1: With pyridine; 1,8-diazabicyclo[5.4.0]undec-7-ene T=80°C; 12 h; 2: With acetic anhydride T=80°C; 3 h; 3: With hydrogen bromide in 2,2,2-trifluoroethanol T=80°C; 14 h; Further stages.;