in diethyl ether 1 h; Ambient temperature;

1: 79.3 percent / triethylamine / ethanol / 2 h / Heating 2: 69.2 percent / p-toluenesulfonic acid monohydrate / 1.17 h / Heating 3: 51.5 percent / diethyl ether / 1 h / Ambient temperature View Scheme

1: 69.2 percent / p-toluenesulfonic acid monohydrate / 1.17 h / Heating 2: 51.5 percent / diethyl ether / 1 h / Ambient temperature View Scheme