反应详情

N-tert-Butyloxycarbonyl-O-benzyltyrosine (LV) (27.6 g) and dry tetrahydrofuran (100 ml) at 0° C. were treated successively with triethylamine (10.3 ml), ethyl chloroformate (7.1 ml) and, after an hr, glycine benzyl ester tosylate (XXXVI) (25 g) and triethylamine (10.3 ml) in dry tetrahydrofuran (100 ml). After being stirred at room temperature during 16 hr, the reaction mixture was evaporated to dryness. The residue was dissolved in ethyl acetate (400 ml) and the solution was washed with 5% citric acid (2×50 ml), 5% sodium bicarbonate solution (2×50 ml) and water 2×50 ml). The organic layer was dried (Na2SO4) and evaporated. The residue was crystallized from methanol-n-hexane to afford the (LVI); 35.7 g, yield 93%; m.p. 101°-4° C; [α]D22 + 1.2° (c 1.29, methanol); Rf4 0.91; single spot with chlorine/tolidine and iodine reagents. τCDCL3 2.65, d, 10H benzylic aromatic protons; 4.86, s,2H and 4.98,s,2H benzylic methylene protons and 8.64,s,9H butyloxy protons.

1. customthe reaction mixture was evaporated to dryness
2. dissolutionThe residue was dissolved in ethyl acetate (400 ml)
3. washthe solution was washed with 5% citric acid (2×50 ml), 5% sodium bicarbonate solution (2×50 ml) and water 2×50 ml)
4. dry with materialThe organic layer was dried (Na2SO4)
5. customevaporated
6. customThe residue was crystallized from methanol-n-hexane
7. customto afford the (LVI)