Efficient Microwave Enhanced Regioselective Synthesis of a Series of Benzimidazolyl/triazolyl Spiro [indole-thiazolidinones] As Potent Antifungal Agents and Crystal Structure of Spiro[3H-indole-3,2'-thiazolidine]-3'(1,2,4-triazol-3-yl)-2,4'(1H)-dione

A microwave-assisted three-component, regioselective one-pot cyclocondensation method has been developed for the synthesis of a series of novel spiro[indole-thiazolidinones] (6a-l) using an environmentally benign procedure at atmospheric pressure in open vessel. This rapid method produces pure products in high yields within few minutes in comparison to a conventional two-step procedure. The crystal structure of one representative compound has been determined by X-ray diffraction. The synthesized compounds have been screened 'in vitro' for antifungal activity against Rhizoctonia solani, Fusarium oxysporum and Collectotrichum capsici. All compounds have shown good activity against these pathogens.