Cyclohexanone → N-Cyclohexyl-D-alanine methyl ester

Temperature

10 °C

To a suspension of D-Alanine methyl ester hydrochloride (16.0 g, 114.6 mmol) in dry dichloromethane (150 mL) was added potassium acetate (11.2 g, 114.6 mmol) and the reaction mixture stirred for ten minutes. The reaction mixture was then cooled to 10° C., cyclohexanone (11.8 mL, 114.6 mmol) was added, followed by sodium triacetoxyborohydride (30.3 g, 143.2 mmol) in portions over a period of ten minutes. Reaction mixture was stirred at room temperature for 16 h after which saturated sodium bicarbonate solution (60 mL) was added and stirred for another 30 minutes. The reaction mixture was further basified with aqueous sodium carbonate to pH=˜10. The organic layer was separated and the aqueous layer extracted with dichloromethane (3×75 mL). The organic layers were combined, washed with brine, dried over anhydrous sodium sulfate, and evaporated to give titled compound (yield: 80%). 1HNMR (300 MHz, CDCl3): δ 0.97-1.21 (m, 4H), 1.26 (d, J=6.9 Hz, 3H), 1.57-1.59 (m, 2H), 1.75-1.67 (m, 3H), 1.89-1.84 (m, 1H), 2.36-2.29 (m, 1H), 3.48 (q, J=6.9 Hz, 1H), 3.70 (s, 3H).

1. customReaction mixture
2. additionwas added
3. stirringstirred for another 30 minutes
4. customThe organic layer was separated
5. extractionthe aqueous layer extracted with dichloromethane (3×75 mL)
6. washwashed with brine
7. dry with materialdried over anhydrous sodium sulfate
8. customevaporated

ORD record

ord-a1badcf7a34d49b88d4db55dc72f76bf

Source dataset

uspto-grants-2016_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09351974B2