Citric Acid → 5(s)-(Boc-amino)-4(s)-hydroxy-6-(p-methoxyphenyl)-2(r)-(phenylmethyl)hexanoic acid

Participants

Reaction Steps

3.00 g (7.05 mmol) of 5(S)-[1(S)-(Boc-amino)-2-(p-methoxy-phenyl)-ethyl]-3(R)-(phenylmethyl)dihydrofuran-2-(3H)-one in 112 ml of dimethoxyethane and 57 ml of water are hydrolysed, under protective gas, with 28 ml of 1M lithium hydroxide solution. After 20 h at RT, the reaction mixture is poured onto an ice-cold mixture of 340 ml of sat. NH4Cl solution, 28 ml of 10% citric acid solution and 140 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, with the title compound being obtained: tRet (II)=14.0 min; FAB-MS (M+H)+ =444.

Provenance & Evidence