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  • 1
    Electronic Resource
    Electronic Resource
    Synthesis of (4E,7S)-(-)-7-Methoxy-4-tetradecenoic Acid, a Major Constituent of the Marine Cyanophyte Lyngbya Majuscula (1995)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1995 (1995), S. 673-676 
    Details
    ISSN: 0947-3440
    Keywords: 4-Tetradecenoic acid, (E,S)-(-)-7-methoxy- ; Oxiranes, optically active ; Orthoesters as carboxyl protecting groups ; Lyngbya majuscula ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The metabolite of the marine cyanophyte Lyngbya majuscula (4E,7S)-(-)-7-methoxy-4-tetradecenoic acid (1) has been synthesized for the first time in optically active form in eight steps in 20% overall yield, Heptyloxirane (3) and the alkyne 4 containing the carboxyl group masked as a tricyclic orthoester were prepared by known methods from 5 and 6 as starting materials. Reaction of lithiated 4 with 3 afforded in 74% yield the alkyne 2 which could easily be transformed into the target molecule. Hydrogenation with Lindlar catalyst produced 7 which could be isomerized to 8 with (E) configuration. Methylation of the 7-hydroxy group in 8 gave 9 which could be transformed into the methyl ester 10 and the (4E,7S)-acid 1 in high yield.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199519950495
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  • 2
    Electronic Resource
    Electronic Resource
    Orthocarbonsäure-ester mit 2,4,10-Trioxaadamantanstruktur als Carboxylschutzgruppe; Verwendung zur Synthese von substituierten Carbonsäuren mit Hilfe von Grignard-Reagenzien (1983)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 66 (1983), S. 2294-2307 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ortho Esters with 2,4,10-Trioxaadamantane Structure as Carboxyl Protecting Group; Applications in the Synthesis of Substituted Carboxylic Acids by Means of Grignard ReagentsThe surprising stability of 2,4,10-trioxa-3-adamantyl derivatives 1 against nucleophilic substitution by organomagnesium compounds is discussed and shown to be caused by unfavourable stereoelectronic and steric factors governing the substitution of these cage compounds (Scheme 2). As a consequence, a number of Grignard reagents 2 containing the carboxyl group masked as 2,4,10-trioxa-3-adamantyl group could be prepared and have been reacted in a second step with various electrophiles (cf. Scheme 4). In the products 7-13 and 15b the carboxyl masking group is removed by mild acid hydrolysis and saponification (cf. Scheme 3) to yield the corresponding acids 16a-21a, 22, and 23a. Acids 21a and 23a have been further transformed to give the macrocyclic lactones 24 and 26, isolated from Galbanum oleo-gum-resin, and acid 22 to give 12-methyl-13-tridecanolide (25), isolated from Angelica root oil. In addition 1-bromo-ω-(2,4, 10-trioxa-3-adamantyl)alkanes 1c and 1b have been used to synthesize (±)-methyl recifeiolate (29b) and pure cis-ambrettolic acid ((Z)-32a).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19830660741
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  • 3
    Electronic Resource
    Electronic Resource
    Regioselektiver Brom/Lithium-Austausch bei 2,5-Dibrom-1-nitrobenzol. - Eine einfache Synthese von 4-Brom-2-nitrobenzaldehyd und 6,6′-Dibromindigo (1989)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 122 (1989), S. 1199-1201 
    Details
    ISSN: 0009-2940
    Keywords: Dibromonitrobenzenes ; Bromine-lithium exchange ; Formylation, regioselective ; Indigo, 6,6′-dibromo- ; Tyrian purple ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Regioselective Bromine/Lithium Exchange in 2,5-Dibromo-1-nitrobenzene. - A Simple Synthesis of 4-Bromo-2-nitrobenzaldehyde and 6,6′-DibromoindigoThe reaction of phenyllithium with 2,5-dibromo-1-nitrobenzene (1) in tetrahydrofuran at -105°C leads to the lithium derivative 2 with high regioselectivity. By reaction with dimethylformamide 2 is converted into 4-bromo-2-nitrobenzaldehyde (3) in 92% yield. The isomeric aldehyde 4 is not formed. With the same reaction sequence 2,4-dibromo-1-nitrobenzene (5) can be transformed into 5-bromo-2-nitrobenzaldehyde (6). From aldehyde 3 and nitromethane Tyrian purple (7) is easily accessible.
    Notes: Die Reaktion von Phenyllithium mit 2,5-Dibrom-1-nitrobenzol (1) in Tetrahydrofuran bei -105°C ergibt mit ausgezeichneter Regioselektivität die Lithium-Verbindung 2, die durch Umsetzung mit Dimethylformamid mit 92proz. Ausbeute den 4-Brom-2-nitrobenzaldehyd (3) liefert. Der isomere Aldehyd 4 wird nicht gebildet. In analoger Weise läßt sich auch der 5-Brom-2-nitrobenzaldehyd (6) aus 2,4-Dibrom-1-nitrobenzol (5) erhalten. Aus dem Aldehyd 3 und Nitromethan kann auf einfache Weise der Antike Purpur (7) synthetisiert werden.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19891220628
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  • 4
    Electronic Resource
    Electronic Resource
    Synthese der enantiomeren Melochinine (1982)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1982 (1982), S. 1466-1477 
    Details
    ISSN: 0170-2041
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Synthesis of the Enantiomeric MelochininesBoth enantiomers of the pyridone alkaloid melochinine (1) have been synthesized in the following way: The dienolate dianion 3a, formed exclusively from 3-hydroxy-2,6-dimethyl-4-pyrone (3) and lithium bis(trimethylsilyl)amide at - 70°C, reacts with 10-(tetrahydro-2-pyranyloxy)-1-undecanal (6) to give 7, then 8 by methylation, 9 by elimination of water, and finally the pyrone 10 by catalytic hydrogenation in 48% overall yield. Reaction of 10 with ammonia/methanol produces rac-1. Natural (-)-(R)-melochinine (1) and its artificial enantiomer are produced by using the aldehydes (R)-6 and (S)-6 in the synthesis described above. The enantiomeric aldehydes (R)-6 and (S)-6 are prepared in three steps from (+)-(R)- and (-)-(S)-1,2-epoxypropane, respectively. The starting material 3 ist produced from 1-(5-methyl-2-furyl)ethanol (2) by treatment with chlorine/water.
    Notes: Beide Enantiomeren des Pyridonalkaloids Melochinin (1) werden auf folgende Weise synthetisiert: Bei der Deprotonierung von 3-Hydroxy-2,6-dimethyl-4-pyron (3) mit Lithium-bis(trimethylsilyl)amid bei - 70°C entsteht ausschließlich das Dienolat-Dianion 3a. Es reagiert bei dieser Temperatur mit 10-(Tetrahydro-2-pyranyloxy)-1-undecanal (6) zur Verbindung 7, welche durch Methylieren, Eliminieren von Wasser und katalytisches Hydrieren über 8 und 9 mit 48% Gesamtausbeute in das Pyron 10 übergeführt wird. Einwirkung von Ammoniak/Methanol auf 10 ergibt rac-1. Das natürliche (-)-(R)-Melochinin (1) und sein in der Natur nicht vorkommendes Enantiomeres werden erhalten, wenn man in der Synthese die Aldehyde (R)-6 und (S)-6 einsetzt. Die enantiomeren Aldehyde 6 werden in drei Stufen aus (+)-(R)- bzw. (-)-(S)-1,2-Epoxypropan erhalten. Das Ausgangsmaterial 3 entsteht aus 1-(5-Methyl-2-furyl)ethanol (2) durch Reaktion mit Chlor/Wasser.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198219820806
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  • 5
    Electronic Resource
    Electronic Resource
    Synthese der Markierungssubstanz der Kirschenfruchtfliege Rhagoletis cerasi L. (1991)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1991 (1991), S. 545-552 
    Details
    ISSN: 0170-2041
    Keywords: Oviposition-deterring pheromone ; Rhagoletis cerasi L. ; Epoxide opening ; 1,5-Cyclooctadiene-CuCl catalysis ; Glucosylation ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of the Oviposition-Deterring Pheromone of Rhagoletis cerasi L.The oviposition-deterring pheromone of Rhagoletis cerasi L. (-)-(8R,15R)-1 and a mixture of the two compounds (-)-(8R and 8S,15R)-1 have been synthesized. In the presence of the 1,5-cyclooctadiene-CuCl complex as catalyst the Grignard reagent of (-)-(R)-4 reacts with the epoxides (-)-(S)-5 and (±)-5 to give (-)-(7R,14R)-6 and (-)-(7R and 7S,14R)-6. The optically active reagent (-)-(R)-4 has been prepared from ( + )-(R)-1,2-epoxypropane. (-)-(S)-5 has been prepared from L-malic acid dimethyl ester. - After converting the 7-hydroxy groups of (7R,14R)-6 and (7R and 7S,14R)-6 into benzyl ethers 7, treatment with methanolic HCl solvolyzed the silyl ether and tricyclic orthoester groups to give the methyl esters (8R,15R)-20 and (8R and 8S,15R)-20. Next, these compounds were transformed into the benzyl ether-benzyl esters (8R,15R)-21 and (8R and 8S,15R)-21 that could be β-glucosylated in high yields with tetrapivaloyl-α-D-bromoglucose to give (8R,15R)-22 and (8R and 8S,15R)-22. Hydrogenolysis of the benzyl groups in 22 gave the corresponding 8-hydroxy acids that could be activated as mixed anhydrides and reacted with 2-aminoethanesulfonic acid to give the taurinamides (8R,15R)-23 and (8R and 8S,15R)-23. In the last step the pivaloyl groups of the glucose moiety of the molecules were removed by alkaline hydrolysis. Treatment of the hydrolysis products with an Amberlyst 15 (H+ form) ion exchanger and then with ammonia gave (8R,15R)-1 and (8R and 8S,15R)-1 as ammonium salts. The tetraacetyl-β-glucosides (13R)-2 and (13S)-3 have been synthesized and allow to deduce the (15R) configuration for the pentaacetyl derivative of the natural compound 1 by comparing their 1H-NMR spectra.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.1991199101100
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  • 6
    Electronic Resource
    Electronic Resource
    Eine einfache Synthese der enantiomeren (E)-9-Hydroxy-2-decensäuren (1994)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1994 (1994), S. 189-192 
    Details
    ISSN: 0170-2041
    Keywords: Apis mellifica L ; Pheromones ; Alkynols ; 2-Decenoic acid, (E)-9-hydroxy ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Simple Synthesis of the Enantiomeric (E)-9-Hydroxy-2-decenoic AcidsThe enantiomeric (E)-9-Hydroxy-2-decenoic acids (1), components of the swarm settling pheromone in Apis mellifica L. (honey bee) have been synthesized. The lithium derivative of 1-hexyne was treated with (R)-(+)-methyloxirane (2), (S)-(-)-2 or (±)-2 to give the alkynols (R)-(-)-3, (S)-(+)-3 or (±)-3, which could be isomerized with the sodium salt of 1,3-propanediamine to give (R)-(-)-8-nonyn-2-ol (4) and (±)-4. These were methoxycarbonylated to produce the esters (R)-(-)-5, (S)-(+)-5 or (±)-5. Selective hydrogenation in pyridine with Pd/BaSO4 as catalyst gave the (Z)-esters (R)-(-)-6, (S)-(+)-6 or (±)-6 which could be isomerized with photochemically generated phenylthio radicals to produce the (E)-esters (R)-(-)-7, (S)-(+)-7 or (±)-7. The acids present in the pheromone (R)-(-)-1, (S)-(+)-1 and (±)-1 could be obtained by basic hydrolysis of the esters. The minor but important component 8 of the swarm settling pheromone has been synthesized by treating the Grignard reagent obtained from 5-bromo-guaiacol benzyl ether with ethylene oxide to give 9 in high yield. Hydrogenolytic removal of the benzyl group in 9 produced 8 directly.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199419940213
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  • 7
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    Ambipolar organic field effect transistors and inverters with the natural material Tyrian Purple (2011)
    American Institute of Physics
    Details
    Publication Date: 2011-12-01
    Electronic ISSN: 2158-3226
    Topics: Physics
    Published by American Institute of Physics
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  • 8
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    Optochemical sensor for determining ozone based on novel soluble indigo dyes immobilised in a highly permeable polymeric film (2005)
    Springer
    Details
    Publication Date: 2005-06-29
    Print ISSN: 1618-2642
    Electronic ISSN: 1618-2650
    Topics: Chemistry and Pharmacology
    Published by Springer
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  • 9
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    Green and biodegradable electronics (2012)
    Elsevier
    Details
    Publication Date: 2012-07-01
    Print ISSN: 1369-7021
    Electronic ISSN: 1873-4103
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Published by Elsevier
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  • 10
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    Resolution and absolute configuration of the enantiomeric spiro[5.5]undecane-3,9-diols (1994)
    Elsevier
    Details
    Publication Date: 1994-03-01
    Print ISSN: 0957-4166
    Electronic ISSN: 1362-511X
    Topics: Chemistry and Pharmacology
    Published by Elsevier
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