Hexane → (S)-2-(benzoyloxy)-4-(benzyloxycarbonylamino)butanoic acid

Participants

Reaction Steps

To a stirring solution of paromomycin sulfate (1, 76 g, 84 mmol) in water (209 mL) and tetrahydrofuran (1084 mL) at 0° C. was added a solution of sodium carbonate in water (254 mL, 218 mmol, 0.86 M), followed by the dropwise addition of benzyl chloroformate (120 mL, 840 mmol). Sodium bicarbonate (70.6 g, 840 mmol) was then added and the reaction was stirred for 3 hours. The two layers were separated and the organic layer was concentrated to a thick oil, which was diluted with ethyl acetate (400 mL) to give a total volume of 1.2 L. This was then dripped into hexane (9 L), and a precipitate formed. The filtrate was decanted off and concentrated to a white foam (2) (69.85 g, 64.5% yield).

Provenance & Evidence