Denitrocyclization in synthesis of dibenzo[b,f][1,4]thiazepin-11(10h)-ones and their derivatives

A convenient synthesis of the novel dibenzo[b,f][1,4]thiazepin-11(10H)-ones is reported. As a key step, the synthetic route includes intramolecular aromatic denitrocyclization of 2-(2,4-dinitro-phenylsulfanyl)-benzoic acid amides. Efficient procedures for denitrocyclization in the presence of different bases are developed. Reduction of the nitro group in the obtained heterocycles resulted in formation of primary amines, which were transformed into amides by acylation with different carboxylic acids. The synthesized compounds have a great potential of bioactivity and are useful objects for biomedicinal screening.