反应详情

温度

110 °C

2,5-Difluorobenzoic acid methyl ester (25 g, 145 mmol), piperazine-1-carboxylic acid tert-butyl ester (27 g, 145 mmol) and K2CO3 (50 g, 363 mmol) are added to 1,4-dioxane and the mixture is heated to 110° C. for 2 days. The reaction mixture is cooled, inorganic salts filtered through sintered funnel and filtrate is concentrated under reduced pressure. Crude compound is purified by column chromatography (silica-gel, 100-200 mesh, eluent; 5% EtOAc in hexane) to afford desired 4-(4-fluoro-2-methoxycarbonyl-phenyl)-piperazine-1-carboxylic acid tert-butyl ester as a syrupy liquid (8.1 g, 16.3%).

1. temperatureThe reaction mixture is cooled
2. filtrationinorganic salts filtered through sintered funnel
3. concentrationfiltrate is concentrated under reduced pressure
4. customCrude compound is purified by column chromatography (silica-gel, 100-200 mesh, eluent; 5% EtOAc in hexane)