Multicomponent Coupling Reactions of Two N-Tosyl Hydrazones and Elemental Sulfur: Selective Denitrogenation Pathway toward Unsymmetric 2,5-Disubstituted 1,3,4-Thiadiazoles

A copper-mediated, three-component reaction between two different N-Ts hydrazones and elemental sulfur was developed, leading to a series of unsymmetric 2,5-disubstituted 1,3,4-thiadiazoles in moderate yields with good functional group compatibility. This procedure features the employment of elemental sulfur and the selective denitrogenation between aryl and alkyl aldehyde N-tosyl hydrazones, allowing rapid access to unsymmetric 2,5-disubstituted 1,3,4-thiadiazoles frameworks with chemical diversity and complexity.