1: With 2-(Mes)-6,7-dihydro-5H-pyrrolo[2,1-c][1,2,4]triazol-2-ium Cl in 1,2-dichloro-ethane T=0°C; 2: With 1,8-diazabicyclo[5.4.0]undec-7-ene in dichloromethane T=0 - 20°C; Further stages.;