The acylation of 5H-2,3-benzodiazepines and 4H-thieno[2,3-d]- and 8H-thieno-[3,2-d]-[1,2]diazepines. Reactions with acid anhydrides and nucleophiles to give fused 7-substituted 1-acyl-1,2-diazepines

Abstract

The acylation of 4-phenyl-5H-2,3-benzodiazepine (1) and its thieno analogues (2) and (3) with acetic anhydride takes a different course from other 2,3-benzodiazepines having a hydrogen atom or a methyl group at position 4. The latter react at N-3 to give the 3-acyl derivatives (11) but 4-phenyl-2,3-benzodiazepine is acylated at N-2 to give the iminium acetate (12) which reacts with alcohols and thiols to give the derivatives (15) in high yield. The reaction of (12) with hydrogen chloride induces rearrangement to an isoquinoline N-imide (18).