Abstract
The reaction of indole-2,3-dione (1a) and/or 1-methylindole-2,3-dione (1b) with mercaptoacetic acid in the presence of 4-toluenesulfonic acid as a catalyst afforded spiro[indoline-3,2′-[1,3]oxathialane]-2,5′-diones (2a, b). Compounds 2a and/or 2b were reacted with the appropriate aliphatic and/or aromatic primary amines to give compounds 3a-j. The reaction of 2a, b with hydrazine hydrate, phenylhydrazine and p-nitrophenylhydrazine yielded spiroderivatives 4a-c. Friedel-Crafts reactions of 2a and 2b with arenes in the presence of aluminium chloride catalyst afforded spiroindoline isothiochroman derivatives 5a-h.