反应详情

To tert-butyl 4-[4-(4-{[(2,2,2-trichloroethoxy)carbonyl]amino}-1,2,5-oxadiazol-3-yl)phenyl]piperazine-1-carboxylate (485 mg, 0.932 mmol), methyl 2-hydroxy-4-methylpentanoate (275 mg, 1.87 mmol) and triphenyl phosphine (490 mg, 1.87 mmol) in dry DMF (15 mL) at 0° C. under dry nitrogen was added diisopropyl azodicarboxylate (0.375 mL, 1.87 mmol) dropwise over ½ hour and the reaction mixture stirred overnight at rt. The reaction was poured into water and the product extracted with Et2O (2×), dried over Na2SO4, concentrated in vacuo and purified by flash chromatography over silica gel (EtOAc/Hex, 2/8) to afford methyl N-(4-{4-[4-(tert-butoxycarbonyl)piperazin-1-yl]phenyl}-1,2,5-oxadiazol-3-yl)-N-[(2,2,2-trichloroethoxy)carbonyl]leucinate.

1. extractionthe product extracted with Et2O (2×)
2. dry with materialdried over Na2SO4
3. concentrationconcentrated in vacuo
4. custompurified by flash chromatography over silica gel (EtOAc/Hex, 2/8)