AC-DAP(BOC)-OH

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: To a mixture of N-(t-butoxycarbonyl)-2(S)-acetylamino-β-alanine (3.0 g) in dimethylformamide (60 ml) was added NaHCO3 (2.05 g) at −2° C., and a solution of benzyl bromide in dimethylformamide (60 ml) was added by using a dropping funnel under stirring. The mixture was stirred overnight around 26° C., then poured into a mixture of ice-water (300 ml) and hexane-ethyl acetate (8:2, 500 ml). After the organic layer was separated, the aqueous layer was extracted again with hexane-ethyl acetate (8:2, 300 ml). The combined organic layer was washed with water (300 ml×2), brine (300 ml) and dried over Na2SO4, and evaporated in vacuo. The residue was purified by silica gel chromatography eluting with hexane-ethyl acetate (8:2) to give N-(t-butoxycarbonyl)-2(S)-acetylamino-β-alanine benzyl ester (3.68 g). The mixture was stirred overnight around 26° C. After the organic layer was separated the aqueous layer was extracted again with hexane-ethyl acetate (8:2, 300 ml) The combined organic layer was washed with water (300 ml×2), brine (300 ml) dried over Na2SO4 evaporated in vacuo The residue was purified by silica gel chromatography eluting with hexane-ethyl acetate (8:2)

反应条件: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: To a solution of N-(t-butoxycarbonyl)-2(S)-benzyloxycarbonylamino-β-alanine (6.15 g) in methanol (120 ml) was added 10% Pd—C (50% wet, 1.2 g). The mixture was stirred vigorously, and hydrogen gas was bubbled for 1 hour. The catalyst was removed by filtration, and the filtrate was evaporated in vacuo. The residue was dissolved in tetrahydrofuran (70 ml) and cooled to 0° C. with ice bath. 1N NaOH (36 ml) was added, then acetic anhydride (3.77 ml) was added dropwise under stirring. The mixture was stirred for additional 1 hour at 0° C., then the pH of the mixture was adjusted to 2.5 with aqueous 20% KHSO4. The resultant mixture was extracted with ethyl acetate-tetrahydrofuran (200 ml-100 ml) twice times. The combined organic layer was dried over Na2SO4 and evaporated in vacuo. The residue was recrystallized from diethyl ether to give N-(t-butoxycarbonyl)-2(S)-acetylamino-β-alanine (3.17 g). hydrogen gas was bubbled for 1 hour The catalyst was removed by filtration the filtrate was evaporated in vacuo The residue was dissolved in tetrahydrofuran (70 ml) 1N NaOH (36 ml) was added acetic anhydride (3.77 ml) was added dropwise under stirring The mixture was stirred for additional 1 hour at 0° C. The resultant mixture was extracted with ethyl acetate-tetrahydrofuran (200 ml-100 ml) twice times The combined organic layer was dried over Na2SO4 evaporated in vacuo The residue was recrystallized from diethyl ether