Abstract
A reaction of appropriate indol-2,3-diones with 4-aminoantipyrine has resulted in the formation of hitherto unknown 3-(2,3-dimethyl-5-oxo-1-phenyl-3-pyrazolin-4-yl-imino)-indol-2-ones in quantitative yields which upon cyclocondensation with mercaptoacetic acid afforded a series of new spiro heterocycles 3′-(2,3-dimethyl-5-oxo-1-phenyl-3-pyrazolin-4-yl) spiro[3H-indol-3,2′-thiazolidine]-2,4′-diones.
Acknowledgment
We thank Danish International Development Agency (DANIDA, Denmark) for the financial support.