Reactions of N-Aminopyridinium Derivatives. I

N-Aminopyridinium halide or its derivatives can be converted into ylide-type compounds, N-iminopyridine or its derivatives, by dehydrohalogenation. Among these ylide compounds, N-acyliminopyridine is quite stable. N-Acylimino compounds thus obtained still have a basic character and readily reacted with various alkylating agents to give novel quaternized pyridine compounds, (N-alkylacylamino) pyridinium salts, in a good yield.