Sodium Hydroxide → (2S,4R)-4-methanesulfonyloxy-2-(4-methylthiosemicarbazidocarbonyl)-1-(4-nitrobenzyloxycarbonyl)pyrrolidine

Participants

Reaction Steps

To a mixture of dimethylformamide (2.9 ml) and tetrahydrofuran (6 ml) was dropwise added phosphorus oxychloride (2.8 ml) at -5°~5° C. and the mixture was stirred at the same temperature for 30 minutes. To the mixture was added a solution of (2S,4R)-2-carboxy-4-methanesulfonyloxy-1-(4-nitrobenzyloxycarbonyl)pyrrolidine (9.65 g) in tetrahydrofuran (20 ml) at -5°~5° C., followed by stirring at the same temperature for 30 minutes. The mixture was dropwise added to a solution of 4-methylthiosemicarbazide (25 g) in a mixture of water (200 ml) and tetrahydrofuran (200 ml) at 0°-10° C. with sitrring, keeping the pH between 8-9 with 1N aqueous sodium hydroxide. The mixture was stirred at the same condition for 2 hours. Tetrahydrofuran was evaporated under reduced pressure to give precipitates. The precipitates were collected by filtration, washed with water and diisopropyl ether successively, and dried over phosphorus pentoxide to give (2S,4R)-4-methanesulfonyloxy-2-(4-methylthiosemicarbazidocarbonyl)-1-(4-nitrobenzyloxycarbonyl)pyrrolidine (9.61 g).

Provenance & Evidence