Hydrogen Peroxide → HCID 22861550, compound

Participants

Reaction Steps

4-{[1(S)-(Cyclohexylmethyl)-2(R),3(S)-dihydroxy-5-methylhexyl]amino}-4-oxo-3(R)-{[(1-(triphenylmethyl)-1H-imidazol-4-yl]methyl}butanoic acid benzyl ester: A 30% aqueous solution of H2O2 (4.70 mL, 41.6 mmol) and lithium hydroxide monohydrate (436 mg, 10.4 mmol) were added serially to cooled solution (0°) of the product of section (c) of this example (6.67 g, 10.4 mmol) in THF-H2O (156 mL: 52 mL). The reaction mixture was stirred at 0° for 2 h and then at room temperature for 2 h. Excess peroxide was quenched at 0° with 1.5N aqueous Na2SO3 solution. THF was removed by distillation under reduced pressure. The concentrate was poured into H2O (500 mL). The mixture was rendered acid by the addition of a 10% (w/v) aqueous solution of citric acid, and then extracted with EtOAc. The extract was washed with brine, dried (MgSO4) and evaporated to dryness under reduced pressure to yield the desired monoprotected dicarboxylic acid, i.e. the 4-(phenylmethyl) ester of 2(R)-{[1-(triphenylmethyl)-1H-imidazol-4-yl]methyl}butanedioic acid. The monoprotected dicarboxylic acid was used for the following coupling step without further purification.

Provenance & Evidence