Lithium Hydroxide → 5(S)-(Boc-amino)-4(S)-hydroxy-6-(p-benzyloxyphenyl)-2(R)-(phenylmethyl)-hexanoic acid

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Reaction Steps

Analogously to Example 1i), 0.502 g (1.00 mmol) of 5(S)-[1(S)-(Boc-amino)-2-(p-benzyloxyphenyl)-ethyl]-3(R)-(phenylmethyl)-dihydrofuran-2-(3H)-one in 16 ml of dimethoxyethane and 8.6 ml of water are hydrolysed with 4 ml of 1M lithium hydroxide solution. The reaction mixture, partially concentrated by evaporation, is poured onto a mixture of ice, 49 ml of sat. NH4Cl solution, 4.1 ml of 10% citric acid solution and methylene chloride, and ethanol is added until the precipitated solid has dissolved. The aqueous phase is extracted with 2 portions of methylene chloride/ethanol approximately 9:1, and the organic phases are washed with brine, dried with Na2SO4 and concentrated by evaporation: TLC Rf (A)=0.22.

Provenance & Evidence