1: Et3N / 2 h / 6 °C 2: 81 percent / K2CO3, tris(3,6-dioxa-heptyl)amine / toluene / 6 h / Heating 3: 99 percent / aq. NaOH / methanol / 1.25 h / Heating 4: 2 N HCl View Scheme