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Pechmann Reaction

(Pechmann Condensation)

Published Online: 15 SEP 2010

DOI: 10.1002/9780470638859.conrr485

Comprehensive Organic Name Reactions and Reagents

Comprehensive Organic Name Reactions and Reagents

How to Cite

2010. Pechmann Reaction. Comprehensive Organic Name Reactions and Reagents. 485:2151–2156.

Publication History

  1. Published Online: 15 SEP 2010

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Abstract

This reaction is an acid-promoted synthesis of coumarin derivatives from the condensation of phenols and β-ketoesters or β-keto carboxylic acids and is generally known as the Pechmann reaction. This reaction, under acidic conditions, involves an esterification or transesterification, followed by a cyclization and dehydration. It has been found that the outcome of this reaction depends on the nature of phenols, β-keto esters, and condensation reagents. The study finds that only phenols with electron-donating groups at the meta-position of the hydroxy group readily undergo the Pechman condensation. On the other hand, the α-substituents and γ-substituents on β-keto esters retard this reaction. This reaction has general application in the preparation of coumarin derivatives.

Keywords:

  • phenols;
  • Lewis acids;
  • ultrasound irradiation;
  • β-keto esters