This study is focused on the synthesis of urea and amide derivatives particularly, since the amide moiety is an essential binding group at the binding site. Urea derivatives 3-7 and 13-14 were obtained by reaction of 2-aminopyrimidines and other amines with diverse isocyanates in pyridine as a solvent under reflux. The urea derivatives were obtained in low yield because of the highly electron deficient nature of the amino group of the 2-aminopyrimidine. Amide derivatives 8-10 were obtained in moderate yields by reaction of compound 1 with aryl chloride derivatives. Also, arylamine 11 was synthesized by Buchwald-Hartwig amination in moderate yields. Most of the compound did not show good activity against A375P melanoma cells, compared with Sorafenib as control compound.
A group of new N,N-bis(5-acetylpyridin-2-yl)phenylamine derivatives was synthesized in good yield applying an optimized Buchwald-Hartwig amination protocol. The synthesized compounds showed UV absorption maxima in the range of 320-360 nm, and showed good luminescence at dilute concentrations in the blue region of the spectra (in the range of 480-497 nm). They showed also a bathochromic shift associating the increase in solvent polarity. The synthesized compounds could be investigated for use in OLEDs or as potential monomers for PLEDs.
Although the pyrimidine derivatives were obtained in low yields ranging from 8% to 20%, we reported the successful preparation of N,N-diaryl-pyrimidin-2-amine derivatives starting from the corresponding 2-aminopyrimidines (1a-1c), by direct palladium-catalyzed arylation using different arylbromides. The reasons of low yields are thought to be the electronic and steric effects by the neighboring aromatic systems. The absorption spectra and photoluminescent spectra of compounds (3a 3g and 4a-4c) were measured using dichloromethane on the concentration of 25 mM by UV vis spectroscopy and luminescent spectroscopy. Pyrimidine derivatives 4a, 4b, and 4c showed moderate emission maxima at 474 nm, 481 nm, and 367 nm, respectively, while other compounds showed very weak photoluminescence or no photoluminescence at all.
Recent years have brought remarkable developments in white light emitting devices (WLEDs) and white organic light-emitting devices (WOLEDs). However, their efficiency, CIE values, CRI and lifetime are still not ideal. This review covers detailed discussion about syntheses of organometallic complexes, inorganic phosphors and quantum dots used in WLEDs, WOLEDs and their electroluminescent properties until December 2007.
Development of white light emitting materials has been an interesting area for scientists and scientists have developed many organic, polymer and inorganic materials for white electroluminescent devices. Among them, single component small molecules gave best results in terms of efficiency, simplicity of device fabrication, and CIE values. Therefore, this review covers detailed discussion about syntheses of small compounds used in white organic light emitting devices until 2007.