Ring-expansion of fused bicyclic aromatic azides; synthesis of 8H-thieno[2,3-c]azepines by photolysis of 6-azidobenzo[b]thiophens in diethylamine

Abstract

Photolysis of certain 6-azidobenzo[b]thiophens in an excess of diethylamine gave a mixture of a 7-amino-6-diethylaminobenzo[b]thiophen and a 6-diethylamino-8H-thieno[2,3-c]azepine, or either of these compounds depending on the reaction conditions.