Notes Journal of Medicinal Chemistry, 1982, Vol. 25, No. 10 1259 pyridine-3-carb0nitrile.~~ In their paper, the authors reported that the nitration of 3 with HN03 in sulfuric acid at 0 “C gave exclusively the 3-nitro isomer 4. This result indicates that under such conditions the directive influence of the pyrrole ring nitrogen on the electrophilic substitution exceeds that of the N-oxide. The different orientation of the electrophile in the nitration of 3 in sulfuric or ...