sulfuric acid in ethylene glycol dimethyl ether T=55°C; 24 h;

1: 33.5 percent / 1 M H2SO4 / 1,2-dimethoxy-ethane / 24 h / 55 °C 2: 69.5 percent / 2) p-TsOH / toluene / Heating; 1) 30 min, 2) 3 h View Scheme

Multi-step reaction with 5 steps 1: 76 percent / acetic acid; dimethylformamide / 2 h / 80 °C2: 1) 60percent sodium hydride / 1) DMF, 0 deg C, 0.5 h, 2) room temperature, 3 h3: 100 percent / H2 / Raney Ni / acetic acid / 3 h4: NaNO2, HOAc / acetic anhydride / 4 h / 0 °C5: CCl4 / 5 h / Heating  

Multi-step reaction with 4 steps 1: 1) 60percent sodium hydride / 1) DMF, 0 deg C, 0.5 h, 2) room temperature, 3 h2: 100 percent / H2 / Raney Ni / acetic acid / 3 h3: NaNO2, HOAc / acetic anhydride / 4 h / 0 °C4: CCl4 / 5 h / Heating  

Multi-step reaction with 3 steps 1: 100 percent / H2 / Raney Ni / acetic acid / 3 h2: NaNO2, HOAc / acetic anhydride / 4 h / 0 °C3: CCl4 / 5 h / Heating