- Aβ Aggregation inhibitors. Part 1: Synthesis and biological activity of phenylazo benzenesulfonamides
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Phenylazo benzenesulfonamides were designed and synthesized as β-amyloid (Aβ40) fibril assembly inhibitors, and evaluated for inhibition of Aβ40 aggregation and neurotoxicity using rat cortical neurons. Compound 2 (LB-152) was the most potent compound in this study, and the para-NMe2 group on the end of the phenylazo moiety may play an important role in preventing Aβ40 fibril formation. LB-152 provides a new lead for further development of potential β-amyloid aggregation inhibitors to treat AD.
- Lin, Shwu-Jiuan,Shiao, Young-Ji,Chi, Chih-Wen,Yang, Li-Ming
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- Rapid and direct spectrophotometric method for kinetics studies and routine assay of peroxidase based on aniline diazo substrates
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Peroxidases are ubiquitous enzymes that play an important role in living organisms. Current spectrophotometrically based peroxidase assay methods are based on the production of chromophoric substances at the end of the enzymatic reaction. The ambiguity regarding the formation and identity of the final chromophoric product and its possible reactions with other molecules have raised concerns about the accuracy of these methods. This can be of serious concern in inhibition studies. A novel spectrophotometric assay for peroxidase, based on direct measurement of a soluble aniline diazo substrate, is introduced. In addition to the routine assays, this method can be used in comprehensive kinetics studies. 4-[(4-Sulfophenyl)azo]aniline (λ max = 390 nm, ? = 32 880 M?1 cm?1 at pH 4.5 to 9) was introduced for routine assay of peroxidase. This compound is commercially available and is indexed as a food dye. Using this method, a detection limit of 0.05 nmol mL?1 was achieved for peroxidase.
- Mirazizi, Fatemeh,Bahrami, Azita,Haghbeen, Kamahldin,Shahbani Zahiri, Hossein,Bakavoli, Mehdi,Legge, Raymond L.
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p. 1162 - 1169
(2016/10/09)
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- Carbonic anhydrase inhibitors. Diazenylbenzenesulfonamides are potent and selective inhibitors of the tumor-associated isozymes IX and XII over the cytosolic isoforms I and II
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A series of diazenylbenzenesulfonamides, azo-dye derivatives of sulfanilamide or metanilamide incorporating phenol and amine moieties, were tested for inhibition of the tumor-associated isozymes of carbonic anhydrase (CA, EC 4.2.1.1), CA IX and XII. These compounds showed moderate-low inhibitory activities against the cytosolic isoforms CA I and II (offtargets) and excellent, low nanomolar inhibitory activity against the transmembrane CA IX and XII (KIs in the range of 3.5-63 nM against CA IX and 5.0-69.4 nM against CA XII, respectively). The selectivity ratio for inhibiting the tumor-associated CA IX over the offtarget CA II was in the range of 15-104 for these diazenylbenzenesulfonamides, making them among the most isoform-selective inhibitors targeting tumor-associated CAs (over the ubiquitous CA II). Since CA IX/XII were recently shown to be both therapeutic and diagnostic targets for hypoxic solid tumors overexpressing these proteins, such compounds held promise for the management of hypoxic tumors, which are largely non-responsible to classical chemo- and radio-therapy.
- Carta, Fabrizio,Maresca, Alfonso,Scozzafava, Andrea,Vullo, Daniela,Supuran, Claudiu T.
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experimental part
p. 7093 - 7099
(2010/03/03)
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- A mechanistic study of the reactions of formaldehyde with aniline in the presence of sulfite
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1H NMR results are reported for the reactions of hydroxymethanesulfonate, 1, with aniline and its derivatives to produce anilinomethanesulfonates, 3. The mechanism of the reaction involves dissociation of 1 to produce formaldehyde, as a steady state intermediate, which reacts with aniline to give a carbinolamine;? subsequent dehydration and reaction with sulfite produces the product. The kinetics of individual steps have been investigated. The release of sulfite from 1, measured by reaction with iodine, is shown to involve the ionised, dianionic form when pH >3. Rate constants, k2, and equilibrium constants, K2, are reported for carbinolamine formation; the values of k2, but not K2, are affected significantly by substituents in the aniline. It is deduced that the rate-limiting step in the overall formation of products 3 changes in the pH range 6-8 from carbinolamine formation to carbinolamine dehydration.
- Atherton, John H.,Brown, Kathryn H.,Crampton, Michael R.
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p. 941 - 946
(2007/10/03)
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