Sodium borohydride → (R)-3-(((benzyloxy)carbonyl)amino)-4-hydroxybutanoic acid

A solution of (R)-benzyl 2,5-dioxotetrahydrofuran-3-ylcarbamate (INTERMEDIATE 1, 53.28 g, 213.79 mmol) in THF (330 ml) was added over a 4 hour period using an additional funnel to a mixture of sodium borohydride (8.09 g, 213.79 mmol) in THF (330 ml) at 0° C. After the addition was complete, the mixture was warmed to room temperature and stirred for 2 hours. The solution was then concentrated under reduced pressure to ¼ of the original volume, cooled to 0° C., and carefully quenched by the slow addition of water (400 ml). The mixture was acidified to pH 4 with 1N aqueous hydrochloric acid and extracted with Et2O (5×300 ml). The combined organic layers were dried (Na2SO4) and concentrated in vacuo to provide the title product (45.9 g, yield: 85%).

1. additionAfter the addition
2. concentrationThe solution was then concentrated under reduced pressure
3. temperaturecooled to 0° C.
4. customcarefully quenched by the slow addition of water (400 ml)
5. extractionextracted with Et2O (5×300 ml)
6. dry with materialThe combined organic layers were dried (Na2SO4)
7. concentrationconcentrated in vacuo

ORD-Eintrag

ord-1d11e833b2134a36b33494a7900eec61

Quelldatensatz

uspto-grants-2015_04

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US09018381B2