反应详情

To a dry degassed DMF solution (50 mL) of 2,2,2-trichloroethyl 4-bromo-5-methylisoxazol-3-ylcarbamate (2.67 g, 7.58 mmol), DL methyl leucate (2.31 g, 15.8 mmol), and triphenyl phosphine (4.11 g, 15.7 mmol) was added diisopropyl azodicarboxylate (3.1 ml, 15.7 mmol) at 0° C. over 2 hours. The reaction was allowed to warm to room temperature while stirring overnight. Water was added and the product was extracted with ether (2×) then ethyl acetate (2×), dried over Na2SO4 and concentrated in vacuo. The crude product was purified by flash chromatography (20% ethyl acetate/hexane) to afford methyl N-(4-bromo-5-methylisoxazol-3-yl)-N-[(2,2,2-trichloroethoxy)carbonyl]leucinate.

1. extractionthe product was extracted with ether (2×)
2. dry with materialethyl acetate (2×), dried over Na2SO4
3. concentrationconcentrated in vacuo
4. customThe crude product was purified by flash chromatography (20% ethyl acetate/hexane)