1: 72 percent / fuming nitric acid, conc H2SO4 / 5 h / 50 °C 2: 78 percent / POCl3 / 3 h / Heating 3: SOCl2 / 3 h / Heating 4: (i-Pr)2NEt / tetrahydrofuran / 2 h / Ambient temperature 5: pyridine / 2.5 h / 90 °C 6: NaH / dimethylformamide / Ambient temperature 7: stannous chloride dihydrate, conc. HCl / acetic acid View Scheme

1: 78 percent / POCl3 / 3 h / Heating 2: SOCl2 / 3 h / Heating 3: (i-Pr)2NEt / tetrahydrofuran / 2 h / Ambient temperature 4: pyridine / 2.5 h / 90 °C 5: NaH / dimethylformamide / Ambient temperature 6: stannous chloride dihydrate, conc. HCl / acetic acid View Scheme

1: SOCl2 / 3 h / Heating 2: (i-Pr)2NEt / tetrahydrofuran / 2 h / Ambient temperature 3: pyridine / 2.5 h / 90 °C 4: NaH / dimethylformamide / Ambient temperature 5: stannous chloride dihydrate, conc. HCl / acetic acid View Scheme

1: (i-Pr)2NEt / tetrahydrofuran / 2 h / Ambient temperature 2: pyridine / 2.5 h / 90 °C 3: NaH / dimethylformamide / Ambient temperature 4: stannous chloride dihydrate, conc. HCl / acetic acid View Scheme