ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Thermal Behaviour of Esters and Nitriles of 2-(3-Acylselenoureido)benzoic and 2-(3-Acylselenoureido)thiophene-3-carboxylic Acids

J. Šibor and P. Pazdera

Department of Organic Chemistry, Faculty of Science, Masaryk University, CZ-611 37 Brno

E-mail: pazdera@chemi.muni.cz

Abstract: The thermally initiated transformation of esters and nitriles of 2-(3-acylselenoureido)benzoic and 2-(3-acylselenoureido)thiophene-3-carboxylic acids under heating without solvent to the temperature ca. 300°C was studied. The thermal behaviour was studied by methods of the thermal analysis. It was found that selenoureas in ester series afford isoselenoureas at the temperature lower than their melting points. This change occurs in the solid state as an exothermic process. The next exothermic change starts by the following increase in temperature. Two molecules of isoselenoureas eliminate one hydrogen molecule by air oxygen action. The oxidation is connected with Se-Se bond formation and diselenides are formed. Nitriles undergo a transformation to di(2-pyrimidyl)diselenides in the course of several steps in melt in the presence of air oxygen.

Full paper in Portable Document Format: 541a28.pdf

Chemical Papers 54 (1) 28–35 (2000)