Lithium Chloride → tert-butyl N-[(2S)-1-hydroxy-3-phenylpropan-2-yl]carbamate

HRID 345010Notes

Reaction equation

HRID 345010 reaction equation
[CH3:1][C:2]([CH3:20])([O:4][C:5]([NH:7][C@H:8]([C:16](OC)=[O:17])[CH2:9][C:10]1[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=1)=[O:6])[CH3:3].[Cl-].[Li+].[BH4-].[Na+]>O1CCCC1.C(O)C>[CH3:3][C:2]([CH3:20])([O:4][C:5]([NH:7][C@@H:8]([CH2:9][C:10]1[CH:11]=[CH:12][CH:13]=[CH:14][CH:15]=1)[CH2:16][OH:17])=[O:6])[CH3:1]

Participants

6

Reactant 3

HCID 433294Lithium ChlorideHCID 4311764Sodium borohydrideHCID 9882138Boc-L-phenylalanine methyl ester

Product 1

HCID 2733675tert-butyl N-[(2S)-1-hydroxy-3-phenylpropan-2-yl]carbamateYield 100%

Reagents, catalysts & solvents 2

HCID 702EthanolSolventHCID 8028TetrahydrofuranSolvent

Procedure

To a solution containing N-[(1,1-dimethylethoxy)carbonyl]-L-phenylalanine, methyl ester (10 g, 35.8 mmole) dissolved in a mixture of tetrahydrofuran (190 ml) and absolute ethanol (190 ml) is added lithium chloride (6.09 g, 143.2 mmole). The resulting homogeneous solution is treated with sodium borohydride (5.42 g, 143.2 mmole) and the reaction is stirred at room temperature under argon for 24 hours. The reaction mixture is next filtered using ether (~700 ml) to rinse the filter cake. The resulting filtrate is rinsed with water (3×200 ml) and brine (200 ml), dried over magnesium sulfate, and concentrated in vacuo to give 9 g of crude product. Recrystallization from ether/hexane gives 7.59 g of the title D compound,; m.p. 94°-96°.

Workup

  1. filtrationThe reaction mixture is next filtered
  2. washto rinse the filter cake
  3. washThe resulting filtrate is rinsed with water (3×200 ml) and brine (200 ml)
  4. dry with materialdried over magnesium sulfate
  5. concentrationconcentrated in vacuo

Sources & evidence

ORD record
ord-089d1eaba0344d5fb0e917683340662d
Source dataset
uspto-grants-1991_10
Patent number
US05055466

Reaction notes

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