Methanol → HCID 131710736, compound

Participants

Reaction Steps

Nα-Cyclohexylcarbonyl-S-benzyl-L-cysteinyl-O-benzyl-L-tyrosyl-O-benzyl-L-serine methyl ester is obtained by reacting Nα-t-butoxycarbonyl-L-serine resin (10 g.) successively with 11.2 g., 30 mmol of Nα-t-butoxycarbonyl-O-benzyl-L-tyrosine, 9.4 g., 30 mmol, of Nα-t-butoxycarbonyl-S-benzyl-L-cysteine and 3.9 g., 30 mmol, of cyclohexane carboxylic acid in the solid phase procedure according to Example 10. The resin is suspended in 250 ml. of absolute methanol containing 25 ml. of triethylamine at room temperature for twenty hours. The resin is removed by filtration. Evaporation of the filtrate gives the crude ester which is purified by chromatography over silica gel in ethyl acetate. The appropriate fractions are chosen by thin layer chromatography, evaporated, and the product held at high vacuum to remove solvents; 3.4 g., [α]D23 -25° (c 1.01, methanol).

Provenance & Evidence