Benzyl chloroformate → HCID 54425150, compound

Participants

Reaction Steps

In 100 ml of a 50% aqueous solution of dioxane was dissolved 3.8 g of (S,S)-3-(3-aminopropyl)-4-[2-benzyloxycarbonylamino-3-(4-methoxyphenyl)propionyl]-2-oxopiperazine-1-acetic acid produced in Reference Example 33. To the solution was added 1.52 g of NaHCO3, to which was added dropwise, under ice-cooling, 1.24 ml of Z-chloride. The mixture was stirred for 1.5 hour at room temperature. Dioxane was distilled off. To the residue was added a 3% aqueous solution of KHSO4 to adjust the pH to 2. The mixture was subjected to extraction with ethyl acetate. The extract solution was washed with a saturated aqueous solution of NaHCO3 and dried (Na2SO4), followed by concentration under reduced pressure. To the concentrate was added ether. The mixture was subjected to decantation twice to afford 4 g of the title compound.

Provenance & Evidence