Dimethylformamide → Boc-Ala-Ala-NH-(CH2)3-Br

Temperatur

25 °C

To a cold (−15° C.) solution of Boc-Ala-Ala-OH (908 mg, 3.5 mmol) and NMM (570 μl, 5.23 mmols) in THF (15 ml) was added ECF (341 μl, 3.6 mmols) under N2 atmosphere and vigorously stirred. After 2 min of stirring, a solution of 1-amino-3-propylbromide hydrobromide (976 mg, 4.90 mmols) in a mixture of THF:DMF (4 mL: 3 mL) was added to the mixture followed by NMM (951 μl, 8.73 mmols) and stirred. After 10 min the mixture was warmed to 25° C. and stirred for further 8 h. THF was removed under reduced pressure and the resulting viscous solution was diluted with water (10 mL) and thoroughly extracted with ethyl acetate. The combined organic extracts were washed with 5 ml saturated citric acid, 5 ml saturated NaHCO3 and dried over by Na2SO4 and concentrated to give a residue, which was purified by silica gel flash column chromatograph (EtOAc:Hexane—3:7) to give the desired product as a solid (m.p. 146° C.) in good yields (1.022 g, 78%). (TLC:EtOAc—Rf—0.39).

1. stirringAfter 2 min of stirring
2. stirringstirred
3. stirringstirred for further 8 h
4. customTHF was removed under reduced pressure
5. additionthe resulting viscous solution was diluted with water (10 mL)
6. extractionthoroughly extracted with ethyl acetate
7. washThe combined organic extracts were washed with 5 ml saturated citric acid, 5 ml saturated NaHCO3
8. dry with materialdried over by Na2SO4
9. concentrationconcentrated
10. customto give a residue, which
11. customwas purified by silica gel flash column chromatograph (EtOAc:Hexane—3:7)

ORD-Eintrag

ord-888d044e8a6e4c1c9996f0dbca0e4de5

Quelldatensatz

uspto-grants-2014_09

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08835602B2