Synthesis of the first novel pyrazole thioglycosides as deaza ribavirin analogues

This study reports a novel and efficient method for the synthesis of the first reported novel class of thiopyrazoles and their corresponding thioglycosides. These series of compounds were designed through the reaction of hydrazine derivatives with sodium dithiolate salt 2 in EtOH at ambient temperature to give the corresponding sodium 5-amino-4-cyano-1H-pyrazole-3-thiolates 4a-d. The latter compounds were treated with α-acetobromoglucose 6a and α-acetobromogalactose 6b in DMF at ambient temperature to give in an excellent yields the corresponding pyrazole S-glycosides 7a-h. Ammonolysis of the pyrazole thioglycosides 7a-h afforded the corresponding free thioglycosides 8a-h.