The cyelodesulfurization of thio‐compounds. Part XVII. Synthesis of some novel 2‐substituted amino‐3,4‐dihydro‐5H‐1,3,4‐benzotriazepin‐5‐ones by cyelodesulfurization of thiosemicarbazides with dicyclohexylearbodiimide (DCCD)

Abstract

A simple method for the synthesis of a novel series of 2‐substituted amino‐3,4‐dihydro‐5H‐1,3,4‐benzotriazepin‐5‐ones (11–16) has been established through two routes. The first involving the cyelodesulfurization of the thiosemicarbazides (3–8) with DCCD and the second reacting mixtures of the acid hydrazide 1 with a variety of the isothiocyanates 2 and DCCD. The structure of the cyclized products was confirmed by nmr and mass spectra.

An Update on the Synthesis of Benzoxazoles

“…Omar et al [45] reported the synthesis of several 2-ethoxycarbonyl-benzoxazoles (76). They are synthesized in high yield by cyclodesulfurization of the corresponding thioureas and thiosemicarbazide derivatives with dicyclohexylcarbodiimide.…”

Synthesis of 4-Aryl-1,3,4-benzotriazepinones from Isatoic Anhydrides and Hydrazonyl Chlorides

“…Moreover, the cyclodesulfurization of 2-aminobenzoyl hydrazines with isothiocyanates has been reported to be another approach for the synthesis of 1,3,4benzotriazepinones. 8 However, due to the functional group restriction of starting materials, a synthetic limitation of this method exists with respect of narrow substrates scope. 1,3,4-Benzotriazepinones could also be synthesized from 2-aminobenzoic acid and hydrazonyl chloride through a two-step synthesis.…”

“…Cyanogen bromide and chloroformate have also been demonstrated to be effective in this condensation reaction with 2-aminobenzoyl hydrazines for synthesizing 1,3,4-benzotriazepinones. Moreover, the cyclodesulfurization of 2-aminobenzoyl hydrazines with isothiocyanates has been reported to be another approach for the synthesis of 1,3,4-benzotriazepinones . However, due to the functional group restriction of starting materials, a synthetic limitation of this method exists with respect of narrow substrates scope.…”