反应详情

A mixture of 4-amino-benzoic acid ethyl ester (16.5 g, 100 mmol), 5-bromo-pyridine-3-carbaldehyde (18.6 g, 100 mmol) and p-toluenesulfonic acid (380 mg, 2 mmol) in toluene (200 mL) was heated to reflux for 12 h. Then the reaction mixture cooled to room temperature. The solvent was removed in vacuo and the residue was washed with ether to afford 4-[(5-bromo-pyridin-3-ylmethylene)-amino]-benzoic acid ethyl ester (33.8 g, quant.) as a light yellow solid: LC/MS m/e calcd for C15H13BrN2O2 (M+H)+: 334.19, observed: 332.9 & 335.0.

1. temperaturewas heated
2. temperatureto reflux for 12 h
3. customThe solvent was removed in vacuo
4. washthe residue was washed with ether