Studies on Heterocyclic Analogs of Azulenes. XI. Syntheses and Cycloadditions of Cyclohepta[4,5]pyrrolo[1,2-a]imidazoles and Cyclohept[d]imidazo[1,2-a]imidazoles

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Abstract
Cyclohepta[4,5]pyrrolo[1,2-a]imidazoles (1,3a-diazacyclopent[a]azulenes) (2) and cyclohept[d]imidazo[1,2-a]imidazoles (1,3a,9-triazacyclopent[a]azulenes) (6) were synthesized from 2-aminocyclohepta[b]pyrroles and 2-aminocycloheptimidazole, respectively, in moderate to good yields. Reactions of 2 and 6 with reactive acetylenes gave 2-azacyclohepta[ef]cycl[3.2.2]azines together with bis(1,3a-diazacyclopent[a]azuleno)[1,7]diaza[12]annulenes (4) and 2,3-diazacyclohepta[ef]cycl[3.2.2]azines together with bis(1,3a,9-triazacyclopent[a]azuleno)[1,7]diaza[12]annulenes (8), respectively. Reactions of 2 and 6 with electron deficient olefins gave 4 and 8, respectively. These reactions proceeded regioselectively via 1,10-dipolar intermediates.