1: 62.8 percent / TsOH / benzene / 86 h / Heating 2: 90 percent / NaH / dimethylformamide / 3 h / 50 °C 3: 81 percent / 2 h / Heating 4: 2 N HCl / 1 h / 80 °C View Scheme

hydrogenchloride 1) reflux, 2 h, 2) 80 deg C, 1 h; Yield given. Multistep reaction. Yields of byproduct given. Title compound not separated from byproducts;