N-methyl-1,3-benzothiazole-2(3H)-selone; trifluoroessigsaeure in dichloromethane T=25°C; 5 h;

1: 68 percent / sodium azide, ammonium chloride / dimethylformamide / 1.2 h / Heating 2: 1.) 1.4 M methanolic hydrochloric acid / 1.) reflux, 1.5 h; 2.) pyridine, roomtemp., overnight 3: 82 percent / barium hydroxide octahydrate / methanol / 0.17 h / Ambient temperature 4: 79 percent / H2 / Pd-black / H2O / 1 h View Scheme