in ethanol 48 h; Ambient temperature;

1: 60 percent / 1N HCl / 0.5 h / Heating 2: 60 percent / polyphosphoric acid / 0.25 h / 150 °C View Scheme

1: 60 percent / 1N HCl / 0.5 h / Heating 2: 1) hexamethyldisilazane, (NH4)2SO4 2) trimethylsilyl trifluoromethanesulfonate / 1) reflux, 3h 2) CH3CN, ambient temp., 3d (isomeric ratio varies with reaction time) 3: 70 percent / NH3 / methanol / 16 h / Ambient temperature View Scheme

1: 60 percent / 1N HCl / 0.5 h / Heating 2: 1) (NH4)2SO4, hexamethyldisilazane 2) trimethylsilyl trifluoromethanesulfonate / 1) reflux, 3h 2) CH3CN, 0-5 deg C, 1h 3: 75 percent / NH3 / methanol / Ambient temperature View Scheme

1: 60 percent / 1N HCl / 0.5 h / Heating 2: 1) hexamethyldisilazane, (NH4)2SO4 2) trimethylsilyl trifluoromethanesulfonate / 1) reflux, 3h 2) CH3CN, ambient temp., 3d (isomeric ratio varies with reaction time) 3: 70 percent / NH3 / methanol / 16 h / Ambient temperature 4: 75 percent / 30percent H2O2 / NH4OH / 16 h / Ambient temperature View Scheme