Citric Acid → Benzyl (3S)-3-[(tert-butoxycarbonyl)(methyl)amino]-3-methylpyrrolidine-1-carboxylate

Participants

Reaction Steps

Benzyl (3S)-3-[(tert-butoxycarbonyl)amino]-3-methylpyrrolidine-1-carboxylate (I-346) (400 mg, 1.20 mmol) and methyl iodide (112 μl, 1.79 mmol) were dissolved in dimethylformamide (12 ml), and with cooling with ice, sodium hydride (55% w/w) (62.6 mg, 1.44 mmol) was added, followed by stirring for 2 hours with cooling with ice. With cooling with ice, aqueous 10% citric acid solution was added to the reaction liquid, followed by extraction with ethyl acetate, and the obtained organic layer was washed with water and saturated brine. After drying over anhydrous sodium sulfate, the insoluble matter was separated by filtration, and the residue obtained by concentration was purified by silica gel column chromatography (eluent, n-hexane:ethyl acetate=2:1, v/v) to obtain the entitled compound (367 mg, 88%) as a colorless oily substance.

Provenance & Evidence