反应详情

A mixture of 3,5-di-tert-butyl-4-hydroxybenzamide (16.0 g, 64.3 mmol), 4-bromo-3-oxopentanoic acid methyl ester (18.6 g, 64.26 mmol), dioxane (60mL), and toluene (600 mL) was refluxed for 5 days with continuous water removal (Dean Stark trap). Then, the volatiles were removed in vacuo and the residue was purified by flash chromatography on silica gel (eluting solvent: hexane/EtOAc 3/1) to give a brown viscous oil (11.2 g). Crystallization of the brown oil from ethyl ether (after cooling to 0° C.) gave a white solid (9.2 g, 40% yield), m.p. 121°-123° C.

1. customThen, the volatiles were removed in vacuo
2. customthe residue was purified by flash chromatography on silica gel (eluting solvent: hexane/EtOAc 3/1)