Gamma-Aminobutyric Acid → Dicyclohexylamine

4-Aminobutyric acid (5.16 g) was dissolved in 20 ml of water. To the resulting solution were added 8.4 ml of N-methylmorpholine and 11.08 g of 2-t-butoxycarbonyloxyimino-2-phenylacetonitrile in 50 ml of acetone. After stirring the resulting mixture overnight at room temperature, about a half of the solvent was distilled off. Water and ethyl acetate were added thereto and thoroughly mixed to separate the solution. The aqueous phase was washed with ethyl acetate, combined with the organic phase, and extracted with 5% aqueous sodium hydrogencarbonate. After combining the aqueous phases, ethyl acetate was added thereto and the pH was adjusted to about 3 with 6 N hydrochloric acid to separate the solution. The aqueous phase was extracted twice with ethyl acetate. The extracts were combined, washed with water, and dried over anhydrous magnesium sulfate. After removal of the desiccant, N,N-dicyclohexylamine was added thereto for crystallization. Crystals were collected by filtration, washed with ether, and dried to obtain 15.07 g of an N,N-dicyclohexylamine salt (yield 79%).

1. distillationabout a half of the solvent was distilled off
2. additionWater and ethyl acetate were added
3. additionthoroughly mixed
4. customto separate the solution
5. washThe aqueous phase was washed with ethyl acetate
6. extractionextracted with 5% aqueous sodium hydrogencarbonate
7. additionwas added
8. customto separate the solution
9. extractionThe aqueous phase was extracted twice with ethyl acetate
10. washwashed with water
11. dry with materialdried over anhydrous magnesium sulfate
12. customAfter removal of the desiccant, N,N-dicyclohexylamine
13. additionwas added
14. customfor crystallization
15. filtrationCrystals were collected by filtration
16. washwashed with ether
17. customdried

ORD record

ord-7013228989ff41b88caba7067d5d04dc

Source dataset

uspto-grants-2001_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06291198B1