67175-28-4Relevant academic research and scientific papers
Nitrophenol derivatives oxidized by cerium(IV) ammonium nitrate (CAN) and their cytotoxicity
Pan, Wen-Bin,Wei, Li-Mei,Wei, Li-Lan,Wu, Chin-Chung,Chang, Fang-Rong,Wu, Yang-Chang
, p. 581 - 588 (2007/10/03)
Oxidation of a series of phenols with cerium(IV) ammonium nitrate (CAN) in acetonitrile undermild conditions yields the mixture of corresponding nitrophenols. In the cases of methylphenols and hydroxy-carboxylic acids, the steric effect may reduce the nitration reaction. Compounds 3 a and 4b showed selective activities to Hep 3B and Hep G2 cancer cell lines, respectively. Compound 2c showed selective activities to Hep G2 and MDA-MB-231 cancer cell lines. Further more, com pound 10b showed selective activities to Hep G2, Hep 3B, MCF-7 and MDA-MB-231 cancer cell lines.
Kinetics and mechanism of aminolysis of phenyl acetates in aqueous solutions of poly(ethylenimine)
Arcelli, Antonio,Concilio, Carlo
, p. 1682 - 1688 (2007/10/03)
Second-order rate constants (kn) for the aminolysis of some phenyl acetates with poly(ethylenimine) (PEI) were obtained in a pH range 4.36-11.20 at 25 °C in 1 M KC1. Linear Bronsted-type plots (log kn vs pKN of PEI) were found for less reactive esters 2-nitrophenyl acetate, 4-acetoxy-3-chlorobenzoic acid, and 4-acetoxybenzenesulfonate with slopes of 0.92, 0.99, and 0.82, respectively. Curved plots were obtained for 3-acetoxy-2,6-dinitrobenzoic acid and 4-acetoxy-3-nitrobenzene-sulfonate, which are consistent with a stepwise reaction. The most likely mechanism involves the existence of a tetrahedral intermediate (T±) and a change in the rate-determining step from its breakdown to its formation when the basicity of the polyamine increases. A semiempirical equation was used to calculate the values of limiting slopes of the plots (0.9 and 0.1 for both esters) and pKN at the center of the curvature of the plots (p-KN° = 7.94 and 9.02, respectively). The values of pKN° are lower than those estimated for the aminolysis of the same esters with simple monomeric amines (pKn° > 11) because of a better leaving ability of the aryl oxide ion from the tetrahedral intermediate when amino groups of PEI instead of simple amines are involved. Estimation of the pK's of the reactive intermediates and of the microscopic rate constants for the proton transfer from T± to PEI or from PEIH+ to T± indicates that either base or acid catalysis is unimportant in the aminolysis of these esters by PEI.
Polyelectrolyte-Catalyzed Acetyl Transfer Reactions. Structure-Reactivity Relationships in the Aminolysis of Phenyl Acetates by Poly(ethyleneimine) and Glycylglycine.
Arcelli, Antonio,Concilio, Carlo
, p. 201 - 226 (2007/10/02)
The aminolysis of a wide series of substituted phenyl acetates by poly(ethyleneimine) (PEI) is studied.Saturation kinetics are observed and the ester-polyamine association equilibrium constants, as well as the rates of decomposition of the resulting intracomplexes, are determined.Unlike the association constants, the rate constants for the reaction of the intracomplex are found to depend on the acidity of the leaving groups.Two Broensted-type relationships are found for anionic and neutral esters having different intercepts but proximate slopes -0.73 and -0.77 respectively, which decrease to lower values with very reactive phenyl acetates.Only one broken Broensted relationship is found for the bimolecular aminolysis by glycylglycine.The results are consistent with the formation of a tetrahedral intermediate by the amino groups of PEI, with a change in the rate-determining step for very reactive esters from the breakdown to the formation of the tetrahedral intermediate.The higher reactivity of PEI, which is more relevant with substrates containing anionic groups, is principally ascribed to the electrostatic polyelectrolyte-substrate binding.A minor role is played by the increase in the acidity of the conjugate acid of the leaving group, i.e. of its leaving ability, caused by the association of the ester with PEI: values of effective molarity in the range of 10 to 15 mol cm-3 are found.
