engleski

Mercuration of thiophene-2-carboxylic acid, 2-thienylethanoic acid and 3-(2-thienil)alanine : preparation and spectral characterization

Thiophene-2-carboxylic acid, 2-thienyl etanoic acid and 3-(2-thienyl)-alanine were mercurated with mercury(II) chloride in aqueous media in the presence of sodium acetate trihydrate. Monomercurated and dimercurated products were obtained depending on the reaction conditions. When mercury(II) acetate was used as the mercuration agent the mixture of mono- and dimercurated products was obtained.The chemical formula and the structure of isolated compounds were deduced from elemental chemical analysis and IR spectra. In the case of soluble products the site and degree of mercuration were determined on the basis of 1^H and 13^C NMR spectra. In monomercurated thiophene-2-carboxylic acid, 2-thienyletanoic acid and 3-(2-thienyl)-alanine the H-5 signal is absent, which together with large downfield shift of the corresponding 13^C signal (ca. 24 and 21 ppm) confirmed that mercuration took place at the C-5. Two- and three-bond 199^Hg-13^C satellite couplings at the C-4 and C-3 as well as four-bond 199^Hg-1^H coupling at the H-4 were also revealed.

direct mercuration; 2-thienyl derivatives; IR; NMR

nije evidentirano