p-Methyl-N-(pentafluorobenzylidene)aniline (1), 1,2,3,4-tetrafluoro-7-methoxyacridine (2), 1,2,3,4,7-pentafluoroacridine (3) and 3-(p-methylanilino)-1,2,4-trifluoro-7-methylacridine (4): four molecules representing key stages in the one-pot synthesis of 1,2,3,4-tetrafluoroacridines by treating pentafluorobenzaldehyde with para-substituted anilines |