An efficient synthesis of 1,5-thiadiazepines and 1,5-benzodiazepines by microwave-assisted heterocyclization

A novel and efficient method for the synthesis of substituted thiazepines and diazepines has been developed. A simple one-pot reaction of chalcones 1a-f with 1-amino-2-mercapto-5-phenyl-1,3,4-triazole and o-phenylenediamine in the presence of a catalytic amount of sodium acetate under microwave irradiation gave 2-(3,8-diphenyl-7,8-dihydro[1,2,4]triazolo[3,4-b][1,3,4]thiadiazepin-6-yl)phenoles 2a-f and 2-(2-phenyl-2,3-dihydro-1H-1,5-benzodiazepin-4-yl)phenoles 3a-f, respectively. The structure of all the synthesized compounds was elucidated on the basis of elemental analysis, IR, H-1 and C-13 NMR, and mass spectral data.