1: sodium ethoxide / ethanol / 5 h / Ambient temperature 2: 1) p-toluenesulfonic acid / 1) benzene, 19 h, reflux, 2) diphenyl ether, 30 min, reflux View Scheme

sodium ethanolate in ethanol 5 h; Ambient temperature;

1: sodium ethoxide / ethanol / 5 h / Ambient temperature 2: 1) p-toluenesulfonic acid / 1) benzene, 19 h, reflux, 2) diphenyl ether, 30 min, reflux 3: 10 percent / potassium carbonate / dimethylformamide / 48 h / Ambient temperature View Scheme