Acridine Chichibabin amination

However, acridine shows variable regiochemistry towards nucleophiles. Chichibabin amination with NaNH2 in liquid ammonia leads exclusively to 9-aminoacridine 6, whereas in N,N-dimethylaniline, the main product is 9,9 -bi(9,10-dihydroacridinyl) 7. 

The question of the rate-determining step in the Chichibabin reaction is still open. Clearly, it is difficult to expect that such a complex process can be controlled by any single parameter. On the basis of the rate of hydrogen gas evolution, the following sequence of the reactivity of aza-heterocyclic compounds has been established 1-R-benzimidazoles > isoquinoline > 1-R-perimidines > benzo[/]quinoline > pyridine acridine. Evidently, this raw indicates that sodamide amination depends on number of factors, involving electron deficiency of the substrate C(a)-atom, ease of the adduct aromatization, substrate basicity, etc. Evidently, acridine s position in this raw reflects the difficulty of the y-amination. 

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