反应详情

温度

35 °C

A mixture of 300 mg of 6-benzyl-6-aza-spiro[2.5]octan-4-one hydrochloride (1.19 mmol, 1 equiv.), 1.5 ml of 2-propanol and 28 ml of 30 mM aq. TRIS-HCl buffer (pH 8.1) was heated to 35° C. The pH was re-adjusted to 8.0. The reaction was started by adding β-NAD (1 mg; free acid; Roche Diagnostics Cat. No. 10 004 626) and ketoreductase KRED-NADH-117 (29.3 mg; Codexis [ex. Biocatalytics]). The suspension was stirred at 35° C. keeping the pH constant at 8.0 by the controlled addition (pH-stat) of 1.0 M aq. sodium hydroxide solution. After roughly 80 area % conversion and 1 d, further 2-propanol (0.3 ml), β-NAD (3 mg; free acid; Roche Diagnostics Cat. No. 10 004 626), ketoreductase K RED-NADH-117 (30 mg; Codexis [ex. Biocatalytics]) and magnesium chloride (12.7 mg) were added. After 4 d, 98.5 area % conversion and 5.9 ml consumption of 1.0 M aq. sodium hydroxide solution the reaction mixture was stopped by the addition of sodium chloride (9 g), ethyl acetate (30 ml) and filter aid (1 g Dicalite Speedex). The mixture was stirred 30 min. and filtered. The filtrate was extracted 3 times with 30 ml ethyl acetate. The combined organic phases were dried over sodium sulfate, filtered and concentrated under reduced pressure to provide the crude product in over 99.9% e.e. Purification by flash chromatography provided the title compound as a colorless oil.

1. custom98.5 area % conversion and 5.9 ml consumption of 1.0 M aq. sodium hydroxide solution the reaction mixture
2. additionwas stopped by the addition of sodium chloride (9 g), ethyl acetate (30 ml)
3. filtrationfilter aid (1 g Dicalite Speedex)
4. stirringThe mixture was stirred 30 min.
5. filtrationfiltered
6. extractionThe filtrate was extracted 3 times with 30 ml ethyl acetate
7. dry with materialThe combined organic phases were dried over sodium sulfate
8. filtrationfiltered
9. concentrationconcentrated under reduced pressure
10. customto provide the crude product in over 99.9% e.e
11. customPurification by flash chromatography