Citric Acid → 5(S)-(Boc-Amino)-4(S)-hydroxy-6-[p-(2-methoxyethoxy)phenyl]-2(R)-[(p-benzyloxyphenyl)methyl]hexanoic acid

Participants

Reaction Steps

3.85 g (6.68 mmol) of 5(S)-[1(S)-(Boc-amino)-2-[p-(2-methoxyethoxy)phenyl]ethyl]-3(R)-[(p-benzyloxyphenyl)methyl]dihydrofuran-2-(3H)-one in 107 ml of dimethoxyethane and 54 ml of water are hydrolysed, under a protective gas, with 26.5 ml of a 1M lithium hydroxide solution. After 17 h at RT, the reaction mixture is treated with an ice-cold mixture of 324 ml of sat. NH4Cl solution, 27 ml of 10% citric acid solution and 134 ml of methylene chloride. Methanol is added in order to dissolve the product completely. The aqueous phase is separated off and extracted 2× with methylene chloride. The organic phases are washed with saline, dried with Na2SO4 and evaporated: tRet (II)=15.8 min; FAB-MS (M+H)+ =594.

Provenance & Evidence