The mechanism of the electrophilic substitution of heteroaromatic compounds. Part VII. The nitration of pyridines in the α-position and rules for the nitration of substituted pyridines

Abstract

Kinetic criteria show that the nitration of 3,5-dimethoxypyridine proceeds on the conjugate acid species in the 2-position, and that the 6-nitration of 3,5-dimethoxy-2-nitropyridine occurs on the free base. Relative reactivities are compared with the corresponding benzenoid compounds. A set of rules is proposed for the nitration of substituted pyridines and their synthetic applications discussed.