1: 98 percent / NaOMe / methanol / 2 h / 23 °C 2: NH3 / methanol / 5 h / 0 °C 3: 91 percent / Et3N / DMAP / acetonitrile / 1 h / 23 °C 4: 65 percent / (CF3CO)2O; pyridine / tetrahydrofuran / -12 - -2 °C 5: 72 percent / Et3N / H2O; methanol / Heating View Scheme