L-Aspartic Acid → N-(tert-butoxycarbonyl)-L-aspartic acid

To a solution of 1.33 g (10 mmol) of L-aspartic acid in a dioxane/water (1:1) mixture (30 ml), 4.2 ml (30 mmol) of triethylamine are added, and the mixture is stirred until solution is complete (approximately 10 min). 2.85 g (10 mmol) of tert-butyl 1,2,2,2-tetrachloroethyl carbonate are then added and the mixture is stirred for 6 hours at 20° C. 50 ml of water are then added and the mixture is extracted with 2×20 ml of ethyl acetate. The aqueous phase is acidified (pH 2-3) with NHCl, and then extracted with 3×30 ml of ethyl acetate. The extract is washed with saturated NaCl solution, dried over MgSO4 and evaporated. The product obtained is crystallised in ethyl acetate and petroleum ether. 1.4 g (60% yield) of the expected acid is obtained. ##STR60##

1. custom(approximately 10 min)
2. stirringthe mixture is stirred for 6 hours at 20° C
3. extractionthe mixture is extracted with 2×20 ml of ethyl acetate
4. extractionextracted with 3×30 ml of ethyl acetate
5. washThe extract is washed with saturated NaCl solution
6. dry with materialdried over MgSO4
7. customevaporated
8. customThe product obtained
9. customis crystallised in ethyl acetate

ORD-Eintrag

ord-0c0661338a584907b09ee85e49489e40

Quelldatensatz

uspto-grants-1988_02

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US04725680