Perhalopyridine: Synthesis and Synthetic Utility

Heterocycles represent a larger group of organic compounds and play an important role in allaspects of pure and applied chemistry. The subgroup of this class called perhalogenated heterocycliccompound since the intensive development of the synthetic chemistry of heterocyclesstarted in the last few years [1]. Nowadays halogenated heterocyclic compounds can befound among potent pharmaceuticals, crop protection agents, and products of technical importance.This merging area of organic, heterocyclic, and chlorine organic chemistry is stillrapidly growing and in the last decades a large number of halogenated heterocyclic materialshave been discovered. Substituted pyridines are important material in organic chemistry, biochemistry,and pharmaceutical chemistry [2]. Preparation of highly substituted pyridine derivativesfrom pyridine itself is very difficult and only limited progress has been made usingsuch an approach. In contrast, perhalogenated pyridine are potentially excellent scaffolds becausethey are highly reactive toward nucleophilic attack as a result of their electron-deficientnature, and in principle, all halogen atoms may be displaced by nucleophiles. Mono-, di-, tritetra-and penta substituted pyridine, fused heterocyclic compound, macrocyles and other usefulorganic compounds have been synthesized from the reaction of corresponding C-, N-, S-,P- and O-centered nucleophiles as well as bidentate nucleophiles with perhalogenated pyridine(Fig. 1) [3].