THE INTERACTION OF THE 4-CARBOXYPHENYLGLYOXAL WITH N-HYDROXYUREA AND N-ALKOXY-N′-ALKYL(ARYL)UREAS. THE STUCTURE OF 5-(4-CARBOXYPHENYL)-4,5-DIHYDROXY-1-METHYL-3-PROPYLOXYIMIDAZOLIDIN-2-ONE

Aim. The investigation of the reaction of 4-carboxyphenylglyoxal with N-hydroxyurea, different N-alkoxy-N'-arylureas and N-propyloxy-N'-methylurea in acetic acid medium and the product structure. Methods. H-1 and C-13 NMR, mass spectra and XRD study. Results. 3-Alkoxy-4,5-dihydroxyimidazolidin-2-ones are the only products of N-alkoxy -N'-alkyl(aryl)ureas interaction with 4-carboxyphenylglyoxal. The possibility of obtaining such dominating products as 3-alkoxy-1-aryl-5-(4-carboxyphenyl)-4,5-dihydroxyimidazolidin-2-ones and 3-alkoxy-1-alkyl-5-(4-carboxyphenyl)-4,5-dihydroxyimidazolidin-2-ones with cis orientation of 4-HO- and 5-HO-groups to each other has been proved in the experimental way. The product structure was revealed by the H-1 and C-13 NMR, mass spectra and XRD study. Also the structure of 5-(4-carboxyphenyl)-4S,5S-dihydroxy-1-methyl-3-propyloxyimidazolidin-2-one is discussed in this article. In this compound the endocyclic C(2)-C(3) bond is elongated to 1.562(2) angstrom) as compared to the average length of C(sp(3))-C(sp(3)) ordinary bond. The N(1) atom has almost planar configuration whereas the N(2) atom has pyramidal configuration. The N(1)-C(1) bond is shorter than the N(2)-C(1) bond. 4-Carboxyphenylglyoxal reacts with N-hydroxyurea in acetic acid at room temperature with the selective formation of 5-(4-carboxyphenyl)-3-hydroxyimidazolidine-2,4-dione. Conclusions. 4-Carboxyphenylglyoxal reacts with N-propyloxy-N'-methylurea and N-alkoxy-N-arylureas in acetic acid at room temperature selectively producing 5-(4-carboxyphenyl)-4,5- dihydroxy-1-methyl-3-propyloxyimidazolidin-2-one and 3-alkoxy-1-aryl- 5-(4-carboxyphenyl) -4,5-dihydro- xyimidazolidin-2-ones with cis orientation of 4-HO- and 5-HO-groups towards each other. In the same conditions 4-carboxyphenylglyoxal interacts with N-hydroxyurea yielding only 5-(4-carboxyphenyl)-3-hydroxyimidazolidine-2,4-dione.