1: 96 percent / various solvent(s) / 15 h / 250 °C 2: 48 percent / POCl3 / dimethylformamide 3: 49 percent / NaOH, H2 / Raney nickel / ethanol / 900.07 Torr View Scheme

in various solvent(s) T=250°C; 15 h;