1H-Pyrrolo[2,3-b]pyridine-2,3-dione → 1H-Pyrrolo[2,3-b]pyridine-2,3-dione 3-[O-(2-fluoro-ethyl)-oxime]

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Reaction Steps

A solution of compound 134a (300 mg, 1.03 mmol) in DMSO (25 mL) was heated at 95° C. at 15 torr for 6.5 hours. The solution containing the corresponding 7-aza isatin was cooled to room temperature, followed by the addition O-(2-Fluoro-ethyl)-hydroxylamine hydrochloride (131 mg, 1.13 mmol). After stirring for 1 hour at room temperature the mixture was quenched with water and extracted with ethyl acetate (6×25 mL). The combined organic phases were washed with brine and dried over MgSO4. The solvent was removed in vacuo and the residue purified by flash column chromatography (gradient, 2% MeOH in methylene chloride to 3%) to give 1H-Pyrrolo[2,3-b]pyridine-2,3-dione 3-[O-(2-fluoro-ethyl)-oxime] (200 mg, 93%) as an orange solid that was further purified by trituration from diethyl ether-methylene chloride (1:1).

Provenance & Evidence