1: 50 percent / Zn, AcOH / aq. ethanol / 1 h / 70 °C 2: 80 percent / PPA, P2O5 / 2 h / 200 °C 3: 1.) SeO2, 2.) 30percent H2O2 / 1.) dioxane, H2O, reflux, 2 h, 2.) AcOH, r.t., 2.5 h View Scheme

trichlorophosphate 3 h; Heating;

1: 42 percent / DBU, MnO2 / tetrahydrofuran / 8 h / Heating 2: 91 percent / POCl3 / 3 h / Heating View Scheme