Synthesis and characterization of fluorescent 4,6-disubstituted-3-cyano-2-methylpyridines
摘要:
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.
Polymer-supported preparation of substituted phenols: A new example of simultaneous cyclization-cleavage reaction on solid phase
作者:Alan R Katritzky、Sergei A Belyakov、Yunfeng Fang、John S Kiely
DOI:10.1016/s0040-4039(98)01771-7
日期:1998.10
A series of variously substituted phenols was synthesized in high yields using the “cyclization-cleavage” approach. Base-catalyzed reactions between α,β-unsaturated ketones and polymer-bound acetonyl groups result in a tandem Michael addition/annulation reaction followed by elimination and rearrangement into phenols. Since all intermediates are on the resin until the last stage, the final reaction
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.
Iron catalyzed enantioselective sulfa-Michael addition: a four-step synthesis of the anti-asthma agent Montelukast
作者:James D. White、Subrata Shaw
DOI:10.1039/c4sc00051j
日期:——
catalyzes asymmetric addition of thiols to α,β-unsaturatedketones under mild conditions. The reaction (sulfa-Michael addition) produces β-thioketones in excellent yield and high enantiomeric excess from a wide range of aliphatic and aromatic thiols using chalcones and other conjugated enones as Michael acceptors. With α-substituted α,β-unsaturatedketones as acceptors, the addition shows strong preference