Versatile Synthesis of N,S-Heterocycles Containing the Antipyrine Moiety

A series of novel sulfide derivatives of expected biological activity were synthesized via the reaction of 4-(chloroacetyl)antipyrine (1) with several sulfur nucleophiles. The quantitatively available 2-aminothiazole derivatives 10 and 11 were coupled with pyrazolopyridinyl and aromatic diazonium salts to furnish a new series of the corresponding pyrazolopyridinylazo and arylazo-thiazole dyes 12 and 13. The reaction of 4-(cyanoacetyl)antipyrine (14) with phenyl isothiocyanate afforded the nonisolable adduct 15, which was used as a precursor for the synthesis of polyfunctionally substituted ketene N,S-acetal, dihydrothiazole, and thiazolidinone ring systems.

Keywords:

• Antipyrine
• sulfur nucleophiles
• aminothiazole
• ball-milling
• azo coupling
• phenyl isothiocyanate
• ketene N,S-acetal
• dihydrothiazole
• thiazolidin-5-one