Reaction of 1,8-diazabicyclo[5.4.0]undec-8-ene with methyl3,5-dinitrobenzoate and 1,3,5-trinitrobenzene

1,8-Diazabicyclo[5.4.0]undec-8-ene (DBU) undergoes a double addition reaction with the title compounds forming crimson 2-aminoindole derivatives.