Synthesis of biologically important novel fluorinated spiro heterocycles under microwaves catalyzed by montmorillonite KSF

The arylidienes of fluorinated spiro thiazolidines (5) containing α,β-unsaturated function have been used as component of Micheal addition with equimolar amount of 2-aminopyridine (6a) to give novel fluorinated spiro [indole-3,2′-pyrido[1,2-a]thiazolo[5,4-e]pyrimidines] (7) in a single step under microwaves in presence of montmorillonite KSF as solid support. The new improved synthetic method for fluorinated spiro [indole-3,2′-thiazolo[4,5-d]pyrimidines] (8) has also been developed involving the reaction of (5) with thiourea under monomode microwave reactor. Comparison with conventional synthesis and multimode microwave oven indicated the enhanced yield with faster reactions under monomode microwave reactor. Structure–activity relationships between the chemical structures and the antimycobacterial, antifungal activity of the evaluated compounds are also discussed.

Graphical abstractNovel fluorinated spiro [indole-3,2′-pyrido[1,2-a]thiazolo[5,4-e]pyrimidines] (7) and spiro [indole-3,2′-thiazolo[4,5-d]pyrimidines] (8) have been synthesized under microwaves in presence of montmorillonite KSF. Structure–activity relationships between the chemical structures and the antimycobacterial, antifungal activity of the evaluated compounds are also discussed. Figure optionsDownload full-size imageDownload as PowerPoint slide