Lithium borohydride → [6-(4-Hydroxy-2-hydroxymethyl-pyrrolidin-1-yl)-6-oxo-hexyl]-carbamic Acid Benzyl Ester

Temperatur

0 °C

To the solution of lithium borohydride (1.34 g) in anhydrous tetrahydrofuran (50 mL) was added a solution of methyl ester 2a in THF (50 mL) over a period of 30 mins at 0° C. After the addition the reaction mixture was brought to room temperature and stirred further under argon. The completion of the reaction was ascertained by TLC after 4 h. (Rf=0.4 in 10% MeOH/CHCl3). The reaction mixture was evaporated to dryness and cooled to 0° C. To the residue 3N HCl (100 mL) was added slowly. After stirring for 30 mins the product was extracted with dichloromethane (3×100 mL). The combined organic layer was washed with brine and dried over sodium sulfate. Organic layer was filtered and evaporated to dryness. Compound 3a was purified by column chromatography first by eluting with ethyl acetate to remove impurities followed by dichloromethane/methanol (5%) gave 14.3 g (70%)

1. additionAfter the addition the reaction mixture
2. customwas brought to room temperature
3. customThe reaction mixture was evaporated to dryness
4. additionTo the residue 3N HCl (100 mL) was added slowly
5. stirringAfter stirring for 30 mins the product
6. extractionwas extracted with dichloromethane (3×100 mL)
7. washThe combined organic layer was washed with brine
8. dry with materialdried over sodium sulfate
9. filtrationOrganic layer was filtered
10. customevaporated to dryness
11. customCompound 3a was purified by column chromatography first
12. washby eluting with ethyl acetate
13. customto remove impurities
14. customgave 14.3 g (70%)

ORD-Eintrag

ord-a8436bf428cf4c1eb156df24f8c66013

Quelldatensatz

uspto-grants-2013_08

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08507661B2