Convenient Synthesis of the Derivatives of Pyrazole Sulfides by Copper-Catalysed Coupling of 5-Chloropyrazole-4-Aldehydes with Disulfides

A cross-coupling reaction of diaryl disulfides with substituted 5-chloropyrazole-4-aldehydes has been developed using 10 mol% of copper powder as the catalyst and caesium carbonate as the base, in DMSO at 90°C for 5–15 h under an atmosphere of nitrogen to give a series of new functionalised pyrazole sulfides in good to excellent yields (71–94%).