反应详情

2-Chloro-4-hydroxy-benzoic acid methyl ester from example E41b (2.0 g, 10.9 mmol) and 4-(2-Bromo-acetyl)-piperazine-1-carboxylic acid tert-butyl ester from Example E41a (3.68 g, 12.0 mmol) in acetonitrile (30 ml) were treated with potassium carbonate (1.6 g, 11.5 mmol), and the mixture heated at reflux 18 h. before the solvents were removed in vacuo. The residue was adsorbed onto silica gel and purified by flash chromatography on silica gel (eluant; 20% EtOAc:80% cyclohexane to 50% EtOAc:50% cyclohexane to 70% EtOAc:30% cyclohexane) to yield the title compound (4.5 g, 100%).

1. temperaturethe mixture heated
2. temperatureat reflux 18 h. before the solvents
3. customwere removed in vacuo
4. custompurified by flash chromatography on silica gel (eluant; 20% EtOAc:80% cyclohexane to 50% EtOAc:50% cyclohexane to 70% EtOAc:30% cyclohexane)