Collect. Czech. Chem. Commun. 1986, 51, 2181-2185

Reaction of 2-butenolide and 4-bromo-2-butenolide with 5-aryl-2-furaldehydes and thiolates

Tatyana Ya. Kaklyuginaa, Larisa A. Badovskayaa, Ludmila N. Sorotskayaa, Nadezhda D. Kozhinaa, Adolf Jurášekb, Rudolf Kadab, Jaroslav Kováčb and Vladimír G. Kulnevicha

a Krasnodar Polytechnical Institute, 350 000 Krasnodar, U.S.S.R.
b Department of Organic Chemistry, Slovak Institute of Technology, 812 37 Bratislava, Czechoslovakia


Condensation of 2-butenolide with 5-(4-X-phenyl)-2-furaldehydes (X = H, CH3, OCH3, Br, Cl, NO2) in methanol in the presence of piperidine as catalyst afforded the corresponding 4-[5-(4-X-phenyl-2-furfurylidene)]-2-butenolides. As shown by 1H NMR spectra, the reaction afforded mixtures of Z- and E-isomers which on crystallization were isomerized to the stable Z-isomers (except when X = NO2). 4-Bromo-2-butenolide reacted with sodium salts of 2-mercaptobenzoxazole and 2-mercaptobenzimidazole to give the corresponding 4-(benzazoyl-2-thio)-2-butenolides, probably by an anion-radical mechanism. With arene thiolates, no substitution of the bromo atom took place and the reaction afforded only the corresponding disulfides. The IR and 1H NMR spectra of the synthesized compounds are discussed.