Direct N-nitration of bis(trifluoromethyl)-containing 2-azanorbornanes

Abstract

As reported earlier, reactions of 3 halo 7,7 bis(tri fluoromethyl) 1 azatricyclo[2.2.1.02,6]heptanes with both hydrogen halides1 and O nucleophiles under conditions of proton catalysis2 afford corresponding 2 azanorbor nanes 1. Apparently, such reactions are due to the very weak basic properties of the resulting bicyclic secondary amines, which form no salts even with excess hydrogen halides in their solutions in ether. In addition, the forma tion of 2 azanorbornanes does not hinder the catalytic effect of H2SO4 on reactions of azatricyclanes with O nucleophiles. Analogous nonfluorinated compounds are known to form stable crystalline salts.3,4 Two CF3 groups vicinal to the nitrogen atom are responsible for the weak basic properties of bis(trifluoromethyl) 2 aza norbornanes and allow their direct N nitration. For ex ample, compounds 1a—f undergo nitration in CCl4 with a mixture of nitric and sulfuric acids to give the corre sponding N nitro derivatives 2a—f.