1121-70-6Relevant articles and documents
Synthesis, characterization, and antibacterial activity of diorganotin(IV) complexes of 4-methylphenol
Sharma, Neeraj,Kumar, Vijay
, p. 2071 - 2085 (2011)
Diorganotin(IV) complexes R2Sn(OC6H 4Me-4)2 (R = Ph, Me, and n-Bu) have been synthesized in good yields by the reaction of Ph2SnCl2, n-Bu 2SnCl2, and Me2SnCl2 with NaOC 6H4Me-4, while complex n-Bu2SnCl(OC 6H4Me-4) has been obtained from the reaction of n-Bu 2SnCl2 with 4-methylphenol in the presence of triethylamine in carbon tetrachloride. The complexes have been characterized by elemental analyses, molar conductance measurements, molecular weight determination, IR, 1H, 13C, and 119Sn NMR spectroscopy as well as by mass spectrometry. The reactions of the complexes with 2- and 3-cyanoanilines yielded 1:2 coordination compounds authenticated by physicochemical as well as by IR, 1H, and 13C NMR spectroscopic data. The bases behaved as monodentate ligands wherein 2-cyanoaniline is bonded through nitrile nitrogen atom, while 3-cyanoaniline is coordinated through amino nitrogen atom. The diorganotin(IV) complexes have also been screened for their antibacterial activity against Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, Shigella flexneri, Proteus mirabilis, and Pseudomonas aeruginosa. The minimum inhibitory concentration values of these complexes show enhanced activity. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. Copyright Taylor & Francis Group, LLC.
Synthesis, characterization and antibacterial activity, of triorganotin(IV) complexes of 4-methylphenol
Sharma, Neeraj,Kumar,Thakur,Kumari,Chaudhry
experimental part, p. 2051 - 2065 (2010/09/04)
The triorganotin(IV) complex of composition Ph3Sn(OArMe-4) has been synthesized in good yields by the reaction of Ph3SnCl with Me3SiOArMe-4/NaOArMe-4, while com-plexes of composition Me 3Sn(OArMe-4) and n-Bu3Sn(OArMe-4) (where -OArMe-4 = -OC6H4CH3-4) have been obtained from the reaction of Me3SnCl and n-Bu3SnCl with 4-methylphenol in the presence of triethylamine in carbon tetrachloride. The complexes have been characterized by elemental analyses, molar conductance measurements, mo-lecular weight determination and IR, 1H and 13C NMR and mass spectral studies. Ther-mal behaviour of the complexes has been studied by TG and DTA techniques. The organotin(IV) complexes have also been screened for their antibacterial properties and are found to exhibit appreciable activity. The reactions of the complexes with 2-, 3-, 4-cyanopyridines yielded 1:1 adducts as confirmed by physicochemical and IR spectral data.
Mechanistic study of Protein Phosphatase-1 (PP1), a catalytically promiscuous enzyme
McWhirter, Claire,Lund, Elizabeth A.,Tanifum, Eric A.,Feng, Guoqiang,Sheikh, Qaiser I.,Hengge, Alvan C.,Williams, Nicholas H.
scheme or table, p. 13673 - 13682 (2009/02/06)
The reaction catalyzed by the protein phosphatase-1 (PP1) has been examined by linear free energy relationships and kinetic isotope effects. With the substrate 4-nitrophenyl phosphate (4NPP), the reaction exhibits a bell-shaped pH-rate profile for kcat/KM indicative of catalysis by both acidic and basic residues, with kinetic pKa values of 6.0 and 7.2. The enzymatic hydrolysis of a series of aryl monoester substrates yields a Bronsted βlg of -0.32, considerably less negative than that of the uncatalyzed hydrolysis of monoester dianions (-1.23). Kinetic isotope effects in the leaving group with the substrate 4NPP are 18(V/K)bridge = 1.0170 and 15(V/K) = 1.0010, which, compared against other enzymatic KIEs with and without general acid catalysis, are consistent with a loose transition state with partial neutralization of the leaving group. PP1 also efficiently catalyzes the hydrolysis of 4-nitrophenyl methylphosphonate (4NPMP). The enzymatic hydrolysis of a series of aryl methylphosphonate substrates yields a Bronsted βlg of -0.30, smaller than the alkaline hydrolysis (-0.69) and similar to the βlg measured for monoester substrates, indicative of similar transition states. The KIEs and the βlg data point to a transition state for the alkaline hydrolysis of 4NPMP that is similar to that of diesters with the same leaving group. For the enzymatic reaction of 4NPMP, the KIEs are indicative of a transition state that is somewhat looser than the alkaline hydrolysis reaction and similar to the PP1-catalyzed monoester reaction. The data cumulatively point to enzymatic transition states for aryl phosphate monoester and aryl methylphosphonate hydrolysis reactions that are much more similar to one another than the nonenzymatic hydrolysis reactions of the two substrates.
