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: Et3N / H2O; acetone / 24 h 2: 4-(dimethylamino)pyridine, dicyclohexylcarbodiimide / CH2Cl2 / 3 h 3: p-TsOH / acetonitrile / 1.75 h / Heating 4: DCC, 1-hydroxybenzotriazole hydrate, diisopropylethylamine / tetrahydrofuran / 1.) 0 deg C, 1.5 h, 2.) room temperature, 18 h 5: tetrabutylammonium fluoride trihydrate / dimethylformamide / 15 h View Scheme

triethylamine in N,N-dimethyl-formamide Ambient temperature;

pyridine; N,N'-disuccinimidyl-carbonate; triethylamine 1.) CH3CN, RT, 44 h, 2.) CH3CN, H2O, RT; Yield given. Multistep reaction;