4,6-Disubstituted-3-cyano-2-methylpyridines, easily prepared by treating alpha,beta-unsaturated carbonyl compounds with beta-aminocrotononitrile in the presence of potassium tert-butoxide, have been found to show intense fluorescence in the region of 400-552 nm. 3-Cyano-4,6-bis(4-methoxyphenyl)-and 3-cyano-4,6-di(2-furyl)-2-methylpyridines show more intense fluorescence than 7-diethylamino-4-methylcoumarin. The 3-cyano group of pyridines increases the fluorescence intensities and improves photostabilities.
Shibata, Katsuyoshi; Katsuyama, Isamu; Izoe, Hideaki, Journal of Heterocyclic Chemistry, 1993, vol. 30, # 1, p. 277 - 281
Direct synthesis of 2-methylpyridines <i>via</i> I<sub>2</sub>-triggered [3 + 2 + 1] annulation of aryl methyl ketoxime acetates with triethylamine as the carbon source
A facile and efficient [3 + 2 + 1] annulation of aryl methyl ketoximeacetates and triethylamine for the synthesis of 2-methylpyridines was disclosed. This reaction demonstrated that I2 was effective in triggering N–O bond cleavage of oxime acetates generating imine radicals. It was noteworthy that this transformation employed triethylamine as the carbon source for the direct formation of pyridines