A study of some 1-alkyl-2,3-dihydroimidazo[1,2-a]benzimidazoles

A series of 1-alkyl-7-nitro (and 7-amino)-2,3-dihydroimidazo1,2-α]benzimidazoles has been prepared. Similarly, a series of 1-alkyl-2,3-dihydroimidazo1,2-α]benzimidazoles has been prepared. The prototropic tautomerism of this system has been studied. The site of electrophilic attack (alkylation) has been examined. 1-Alkylation takes place under strongly basic conditions and 9-alkylation occurs under neutral conditions.