IN recent papers we showed that ammonia (in ether) l and methylamine (in 3% ethanol- ether) a reacted with pentafluoronitrobenzene to replace mainly (-70%) the fluorine ortho to the nitrogroup. In contrast, with dimethylamine (in 3% ethanol-ether), 2 with sodium methoxide (in methanol), with pentafluorophenylmagnesium bromide (in tetrahydrofuran), 3 and with pentafluorophenyllithium (in ether),* the para-fluorine was predominantly (> 80y0 ...