1: 9.1 g / 1.) conc. hydrochloric acid, sodium nitrite, 2.) phosphinous acid / H2O; dioxane / 20 h / 0 °C 2: 92 percent / hydrogen, triethylamine / Engelhard 10percent palladium-charcoal / ethanol View Scheme

hydrogenchloride; hypophosphorous ether; sodium nitrite in 1,4-dioxane; water T=0°C; 20 h;