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温度

0 °C

1-(tert-Butoxycarbonyl)-4-(4-fluorophenyl)piperidine-4-carboxylic acid (9.5 g, 29.3 mmol) was suspended in tetrahydrofuran (60 mL) and cooled to 0° C. To this solution was added borane tetrahydrofuran complex (1 M in tetrahydrofuran, 59 mL, 59 mmol) cautiously over 15 min. The reaction mixture was allowed to warm to room temperature overnight and then heated at reflux for 24 h. The mixture was cooled to 0° C., treated with excess methanol, diluted with ethyl acetate, washed with 1 N sodium hydroxide (2×), then brine (2×), dried over sodium sulfate, and concentrated. Column chromatography on silica gel (40% ethyl acetate/hexanes) gave 6.6 g (72%) as a white powder. 1H-NMR (CDCl3, 300 MHz) 7.24-7.29 (m, 2H), 7.00-7.05 (m, 2H), 3.66-3.71 (m, 2H), 3.49 (s, 2H), 2.96-3.05 (m, 2H), 2.06-2.10 (m, 2H), 1.69-1.77 (m, 2H), 1.40 (s, 9H). Mass spec.: 310.21 (MH)+.

1. temperatureto warm to room temperature overnight
2. temperatureheated
3. temperatureat reflux for 24 h
4. temperatureThe mixture was cooled to 0° C.
5. washwashed with 1 N sodium hydroxide (2×)
6. dry with materialbrine (2×), dried over sodium sulfate
7. concentrationconcentrated
8. customColumn chromatography on silica gel (40% ethyl acetate/hexanes) gave 6.6 g (72%) as a white powder