in methanol 8 h; Heating;

1: 1.) piperidine, acetic acid, 2.) triethylamine / 1.) ethanol, 78 deg C, 2.) EtOH, 78 deg C, 36 h 2: 16 percent / 85percent phosphoric acid 3: 63 percent / methanol / 8 h / Heating View Scheme