The synthesis of some new sulfur-bearing various heterocyclic systems derived from asymmetrical N,N `-disubstituted thiourea derivatives

The heterocyclization of an asymmetrical N , N `-disubstituted thiourea (1a-d) in ring closure reactions with Br-2/AcOH, ethyl chloroacetate, diethyl oxalate, diethyl malonate, and hydrazine hydrate led to the direct formation of sulfur-bearing various heterocyclic systems (2-8) in which the thiaenolization is toward the aryl group. The synthetic work and reactivity investigations have been well supported by standard modern spectroscopic techniques (IR, H-1 NMR, C-13 NMR, mass spectrum, and microanalysis).