1: 84 percent / 1.) aq.NaOH, 2.) 4 M HCl / 1.) 100 deg C, 10 h, 2.) 150-160 deg C, 4 h, 2: 85 percent / Na / toluene / 0.5 h / 110 °C 3: 74 percent / 57percent H3PO4 / 3 h / 50 - 60 °C View Scheme