Methylpyridinium

Methylpyridinium is an ion with the formula C5H5NCH3+. It is the N-methylated derivative of pyridine. It confers no color to its salts. The ion is classified as an quaternary ammonium ion.

Preparation and occurrence
Methylpyridinium is prepared by treating pyridine with dimethylsulfate:
 * C5H5N + (CH3O)2SO2  ->  [C5H5NCH3]+CH3OSO3-

It is found in some coffee products. It is not present in unroasted coffee beans, but is formed during roasting from its precursor chemical, trigonelline. It is under investigation by scientists regarding its potential anti-carcinogenic properties, particularly an effect on colon cancer.

Ionic liquid
The chloride salt of N-methylpyridinium behaves as an ionic liquid. Mixtures of that salt and zinc chloride have been characterised over the temperature range 150 –.