Acetic Acid → 6-Bromo-1'-(methylsulfonyl)spiro[indoline-3,4'-piperidin]-2-one

Participants

Reaction Steps

Cesium carbonate (3.4 g, 10.6 mmol) was added portionwise over a 20 minute period to a stirred solution of tert-butyl 6-bromo-2-oxoindoline-1-carboxylate (preparation 8a, 1.0 g, 3.2 mmol) and N,N-bis(2-iodoethyl)methanesulfonamide (preparation 12b, 1.42 g, 3.5 mmol) in N,N′-dimethylformamide (50 mL) under an argon atmosphere. After the addition the mixture was warmed to room temperature and stirred overnight. Acetic acid (0.2 mL) followed by ethyl acetate and water were added to the reaction mixture and the organic layer was separated, washed with water, dried (MgSO4) and evaporated. The residue was treated with a 5M solution of hydrogen chloride in 1,4-dioxane (25 mL) and the mixture was stirred and heated to 70° C. After 30 minutes, the mixture was concentrated in vacuo and the residue was purified by flash chromatography (98:2 dichloromethane/methanol) to give the title compound (0.33 g, 29%) as a pale yellow solid.

Provenance & Evidence