0040-4039/$ see front matter 2011 Elsevier Ltd. A doi:10.1016/j.tetlet.2011.11.097 ⇑ Corresponding author. Tel.: +381 11 3336738; fax E-mail address: [email protected] (B.J. Draku Rate constants for the esterification of eleven 2-[(carboxymethyl)sulfanyl]-4-oxo-4-arylbutanoic acids with diphenyldiazomethane in ethanol at 30 C were determined, and correlated with substituent constants using...

Three series of thioglycosyl donors differing only in their respective aglycon substituents within each series have been prepared as representatives of typical glycosyl donors. The relative anomeric reactivities of these donors were quantified under competitive glycosylation conditions with various reaction time, promoters, solvents and acceptors. Over three orders of magnitude reactivity diffe...

C-K Wong, C J K Hammett, R The, J K French, W Gao, B J Webber, J M Elliott, A W Hamer, J A Ormiston, M W I Webster, R A H Stewart, R V Ameratunga, H D White . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...

A series of five 3-nitroflavones were tested for their ability to inhibit the formation of colon aberrant crypt foci (ACF) induced by a s.c. injection of azoxymethane (C2H6N2O) in rats. Our aim was to relate the electron-donating effects of the 3-nitroflavones as characterized by their Hammett substitution constants with their efficacy in inhibiting ACF. In a first assay (initiation, protocol A...

Systematic studies on phenol derivatives facilitates an explanation of the enhancement or inhibition of the luminol-H2O2-horseradish peroxidase system chemiluminescence. Factors that govern the enhancement are the one-electron reduction potentials of the phenoxy radicals (PhO./PhOH) vs. luminol radicals (L./LH-) and the reaction rates of the phenol derivatives with the compounds of horseradish ...

Substituent effects on the physical properties and pKa of phenol were studied using density functional theory [B3LYP /6-311G(d,p)] calculations. Substituents alter the physical properties of phenol such as the hydroxyl-group C-0 and 0-H bond lengths, the C-0-H bond angle, and the energy barrier to rotation about the C-0 bond, and also influence the hydroxyl-group pK •. Except for the rotational...

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...

A series of molybdenum(vi) cis-dioxo complexes containing tetradentate salan ligands with different para-substitutions on the phenoxy group have been prepared. These complexes catalyse the oxygen atom transfer reaction between dimethylsulfoxide and triphenylphosphine. During oxo transfer catalysis, the complexes are resistant to formation of catalytically inactive oxo-bridged dimeric Mo(v) comp...

Spin-crossover (SCO) behavior of a series of [Fe(X-pybox)2](ClO4)2 was investigated, where X-pybox stands for 4-X-substituted 2,6-bis(oxazolin-2-yl)pyridine with X = H, Cl, Ph, CH3O, and CH3S. We confirmed that the mother compound [Fe(H-pybox)2](ClO4)2 underwent SCO above room temperature. After X was introduced, the SCO temperatures (T1/2) were modulated as 310, 230, and 330 K for X = Cl, Ph, ...