Molecules 1997, 2(9), 135-151; doi:10.3390/20900135
Article

Photoisomerization of Ethyl 2–(3–Acylselenoureido)thiophene– 3–carboxylates and Their Benzoanalogues

Pavel Pazdera 1,* email, Jiri Sibor 1 , Radek Marek 1 , Michal Kuty 1  and Jaromir Marek 2
1 Department of Organic Chemistry, Faculty of Science, Masaryk University, CZ–611 37 Brno, Czech Republic 2 Department of Inorganic Chemistry, Faculty of Science, Masaryk University, CZ–611 37 Brno, Czech Republic
* Author to whom correspondence should be addressed.
Received: 6 January 1997 / Accepted: 24 May 1997 / Published: 15 September 1997
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Abstract: Synthesis, isomerisation and structure elucidation of the title compounds 1–6 and its isomers 7–12 by FTIR, 1H, 13C, 15N, 77Se NMR spectroscopy is reported. Ethyl 2–(3–acylselenoureido)thiophene–3–carboxylates and their benzoanalogues (where acyl is benzoyl and pivaloyl) were prepared by addition of ethyl 2–aminothiophene–3–carboxylates and ethyl 2–aminobenzoate on benzoyl– or pivaloylisoselenocyanate in acetone solution. An isomerization of 1–6 to the corresponding 3–acylisoselenoureas 7–12 was obtained. The isomerisation proceeds either by irradiation with light (340–400 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–ray analysis. Molecular design of 2 and 8 was modeled during application of ab initio quantum chemistry calculation.
Keywords: N–Acylselenoureas; N–acylisoselenoureas; 2–aminothiophene–3–carboxylic acid derivatives; 2–aminobenzoic acid derivatives; isomerisation

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MDPI and ACS Style

Pazdera, P.; Sibor, J.; Marek, R.; Kuty, M.; Marek, J. Photoisomerization of Ethyl 2–(3–Acylselenoureido)thiophene– 3–carboxylates and Their Benzoanalogues. Molecules 1997, 2, 135-151.

AMA Style

Pazdera P, Sibor J, Marek R, Kuty M, Marek J. Photoisomerization of Ethyl 2–(3–Acylselenoureido)thiophene– 3–carboxylates and Their Benzoanalogues. Molecules. 1997; 2(9):135-151.

Chicago/Turabian Style

Pazdera, Pavel; Sibor, Jiri; Marek, Radek; Kuty, Michal; Marek, Jaromir. 1997. "Photoisomerization of Ethyl 2–(3–Acylselenoureido)thiophene– 3–carboxylates and Their Benzoanalogues." Molecules 2, no. 9: 135-151.

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