Mechanism of the Formation of 1,2,4-Thiadiazoles by Condensation of Aromatic Thiroamides and of N-Substituted Thioureas

摘要

The condensation reaction of thiobenzamide,(as well as thionicotinamide and isothionicontinamide)in the presence of dimethyl sulfoxide and of an acid, affords 2,5-diphenyl-1,2,4-thiadiazole. Under the same experimental conditions, N-subsituted thioureas are also condensed to 1,2,4-thiadiazole derivatives; their structure is ascertained by spectroscopic properties and by X-ray diffraction.Some information on the mecahnism of thiadiazoles formation form both stating classes of compounds, thiobenzamides and N-substituted thiourea, is collected and discussed.