1-Methylpyridinium salts showed no reaction with excessive hydroxylamine, but nicotinic acid derivatives in HMPT gave the corresponding N-oxides. 3-Acetyl-1-methylpyridinium iodide generated the hydroximino-pyridine 1-oxide 13 and the isoxazoles 14, 15E, and 15Z. 2- and 4-Cyano-l-methylpyridinium iodides underwent no ring cleavage, but altered only the functional group. However, the 3-cyano compound was converted into the corresponding pyridine N-oxides with carboxamide, hydroxyamidine and carbaldoxime groups.