反应详情

Compound 20 (0.75 g, 2.43 mmol) was dissolved in 30 mL of methanol. A catalytic amount of 5% palladium on barium sulfate (0.30 g) was added. The mixture was hydrogenated at 1 atm for 5 hr. The catalyst was removed by filtration and the methanol was evaporated. This residue was dissolved in 40 mL of methylene chloride. N-Boc-S-trityl cysteine (1.12 g, 2.43 mmol) was added at 0° C. followed by EDCI (1 eq) and HOBT (1 eq). The mixture was stirred for 24 hr. After workup and evaporation of solvents, the residue was purified by flash column chromatography (hexane:ethyl acetate=3.2:1) to give 21 (570 mg, 44%). m.p. 84-86° C. 1H NMR (CDCl3) δ 8.17 (s, 1H), 7.95 (d, 7.7 Hz, 1H), 7.70 (d, 7.7 Hz, 1H), 7.50-7.30 (m, 9H), 7.30-7.10 (m, 11H), 6.44 (br, 1H), 4.86 (br, 1H), 4.45 (d, 4.0 Hz, 2H, CH2Ph), 3.87 (br, 1H, Cys α H), 2.75 (dd, 7.2 and 12.8 Hz, 1H, CH2S), 2.55 (dd, 5.3 and 12.8 Hz, 1H, CH2S), 1.62 (s, 9H), 1.36 (s, 9H). Anal. (C45H48N2O5S) C, H, N, S.

1. customThe catalyst was removed by filtration
2. customthe methanol was evaporated
3. dissolutionThis residue was dissolved in 40 mL of methylene chloride
4. customAfter workup and evaporation of solvents
5. customthe residue was purified by flash column chromatography (hexane:ethyl acetate=3.2:1)