1,5-Diazabicyclo[5.4.0]undec-5-ene 1,8-Diazabicyclo[5.4.0]undec-7-ene 2,3,4,6,7,8,9,10-Octahydropyrimido[1,2-.alpha.]azepine 6674-22-2 DBU NSC111184 Pyrimido[1,2-a]azepine, 2,3,4,6,7,8,9,10-octahydro-