反应详情

温度

25 °C

To a solution of cis-2-amino-cyclohexanecarboxylic acid ethyl ester hydrochloride (2.80 g, 12.81 mmol) in tetrahydrofuran (100 mL) at 25° C. was added magnesium sulfate (4.0 g), triethylamine (1.36 g, 13.48 mmol), and 4-fluorobenzaldehyde (3.26 g, 26.29 mmol) sequentially. The reaction was stirred at 25° C. for 16 h. The mixture was passed through a short pad of Celite and the filtrate was concentrated and dried in vacuo. The residue was re-dissolved in methanol (100 mL) at 25° C. To this solution was slowly added sodium borohydride (1.0 g, 26.29 mmol). The mixture was stirred at 25° C. for 1 h. It was then poured into a 1/2 saturated aqueous sodium bicarbonate solution and the mixture was extracted into ethyl acetate (3×100 mL). The organic layer was dried over sodium sulfate, filtered, and concentrated in vacuo to afford a clear oil. Purification by flash column chromatography (Teledyne Isco RediSep Column; 0-50% ethyl acetate in hexanes) afforded the desired product, 2-(4-fluoro-benzylamino)-cyclohexanecarboxylic acid ethyl ester (4.47 g, 16.0 mmol, >100%, product still contains ethyl acetate), as a clear oil which was directly used in the next step. LC-MS (ESI) calcd for C16H22FNO2 279.16, found 280.0 [M+H+].

1. concentrationthe filtrate was concentrated
2. customdried in vacuo
3. dissolutionThe residue was re-dissolved in methanol (100 mL) at 25° C
4. stirringThe mixture was stirred at 25° C. for 1 h
5. extractionthe mixture was extracted into ethyl acetate (3×100 mL)
6. dry with materialThe organic layer was dried over sodium sulfate
7. filtrationfiltered
8. concentrationconcentrated in vacuo
9. customto afford a clear oil
10. customPurification by flash column chromatography (Teledyne Isco RediSep Column; 0-50% ethyl acetate in hexanes)