Two dinitrofluorobenzenes (1 and 2) and the commercially available 2,4-isomer were required in connection with a mechanistic study on the Elbs oxidation. Although the 2,6-isomer (1) had been prepared previously using four different procedures, all involving reaction of 2,6-dinitrochlorobenzene with a solid fluoride salt, the yields were difficult to reproduce. The difficulty seems to lie in the physical state of the fluoride salts as was nicely discussed by Smyth et al. This paper describes a fifth modification which includes DMSO for rate acceleration, azeotropic drying, and a finely divided fluoride reagent made from a mixture of CsF and KF.
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