Polyfluorinated 2,4-diaryl-2,3-dihydro-1H-1,5-benzodiazepines: Synthesis and new rearrangement into polyfluorodihydrobenzimidazo[1,2-a]quinolines

Interaction of polyfluorinated chalcones (pentafluorobenzalacetophenone, benzalpentafluoroacetophenone and decafluorochalcone) with 1,2-diaminobenzene in alcohols in the presence of triethylamine or quaternary ammonium salt (TEBAC) has been investigated. In the presence of TEBAC in 2-propanol polyfluorinated 2,4-diaryl-2,3-dihydro-1H-1,5-benzodiazepines are formed. Some of them undergo intramolecular fluorine substitution and unusual rearrangement into a previously unknown polyfluoro-containing tetracyclic compounds—(6aR)-1,2,3,4-tetrafluoro-6a-aryl-6a,7-dihydrobenzimidazo[1,2-a]quinolines, under the reaction conditions as well as in absence of TEBAC. The structures are established on NMR spectra and confirmed by X-ray.