1: 2.) conc. H2SO4 / 1) toluene, reflux, 6 h; 2) reflux, 8 h 2: H2 / Pd/C / acetic acid / 5 h / Ambient temperature 3: 1.) pyridine, 2.) aq. NaOH / 1) room temperature, 16 h; 2) methanol, reflux, 1 h 4: trimethylsilyl polyphosphate / dimethylformamide / 4 h / 130 °C 5: conc. HCl / acetic acid / 1 h / Heating View Scheme

1: 90 percent / acetic anhydride / 1) 60 deg C, 1 h; 2) reflux, 10 min 2: 2.) conc. H2SO4 / 1) toluene, reflux, 6 h; 2) reflux, 8 h 3: H2 / Pd/C / acetic acid / 5 h / Ambient temperature 4: 1.) pyridine, 2.) aq. NaOH / 1) room temperature, 16 h; 2) methanol, reflux, 1 h 5: trimethylsilyl polyphosphate / dimethylformamide / 4 h / 130 °C 6: conc. HCl / acetic acid / 1 h / Heating View Scheme

1: H2 / Pd/C / acetic acid / 5 h / Ambient temperature 2: 1.) pyridine, 2.) aq. NaOH / 1) room temperature, 16 h; 2) methanol, reflux, 1 h 3: trimethylsilyl polyphosphate / dimethylformamide / 4 h / 130 °C 4: conc. HCl / acetic acid / 1 h / Heating View Scheme

hydrogenchloride in acetic acid 1 h; Heating; Yield given;

1: 1.) pyridine, 2.) aq. NaOH / 1) room temperature, 16 h; 2) methanol, reflux, 1 h 2: trimethylsilyl polyphosphate / dimethylformamide / 4 h / 130 °C 3: conc. HCl / acetic acid / 1 h / Heating View Scheme

1: trimethylsilyl polyphosphate / dimethylformamide / 4 h / 130 °C 2: conc. HCl / acetic acid / 1 h / Heating View Scheme