1972 年 92 巻 1 号 p. 73-91
Various derivatives of N-aminopyridine were synthesized and these derivatives were found to undergo reaction with various nucleophilic reagents under variety of conditions. Progress of this reaction seemed to depend on the activity of the reagents as a nucleophilic species, substituent effect of the substrate, and reaction conditions. As for the substituent effect, electron-withdrawing nature of the substituent on the amino group determines the activity of the substrate while that of the substituent on ring carbon determines the orientation of the reaction, the greater the electron-withdrawing nature of ring carbon, the greater the orientation towards the 2-position. The reaction results in addition and/or substitution reaction and the reaction can be explained witho utinconsistency by assuming the progress of this reaction in two steps of addition and liberation even when only a substitution product is obtained. Depending on whether the addition step is reversible or irreversible, each step will be controlled either by thermokinetics or by chemical kinetics, and orientation towards the 4- or 2-position will be determined by which of these forces would be stronger. Discussions are made on this mechanism.