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Abstract: One-pot synthesis of a new 2-pyrone dye (3a) by the reaction of 4-diethylamino-acetophenone (1) with methyl 2-cyano-3,3-bis(methylsulfanyl)acrylate (2) in the presence of sodium hydroxide as the base was carried out in DMSO. Compound 4a was synthesized by the replacement of methylsulfanyl group of 3a with dimethylamine at 4-position of pyrone ring. Similarly, compound 5a was prepared via the reaction of 3a with diethyl malonate. Compounds 3a–5a exhibited the following fluorescence in the solid state: red (3a), green (4a), and orange (5a). In addition, it was revealed that 2-pyrone dyes exhibit fluorescence in various solvents and show positive solvatochromism. Compounds 3a and 5a exhibited intense fluorescence in chloroform and dichloromethane (fluorescence quantum yield Φ: 0.94–0.95). In contrast, compound 4a exhibited intense fluorescence in polar solvents (methanol: Φ = 0.92). These 2-pyrone dyes have the potential for applications in various fields. [Copyright &y& Elsevier]

A very simple and facile one-pot method for the synthesis of pyrimidine derivatives is presented. In this method, 2-aryl-pyrimidine derivatives were prepared by the reaction of ketene N,S-acetal 1 with commercially available aryl aldehydes by heating under solvent and catalyst-free conditions. The synthesized pyrimidine derivatives showed blue-green fluorescence in solid state. [ABSTRACT FROM AUTHOR]

Abstract: A combined experimental and computational study was performed for the spectroscopic properties of novel 2(1H)-pyridones. The compounds were found to be virtually non-fluorescence in solution while modestly fluorescent in solid state. The solvent effects on the UV–vis and fluorescence maxima were estimated by means of a series of ab-initio quantum chemical calculations in conjunction with Polarizable Continuum Model (PCM) method. Influence of structural displacements and intermolecular interactions in crystalline state were examined in details on the spectra of two representative compounds by using Fragment Molecular Orbital (FMO) scheme. The FMO pair interaction analysis of the spectra indicate that (1) intermolecular hydrogen bonds provoke bathochromic shifts (2) electrostatic interactions induce hypsochromic shifts (3) crystal packing effects induce hypsochromic shifts in total from the maxima in vacuo. [Copyright &y& Elsevier]

Novel highly emissive 2-pyridone-based compounds 3a,b and 4a–d were synthesized by a convenient one-pot method from 4-(dialkylamino)acetophenones ( 1a , b ) and cyanoketene dithioacetal ( 2a ) or sulfonyl ketene dithioacetals ( 2b , c ), and their fluorescence properties were investigated. A simple structure modification of 2-pyridones significantly affected their optical properties including the emission wavelength and fluorescence intensity. All the 6-(4-dialkylamino)phenyl-2-pyridones showed positive solvatofluorochromism and intense blue-green fluorescence in nonpolar solvents such as chloroform ( Ф : 0.80–0.92) and dichloromethane ( Ф : 0.83–0.94). A hypsochromic shift of the fluorescence emission maxima and strong fluorescence in a polar solvent were observed by substituting the dimethylamino group with a diethylamino group. Introduction of a sulfonyl group disturbed the molecular planarity of compounds 4a , 4b , and 4d , resulting in a strong fluorescence in acetone ( Ф : 0.86–0.95) and acetonitrile ( Ф : 0.59–0.88). These results indicate that 2-pyridone-based compounds have great potential as fluorophores for various practical applications. [ABSTRACT FROM AUTHOR]