The Synthesis of Zinquin Ester and Zinquin Acid, Zinc(II)-Specific Fluorescing Agents for Use in the Study of Biological Zinc(II)

Abstract

The syntheses of Zinquin ester [ethyl [2-methyl-8-(p- tolylsulfonylamino )-6-quinolyloxy]acetate] and the corresponding acid, both of which are zinc(II)-specific fluorophores , are described. 6-Methoxy-2-methyl-8-(p- tolylsulfonylamino ) quinoline (2) can be demethylated , with boron tribromide, to form either the expected phenol or a mixture of the phenol and the corresponding 5-bromo derivative depending upon the reaction conditions. These compounds react with ethyl bromoacetate to give the corresponding esters, as well as the 5-ethoxycarbonyl derivative formed by electrophilic substitution. Halogenation of the sulfonamide (2) occurs readily at the 5-position. The 5-iodo product undergoes a Heck coupling with ethyl acrylate . The crystal structures of ethyl [5-ethoxycarbonylmethyl-2-methyl-8-(p- tolylsulfonylamino )-6-quinolyloxy]acetate and [5-carboxymethyl-2-methyl-8-(p- tolylsulfonylamino )-6-quinolyloxy]acetic acid are described.

Use of a Zinc Fluorophore to Measure Labile Pools of Zinc in Body Fluids and Cell-Conditioned Media

“…Zinquin [ethyl-(2-methyl-8- p -toluenesulfonamido-6-quinolyloxy)-acetate] was synthesized according to a previously published method (22). It can be obtained from Dr. David Ward (Department of Chemistry, University of Adelaide, Adelaide, South Australia; david.ward@adelaide.edu.au) or from several other commercial sources including Toronto Research Chemicals (North York, ON, Canada) and Sigma-Aldrich (St. Louis, MO, USA).…”

Intracellular Zinc Depletion Induces Caspase Activation and p21Waf1/Cip1Cleavage in Human Epithelial Cell Lines

“…Major materials and their suppliers were: EDTA, EGTA, herring sperm DNA, Nonidet P-40 (NP-40), dithiothreitol (DTT), sucrose, HEPES (Sigma Chemical, St. Louis); complete protease inhibitor cocktail (Boehringer Mannheim, Mannheim, Germany); penicillin/streptomycin, EDTA/trypsin, RPMI 1640 culture medium, glutamine, CHAPS (ICN, Aurora, OH); gentamicin (David Bull Laboratories, Melbourne); Coomassie brilliant blue G-250 (BDH, Sydney); fetal bovine serum (FBS; Biosciences, Sydney); zDEVD-AFC, zVAD-fmk, zDEVD-fmk (Kamiya Biomedical, Tukwila, WA); VEID-AFC (Calbiochem NSW, Alexandria, Australia); Zinquin, ethyl-[2-methyl-8-p-toluenesulphonamido-6-quinolyloxy]acetate [23] was obtained from A. D. Ward, Department of Chemistry, University of Adelaide, South Australia), dissolved in DMSO as a 5 mM stock solution and stored in aliquots at Ϫ20ЊC in the dark. All other reagents were reagent grade, unless indicated.…”

Visualization of labile zinc and its role in apoptosis of primary airway epithelial cells and cell lines

“…The major materials were EDTA, EGTA, herring sperm DNA, Hoechst 33258, Nonidet P-40 (NP-40), dithiothreitol, sucrose, HEPES, TPEN, sodium pyrithione, amphotericin B, insulin, transferrin, epidermal growth factor (EGF), protease (from Streptomyces griseus), and retinoic acid (all from Sigma, St. Louis, MO); hematoxylin staining solution, eosin staining solution, H 2 O 2 (30% wt / vol), and sodium butyrate (all from BDH, Poole, UK); LHC-9 basal medium (Clonetics, Walkersville, MD), RPMI 1640 medium, penicillin-streptomycin, EDTA-trypsin, L-glutamine, 3-[(3-cholamidopropyldimethylammonio)-1-propanesulfonate] (CHAPS; ICN, Aurora, OH); fetal bovine serum (Biosciences, Sydney, Australia), Percoll (Amersham Pharmacia Biotech, Uppsala, Sweden); gentamicin (David Bull Laboratories, Melbourne, Australia); Asp-Glu-Val-Asp 7-amino-4-(trifluoromethyl)coumarin (DEVD-AFC) and Tyr-Val-Ala-Asp-AFC (YVAD-AFC; both from Kamiya Biomedical, Tukwila, WA); Val-Asp-Val-Ala-Asp-AFC (VDVAD-AFC), Leu-Glu-Val-Asp-AFC (LEVD-AFC), Trp-Glu-His-Asp-AFC (WEHD-AFC), Val-Glu-Ile-Asp-AFC (VEID-AFC), and Leu-Glu-His-Asp-AFC (LEHD-AFC; all from Calbiochem); epoxypropane and Procure 812 resin (both from Electron Microscopy Sciences, Fort Washington, PA); Tissue-Tek optimum cutting temperature compound (Miles); and ethyl-(2-methyl-8-p-toluenesulfonamido-6-quinolyloxy)acetate [Zinquin (21); Department of Chemistry, University of Adelaide, Adelaide, Australia]. All other reagents not listed were of reagent grade unless otherwise indicated.…”