Abstract
A series of new spiro[3H-indole-3,2′-thiazolidine]-2,4′(1H)-diones (IV) and spiro[3H-indole-3,2′-tetrahydro-1,3-thiazine]-2,4′(1H)-diones (V) have been synthesized in 85–93% yield by the one-pot environmentally benign microwave induced technique involving the cyclocondensation of 3-arylimino-2H-indol-2-ones (III) with thioacids viz. mercapto aceticacid (a)/3-mercapto propionicacid (b) using montmorillonite KSF as inorganic solid support. Intermediates (III) were synthesized in situ by the reaction of indole-2,3-diones (I) and substituted anilines (II). The spiro compounds have been further subjected to solvent-free acetylation, aminoalkylation and thiation under microwave irradiation using solid supports. The synthesized compounds have been screened in vitro for antifungal activity against Rhizoctonia solani, Fusarium oxysporum, and Collectotrichum capsici, and antitubercular acivity against Mycobacterium tuberculosis.
Financial assistance from UGC, New Delhi is gratefully acknowledged. R.S. thanks CSIR, New Delhi for the award of SRF. We are also thankful to Tuberculosis Antimicrobial Acquisition and Coordinating Facility (TAACF), USA for antitubercular activity and Department of Pathology, Durgapura, Jaipur for antifungal screening. We also are grateful to the Director, RSIC, CDRI, Lucknow, India for providing mass spectra and elemental analyses.
Notes
∗Both and are D2O exchangeable.
∗Final temperature is measured by introducing a glass thermometer in the reaction mixture at the end of exposure to microwave irradiation.