fluoridepyridine

Fluoropyridine refers to aromatic heterocycles in which fluorine replaces a hydrogen on the pyridine ring. The term covers three regioisomers: 2-, 3-, and 4-fluoropyridine. Alternative names found in older literature include pyridinyl fluoride or pyridine fluoride.

All share the formula C5H4FN; physical properties vary by isomer. Fluoropyridines are colorless liquids or low-melting solids; boiling points vary with substitution. The fluorine substituent withdraws electron density, reducing basicity and influencing electrophilic and nucleophilic reactions. The C−F bond is strong, contributing to stability and metabolic resistance, making fluoropyridines valuable building blocks in medicinal and agrochemical research.

Fluoropyridines are typically prepared by electrophilic fluorination of halopyridines using reagents such as N-fluorobenzenesulfonimide (NFSI) or Selectfluor, or by deoxyfluorination of hydroxy or oxide derivatives. Other routes include fluorination of pyridine N-oxides followed by reduction. Purification is by standard methods; they are commercially available.

Applications: They serve as versatile intermediates for pharmaceuticals, agrochemicals, and functional materials; used to introduce fluorine into heteroaromatics or as handles for further functionalization.

Safety: Fluoropyridines are irritants and may be toxic; handle with care.