1: 0.4N HCl / 1.) 95 deg C, 90 min; 2.) RT, 30 min 2: pyridine / 20 h / 20 °C View Scheme

1: 0.4N HCl / 1.) 95 deg C, 90 min; 2.) RT, 30 min 2: pyridine / 20 h / 20 °C 3: 65 percent / CF3SO2OSiMe3, hexamethyldisilazane / CH2Cl2 / 20 h / Ambient temperature 4: 97 percent / CH3ONa / methanol / Ambient temperature View Scheme