%0 Journal Article
%T Photoisomerization of Ethyl 2每(3每Acylselenoureido)thiophene每 3每carboxylates and Their Benzoanalogues
%A Pavel Pazdera
%A Jiri Sibor
%A Radek Marek
%A Michal Kuty
%A Jaromir Marek
%J Molecules
%D 1997
%I MDPI AG
%R 10.3390/20900135
%X Synthesis, isomerisation and structure elucidation of the title compounds 1每6 and its isomers 7每12 by FTIR, 1H, 13C, 15N, 77Se NMR spectroscopy is reported. Ethyl 2每(3每acylselenoureido)thiophene每3每carboxylates and their benzoanalogues (where acyl is benzoyl and pivaloyl) were prepared by addition of ethyl 2每aminothiophene每3每carboxylates and ethyl 2每aminobenzoate on benzoyl每 or pivaloylisoselenocyanate in acetone solution. An isomerization of 1每6 to the corresponding 3每acylisoselenoureas 7每12 was obtained. The isomerisation proceeds either by irradiation with light (340每400 nm) or in the case of benzoylderivatives 1, 3, 5 by treatment with acetic acid. On the other hand the acid action in the pivaloyl set inhibited this isomerisation and evoked the retroisomerisation reaction of 8, 10, 12 to 2, 4, 6. Thermal analyses showed that isomerisation can be initiated also by heating. These changes proceed in the solid phase as an exothermic process at an elevated temperature but always below the temperature of melting. The structure 2 was supported by X每ray analysis. Molecular design of 2 and 8 was modeled during application of ab initio quantum chemistry calculation.
%K N每Acylselenoureas
%K N每acylisoselenoureas
%K 2每aminothiophene每3每carboxylic acid derivatives
%K 2每aminobenzoic acid derivatives
%K isomerisation
%U http://www.mdpi.com/1420-3049/2/9/135