1: 10percent aq. NaOH / 3 h / Heating 2: 1) TFA / 1) TFA, EtOH, overnight, 2) RT, 48 h 3: 81 percent / 5 h / 180 °C / 2 Torr 4: POCl3 / diethyl ether / Ambient temperature 5: NaOH / H2O / 0.5 h / Heating View Scheme

1: 10percent aq. NaOH / 3 h / Heating 2: 1) TFA / 1) TFA, EtOH, overnight, 2) RT, 48 h 3: 81 percent / 5 h / 180 °C / 2 Torr View Scheme

1: With sodium hydroxide; water T=180°C; 1.5 h; 2: With sulfuric acid in water T=20°C; pH=2;