A kinetic study on aminolysis of 4-chloro-2-nitrophenyl X-substituted-benzoates (6a-i) in MeCN is reported. The Hammett plot for the reactions of 6a-i with piperidine consists of two intersecting straight lines, while the Yukawa-Tsuno plot exhibits an excellent linear correlation with ρX = 1.03 and r = 0.78. The nonlinear Hammett plot is not due to a change in rate-determining step (RDS) but is...

Abstract The electron‐donating and ‐accepting power of organic substituents is an important parameter affecting many properties parent molecules, most notably their reactivity p K a ionisable groups. These substituent are described by Hammett σ constants obtained measuring ionization substituted benzoic acids. Although values the have been measured for common functional groups, data not availab...

Polarographic reduction of 2-arylazo2-bromo-5,5-dimethylcyclohexane-1,3-diones takes place in a single step involving two electrons. Well-defined, diffusion controlled, irreversible waves are obtained in the pH range 2.0 -11.0. The Ei,2 value shifts towards more negative potentials with increasing pH. Methyl, Methoxy, chloro, bromo and ethoxy groups show positive polarographic ortho shift (~o)....

The cationic ruthenium catalyst Ru(3)(CO)(12)/NH(4)PF(6) was found to be highly effective for the intermolecular coupling reaction of pyrroles and terminal alkynes to give gem-selective alpha-vinylpyrroles. The carbon isotope effect on the alpha-pyrrole carbon and the Hammett correlation from a series of para-substituted N-arylpyrroles (rho = -0.90) indicate a rate-limiting C-C bond formation s...

A straightforward stereoselective and enantiodivergent cyclization strategy for the construction of γ-lactams is described. The cyclization strategy makes use of chiral malonic esters prepared from enantiomerically enriched monoesters of disubstituted malonic acid. The cyclization occurs with the selective displacement of a substituted benzyl alcohol as the leaving group. A Hammett study illust...

A series of p- and m-substituted phenols were examined for their effect on the cyclooxygenase activity of prostaglandin H synthase in 0.1 M phosphate buffer at pH 8.0 and 25.0 +/- 0.1 degrees C. A biphasic response was observed. At low concentrations phenols stimulate, but at higher concentrations inhibit, cyclooxygenase activity. Both enhancement and inhibition are increased by phenolic substi...

A set of different donor-π-acceptor compounds having dicyanovinyl as the acceptor and aryl moieties as donors were synthesized by Knoevenagel condensation. The UV-visible absorption and fluorescence spectra were investigated in different solvents. The optical band gab energy (Eg) was linearly correlated with the Hammett resonance effect of the donor to reveal that the higher the value of Hammet...

Yeast alcohol dehydrogenase has been found to catalyze the reduction of a series of para-substituted benzaldehydes at markedly different rates. By steady state kinetic analysis, values of kB and ko have been obtained for yeast alcohol dehydrogenase reduction of $-Br-, p-Cl-, H-, &CH3, &CH80benzaldehyde by reduced nicotinamide adenine dinucleotide (NADH) and reduced nicotinamide adenine dinucleo...

Kinetic studies of the reactions of α-bromoacetanilides [YC6H4NHC(=O)CH2Br] with substituted benzylamines (XC6H4CH2NH2) have been carried out in dimethyl sulfoxide at 35.0 C. The Hammett plots for substituent (Y) variations in the substrate (log kN vs. σY) are biphasic concave upwards/downwards with breaks at Y = 4-Cl (σY = 0.23). The Hammett coefficients ρY and the cross-interaction constant ρ...

A series of paddlewheel diruthenium(ii, ii) complexes with various chlorine-substituted benzoate ligands (Cl-series) was synthesized as tetrahydrofuran (THF) adducts [Ru2(ClxPhCO2)4(THF)2]; where ClxPhCO2(-) = o-chlorobenzoate, ; m-chlorobenzoate, ; p-chlorobenzoate, ; 2,3-dichlorobenzoate, ; 2,4-dichlorobenzoate, ; 2,5-dichlorobenzoate, ; 2,6-dichlorobenzoate, ; 3,4-dichlorobenzoate, ; 3,5-dic...