نتایج جستجو برای: substituent effect
تعداد نتایج: 1646024 فیلتر نتایج به سال:
When various p-substituted phenols (substituent = NO2, CN, CH2OH, COCH3, COPh, COOH, F, Cl, and Br) were incubated with rat liver microsomes, the substituent was eliminated to produce hydroquinone, and the reaction was inhibited by CO and a cytochrome P450-specific inhibitor. In the case of p-cresol (substituent = CH3), p-toluquinol was formed instead of hydroquinone. Experiments using 18O2 pro...
Candida antarctica lipase B catalyzed the stereoselective ammoniolysis of N-alkyl aziridine-2-carboxylates in tBuOH saturated with ammonia and yielded the (2S)-aziridine-2-carboxamide and unreacted (2R)-aziridine-2-carboxylate. Varying the N-1 substituent on the aziridine ring changed the rate and stereoselectivity of the reaction. Substrates with a benzyl substituent or a (1'R)-1-phenylethyl s...
In this study, absorption spectra of sixteen azo dyes have been recorded in various solvents. These azo dyes have substituents such as OH, SO3H, Cl, I, NO2, C2H5 and OCH3 in different positions of phenyl ring. There is a shift in λmax whose amount is dependent upon the type and position of substituent on the ring. The effects of substituent on the absorption spectra of azo dyes are interpreted ...
The interpretation of nuclear magnetic resonance (NMR) chemical shifts plays an increasingly important role in the structure elucidation flavonoids. Despite fact that 3H signal methoxy (OMe) group appears as a singlet 1 H NMR spectrum, its shift is not reliably indicative OMe-substitution aromatic rings, unlike 13 C shift, which can be useful for determination molecular For example, ortho-subst...
We have developed a highly atom efficient synthesis of tetrasubstituted 3(2H)-furanones from easily accessible starting materials such as C,N-diarylaldonitrones and dibenzoylacetylene. Control experiments revealed that reaction aldonitrones having electron-withdrawing groups on the C-aryl substituent in polar aprotic solvents exhibited high product selectivity while temperature has only negligi...
We developed a simplified assay for estimating efflux by measuring the effect of reserpine on the growth of Streptococcus pneumoniae and Staphylococcus aureus over 7 h. Reserpine enhanced ciprofloxacin and levofloxacin 17 to 68%. The hydrophobic drug trovafloxacin and the drug moxifloxacin, with a bulky C-7 substituent but hydrophilicity similar to that of levofloxacin, showed little (0 to 11%)...
We demonstrated recently that organocatalysts, based on a nucleophilic core (N-alkylimidazole or 4-aminopyridine) and decorated with an extensive secondary-sphere envelope (connected to the through benzyl substituent), strongly affect site selectivity in acylation phosphorylation of amphiphilic diols, sometimes entirely overriding innate predisposition substrate. Preliminary studies pointed out...
Linear free energy relationships (LFER) were applied to the IR, Hand C-NMR spectral data of N-(substituted phenyl)-2-cyanoacetamides. A variety of substituents were employed for phenyl substitution and fairly good correlations were obtained using the simple Hammett and the Hammett–Taft dual substituent parameter equations. The correlation results of the substituent induced C-NMR chemical shifts...
In this work, the radial distribution function (RDF) of H2 adsorption on coronene (C24) and its Si Substituted forms was investigated by Monte Carlo method. The effect of number and position of silicon substituent on the Coronene (C24) was compared. The maximum value of RDF at 298 K and 0.1 MPa is 4.34 for 18 Si, A structure at 0.73 Å. On the basis of results, t...
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