1,4-diaza-bicyclo[2.2.2]octane; 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine; 1,8-diazabicyclo[5.4.0]undec-7-ene; triethylamine in methanol Lossen Rearrangement; 3 h; RefluxGreen chemistry;

sodium hydroxide in dimethyl sulfoxide T=80°C; Lossen rearrangement; 1.5 h;