نتایج جستجو برای: electron withdrawing
تعداد نتایج: 310077 فیلتر نتایج به سال:
We synthesized C-10 substituted triazolyl artemisinins by the Huisgen cycloaddition reaction between dihydroartemisinins (2) and variously substituted 1, 2, 3-triazoles (8a-8h). The antimalarial activities of 32 novel artemisinin derivatives were screened against a chloroquine-resistant parasite. Among them, triazolyl artemisinins with electron-withdrawing groups showed stronger antimalarial ac...
Substituent effects on iminoboranes XBNH, HBNX and XBNX (X = H, CH3, NH2, OH, F) have been analyzed in the framework of the NBO, AIM and ELF approaches, using B3LYP/6-311++G(d,p) optimized geometries and electron densities. Boron-substituted derivatives, XBNH, are more stable than the corresponding nitrogen-substituted isomers HBNX, with the energy difference increasing as the electron withdraw...
triphenyl phosphine(pph3), an efficient and reusable catalyst, catalysed the synthesis of 2-amino-3-cyano-6-methyl-4-aryl-4h-pyran-5-ethylcarboxylate derivatives by one-pot condensation of aromatic aldehydes, malononitrile and ethyl acetoacetate in etoh-h2o (1:1) at reflux conditions. the results show that aromatic aldehydes containing electron-donating groups or electron-withdrawing groups cou...
An array of aromatic aldehydes with electron withdrawing groupunderwent crossed-Aldol condensation with cycloalkanone in the presence of catalytic amounts of DBSA under aqueous media to afford the corresponding α, ά-bis(substituted-benzylidene) cycloalkanones in good yields. The electronic effects on aromatic aldehydes could be observed. The present method is operationally simple and use of wat...
A method for preparation of a new stable Cu(I) catalyst supported on weakly acidic polyacrylate resin without additional stabilizing ligands is described. A simple and efficient methodology for Ullmann Cu(I) catalyzed C-N cross coupling reactions using this original catalyst is reported. Coupling reactions of 4-chloropyridinium chloride with anilines containing electron donating (EDG) or electr...
1,6-Enynes with electron-donating substituents at the alkyne undergo gold(I)-catalysed single cleavage skeletal rearrangement, whereas substrates with electron-withdrawing substituents evolve selectively to double cleavage rearrangement. Theoretical calculations provide a qualitative rationale for these effects, and suggest that bicyclo[3.2.0]hept-5-enes are involved as intermediates. We provid...
Thiol and selenol esters were synthesized by a direct oxidative coupling reaction of aldehydes with disulfides or diselenides in ethyl acetate under metal-free conditions. Among the oxidants examined, tert-butyl peroxide (TBP) was shown to give the best results. For the substrates with both electron-donating and electron-withdrawing substituents, the reaction proceeded smoothly and gave moderat...
A series of benzimidazolylbenzenesulfonamide compounds containing electron-releasing and electron-withdrawing substituents were synthesized and tested for their in vitro antibacterial activity. Two BZS compounds showed strong antibacterial activity against methicillin-resistant Staphylococcus aureus and Bacillus subtilis. Quantitative studies of their structure-activity relationship using a sim...
The electronic structures and charge transport properties of 1,3,5-tripyrrolebenzene (TPB) and its substituted derivatives with –F and –CN groups have been investigated by DFT calculations in combination with the Marcus hopping model. The dimer geometry was optimized by density functional theory method with dispersion force correction being included (DFT-D). Consequently, the charge transfer in...
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