1: 70 percent aq. sulfuric acid / 2 h / 60 °C 2: 89 percent / phosphoryl trichloride / 0.5 h / Heating 3: 84 percent / hydrogen, triethylamine / palladium 10 percent on charcoal / ethanol / 4 h / 25 °C View Scheme

sulfuric acid T=60°C; 2 h; Yield given;