hydrogenchloride in acetonitrile T=5°C; 10 h;

1: 1->3-(dimethylamino)propyl>-3-ethylcarbodiimide hydrochloride / dimethylformamide / 18 h / Ambient temperature 2: 4.6 g / NEt3 / dimethylformamide / Ambient temperature 3: 0.4 g / conc. aq. HCl / acetonitrile / 10 h / 5 °C View Scheme

1: 1.) N,N-disuccinimidyl carbonate, pyridine, 2.) NEt3 / 1.) CH3CN, RT, 44 h, 2.) CH3CN, H2O, RT 2: 0.4 g / conc. aq. HCl / acetonitrile / 10 h / 5 °C View Scheme

1: 3.86 g / p-toluenesulfonic acid / acetic acid / 44 h / Heating 2: 6.3 g / 20percent HBr/glacial acetic acid / 2 h / Ambient temperature 3: 3.64 g / 2.5 N aq. NaOH / methanol / 18 h / Ambient temperature 4: 1.) N,N-disuccinimidyl carbonate, pyridine, 2.) NEt3 / 1.) CH3CN, RT, 44 h, 2.) CH3CN, H2O, RT 5: 0.4 g / conc. aq. HCl / acetonitrile / 10 h / 5 °C View Scheme

1: 6.3 g / 20percent HBr/glacial acetic acid / 2 h / Ambient temperature 2: 3.64 g / 2.5 N aq. NaOH / methanol / 18 h / Ambient temperature 3: 1.) N,N-disuccinimidyl carbonate, pyridine, 2.) NEt3 / 1.) CH3CN, RT, 44 h, 2.) CH3CN, H2O, RT 4: 0.4 g / conc. aq. HCl / acetonitrile / 10 h / 5 °C View Scheme

1: 6.8 g / SOCl2 / 20 h / Heating 2: 3.86 g / p-toluenesulfonic acid / acetic acid / 44 h / Heating 3: 6.3 g / 20percent HBr/glacial acetic acid / 2 h / Ambient temperature 4: 3.64 g / 2.5 N aq. NaOH / methanol / 18 h / Ambient temperature 5: 1.) N,N-disuccinimidyl carbonate, pyridine, 2.) NEt3 / 1.) CH3CN, RT, 44 h, 2.) CH3CN, H2O, RT 6: 0.4 g / conc. aq. HCl / acetonitrile / 10 h / 5 °C View Scheme

1: 4.6 g / NEt3 / dimethylformamide / Ambient temperature 2: 0.4 g / conc. aq. HCl / acetonitrile / 10 h / 5 °C View Scheme