Reaction #49170

Reaction equation

lithium borohydride

methyl ester

1-(6-Benzyloxycarbonylamino-hexanoyl)-4-hydroxy-pyrrolidine-2-carboxylic acid methyl ester

→

[6-(4-Hydroxy-2-hydroxymethyl-pyrrolidin-1-yl)-6-oxo-hexyl]-carbamic acid benzyl ester

Solvents

tetrahydrofuran

THF

MeOH CHCl3

Conditions

Workup

1. 1
   workup.ADDITIONAfter the addition the reaction mixture
2. 2
   Otherwas brought to room temperature
3. 3
   OtherThe reaction mixture was evaporated to dryness
4. 4
   workup.ADDITIONTo the residue 3N HCl (100 mL) was added slowly
5. 5
   Extractionwas extracted with dichloromethane (3×100 mL)
6. 6
   WashThe combined organic layer was washed with brine
7. 7
   Dryingdried over sodium sulfate
8. 8
   FiltrationOrganic layer was filtered
9. 9
   Otherevaporated to dryness
10. 10
    OtherCompound 3a was purified by column chromatography first
11. 11
    Washby eluting with ethyl acetate
12. 12
    Otherto remove impurities
13. 13
    Othergave 14.3 g (70%)

Procedure

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 stiired 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%).

Source