sodium azide; iodine cloride in acetonitrile T=25°C; 36 h;

sodium methylate in methanol T=20°C; 0.5 h;

carbonic acid diphenyl ester; copper; sodium hydrogencarbonate in N,N-dimethyl-formamide T=140 - 150°C;

1: 95 percent / TFA / dimethylformamide / 10 h / 80 °C 2: 89 percent / pyridine / 0.5 h / 20 °C 3: 70 percent / I2; ceric(IV) ammonium nitrate / acetonitrile / 1 h / 80 °C 4: 80 percent / NaOMe / methanol / 0.5 h / 20 °C View Scheme

1: 80 percent / diphenyl carbonate; NaHCO3 / dimethylformamide / 1.67 h / 140 °C 2: 95 percent / TFA / dimethylformamide / 10 h / 80 °C 3: 89 percent / pyridine / 0.5 h / 20 °C 4: 70 percent / I2; ceric(IV) ammonium nitrate / acetonitrile / 1 h / 80 °C 5: 80 percent / NaOMe / methanol / 0.5 h / 20 °C View Scheme

1: 70 percent / I2; ceric(IV) ammonium nitrate / acetonitrile / 1 h / 80 °C 2: 80 percent / NaOMe / methanol / 0.5 h / 20 °C View Scheme