ChemInform Abstract: Preparation and Photolysis of Diaryl Esters of Acetylenedicarboxylic Acid.

Abstract

Abstract Two diaryl acetylenedicarboxylates 1 a,b have been prepared in moderate yields by direct reaction of acetylenedicarboxylic acid with the corresponding phenols catalyzed by sulfuric or p -toluenesulfonic acids and also through acetylenedicarbonyl chloride. The accompanying by-products have been characterized. Attempted esterification using N,N′-dicyclohexylcarbodiimide as condensing agent gives an asymmetric ester amide 11a and a substituted uracil 12a . Photolysis of the aryl esters 1 a,b in benzene solution affords the benzocoumaran-3-ones 14a,b . In the case of 1b , minor amounts of a polycyclic condensed 4-chromanone 17b have also been observed. These results shows that the nature of the substituent attached at the β-position of the C  C triple bond plays an important role in the cyclization of o -hydroxyaryl ethynyl ketones.