4-Methylpyridine

4-Methylpyridine is the organic compound with the formula CH₃C₅H₄N. It is one of the three isomers of methylpyridine. This pungent liquid is a building block for the synthesis of other heterocyclic compounds. Its conjugate acid, the 4-methylpyridinium ion, has a pK_a of 5.98, about 0.7 units above that of pyridine itself.^[1]

4-Methylpyridine

Names
Preferred IUPAC name 4-Methylpyridine
Other names 4-Picoline γ-picoline
Identifiers
CAS Number	108-89-4 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:32547 N
ChemSpider	13874733 N
ECHA InfoCard	100.003.298
PubChem CID	7963
UNII	TJD6V9SSO7 Y
CompTox Dashboard (EPA)	DTXSID4021892
InChI InChI=1S/C6H7N/c1-6-2-4-7-5-3-6/h2-5H,1H3 N Key: FKNQCJSGGFJEIZ-UHFFFAOYSA-N N
SMILES Cc1ccncc1
Properties
Chemical formula	C6H7N
Molar mass	93.129 g·mol−1
Appearance	colorless liquid
Density	0.957 g/mL
Melting point	2.4 °C (36.3 °F; 275.5 K)
Boiling point	145 °C (293 °F; 418 K)
Solubility in water	Miscible
Magnetic susceptibility (χ)	−59.8·10−6 cm3/mol
Hazards
Flash point	39 °C (102 °F; 312 K)
Autoignition temperature	538 °C; 1,000 °F; 811 K
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Production and uses

4-Methylpyridine is both isolated from coal tar and is synthesized industrially. It forms via the reaction of acetaldehyde and ammonia in the presence of an oxide catalyst. The method also affords some 2-methylpyridine.

4-Methylpyridine is of little intrinsic value but is a precursor to other commercially significant species, often of medicinal interest. For example, ammoxidation of 4-methylpyridine gives 4-cyanopyridine, the precursor to a variety of other derivatives such as the antituberculosis drug isoniazid.^[1]

Toxicity

Like most alkylpyridines, the LD50 of 4-methylpyridine is modest, being 1290 mg/kg (oral, rat).^[1]