1,3-Dipolar cycloaddition of 3-phenylamino-5-phenylimino-1,2,4-dithiazole to 1-acyl-2-phenylacetylenes—A new route to functionalized 1,3-thiazole derivatives

3-Phenylamino-5-phenylimino-1,2,4-dithiazole reacted with 1-acyl-2-phenylacetylenes in ethanol or toluene on heating (78–80°C, 1 h) in chemo- and regioselective fashion to give previously unknown N -[5-acyl-3,4-diphenyl-1,3-thiazol-2(3 H )-ylidene]- N ′-phenylthioureas (yield 57–60%). The structure of N -[5-benzoyl-3,4-diphenyl-1,3-thiazol-2(3 H )-ylidene]- N ′-phenylthiourea was proved by X-ray analysis.