Structural Isomerization of 2-Anilinonicotinic Acid Leads to a New Synthon in 6-Anilinonicotinic Acids

Abstract

Through structural modification of 2-anilinonicotinic acid by isomerization, a new synthon, acid-aminopyridine, is created, and the two original synthons, i.e., the acid−acid homosynthon and acid−pyridine heterosynthon are no longer observed in the newly designed 6-anilinonicotinic acids. The new synthon has a hydrogen-bond strength rivaling that of the acid−acid homosynthon and the acid−pyridine heterosynthon, as suggested by theoretical calculations, which explains its formation.

Effect of Homologation on the Polymorphism of Anthranilic Acids

“…However, this rotatability does not necessarily lead to polymorphism in these compounds as FA − and many substituted FAs currently have only one known form. Still, substitution on either or both aromatic rings changes their polymorphability, and synthon polymorphism , and packing polymorphism , are also possible.…”