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  • 1
    Electronic Resource
    Electronic Resource
    Acid catalyzed condensation of isoprene with orcinol: Synthesis of 2,2-dimethylchromans and 5-methylxanthyletin derivatives (1983)
    Springer
    Monatshefte für Chemie 114 (1983), S. 71-77 
    Details
    ISSN: 1434-4475
    Keywords: 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone ; 2,2-Dimethylchromans ; 2-Methylbuta-1,3-diene ; 5-Methylxanthyletin ; Orcinol ; Pechmann condensation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Kondensation von Orcin mit Isopren in Gegenwart von Orthophosphorsäure führt in einem Schritt zu 2,2-Dimethylchromanen. Außerdem wird ein neuer Weg für die Synthese von 5-Methylxanthyletinderivaten aufgezeigt.
    Notes: Abstract Condensation of orcinol with 2-methylbuta-1,3-diene (isoprene) has been achieved in the presence of orthophosphoric acid as catalyst leading to the exclusive formation of 2,2-dimethylchromans in one step. A novel route for the synthesis of 5-methylxanthyletin derivatives is described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00809377
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  • 2
    Electronic Resource
    Electronic Resource
    A convenient synthesis of crotylbenzaldehydes and 2-methylformyl-chromans (1984)
    Springer
    Monatshefte für Chemie 115 (1984), S. 1059-1064 
    Details
    ISSN: 1434-4475
    Keywords: Buta-1,3-diene ; Crotylbenzaldehydes ; Regiospecific crotylation ; Orthophosphoric acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die Kondensation von Hydroxybenzaldehyden (2,3,4-Trihydroxy-, 2,4-Dihydroxy-, 2,4-Dihydroxy-6-methyl-, und 2,4-Dihydroxy-3-jod-6-methyl-benzaldehyd) mit Buta-1,3-dien in Gegenwart von Orthophosphorsäure ergibt in einer Stufe Crotylbenzaldehyde. Diese lassen sich durch Cyclisierung zu den entsprechenden 2-Methylformylchromanen umsetzen.
    Notes: Abstract Condensation of hydroxybenzaldehydes viz., 2,3,4-trihydroxy-, 2,4-dihydroxy-, 2,4-dihydroxy-6-methyl-, and 2,4-dihydroxy-3-iodo-6-methylbenzaldehydes with buta-1,3-diene in the presence of orthophosphoric acid yields crotylbenzaldehydes in one step. The latter compounds on cyclisation afford the corresponding 2-methylformylchromans.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00798772
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  • 3
    Electronic Resource
    Electronic Resource
    A facile synthesis of 4-aryl-2H-1-benzopyran-2-ones (1985)
    Springer
    Monatshefte für Chemie 116 (1985), S. 869-872 
    Details
    ISSN: 1434-4475
    Keywords: 4-Aryl-2H-1-benzopyran-2-ones ; Ethoxycarbonylmethylene-triphenylphosphorane ; Friedel-Crafts reaction ; 2-Hydroxybenzophenones ; Wittig reaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die Reaktion der 2-Hydroxybenzophenone1,3,7 und8 mit Ethoxycarbonyl-methylentriphenylphosphoran ergab die 4-Aryl-2H-1-benzopyran-2-one2 und4–6 in ausgezeichneten Ausbeuten.
    Notes: Abstract Reaction of 2-hydroxybenzophenones (1,3,7,8) with ethoxycarbonyl-methylenetriphenylphosphorane affords 4-aryl-2H-1-benzopyran-2-ones (2,4–6) in excellent yields.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00809163
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  • 4
    Electronic Resource
    Electronic Resource
    Propagator matrix formulation for earth currents of deep internal origin (1973)
    Springer
    Pure and applied geophysics 105 (1973), S. 858-863 
    Details
    ISSN: 1420-9136
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Summary The problem of the distribution of the poloidal electric field in the mantle, originating from the core-mantle boundary, is formulated in terms of propagator matrices suitable for calculations for a wide variety of piece-wise continuous models of the mantle. The elements of the propagator matrix for some interesting variations of the electric conductivity are presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00875834
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  • 5
    Electronic Resource
    Electronic Resource
    Geothermic models of variable thermal conductivities and source functions (1969)
    Springer
    Pure and applied geophysics 72 (1969), S. 90-116 
    Details
    ISSN: 1420-9136
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Summary Temperature distributions are investigated for the stratified earth having planar and spherical boundaries under the assumptions of (i) Steady state heat flow (ii) layered non-uniform distribution of sources, and (iii) non-uniform thermal conductivities in each individual layer. The non-uniformity in source conditions and conductivity distributions is approximated by exponential and generalized power law functions of depths. The corresponding heat conduction equations are solved so as to satisfy an appropriate set of boundary conditions. The solutions will be useful in providing an analytical basis for an accurate and reliable description of the (a) thermal structure for a variety of new models, and (b) complex interplay of source and conductivity variations in defining possible temperatures in the interior of the earth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00875697
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  • 6
    Electronic Resource
    Electronic Resource
    Propagator matrix formulation of heat transfer in spherically stratified media (1968)
    Springer
    Pure and applied geophysics 70 (1968), S. 74-80 
    Details
    ISSN: 1420-9136
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Summary In the paper we have transformed the steady and unsteady conductive heat transfer differential equation in spherical coordinates into a system of first order differential equations and processed them by method of propagator matrices to extrapolate the known surface heat flux and temperature to any desired depth. The elements of propagator matrices have been summarised for various piecewise continuous conductivity and rate of heat generation functions to approximate inhomogeneities in the earth. In the analysis the rate of heat generation is either assumed to depend linearly upon temperature or correspond to first order irreversible chemical reactions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00875142
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  • 7
    Electronic Resource
    Electronic Resource
    Synthesis of obtusinin and 7-(3′-hydroxymethylbut-2′-enyloxy)-6-methoxy-2H-1-benzopyran-2-one (1982)
    Springer
    Monatshefte für Chemie 113 (1982), S. 197-200 
    Details
    ISSN: 1434-4475
    Keywords: Osmium tetraoxide ; Potassium borohydride ; Regiospecific oxidation ; Selenium dioxide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Obtusinin (1) wurde über 6-Methoxy-7-(3′-methylbut-2′-enyloxy)-2H-1-benzopyran-2-on (3) mit OsO4 synthetisiert. Die Darstellung von 7-(3′-Hydroxymethylbut-2′-enyloxy)-6-methoxy-2H-1-benzopyran-2-on (2) wurde mittels regioselektiver Oxidation von3 mit SeO2, gefolgt von Reduktion des gebildeten Aldehyds mit KBH4, bewerkstelligt.
    Notes: Abstract Obtusinin (1) has been synthesised by the reaction of 6-methoxy-7-(3′-methylbut-2′-enyloxy)-2H-1-benzopyran-2-one (3) with OsO4. Synthesis of 7-(3′-hydroxymethylbut-2′-enyloxy)-6-methoxy-2H-1-benzopyran-2-one (2) has been achieved by the regiospecific oxidation of3 with SeO2 followed by reduction of the formed aldehyde with KBH4.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00799019
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  • 8
    Electronic Resource
    Electronic Resource
    A novel synthesis of 4-propyl-2H-1-benzopyran-2-ones (1984)
    Springer
    Monatshefte für Chemie 115 (1984), S. 765-768 
    Details
    ISSN: 1434-4475
    Keywords: Ethoxycarbonylmethylenetriphenylphosphorane ; 2-Hydroxybutyrophenones ; Insecicidal properties ; 4-Propyl-2H-1-benzopyran-2-ones ; Wittig reaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die Reaktion von 2-Hydroxybutyrophenonen1–5 ergab mit Ethoxycarbonylmethylentriphenylphosphoran die 4-Propyl-2H-1-benzopyran-2-one6–10
    Notes: Abstract Reaction of 2-hydroxybutyrophenones1–5 with ethoxycarbonylmethylenetriphenylphosphorane furnishes the 4-propyl-2H-1-benzopyran-2-ones6–10.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01120972
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  • 9
    Electronic Resource
    Electronic Resource
    TransientEM screening in two concentric spherical shell model (1972)
    Springer
    Pure and applied geophysics 94 (1972), S. 226-232 
    Details
    ISSN: 1420-9136
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Summary Different results have been obtained by Negi and Wait in connection with the effect of overburden in electromagnetic exploration by assuming different definitions of screening factor. Both definitions are based on frequency domain considerations. We shall describe the screening characteristics for a transient field with a two-concentric shell model with screening factor=(magnetic field of target and screen-magnetic field of screen alone)/(field of target alone). It is found that the screening factor does become more than one in some situations which means that the EM response of target is more in some cases when the screen is present than when it is absent.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00875683
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  • 10
    Electronic Resource
    Electronic Resource
    A method of the calculation of the mantle-electrical conductivity by the inversion of the geomagnetic secular variation data (1974)
    Springer
    Pure and applied geophysics 112 (1974), S. 149-152 
    Details
    ISSN: 1420-9136
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Summary An optimization technique is described for inverting the geomagnetic secular variation data to find out the electrical conductivity. It is simpler and more straightforward than the exact technique based on the Gelfand-Levitan theory of the inverse boundary value problem for the second-order differential equation [1].
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00875929
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