反应详情

To a solution of 4-(1-hydroxy-heptyl)-benzoic acid methyl ester (1000 mg, 4.0 mmol) in toluene (40 mL) is added 1,1′-(azodicarbonyl)dipiperidine (ADDP, 1514 mg, 6.0 mmol) at 0° C., followed by the additions of tributylphosphine (1.49 mL, 6.0 mmol) and 4-bromo-3,5-dimethyl-phenol (965 mg, 4.8 mmol). The reaction mixture is warmed up to room temperature and stirred overnight. The mixture is loaded on silica gel, eluted with hexanes with a gradient from 0% of ethyl acetate to 50% of ethyl acetate giving 4-[1-(4-bromo-phenoxyl)-heptyl]-benzoic acid methyl ester. The ester product (1800 mg) is taken into ethanol (5 mL), treated with sodium hydroxide (5N aqueous, 5 mL) for 3 h at room temperature. The mixture is concentrated, diluted with ethyl acetate, acidified with 5 N HCl (5 mL), extract with ethyl acetate. The organic layers are dried and concentrated giving 4-[1-(4-bromo-3,5-dimethyl-phenoxyl)-heptyl]-benzoic acid (1790 mg).

1. washeluted with hexanes with a gradient from 0% of ethyl acetate to 50% of ethyl acetate