反应详情

温度

0 °C

A solution of 3-pyrazolidinecarboxylic acid, 1,1-dimethylethyl ester (10.935 g., 63.5 mmol.) in dry acetonitrile (90 ml.) was cooled to 0° C. (ice-salt bath) and treated with dry pyridine (11.0 ml.) followed by a solution of benzylchloroformate (12.54 g., 10.5 ml., 69.9 mmol.) in dry acetonitrile (25 ml.). The reaction was stirred at 0° C. for 3 hours, evaporated to dryness and the syrup obtained was redissolved in ethyl acetate (250 ml.). The solution was washed with 5% sodium bicarbonate (2×25 ml.) and brine (25 ml.), dried (anhydrous sodium sulfate), filtered, evaporated to dryness and dried in vacuo. The crude product mixture was chromatographed on a silica gel column (Merck), eluting the column with ethyl acetate:hexane mixtures (1:4; 1:2) to give 11.144 g. of title product as a syrup.

1. customevaporated to dryness
2. customthe syrup obtained
3. washThe solution was washed with 5% sodium bicarbonate (2×25 ml.) and brine (25 ml.)
4. dry with materialdried (anhydrous sodium sulfate)
5. filtrationfiltered
6. customevaporated to dryness
7. customdried in vacuo
8. customThe crude product mixture was chromatographed on a silica gel column (Merck)
9. washeluting the column with ethyl acetate
10. customhexane mixtures (1:4; 1:2) to give 11.144 g