Synthetic approaches to some new sulfur-containing heterocycles of anticipated immunosuppressive activity

Several new isolated or fused heterocyclic ring systems that accomodate the isothioureido functionality, often associated with immunosuppressive activity, were synthesized for possible use as immunosuppressive agents. Preparation of these anchored heterocycles was achieved via a multi-step synthesis starting with the key intermediate thiazolyl thiourea derivative (I). Structure of the newly synthesized products was confirmed using both of elemental and spectral analyses.