Imidazole → 5(S)-(Boc-Amino)-4(S)-(tert-butyldimethylsilyloxy)-6-phenyl-2(R)-[(o-fluorophenyl)methyl]hexanoic acid

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Reaction Steps

In analogy with Example 1j, 1.5 g (3.47 mmol) of 5(S)-(Boc-amino)-4(S)-hydroxy-6-phenyl-2(R)-[(o-fluorophenyl)methyl]hexanoic acid in 15 ml of DMF are silylated with 2.4 g (16 mmol) of tert-butyldimethylchlorosilane and 1.95 g (28.5 mmol) of imidazole. Hydrolysis of the silyl ester function with 2.8 g of potassium carbonate in 50 ml of methanol/THF/water, 4:1:1, yields the title compound after column chromatography (SiO2, hexane/ethyl acetate, 2:1): TLC Rf (D)=0.33; tRet (II)=20.7 min.

Provenance & Evidence