Systèmes aromatiques à 10 électrons π dérivés de l'aza-3a pentalène. XXXII. Recherches dans la série du pyrazolo[1,5-a]benzimidazole

The aromaticity of a 3a-azepentalene derivative, the 2-methyl-pyrazolo1,5-a]benzimidazole, has been studied by comparison of its chemical reactivity with those of a model compound, the l-phenyl-3-methyl-5-aminopyrazole. The mono- and di-protona-tion, alkylation, quaternization, formylation, acetylation reactions and the behaviour of the N-acetyl derivatives have been investigated. The conclusion favours a strongly polarized aromatic structure.