4-Methylmorpholine → N-[(1,1-Dimethylethoxy)carbonyl]-D-alanine 2,5-dioxo-1-pyrrolidinyl ester

Compound (1) was dissolved in dichloromethane (20 ml.) and N-methyl-morpholine (308 mg.) was added. This solution was cooled in a dry ice-acetone bath (-17°~-19° C.) under stirring, and to the solution, isobutylchlorocarbonate (417 mg.) was added. The reaction mixture was allowed to react for 20 minutes at the same temperature. To the resulting reaction mixture was added to the solution of Compound (2) (1.41 g.) in a mixture of dichloromethane (40 ml.) and N,N-dimethylformamide (4 ml) containing bis (trimethylsilyl)acetamide (3 ml.). The reaction mixture was stirred for 2 hours at -18° C. -10° C. and concentrated under reduced pressure to give an oily residue, which was dissolved in ethylacetate (100 ml.) and washed with 0.5N-Hcl. The organic layer was washed with brine and dried over MgSO4. Evaporation of the solvent gave a white foam which was throughly washed with ether to afford Compound (3) (2.42 g.) as white powder, mp. 145°~149° C. (decomp.)

1. temperatureThis solution was cooled in a dry ice-acetone bath (-17°~-19° C.)
2. customto react for 20 minutes at the same temperature
3. customTo the resulting reaction mixture
4. stirringThe reaction mixture was stirred for 2 hours at -18° C. -10° C.
5. concentrationconcentrated under reduced pressure
6. customto give an oily residue, which
7. washwashed with 0.5N-Hcl
8. washThe organic layer was washed with brine
9. dry with materialdried over MgSO4
10. customEvaporation of the solvent
11. customgave a white foam which
12. washwas throughly washed with ether

ORD-Eintrag

ord-6559c0c6130249229e6093ec150a32be

Quelldatensatz

uspto-grants-1984_07

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US04458078