1.1: 78 percent / acetonitrile / 12 h / Heating 2.1: 86 percent / diisopropylamine; phosphoryl chloride / CH2Cl2 / 1 h / -30 °C 3.1: 100 percent / aq. potassium hydroxide / tetrahydrofuran / 5 h / 20 °C 4.1: toluene / 0.17 h / 20 °C 4.2: toluene / 15 h / 20 °C 5.1: aq. HCl / tetrahydrofuran / 0.5 h / 20 °C View Scheme