selenium T=300°C; 8 h;

1: 85 percent / NaOH / aq. ethanol / r.t., 30min., then reflux, 4h 2: 84 percent / polyphosphoric acid / 1.5 h / 190 - 200 °C 3: 63 percent / Se powder / 8 h / 300 °C View Scheme

1: 85 percent / NaOH / aq. ethanol / r.t., 30min., then reflux, 4h 2: 84 percent / polyphosphoric acid / 1.5 h / 190 - 200 °C 3: 63 percent / Se powder / 8 h / 300 °C View Scheme

1: 94 percent / LiAlH4 / diethyl ether / 3 h / Heating 2: 85 percent / NaOH / aq. ethanol / r.t., 30min., then reflux, 4h 3: 84 percent / polyphosphoric acid / 1.5 h / 190 - 200 °C 4: 63 percent / Se powder / 8 h / 300 °C View Scheme

1: 1. conc. hydrochloric acid, NaNO2; / 1. 0 degC, 30min.; 2. 40 - 45 degC 2: 94 percent / LiAlH4 / diethyl ether / 3 h / Heating 3: 85 percent / NaOH / aq. ethanol / r.t., 30min., then reflux, 4h 4: 84 percent / polyphosphoric acid / 1.5 h / 190 - 200 °C 5: 63 percent / Se powder / 8 h / 300 °C View Scheme

1: 84 percent / polyphosphoric acid / 1.5 h / 190 - 200 °C 2: 63 percent / Se powder / 8 h / 300 °C View Scheme