Iodine assisted synthesis of CF3 appended spirodihydrofuryl/cyclopropyl oxindoles by changing the active methylene sources

Abstract

This paper describes the synthesis of two distinct types of CF₃-containing spirooxindoles by varying the active methylene sources. The reaction was carried out in DMSO, assisted by molecular iodine and Na₂CO₃via systematic application of Michael reaction and iodine mediated cyclisation. With 5-methyl-2,4-dihydro-3H-pyrazol-3-one as the methylene source, the final products obtained were spirodihydrofuropyrazolyl oxindoles, whereas 1H-indene-1,3(2H)-dione as the methylene source gave the final compounds spirocyclopropyl oxindoles. Modest to good yields were obtained for both the spiro systems.