Selective Dimerizations of Substituted N-Aminopyridinium Salts and Their Benzologues

Article abstract of DOI:10.1021/jo00274a020

N-Aminopyridinium salts bearing ester, aroyl, and cyano functions in position 2 as well as their differently annelated benzologues were reacted with hydroxide ion and alkoxides.In the case of ester compounds 1, 3, and 5, transesterification and dimerization reactions were found.Keto salts 7, 13, and 15 showed dimerization reactions coupled with methanolysis.Monocyclic cyano salt 17 gave amino-as-triazinium double salt 20 while the benzologues (21 and 27) showed three different reactions depending on the conditions used: (a) removal of the cyano group (formation of 22 and 28), (b) formation of new fused 1,2,4-triazole derivatives (26 and 29), and (c) formation of tetrazine-fused dimers (24 and 30).All N-amino-3-substituted-isoquinolinium salts (32) resulted in dimerizations retaining the 3-substituent.Comparison of these results showed that reactivity of the N-amino compound is mainly influenced by the nature of the substituents and by the relative position of the fused benzene ring with respect to the N-amino function.