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

Participants

Reaction Steps

2.6 g (4.89 mmol) of 5(S)-[1(S)-(Boc-amino)-2-(p-benzyloxy-phenyl)-ethyl]-3(R)-[(p-methoxyphenyl)methyl]dihydrofuran-2-(3H)-one in 50 ml of dimethoxyethane are hydrolysed, under an N2 atmosphere, with 19.6 ml of a 1 M lithium hydroxide solution in water. After 25 h at RT, the dimethoxyethane is evaporated off on a RE, and the residue is treated with an ice-cold mixture of 150 ml of sat. NH4Cl solution, 25 ml of 10% citric acid solution and methylene chloride. The aqueous phase is separated off and extracted 2× with methylene chloride. The organic phases are washed with saline, dried with Na2SO4 and evaporated to give the title compound: TLC Rf (B)=0.28; tRet (II)=16.4 min.

Provenance & Evidence