Thiazole derivatives R 0260Synthesis and Antimicrobial Activity of 5-(R 1 -Benzyl)-2-(R-benzylidenehydrazono)-3-(2-furylmethyl)thiazolidin-4-ones. -Among the title thiazolidinones prepared, only derivatives (IIIa) and (IIIb) containing a tolylmethyl residue at the thiazolidinone ring possess antimicrobial activity. -(TSYALKOVSKII, V. M.; KUTSYK, R. V.; MATIYCHUK, V. S.; OBUSHAK, M. D.; KLYUFINSKA, T. I.; Khim.-Farm. Zh. 39 (2005) 5, 20-22; L'viv Natl. Univ., L'viv 79602, Ukraine; Russ., Abstr. Eng.) -Mischke 41-132

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Meerwein reactions of arenediazonium bromides with methyl and ethyl acrylates gave 3-aryl-2-bromopropionic acid esters which were subjected to cyclocondensation with N- (2-pyridyl)-and N-(6-methyl-2-pyridyl)thioureas to obtain 5-R 1 -benzyl-2-(R 2 -2-pyridylimino)thiazolidin-4-ones. The latter were shown to exist in solution as E isomers of the imino form. * For communication XII, see [1].The thiazolidine ring is a promising and effective structural fragment for the design of biologically active compounds [2][3][4]. Methods of synthesis of combinatorial libraries of 4-thiazolidinone derivatives have been developed [5][6][7]. In the recent time, 5-R-benzylthiazolidine-2,4-diones attract increased interest, and some compounds of this series have already been introduced into medical practice as antidiabetic agents [8][9][10][11]. By contrast, 2-imino derivatives of 4-thiazolidinone have been studied to a lesser extent, despite the possibility for introducing an additional pharmacophoric fragment into the 2-position. A probable reason is the limited set of convenient methods for the synthesis of such compounds with various substituents in both the thiazolidine ring and the imino fragment. A general procedure for the synthesis of 2-iminothiazolidin-4-ones is based on cyclocondensation of monoand disubstituted thioureas with α-halo acids and their esters [2,12]. However, the application of this procedure is limited due to the fact that the cyclization is selective only when the nitrogen atoms in thioureas are characterized by considerably different nucleophilicities [13] or when other structural factors are favorable (e.g., hydrogen bond formation) [14].5-Benzyl-2-iminothiazolidin-4-ones can be prepared by reaction of 3-aryl-2-bromopropionic acid esters with thiourea [15,16]. In the present work we made an attempt to synthesize 5-benzylthiazolidin-4-ones containing a 2-pyridylimino group in position 2. We found that methyl and ethyl 3-aryl-2-bromopropionates IIa-IIr react with N-(2-pyridyl)thioureas IIIa and IIIb to give the corresponding 5-R 1 -benzyl-2-(R 2 -2-pyridylimino)thiazolidin-4-ones IVa-IVp and Va-Ve (Scheme 1). The reactions were carried out by heating the reactants for a short time in alcohol in the presence of a base. No elimination of hydrogen bromide from esters IIa-IIr (with formation of cinnamic acid derivatives) occurred under these conditions. Compounds IVa-IVp and Va-Ve were isolated in high yields as colorless crystalline substances which were sparingly soluble in alcohol, dioxane, and DMF. It should be noted that some 2-(2-pyridylimino)thiazolidin-4-ones were found to exhibit antibacterial activity [13].Esters IIa-IIr were prepared by reaction of arenediazonium bromides Ia-Ir with methyl or ethyl acrylate according to Meerwein [17]. The reactions were exothermic, and they were carried out at room temperature or on slight heating. Compounds IIa-IIr can be distilled under reduced pressure; they were isolated as light yellow liquids or crystalline substances. N-(2-Pyridyl)thioureas IIIa and IIIb wer...

thiazolidin-4-ones. -The title compounds, e.g. (V), which are prepared via Meerwein reaction of aryldiazonium bromides with acrylates, may have biologically interesting properties. -(MATIICHUK, V. S.; OBUSHAK, N. D.; TSYALKOVSKII, V. M.; Russ. J. Org. Chem. 41 (2005) 7, 1050-1054; Ivan Franko Natl. Univ. L'viv, L'viv 79005, Ukraine; Eng.) -M. Bohle

Organo-selenium compoundsOrgano-selenium compounds S 0130 Synthesis of 5-R-Benzyl-2-iminoselenazolidin-4-ones -[via reaction of α-bromo esters (III) with selenourea]. -(MATIICHUK, V. S.; OBUSHAK, N. D.; TSYALKOVSKII, V. M.; Chem. Heterocycl. Compd. (N. Y.) 39 (2003) 7, 972-973; Dep. Chem., Ivan Franko Natl. Univ. L'viv, L'viv 79005, Ukraine; Eng.) -Staver 18-189