated from the marine sponge Dysidea fragilis and from its prey, the nudibranchs Hypselodoris godeffroyana and Chromodoris maridadilus. The structures were established by spectral analysis and chemical transformations. Both compounds possess antifeedant properties when assayed in the laboratory against common reef fishes, Chaetodon spp.
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    Synthesis of 5-Methyluridine and Its 5′-Mercapto-, 2-Amino-, and 4′,5′-Unsaturated Analogues (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2179-2186 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The stereospecific cis-hydroxylation of 1-(2,3-dideoxy-β-D-glyceropent-2-enofuranosyl)thymine (1) into 1-β-D-ribofuranosylthymine (2) by osmium tetroxide is described. Treatment of 2′,3′-O, O-isopropylidene-5-methyl-2,5′-anhydrouridine (8) with hydrogen sulfide or methanolic ammonia afforded 5′-deoxy-2′,3′-O, O-isopropylidene-5′-mercapto-5-methyluridine (9) and 2′,3′-O, O-isopropylidene-5-methyl-isocytidine (10), respectively. The action of ethanolic potassium hydroxide on 5′-deoxy-5′-iodo-2′,3′-O, O-isopropylidene-5-methyluridine (7) gave rise to the corresponding 1-(5-deoxy-β-D-erythropent-4-enofuranosyl)5-methyluracil (13) and 2-O-ethyl-5-methyluridine (14).The hydrogenation of 2 and its 2′,3′-O, O-isopropylidene derivative 4 over 5% Rh/Al2O3 as catalyst generated diastereoisomers of the corresponding 5-methyl-5,6-dihydrouridine (17 and 18).
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    Photochemische Reaktionen 114. Mitteilung [1]. Zur Photochemie cyclischer Acetale vom 1,3-Dioxa-4,6-cycloheptadien-Typus (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2221-2229 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photochemistry of Cyclic Acetals of the 1,3-Dioxa-4,6-cycloheptadiene TypeUV.-irradiation (λ=254 nm) of 3 gives the isomers (E)-5 (4%), (Z)-5 (60%) and 6 (3%). On triplet sensitization (acetone; λ ≥ 280 nm) 3 is converted to (E)-5 (3%), (Z)-5 (7%) and 7 (9%). - The 1π,π*-excitation (λ=254 nm) of 4 yields the isomers 2 (9%), 8 (10%), 9 (34%), 10 (20%) and 11 (3%). On thermolysis (200°) 4 gives 10 (87%) by a Claisen-rearrangement.
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    Photochemische Reaktionen 115. Mitteilung [1]. Zur Photochemie konjugierter γ,δ-Epoxyenone: Der Einfluss eines Hydroxylsubstituenten in ∊-StellungMit den besten Wünschen Herrn Dr. Willy G. Stoll zum 70. Geburtstag zugeeignet (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2230-2257 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photochemistry of Conjugated γ,δ-Epoxyenones: The Influence of a Hydroxy Substituent in ∊-PositionOn 1n, π*- or 1π,π*-excitation (λ ≥ 347 or λ=254 nm), the ε-hydroxy-γ;,δ-epoxyenone 8 undergoes fission of the C(γ)—O bond followed by the cleavage of the C(δ)-C(ε) bond. This hitherto unknown sequence of reactions is evidenced by the structure determination of the new type products 10-17 and 25, including a synthetic proof for 12 and the X-ray analysis of 11 (X-ray data: triclinic P1; a=7,386(2), b=8,904(4), c=9,684(5)Å; α=82,29(4)°, β=74,46(3)°, γ=82,29(3)°; Z=2).The selective 1π,π*-excitation also induces competitive C(γ)-C(δ) bond cleavage to yield the bicyclic acetal 18 and a ketonium-ylide intermediate a, which photochemically forms a carbene b giving the allene 19 and the cyclopropene 20.On 1n,π*-excitation of the acetate 9 the initial C(γ)-O bond fission is, in contrast to the behaviour of the corresponding alcohol 8, followed by a 1,2-methyl shift affording (E/Z)-28 or by a cyclization-autoxidation process yielding the lactone 29.
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    Zur Synthese sulfonierter Derivate von 4- und 5-Aminoindan (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2280-2286 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: On the Synthesis of Sulfonated Derivatives of 4- and 5-AminoindanBaking the hydrogensulfate salt of 4-aminoindan (1) and 5-aminoindan (2) led, respectively, to 4-aminoindan-7-sulfonic acid (3) and 5-aminoindan-6-sulfonic acid (4). Acid 4 was also obtained by direct sulfonation of 2. 4-Aminoindan-6-sulfonic acid (5) and 6-aminoindan-4-sulfonic acid (6) were prepared by sulfonation of 4-nitroindan (7) and 5-nitroindan (9), respectively, to 4-nitroindan-6-sulfonic acid (8) and 6-nitroindan-4-sulfonic acid (10), followed by a Béchamp-reduction. Treatment of 1 with amidosulfuric acid gave 3, whereas the same reaction with 2 led to a mixture of 4 and 5-aminoindan-4-sulfonic acid (11). Independent synthesis of 11 was achieved by the following sequence of reactions: sulfur dioxide treatment of the diazonium chloride derived from 4-amino-5-nitrodan (13) gave 5-nitroindan-4-sulfonyl chloride (14); hydrolysis to 5-nitroindan-4-sulfonic acid (15), and final reduction. The 4-aminoindan-5-sulfonic acid (16) was synthesized by treatment of 4-amino-7-bromoindan (18) with amidosulfuric acid to give 4-amino-7-bromoindan-5-sulfonic acid (19) followed by hydrogenolysis. Sulfonation of 4-acetyl-amino-7-bromoindan (17) with oleum followed by hydrolysis led to 7-amino-4-bromoindan-5-sulfonic acid (20), the structure of which was confirmed by reductive dehalogenation to 5.
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    Micellar Solubilization of Biopolymers in Hydrocarbon Solvents III. Empirical Definition of an Acidity Scale in Reverse Micelles (1980)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 63 (1980), S. 2302-2311 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This paper deals with the problem of defining, and measuring, the pH inside the water pool (which we define as pHwp) of reverse micelles, i.e. micelles formed by surfactants dissolved in apolar solvents in the presence of minimal amounts of water. The conceptual and experimental difficulties are discussed, and it is argued that no absolute determination of pHwp is possible, mostly because water in the water pools of reverse micelles is a new solvent, for which no standardization of acidity is available. The problem can be approached only on the basis of an empirical acidity scale.An empirical acidity scale for water pools in reverse micelles of bis (2-ethyl-hexyl) sodium sulfosuccinate (AOT) in isooctane has been defined by measuring the 31P-chemical shifts of phosphate buffers. The chemical shifts in bulk water were compared to those found in reverse micelles under the assumption that the pK of phosphate ion is the same in the two systems. It was found that in most cases there was little difference (less than 0.4 pH units) between pHwp and the pH of the starting buffer in bulk water (which we define as pHst). However, this difference between pHwp and pHst may become much larger in certain cases.The difference (pHwp-pHst) is measured under a variety of conditions, and this permits the determination of an operational acidity in the micelle water pools as a function of the pHst with which the aqueous micelles are prepared. The significance of such data for interpreting the behaviour of enzymes confined in the micelles water pool is discussed. Based on the pHwp scale, the apparent pKa of phenol-red and 4-nitrophenol were determined in reverse micelles containing different buffers and different water content. The pKa values obtained were rather sensitive to changes of both these factors, which was taken to signify that organic dies have only a very limited applicability to measure the acidity of the water pools of reverse micelles.
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    A Note on Stereochemical Observations of the Deprotonation of Ethyl 2-Alkenoates (1981)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 64 (1981), S. 1023-1025 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Deprotonation of ethyl (E)-2-alkenoates 1, 3 and 4 yields after protonation the double bond migrated (3 Z)-isomers 5, 7 and 9 as major products. In contrast, deprotonation and reprotonation of ethyl (Z)-2-pentenoate (2) gives the (3 E)-isomer 6 exclusively. These findings are explained by reaction paths starting from different ester conformations.
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    Ein neuer Reaktionsweg zu 1, 3-Dicarbonylderivaten. Modelluntersuchungen am A/B-Teil von 3-Oxo-5α-steroiden (1981)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 64 (1981), S. 1026-1031 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A New Route to 1, 3-Dicarbonyl Derivatives, Model Investigations on the A/B-Part of-3-Oxo-5α-steroidsStarting from 1 the 1, 3-dicarbonyl compounds 4a-d were synthetized via the enynes 2a-e and the relatively unstable epoxides 3a-d. The latter were reacted with 95% formic acid to gave 4a-d; small amounts of the furane derivatives 5a-c were identified as by-products in this last step. In the presence of catalytic amounts of HgSO4 the epoxides 3a-c yielded with 95% formic acid the furanes 5a-c, but no detectable amounts of 4a-c.
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    Some Observations Concerning 1H-NMR. Spectra of 5-hydroxy- and 5-acetoxy-steroid compounds (1981)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 64 (1981), S. 1032-1039 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: It was found that analysis of the 1H-NMR. signals (at 360 (preferably) and/or 100 MHz) of the protons at C (4) and of the equatorial α-proton at C (6), particularly when these are located in the 2-3 ppm region and therefore convenient for detection and identification, may be of valuable aid in the structural and configurational characterization of 5-hydroxy- and 5-acetoxy-steroids (unsubstituted or containing a hydroxy or acyloxy substituent at C (3)).
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    Heterodiamantane und strukturell verwandte Verbindungen. III.Teil II, vgl. [1].. Pentacyclische diäther der C11-reihe. 5, 13-Dioxapentacyclo-[6.5.0.02,6.03,12.04,9]tridecan, 4, 13-dioxapentacyclo [6.4.1.02,7.03,10.05,9]tridecan und 3, 10-dioxapentacyclo [7.3.1.02,7.04,12.06,11]tridecan (1981)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 64 (1981), S. 996-1022 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Heterodiamantanes and Structurally Related Compounds. Part III. The Pentacyclic C11-Diethers 5, 13-Dioxapentacyclo [6.5.0.02,6.03,12.04,9]tridecane, 4, 13-Dioxapentacyclo [6.4.1.02,7.03,10.05,9]tridecane, and 3, 10-Dioxapentacyclo [7.3.1.02,7.04,12.06,11]tridecaneIn connection with the studies on heterodiamantanes and structurally related compounds the three novel pentacyclic diethers 3-5 were prepared starting from the cyclopentadienone dimer 6. All four compounds have as common features a central carbocyclic 6-membered ring with four axial alkyl substituents and two oxygen functions in 1, 4 position. The required eleventh C-atom was introduced by dichlorocarbene addition either to 6 ( → 7) (Scheme 2) or to 29 ( → 28) (Scheme 4).Diether 3 was obtained by reduction of 26 (Scheme 2), a suitable precursor prepared either by intramolecular addition (24 → 26; Scheme 2) or substitution (30 → 26, 31 → 26; Scheme 4), as well as by direct substitution (44 → 3, 42 → 3; Scheme 5). Diether 4 was the product of a direct substitution (39 → 4, 36 → 4; Scheme 5). The synthesis of diether 5 was achieved from the addition product 51 (resulting from the alcohols 47 and 48; Scheme 6).Diether 4 is the thermodynamically least stable of the three diethers 3-5. It was easily isomerized to 5 on treatment with concentrated sulfuric acid in benzene whereas 3 and 5 remained unchanged under these conditions.
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    Cryptates Sphériques. Synthèse et Complexes d'Inclusion de Ligands Macrotricycliques SphériquesDédié à la mémoire du Professeur Frantisek Šorm (1981)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 64 (1981), S. 1040-1057 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Spherical Cryptates. Synthesis and Inclusion-Complexes of Spherical Macrotricyclic LigandsA general strategy for the synthesis of spherical macrotricyclic ligands has been developed. Four spherical cryptands, SC-24, SC-25, SC-26 and SC-27 have been obtained by this route. The synthesis and cation-complexing properties of these compounds are described in detail. Stability constants and cation exchange rates of the spherical cryptates obtained with alkali and alkaline-earth cations have been determined. Highly stable complexes are formed by SC-24; the Rb+ and Cs+ cryptates of SC-24 are the most stable complexes of these cations known to date. The size of the intramolecular cavity affects the complexation selectivity. The cation exchange rates are very slow, and the corresponding free energies of activation are even larger than, for macrobicyclic cryptates of similar stability. Both the high complex stabilities and the high activation energies required for cation exchange indicate a marked ‘spherical cryptate effect’ resulting from the highly connected nature of the molecular architecture of spherical macrotricyclic ligands.
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    Rates of Proton Abstraction from Conjugated Dienes in the Gas Phase (1981)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 64 (1981), S. 1058-1062 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The rates of proton transfer from 2, 4-hexadiene, 1, 3-cycloheptadiene, cyclopentadiene and acetone to t-butoxide have been measured in the gas phase using pulsed-ion-cyclotron-resonance spectroscopy. The rate constants are (units of 10-10 cm3 molecule-1 s-1): 2.7 ± 0.4, 3.8 ± 0.4, 6.1 ± 0.7 and 10.8 ± 1.5, respectively. These results are analyzed in terms of the properties of the encounter complex and reaction transition states. The reaction profile for t-butoxide + cyclopentadiene is modeled using RRKM theory and an estimate for the central barrier height is obtained.
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    Reaktionen von 2- und 3-phenylsubstituierten Alkylakyliden-iminium-Ionen in der Gasphase. 5. Mitteilung über stossinduzierte Fragmentierungen von felddesorbierten Kationen4. Mitt. s. [1]. (1981)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 64 (1981), S. 1083-1091 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactions of 2- and 3-Phenyl Substituted Alkylalkylidene Iminium Ions in the Gas PhaseThe collision-induced fragmentations of 2- and 3-phenyl substituted alkylalkylidene iminium ions are reported. Besides the homolytic cleavage of the azaallyl bond a nucleophilic attack of the unsubstituted phenyl group at the iminium function is observed in the gas phase, yielding carbonium ions such as cyclopropanspirobenzenium (3), indanylium (10) and indenylium ions (11).
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    Carotenoids and Related Compounds. Part 36.Part 35: [1].. Further syntheses of zeaxanthin and rhodoxanthinDedicated to Prof. Conrad Hans Eugster on the occasion of his 60th birthday (1981)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 64 (1981), S. 1092-1097 
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    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A modification of a previously reported synthesis of zeaxanthin (1), and routes to both zeaxanthin and rhodoxanthin (2) from α-ionone, are described.
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    The Influence of Molecular Host Lattices on Electronic Properties of Orbitally (Near-) Degenerate Transition Metal ComplexesHerrn Prof. Dr. Conrad Hans Eugster zum 60. Geburtstag gewidmet (1981)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 64 (1981), S. 1063-1082 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Transition metal complexes often have low-lying excited electronic states and, as a consequence, tend to be electronically labile, i.e., their electronic properties exhibit pronounced sensitivity to external perturbations. Often drastic changes in various spectroscopic properties indicating substantial electronic rearrangements can be induced be relatively weak intermolecular forces as provided by nonpolar solvents or solid molecular host lattices. This behaviour can be explained by crossing of potential surfaces in the vicinity of the absolute minimum. Many physical properties of a given orbitally (near-) degenerate system depend strongly on the relative magnitude of some characteristic parameters determining the shape of the ground Born-Oppenheimer potential surface(s), e.g. barrier height versus zero-point energy, distance between minima versus zero-point amplitude, energy difference between minima, etc. Typical examples are systems exhibiting Jahn-Teller activity, spin-crossover, mixed valence, exchange coupling and other types of electronic near-degeneracies. In paramagnetic systems changes in the electronic wavefunction can be most conveniently detected and analyzed by using EPR. spectroscopy.In paramagnetic sandwich complexes we studied two types of orbital degeneracies: Jahn-Teller degeneracies (d7-systems such as Co (cp)2, Ni(cp)2+ and Fe (cp) (bz), low-spin d5-systems such as Mn (cp)2) and low-spin/high-spin equilibria (d5-systems such as Mn (cp)2). By diluting these complexes and ring-substituted derivatives in a large variety of diamagnetic host systems we have been able to control the 6A/2E equilibrium of Mn (cp)2 by influencing the metal-to-ring distance and by changing the degree of ring alkylation; similarly we have been able to vary the relative weights of the two electronic states contributing to the two-fold degenerate electronic ground state of d5- and d7-systems to a large degree by variation of the local asymmetric fields offered by the lattice sites of the host systems.For comparison the electronic ground state properties of octahedral Cu(II) complexes with CuN6 CuO6 chromophores, of V (CO)6 and tetrahedral VCl4 were also studied by EPR. between 4K and room temperature in several host systems. Characteristic differences in the details of the temperature and host dependence of the EPR. spectra in all these electronically labile systems can be explained in terms of differences in the vibronic coupling type (E ⊗ e vs. T ⊗ e, t), the strength of linear and/or quadratic JT-coupling and the effects produced by spin-orbit coupling.
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    Synthese und Struktur porphinoider Nickel-Komplexe mit axial orientierten Seitenketten10. Mitt. über «Synthese und Reaktionen porphinoider Metallkomplexe». 9. Mitt. [1]. (1981)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 64 (1981), S. 1098-1112 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and Structure of Porphine-type Nickel Complexes Containing Axially Oriented SidechainsThe structure of (±)-[1, 11-dimethoxy-10 H-HDP (2-)]nickel (3), the product of the thermodynamically controlled addition of methanol to [6 H-HDP]nickel-bis-(tetrafluoroborate) (1), was determined by X-ray analysis. The two methoxy groups in 3 are cis-oriented. The syntheses and spectroscopic properties of [1, 11-diethoxy-10 H-HDP (2-)]nickel (5), [1, 11-dineopentyloxy-10 H-HDP (2-)]nickel (6) as well as the bridged complexes [1, 11-pentamethylenedioxy-10 H-HDP (2-)]nickel (4) and [1, 11-(E)-2,3-(dimethyl-2-butenylenedioxy)-10 H-HDP (2-)]nickel (7) are described. Reaction of 1 with bromide ions or 4-methylpyridine leads to the formation of the corresponding hexacoordinated, paramagnetic complexes dibromo [6 H-HDP]-nickel (II) (8) and bis (4-methylpyridine)[6 H-HDP]nickel-bis (tetrafluoroborate) (9).
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    Synthesis of Reactive Intermediates for Natural Cyclopentane Derivatives from (-)-Quinic Acid: Preparation of 11α-hydroxy-13-oxaprostanoic acidDedicated to the memory of Prof. Frantisek Sorm (1981)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 64 (1981), S. 1140-1144 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We describe a flexible, stereocontrolled synthesis of enantiomerically pure substituted cyclopentenes and cyclopentanes - including 11α-hydroxy-13-oxaprostanoic acid 20 - (-)-quinic acid via an acyclic precursor 6 by an intramolecular aldolisation-dehydration reaction.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/hlca.19810640419
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    Chiral 1, 4-Benzodiazepin-2-one, template for enantioselective synthesis of α-amino acids and their α-deuterio congeners. Preliminary communication (1981)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 64 (1981), S. 1145-1149 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Absolute conformation of 7-chloro-5-phenyl-1-[(S)-α-phenylethyl]-1, 3-dihydro-2H-1, 4-benzodiazepin-2-one (1c) in crystal, and its inversion rate in solution were determined, enabling prognosis of direction of asymmetric induction during C(3)-alkylation.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19810640420
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  • 97
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    Anwendung der α-Alkinon-Cyclisierung: Synthese von rac-ModhephenVorgetragen von M. Karpf an der Versammlung der Schweizerischen Chemischen Gesellschaft am 17. Oktober 1980 in Bern; als vorläufige Mitteilung erschienen in [1]. Anmerkung bei der Korrektur: Vor kurzem sind zwei weitere Synthesen von Modhephen veröffentlicht worden: (a) A.B. Smith, III & P.J. Jerris, J. Am. Chem. Soc. 103, 194 (1981); (b) H. Schostarez & L.A. Paquette, J. Am. Chem. Soc. 103, 722 (1981).Herrn Prof. Dr. Conrad Hans Eugster zu seinem 60. Geburtstag gewidmet (1981)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 64 (1981), S. 1123-1133 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Application of the α-Alkynone Cyclization: Synthesis of rac-Modhephenerac-Modhephene 1, the first sesquiterpene with a propellane C-skeleton and its epimer rac-epi-modhephene 27, were synthesized starting from bicyclo[3.3.0]oct-1(5)-en-2-one (2). The key step in the construction of the [3.3.3]-propellane system is an application of the α-alkynone cyclization, namely 3 → 4 and 11 → 14. The preferred formation of the propellanes 4 and 14 in this step shows that the insertion of the postulated alkylidene carbene intermediate into tertiary C,H-bonds outweighs the one into the secondary ring-C,H-bonds leading to 12/13 and 15/16, respectively. The two starting materials for the α-alkynone cyclization, 3 and 11, were prepared from 2 by the reactions shown in Scheme 3. The further elaboration and separation of the cyclization products 4 and 14 to rac-modhephene 1 and its epimer 27 are outlined in Scheme 5.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19810640417
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  • 98
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    Studies on the Conversions of Diols and Cyclic Ethers. Part 48Part 47: [1].. Dehydration of alcohols and diols on the action of dimethylsulfoxide (1981)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 64 (1981), S. 389-398 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The transformations of 13 alcohols and 13 diols in the presence of a small amount dimethylsulfoxide (1/16 mol) were studied. Relationships were found between the type of the hydroxy compound and the selectivity of the transformation, and conclusions were drawn regarding the transformation mechanism. The ether formation observed with certain alcohols proceeds via a carbenium cation. The reaction conditions applied were found suitable for inducing water elimination from the ditertiary 1,2- and 1,3-diols (pinacol rearrangement, 1,2-elimination). From the 1,4- and 1,5-diols the corresponding oxacycloalkanes can be obtained in good yield. Cyclodehydration occurs by intramolecular nucleophilic substitution, via a concerted mechanism. The effect of DMSO is exerted directly, and protoncatalysis occurs simultaneously.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19810640204
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  • 99
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    Un nouvel exemple de nucléoside à sucre ramifié insaturé: la désoxy-3′-méthylidène-3′-adénosine (1981)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 64 (1981), S. 425-429 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A Novel Example of Unsaturated Branched-chain Sugar Nucleoside: 3′-Deoxy-3′-methylidene-adenosineStarting from 5-O-benzoyl-3-C-methylidene-3-deoxy-1,2-O-isopropylidene-α-D-erythro-pentofuranose (11) the title compound 8 has been prepared. Its α-anomer (9) and the acyclic sugar nucleoside 10 have been obtained as by-products. Adenosine deaminase slowly deaminated 8, 9 being not affected. Compound 8 exhibited no antiviral activity, whereas one of its saturated analogues (13) inhibited the multiplication of the herpes-1 (HF) virus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19810640207
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  • 100
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    Natural Occurrence of Enantiomeric and meso-Astaxanthin. 5. Ex wild salmon (Salmo salar and Oncorhynchus) (1981)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 64 (1981), S. 449-457 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The configurational isomers of astaxanthin (3,3′-dihydroxy-β,β-carotene-4,4′-dione) from the flesh of salmon (Salmo salar and Oncorhynchus) caught at different places in Europe and Canada were isolated and analyzed as (-)-camphanic acid diesters by means of HPLC. The biological variation in the composition of the configurational isomers in seven fish was surprisingly similar: 78 to 85% of (3S, 3′S)-astaxanthin, 12 to 17% (3R, 3′R)-astaxanthin and 2 to 6% meso-astaxanthin.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19810640209
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