Reactions of N-Aminopyridinium Derivatives. VII. : Reaction of N-Aminopyridinium Derivatives with Diazonium Salts

Abstract

Coupling of diazonium salt with N-aminopyridinium derivatives (I and II) affords an azido derivative and pyridine. Diazonium salts used were p-nitro-(III), m-nitro-(IV), and o-nitro-benzene (V), and diazonium chlorides of benzene (VI), pyridine (VII), pyridine 1-oxide (VIII), 4-ethoxycarbonylpyrazole (XXIV), 4, 5-dimethylthiazole (XXVII), and 2, 4-dinitrobenzenediazonium sulfate (XXX). Attempts to isolate the intermediate (XXIII or XXV) in the reaction of III or XXIV with N-aminopyridinium chloride (I) did not materialize due to the lability of the intermediate but some assumption was made on the mechanism of deamination which is similar to that of deoxygenation of pyridine 1-oxide with phosphorus trichloride. Reaction of III with N-aminopyridinium iodide (II) afforded p-nitroiodobenzene (XIX) and a small amount of the azido compound (IX), while the reaction of XXVII and I afforded an azoxy compound (XXVIII) besides the azido compound (XXIX).