• B H Patwardhan

      Articles written in Proceedings – Section A

    • Ultraviolet spectra of α-carboxystilbenes—I

      G Bagavant B H Patwardhan

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      The ultraviolet spectra of α-carboxy and α-carbomethoxystilbenes obtained in the Claisen/Stobbe reaction of methyl phenyl acetate and aromatic aldehydes is reported. All these compounds possess the characteristiccis stilbene spectral curve. Electronic effects of substituents in the acid show characteristic bathochromic shifts. A fewtrans α-carboxystilbenes have been prepared and their spectra have the characteristictrans stilbene pattern.

    • Ultraviolet spectra of α-carboxystilbenes - II. α-o-carboxyphenylcinnamic acids

      G Bagavant B H Patwardhan

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      The ultraviolet spectra of methyl-α-o-carboxyphenyl cinnamates and α-o-carboxyphenylcinnamic acids is reported. These compounds possess the characteristiccis stilbene spectral curve, thereby supporting Loewenthal and Pappo’s suggestion that these compounds havecis Ph/Ph-COOR configuration. Formation of this isomer in the Stobbe reaction of dimethyl homophthalate and aryl aldehydes has been rationalized as proceedingvia the erythro conformer of the oxyanion.

    • Synthesis ofα-aryloxy cinnamic acids

      G Bagavant M K Gurjar B H Patwardhan

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      The Perkin-Oglialoro reaction was used for the synthesis of α-aryloxycinnamic acids, but the yields were very low. The potassium tertiary butoxide catalysed condensation of aryloxyacetic ester and aldehydes leads to the formation ofα-aryloxycinnamic acids and its corresponding ester, in good yields through an “oxocyclic intermediate pathway”. The sodium ethoxide catalysed condensation however yields only the esters through an “aldol pathway”, which on saponification give α-aryloxycinnamic acids. These alternative synthetic approaches to Perkin-Oglialoro reaction products, afford excellent methods for the synthesis of α-aryloxycinnamic acids.

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