C5H4FN

C5H4FN is the molecular formula associated with fluoropyridines, a family of isomeric heteroaromatic compounds derived from pyridine (C5H5N) by replacing one hydrogen with fluorine. The formula encompasses three structural isomers: 2-fluoropyridine, 3-fluoropyridine, and 4-fluoropyridine. In each isomer the fluorine occupies a different position relative to the ring nitrogen; the pyridine nitrogen is considered position 1, with fluorine at position 2, 3, or 4 respectively.

Preparation and occurrence: Fluoropyridines are prepared by various fluorination methods, including electrophilic fluorination of pyridines or substitution reactions on halogenated pyridines. They are used as building blocks in organic synthesis and often serve as precursors to more complex nitrogen-containing compounds.

Properties: They are generally colorless and can be volatile, with moderate polarity due to the pyridine nitrogen and the C–F bond. They tend to have lower water solubility than pyridine and can act as irritants. The different isomers can exhibit varying reactivity in subsequent transformations because of the fluorine position.

Applications and significance: In medicinal chemistry and agrochemistry, fluoropyridines provide useful scaffolds and reactive handles for cross-coupling and other functionalization reactions. They influence electronic properties and metabolic stability of target molecules, and C5H4FN derivatives are widely used as building blocks in research and development.

Safety: Handling requires standard chemical-safety precautions. Fluoropyridines are typically flammable and may be irritating to skin or eyes; work should be conducted in a ventilated area with appropriate personal protective equipment.