Novel Fluorinated Spiro [Indole-indazolyl-thiazolidine]-2,4′-diones: Design and Synthesis

The reaction of indol-2,3-diones ( 1a–i ) with 5-aminoindazole ( 2 ) has resulted in the formation of hitherto unknown 3-(indazol-5-yl)iminoindol-2-ones ( 3a–i ) in quantitative yields which, on 1,3-dipolar cyclocondensation with mercaptoacetic acid ( 4 ), has afforded a series of new spiro heterocycles, 3′-(indazol-5-yl) spiro[3H, indol-3, 2′ -thiazolidine]-2,4′-diones* ( 5a–i ).

Keywords:

• molecular modification
• Schiff's bases
• Spiro[indole-indazolyl-thiazolidine]-2,4′-dione

Acknowledgments

The authors are thankful to Department of Science and Technology (DST), New Delhi for financial assistance.

P. K. and R. S. are grateful to Council of Scientific and Industrial Research (CSIR), New Delhi for grant of Senior and Junior Research Fellowships respectively.

Presented at IUPAC International Conference on Biodiversity and Natural Products: Chemistry and Medical Applications, Jan 26–31, 2004, New Delhi, India.