Triethylamine → (2S,4R)-2-(2-hydroxyethyloxymethyl)-4-methanesulfonyloxy-1-(4-nitrobenzyloxycarbonyl)pyrrolidine

A solution of isobutyl chloroformate (1.08 ml) in tetrahydrofuran (3 ml) was dropwise added to a solution of (2S,4R)-2-(carboxymethyloxymethyl)-4-methanesulfonyloxy-1-(4-nitrobenzyloxycarbonyl)pyrrolidine (2.4 g) and triethylamine (1.55 ml) in tetrahydrofuran (50 ml) at -10°~5° C., and the mixture was stirred at the same temperature for 0.5 hour. The precipitate was filtered off. To the filtrate was added sodium borohydride (0.7 g) and water (30 ml) at 0° C. After 1 hour, glacial acetic acid (3 ml) was added to the mixture. The mixture was poured into a mixture of water (50 ml) and ethyl acetate (50 ml). The organic layer was separated, washed with water, saturated aqueous sodium hydrogen carbonate and brine in turn, dried over magnesium sulfate, and concentrated under reduced pressure to give a syrup. The syrup was subjected to a column chromatography on silica gel (30 g) and eluted with a mixture of methanol and chloroform (5:95 V/V) to give (2S,4R)-2-(2-hydroxyethyloxymethyl)-4 -methanesulfonyloxy-1-(4-nitrobenzyloxycarbonyl)pyrrolidine (2.10 g).

1. filtrationThe precipitate was filtered off
2. additionTo the filtrate was added sodium borohydride (0.7 g) and water (30 ml) at 0° C
3. waitAfter 1 hour
4. additionglacial acetic acid (3 ml) was added to the mixture
5. additionThe mixture was poured into a mixture of water (50 ml) and ethyl acetate (50 ml)
6. customThe organic layer was separated
7. washwashed with water, saturated aqueous sodium hydrogen carbonate and brine in turn
8. dry with materialdried over magnesium sulfate
9. concentrationconcentrated under reduced pressure
10. customto give a syrup
11. washeluted with a mixture of methanol and chloroform (5:95 V/V)

ORD record

ord-1df70fa7d66c4c8ba95d9784357c262a

Source dataset

uspto-grants-1991_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04983596