Polyhalogenonitrobenzenes and derived compounds: Part 5. Improved preparations of 1,2,3,4-tetrafluoro-5,6-dinitrobenzene and 3,4,5,6-tetrafluoro-1,2-phenylenediamine, and the use of the latter for the synthesis of tetrafluorobenzheterocycles

Article abstract of DOI:10.1016/S0022-1139(96)03517-8

The preparation of 2,3,4,5-tetrafluoro-6-nitroaniline (3) by amination of pentafluoronitrobenzene has been speeded up, scaled up and the yield increased by controlling the reaction by TLC monitoring and using 'dry column' chromatography. Compound (3) was readily converted to 1,2,3,4-tetrafluoro-5,6-dinitrobenzene (2) by peroxytrifluoroacetic acid and to 3,4,5,6-tetrafluoro-1,2-phenylenediamine (1) by SnCl₂/HCl, Compound (1) was shown to be a versatile intermediate for the synthesis of tetrafluoro-benzimidazoles, -triazoles and -quinoxalines. The fungicidal activity of the latter are reported here.