The result obtained indicates the formation of a reaction product whose structure does not contain a fragment of an aldehyde molecule. It should be noted that, in the absence of metallic magnesium and an alkyl-substituted aldehyde in the reaction mixture, pyridine does not undergo any transformation. It is known that TaCl 5 , when reacted with sodium amalgam in a toluene solution, is reduced to TaCl 4 , which has paramagnetic properties . Based on this transformation, we can assume that paramagnetic TaCl 4 is formed in the presence of the aromatic heterocycle pyridine. Our further research will focus on understanding the mechanism of this reaction and expanding the scope of its application by using pyridine derivatives and other heterocyclic compounds.