Reaction of Trichloromethylarenes with Pyridine: A Novel Synthesis of N-(4-Pyridyl)pyridinium Salts and Aromatic Aldehydes

We have shown that in reductive condensation of trichloromethylarenes with hydroxylamine and hydrazines in pyridine the reduction stage, involving the exchange of one chlorine atom for a hydrogen atom, can proceed without participation of hydroxylamine or hydrazine via the interaction of trichloromethylarene with pyridine leading to the formation of N-[N′-(α-chlorobenzyl- 4-pyridyl)]pyridinium salts which give after hydrolysis N-(4-pyridyl)pyridinium dichloride and respective aromatic aldehydes in high yields.