Heterocyclic compounds from 3,3‐dimercapto‐1‐aryl‐2‐propen‐1‐ones. Note 3. Condensation with N‐methyl‐o‐phenylenediamine and N‐benzyl‐o‐phenylenediamine

Two seven‐membered ring compounds and three five‐membered ring compounds were obtained by reaction in hot xylene of 3,3‐dimercapto‐l‐phenyl‐2‐propen‐1‐one (1) with N‐alkyl‐o‐phenylenediamines (2). Compounds isolated were the 4‐phenyl‐5‐alkyl‐1,5‐dihydro‐2H‐1,5‐benzodiazepine‐2‐thiones (3) the 1‐alkyl‐4‐phenyl‐1,3‐dihydro‐2H‐1,5‐benzodiazepine‐2‐thiones (4), the 1‐alkyl‐2‐phenacylbenzimidazoles (5), the 1‐alkyl‐2‐phenylbenzimidazoles (6) and the 1‐alkyl‐2‐methylbenzimidazoles (7). The structures of these compounds were elucidated from their chemical reactivity and their nmr and ir spectra.