in methanol; acetic acid 2 h; Ambient temperature;

triethylamine in dichloromethane 1.) 10 h., room temp.; 2.) reflux, 2 h.;

lead(IV) acetate in acetic acid 5 h;

1: 84 percent / ammonia / methanol / 72 h 2: 66 percent / sodium acetate, bromine / acetic acid / 3 h 3: 71 percent / triethylamine / propan-2-ol / 1 h / Heating 4: 20 percent / propan-2-ol / 3 h / Heating View Scheme