A facile and efficient addition reaction of nitrogen-containing heterocyclic compounds with DMAD under neat conditions

摘要

A simple and efficient method was developed for the reaction of dimethyl acetylenedicarboxylate with benzothiazole, isoquinoline, quinoline, 3-bromopyridine, pyridine, benzoxazole, benzimidazole, and 5,6-dimethyl benzimidazole for the high-yield synthesis of the related heterocyclic products (1-8) in very short reaction time under neat procedure. The reaction of isoquinoline, 3-bromopyridine, and pyridine afforded to diastereomeric mixtures of products 2, 4, and 5, respectively. However, only one isomer of products 1, 3, 6, 7, and 8 were identified from the reaction of benzothiazole, quinoline, benzoxazole, benzimidazole, and 5,6-dimethyl benzimidazole, respectively. Benzotriazole afforded to product 9 under these conditions. For comparison, the reactions were examined in different reaction mediums and/or under microwave irradiation.