The Synthesis of Zinquin Ester and Zinquin Acid, Zinc(II)-Specific Fluorescing Agents for Use in the Study of Biological Zinc(II)
IB Mahadevan, MC Kimber, SF Lincoln, ERT Tiekink, AD Ward, WH Betts, IJ Forbes and PD Zalewski
Australian Journal of Chemistry
49(5) 561 - 568
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.
Full text doi:10.1071/CH9960561
© CSIRO 1996