Triethylamine → 3-(4-Benzyloxy-phenyl)-2(S)-[2(S)-(4-tert-butyl-benzenesulfonylamino)-4-methyl-pentanoylamino]-propionic acid tert-butyl ester

Participants

Reaction Steps

A solution of the product from Example AI ([S-(R*,R*)]-2-{2-amino-4-methyl-pentanoylamino}-3-(4-benzyloxy-phenyl)-propionic acid tert-butyl ester) (0.20 g, 0.45 mmol) and triethylamine (0.13 mL, 0.90 mmol) in 5 mL of CHCl3 was cooled to 0° C. and treated with 4-tert-butylphenylsulfonyl chloride (0.10 g, 0.45 mmol). The reaction mixture was warmed to room temperature and treated with saturated aqueous NaHCO3. The organic phase was separated from the aqueous phase. The aqueous phase was extracted with additional CHCl3, and the combined organic extracts were dried MgSO4, filtered, and concentrated. The residue was purified by chromatography (silica gel, 1:1 heptane/ethyl acetate). The chromatography product was crystallized from hot heptane/ethyl acetate to give the title compound as a white solid 0.20 g 70%), mp=142-143° C.

Provenance & Evidence