Participation of o-carboxylate groups in aromatic nucleophilic substitution

Abstract

2-Chloro-3,5-dinitrobenzoicacid (1a) reacts with phenols and alcohols in pyridineto give aryl and alkyl 3,5-dinitrosalicylates (2; R = aryl or alkyl), exclusively in most cases, and along with aryl 2-aryloxy-3,5-dinitrobenzoates (5; R¹= R²= aryl) in a few cases. Methyl 2-chloro-3,5-dinitrobenzoate (1b) furnishes methyl 2-aryloxy-3,5-dinitrobenzoates (5; R¹= Me, R²= aryl) and aryl salicylates (2; R = aryl). The formation of the aryl salicylates must involve participation of the o-carboxy and o-alkoxycarbonyl groups. The β-lactone (8) and the ortho-ester (14) are suggested as intermediates to explain the observed acylations.