4-Methylmorpholine → N-[(1,1-Dimethylethoxy)carbonyl]-L-alanyl-L-proline phenylmethyl ester

Temperature

0 °C

Boc-Ala-OH (56.76 g, 0.3 mole) dissolved in acetonitrile (500 mL) and cooled to 0° C. before adding NMM (32.97 mL). The solution was cooled to -15°±1° C. and isobutyl chloroformate (41.01 mL) was added slowly under stirring while maintaining the temperature at -15° C. After stirring the reaction mixture for 10 min at this temperature, HOBt (40.56 g, 0.3 mole) was added. The reaction mixture was stirred for an additional 10 min and a pre-cooled solution of HC; H-Pro-OBzL (72.5 g, 0.3 mole) and NMM (32.97 mL) in DMF (600 mL) were added slowly. After 20 min, the pH of the solution was adjusted to 8 by the addition of NMM and the reaction was continued overnight. The solvent was removed under reduced pressure and the residual DMF solution was poured into about 2000 mL of ice-cold 90% saturated KHCO3 solution and stirred for 30 min. Since the peptide did not precipitate out, it was extracted into CHCl3, which was washed with water, 20% citric acid, and water, and dried over Na2SO4, and the solvent was washed with water, 20% citric acid, and water, before drying over Na2SO4, and removing solvent under reduced pressure. The resulting oil was recrystallized from ether/petroleum ether. The crystals were filtered, washed with petroleum ether, and dried to obtain 79.9 g (yield, 70.75 %) of I. R1f, 0.5; R2f 0.61.

1. temperatureThe solution was cooled to -15°±1° C.
2. temperaturewhile maintaining the temperature at -15° C
3. additionwas added
4. stirringThe reaction mixture was stirred for an additional 10 min
5. waitthe reaction was continued overnight
6. customThe solvent was removed under reduced pressure
7. additionthe residual DMF solution was poured into about 2000 mL of ice-cold 90% saturated KHCO3 solution
8. stirringstirred for 30 min
9. customSince the peptide did not precipitate out
10. extractionit was extracted into CHCl3, which
11. washwas washed with water, 20% citric acid, and water
12. dry with materialdried over Na2SO4
13. washthe solvent was washed with water, 20% citric acid, and water
14. dry with materialbefore drying over Na2SO4
15. customremoving solvent under reduced pressure
16. customThe resulting oil was recrystallized from ether/petroleum ether
17. filtrationThe crystals were filtered
18. washwashed with petroleum ether
19. customdried
20. customto obtain
21. custom79.9 g (yield, 70.75 %) of I

ORD record

ord-ca67efdd8d104e7d81ee4003787d5bba

Source dataset

uspto-grants-1996_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05527610