Lithium Hydroxide → 5(S)-(Boc-Amino)-4(S)-hydroxy-6-(p-benzyloxyphenyl)-2(R)-[(p-benzyloxyphenyl)methyl]hexanoic acid

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Reaction Steps

2.7 g (4.43 mmol) of 5(S)-[1(S)-(Boc-amino)-2-(p-benzyloxyphenyl)ethyl]-3(R)-[(p-benzyloxyphenyl)methyl]dihydrofuran-2-(3H)-one in 59 ml of dimethoxyethane and 31.8 ml of water are treated, while excluding air, with 14.8 ml of a 1M lithium hydroxide solution. The mixture is then stirred at RT for 3 h and partially evaporated. The residue is poured onto a mixture of ice, 181 ml of sat. NH4Cl solution, 16.2 ml of 10% citric acid solution and 400 ml of ethyl acetate, and THF is added until the precipitated solid dissolves. The aqueous phase is separated off and extracted with 2 portions of ethyl acetate, and the organic phases are washed with saline, dried with Na2SO4, evaporated and digested in hexane: TLC Rf (C)=0.07.

Provenance & Evidence