1: 90 percent / acetic anhydride / 1) 60 deg C, 1 h; 2) reflux, 10 min 2: 3 percent / 2.) conc. H2SO4 / 1) toluene, reflux, 6 h; 2) reflux, 8 h View Scheme

sulfuric acid 1) toluene, reflux, 6 h; 2) reflux, 8 h; Yield given. Multistep reaction;

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: 26 percent / trimethylsilyl polyphosphate / dimethylformamide / 4 h / 130 °C 4: 77 percent / aq. HCl / ethanol / 2 h / Heating 5: dimethylformamide / 3 h / 75 °C 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 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: 26 percent / trimethylsilyl polyphosphate / dimethylformamide / 4 h / 130 °C 4: 77 percent / aq. HCl / ethanol / 2 h / Heating View Scheme