1: triethylamine, (PhO)2P(O)N3 / benzene / 20 h / Heating 2: 18 h / Heating 3: 1.) NaHCO3, Me2SO4, 2.) NaOH / 1.) MeOH, 35 deg C, 40 h, 2.) MeOH, H2O, 40 deg C, 2 h View Scheme