hydroxylamine-O-sulfonic acid → 7-Methylfuro[3,2-c]pyridine-2-sulfonamide

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Reaction Steps

To a solution of 7-methylfuro[3,2-c]pyridine (1.33 g, 10 mmol) in distilled tetrahydrofuran (20 ml), under a nitrogen atmosphere and cooled to -70° C., was added dropwise 0.7M lithium diisopropylamide in tetrahydrofuran (15.5 ml, 11 mmol) to give a gummy precipitate. After stirring for 0.5 hour, sulfur dioxide gas was bubbled over the reaction surface to give a white precipitate. After slowly warming this mixture to room temperature, hexane was added and the precipitate collected by filtration. This precipitate was washed with diethyl ether and air dried. The resultant lithium sulfinate salt (3.5 g) was dissolved in water (25 ml) and sodium acetate trihydrate (8.2 g, 60 mmol) and hydroxylamine-O-sulfonic acid (2.33 g, 20 mmol) were added. After stirring for 20 hours, the precipitated product was collected by filtration, then dissolved in ethyl acetate/methanol, dried over anhydrous sodium sulfate and filtered through a charcoal pad. The resultant solution was evaporated and the residue triturated with diethyl ether to give solid product (1.24 g, 58% yield). Recrystallization from ethyl acetate gave 1.1 g, m.p. 179.5°-181.5° C.

Provenance & Evidence