Electron Deficient Dienes.4.A Synthetic Equivalentof 4-Methyleneglutaconic Acid, its Mono and Diethyl Estersand their Use in a Concise General Synthesis of IsophthalicAcids and Isophthalates

Abstract

Reaction of a series of 2′-hydroxybenzophenone-3-carboxylic acid ethyl esters under Dakin reaction conditions affords isophthalic acid monoethyl esters, which can be converted into the corresponding diethyl isophthalates (6 examples) and isophthalic acid (1 example) by esterification and hydrolysis, respectively. This transformation renders the direct precursor of the benzophenones a synthetic equivalent of 4-methyleneglutaconic acid (4-methylenepent-2-enedioic acid) and its mono and diethyl esters.