Collect. Czech. Chem. Commun. 1989, 54, 215-224

Synthesis of 2-aryl-3-furancarboxylic acids by arylation of 3-furancarboxylic acid

Adolf Jurášek, Daniela Berecinová, Miroslav Čakrt, Miloslava Dandárová, Zdeněk Friedl, Jarmila Štetinová and Jaroslav Kováč

Department of Organic Chemistry, Slovak Technical University, 812 37 Bratislava


Arylation of 3-furancarboxylic acid (3-FCA) with 4-X-phenyldiazonium chlorides catalyzed by copper dichloride afforded the non-planar 2-(4-X-phenyl)-3-furancarboxylic acids (X = H, CH3, OCH3, Cl, Br, NO2). Arylation of 3-FCA with 2-X-phenyldiazonium chlorides (X = COOCH3, NO2) yielded 2-(2-methoxycarbonylphenyl)-3-furancarboxylic acid and a 3:1 mixture of 2-(2-nitrophenyl)- and 5-(2-nitrophenyl)-3-furancarboxylic acids, respectively. The pKa values of 2-(4-X-phenyl)-3-furancarboxylic acids linearly well correlate with the Hammett's σp0 constants of substituents. The IR, UV, mass, and 13C NMR spectra of the above-mentioned compounds are commented and the mechanism of arylation is discussed.