Imidazole → 5(S)-(Boc-amino)-4(S)-(tert-butyldimethylsilyloxy)-6-phenyl-2(R)-(m-cyanophenylmethyl)-hexanoic acid

Participants

Reaction Steps

Analogously to Example 1j), 1.4 g (3.2 mmol) of 5(S)-(Boc-amino)-4(S)-hydroxy-6-phenyl-2(R)-(m-cyanophenylmethyl)-hexanoic acid in 20 ml of DMF are silylated with 2.2 g (14.6 mmol) of tert-butyldimethylchlorosilane and 1.8 g (26 mmol) of imidazole. Hydrolysis of the silyl ester function with 2.6 g of potassium carbonate in 55 ml of methanol/THF/water 8:1:2, followed by column chromatography (SiO2, ethyl acetate/hexane 1:1), yields the title compound: TLC Rf (A)=0.39; tRet (I)=19.8 min.

Provenance & Evidence