L-Alanine → Tert-butoxycarbonylalanine

Triethylamine (1.68 ml.) was added to a suspension of L-alanine (0.89 g.) in a mixture of water (5 ml.) and tert-butyl alcohol (5 ml.) to give homogeneous solution. To the solution was added diethyl 2-tert-butoxycarbonyloxyiminomalonate (4.0 g.) and the mixture was stirred for 1 hour at room temperature. tert-Butyl alcohol was distilled off from the reaction mixture under reduced pressure and to the residue were added ether and a 5% sodium bicarbonate aqueous solution, after which the mixture was adjusted to pH 7 with a citric acid aqueous solution. The aqueous layer was separated and ethyl acetate was added thereto, and the mixture was adjusted to pH 3 with a citric acid aqueous solution. The mixture was shaken enough and the ethyl acetate layer was separated, washed with water and dried. The solution was concentrated under reduced pressure and the residue was recrystallized from a mixture of ether and petroleum ether to give N-tert-butoxycarbonyl-L-alanine (1.59 g.), mp 82° to 84° C.

1. customto give homogeneous solution
2. distillationtert-Butyl alcohol was distilled off from the reaction mixture under reduced pressure and to the residue
3. additionwere added ether
4. customThe aqueous layer was separated
5. additionethyl acetate was added
6. stirringThe mixture was shaken enough
7. customthe ethyl acetate layer was separated
8. washwashed with water
9. customdried
10. concentrationThe solution was concentrated under reduced pressure
11. customthe residue was recrystallized from a mixture of ether and petroleum ether

ORD record

ord-d0b76222ed104c57bb8ef33230a9807f

Source dataset

uspto-grants-1977_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04010178