triethylamine in acetonitrile T=25°C; 19 h;

in ethanol

1: 53 percent / sodium dichromate, AcOH, conc. H2SO4 / 1 h / 90 °C 2: 1.) (COCl)2, DMF, 2.) aq. NH3 / 1.) CH2Cl2, 25 deg C, 4 h, 2.) CH2Cl2, 10 min 3: 95 percent / P2O5, hexamethyldisiloxane / CH2Cl2 / 4 h / 100 °C 4: 54 percent / Et3N / acetonitrile / 19 h / 25 °C View Scheme

1: 1.) (COCl)2, DMF, 2.) aq. NH3 / 1.) CH2Cl2, 25 deg C, 4 h, 2.) CH2Cl2, 10 min 2: 95 percent / P2O5, hexamethyldisiloxane / CH2Cl2 / 4 h / 100 °C 3: 54 percent / Et3N / acetonitrile / 19 h / 25 °C View Scheme

1: 95 percent / P2O5, hexamethyldisiloxane / CH2Cl2 / 4 h / 100 °C 2: 54 percent / Et3N / acetonitrile / 19 h / 25 °C View Scheme