反应详情

Reaction of N-benzyloxycarbonyl-D-valine with isopropylamine by the method of Example 20, Part A afforded a quantitative yield of N-benzyloxycarbonyl-D-valine isopropylamide of Rf 0.61 (TLC, ethyl acetate/hexane, 1:1, vanillin spray). Hydrogenolysis over Pd/C by the method of Example 20, Part B gave D-valine isopropylamide in 71% yield, Rf 0.50. Coupling with beta-benzyl N-Cbz-L-asparate provided the diblocked dipeptide amide (procedure of Example 20, Part C), Rf 0.40 (TLC, ethyl acetate/hexane, 1, vanillin spray), in 62% yield as an off-white solid. This was converted to the desired title compound by the procedure of Example 20, Part D, in 90.6% yield, M.P. 226°-227° C. (decomp.), Rf 0.44. Sweetness, 1-2 x sucrose.