4-[4-(4-Fluoro­phen­yl)-2-methyl-5-oxo-2,5-dihydro­isoxazol-3-yl]-1-methyl­pyridinium iodide–4-[3-(4-fluoro­phen­yl)-2-methyl-5-oxo-2,5-dihydro­isoxazol-4-yl]-1-methyl­pyridinium iodide (0.6/0.4)

摘要

The crystal structure of the title compound, C16H16FN2O2 +·I−, was determined as part of a study of the biological activity of isoxazolone derivatives as p38 mitogen-activated protein kinase (MAPK) inhibitors. The X-ray crystal structure of 4-[4-(4-fluoro­phenyl)-2-methyl-5-oxo-2,5-dihydro­isoxazol-3-yl]-1-methyl­pyridinium iodide showed the presence of the regioisomer 4-[3-(4-fluoro­phenyl)-2-methyl-5-oxo-2,5-dihydro­isoxazol-4-yl]-1-methyl­pyridinium iodide. The synthesis of the former compound was achieved by reacting 4-(4-fluoro­phenyl)-3-(4-pyridyl)isoxazol-5(2H)-one after treatment with Et3N in dimethyl­formamide, with iodo­methane. The unexpected formation of the regioisomer could be explained by a rearrangement occurring via aziridine of the isoxazolone compound. The regioisomers have site occupancies of 0.632 (4)/0.368 (4). The two six members rings make a dihedral angle of 66.8 (2)°.