Ligand‐Free Cu(0) Catalyzed C–S Cross‐Coupling Ullmann‐type Reaction: S‐Arylation of 5,4‐Disubstituted‐2,4‐dihydro‐3H‐1,2,4‐triazole‐3‐thiones.

Studied the S-arylation of 5,4-disubstituted-2,4-dihydro-3H-1,2,4-triazole-3-thiones under ligand-free Cu(0) catalyzed Ullmann-type reaction conditions. Optimum reaction conditions and the effect of substituents in the arylating agent on the course of the reaction were revealed. The presence of EWG in aryl halides allows the reaction to be carried out without a catalyst, in particular, the presence of EWG in the para position of the aromatic ring has a limiting effect on the leaving group independent of the halogen.