Mitotic spindle dynamics represents an important target of anticancer drugs. Many small natural and semi-synthetic drugs influence tubulin assembly and cause apoptosis of excessively dividing cells. Molecules attacking the colchicine domain of tubulin block its polymerization. Despite this there are colchicine site inhibitors (CSIs) not used in cancer treatment due to their high toxicity, low activity or poor solubility. On the basis of the structure-activity relationships, aryltetralin and dibenzylbutyrolactone lignan-like molecules were designed in an attempt to obtain active drugs. Structure modifications embraced the elimination of typically toxic groups. Two new dibenzylbutyrolactone-type compounds were prepared by total synthesis from substituted benzaldehyde, benzyl bromide and dimethyl succinate. The Stobbe condensation of the substituted benzaldehyde with dimethyl succinate followed with the selective hydrogenation of the double bond and the selective reduction of the ester in the presence of carboxyl led to the β-benzylbutyrolactone. Alkylation of butyrolactone enolate with a substituted benzyl bromide provided the final 2-hydroxy-5\'-methoxy-4\'-O-methyl arctigenin (1) after phenolic group deprotection. The target 2,5\'-dimethoxy-4\'-O-methyl arctigenin (2) was obtained by means of one-step methylation of dibenzylbutyrolactone derivative 1.

This communication deals with the synthesis and evaluation of some pyrazinamide (PZA) analogues/prodrugs. A series of sixteen pyrazinamide analogues with the –CO-NH-CH₂- or -NH-CH₂- linkers connecting the pyrazine and benzene rings was prepared by using the microwave assisted coupling reaction of substituted methyl-pyrazinecarboxylate with ring-substituted benzylamines and characterized. The results of in vitro antimycobacterial screening indicated some interesting antimycobacterial activity in the series of N-benzylpyrazine-2-carboxamides. From the second series, 3-(3,4-dichlorobenzylamino)pyrazine-2-carboxamide was the most active in the inhibition of photosynthetic electron transport (PET) in spinach (Spinacia oleracea L.) chloroplasts (IC₅₀ = 2.2 μmol mL^-1).

Surfactants are organic compounds which contain hydrophobic groups acting as tail and hydrophilic groups acting as head, thus they are solved hardly in water and organic solvents.Surfactants are able to change surface energy within levels considerably. Property of surfactant comes from its double molecular structure. It means that it contains two hydrophilic and hydrophobic groups at the same time. A novel type of surfactants known as bolaform is studied and synthesized in this study. Bolaforms have two polar head groups connected via a poly methylen chain. They are categorized into anionic, cationic and non ionic depending on the head group\'s charge. Micelle extraction of metallic ions, using as molecules sensitive to light and usage in synthesis of mesoporous silica structure for different applications such as in catalysts are among bolaforms\' applications. Structural formula of synthesized kinds with the same spacer and different heads is as follows. Bolaform A with structural formula of Br^-(CH₃)₃N⁺(CH₂)₁₂ N⁺(CH₃)Br ^– with side branches of methyl in head group and bolaform B with structural formula of Br^-(CH₃ CH₂)₃N⁺(CH₂)₁₂ N⁺(CH₃ CH₂)₃Br ^– . IR and NMR identification techniques approves obtained product. Using surface tension measurement device it can be observed that synthesized bolaforms have suitable CMC (relatively low); in other words, bolaform\'s surfactants with long spacer have surface activity property.

Polyfluoroarenesulfonyl halides can be successfully used for the introduction of polyfluoroarenesulfonyl moiety in organic compounds. Recently we realized a simple and efficient method for preparation of polyfluoroarenesulfonyl bromides by the action of electrophilic brominating agents on polyfluoroarenethiols. We have shown that the nature of halogen atom in SO₂Hal group influence the chemical properties of polyfluoroarenesulfonyl halides. Thus, the reactions of polyfluoroarenesulfonyl bromides with alkenes such as hexene-1 or allyl chloride provided the corresponding adducts in high yields, while the conversion of polyfluoroarenesulfonyl chlorides at the same conditions was poor and C₆F₅SO₂F was unreactive. The formation of adducts apparently occurs with participation of polyfluoroarenesulfonyl radicals. At the same time the reaction of polyfluoroarenesulfonyl bromides with allyl bromide resulted in allyl polyfluoroaryl sulfones. This fact is explained by the addition of polyfluoroarenesulfonyl radical to alkene double bond and subsequent elimination of bromine. In reactions of allyl polyfluoroaryl sulfones with polyfluoroarenesulfonyl bromides the replacement of Ar_FSO₂ group in sulfone by another one takes place. According to these data the reversibility of allyl polyfluoroaryl sulfone formation can be suggested. Surprisingly the reactions of polyfluoroarenesulfonyl chlorides or bromides with polyfluoroarenethiols gave mixtures of polyfluorinated diaryl disulfides, whereas replacement of fluorine atom at the 4-position of aromatic ring of C₆F₅SO₂F occured. It turned out that reactions of polyfluoroarenesulfonyl chlorides or bromides with some n‑nucleophiles probably proceeded with electron transfer. For example, such process could take place in reactions of polyfluoroarenesulfonyl chlorides or bromides with alkali metal halides.

Polyfluoroarylmetallic compounds are the important group of polyfluoroarenes. Among the chemical transformations of polyfluoroarylmetallic compounds, it is of interest to study the properties of polyfluoroaromatic zinc compounds and their role as reactive intermediates. Polyfluoroaromatic zinc compounds were prepared from chloropentafluorobenzene and perfluoroarenes [1,2]. Recently, these organozinc compounds were converted to hydro-, bromoperfluoroarenes, perfluorobiaryls, allylpolyfluoroarenes, N,N-dimethyl-bis(polyfluoroaryl)methanamines, polyfluoroaromatic ketones [1-4]. Search for the ways of synthesis of polyfluoroaromatic aldehydes is another important aspect of chemistry of polyfluoroarylzinc compounds. We have found that interaction of these organozinc compounds with Vilsmeier-Haack reagent formed from oxalyl chloride and DMF, and subsequent treatment of the reaction mixtures with water led to the corresponding polyfluoroaromatic aldehydes. When methanol was used instead of water, polyfluorinated acetales were obtained. From 1,4-dibromo-2,3,5,6-tetrafluorobenzene and zinc in the presence of tin (II) chloride in DMF, dizinc compound was obtained that was then converted to 2,3,5,6-tetrafluoroterephthalaldehyde by reaction with Vilsmeier-Haack reagent. The mechanisms of transformations are discussed. References [1] A.O. Miller, V.I. Krasnov, D. Peters, V.E. Platonov and R. Miethchen, Tetrahedron Lett., 2000, 41, 3817-3819. [2] A.S. Vinogradov, V.I. Krasnov and V.E. Platonov, Russ. J. Org. Chem., 2008, 44, 95-102. [3] A.S. Vinogradov, V.I. Krasnov and V.E. Platonov, Coll. Czech. Chem. Commun. 2008, 73, 1623–1630. [4] A.S. Vinogradov, V.I. Krasnov and V.E. Platonov, Russ. J. Org. Chem., 2010, 46, 344-351.

Photochemical oxidations of propylene by means of nitromethane and nitroethane were studied by UB3Lyp/6-31g in both the triplet and singlet states. It was studied the reaction paths giving propylene oxide. Gaussian03 was used to perform the calculations of the transition states of the reactions using QST2 and QST3 methods. Activation energies were calculated for every stage of the reactions. It was shown that the reaction proceeds mainly on the triplet potential surface energy.

A novel class of backbone-modified oligonucleotide analogs has emerged since the discovery of Cu^I-catalyzed [3+2] azide-alkyne cycloaddition. These are oligonucleotide analogs with 1,4-substituted 1,2,3-triazoles in internucleotide linkages. Of all such analogs known to date, only the triazole-linked deoxythymidine decamer has been reported to show enhanced binding affinity to complementary DNA. Importantly, it is a fully modified (dT)₁₀ analog. Irregular oligonucleotides bearing the same backbone modification have not been described so far. With a goal of investigating sequence and regularity dependence of the effect of this modification on duplex stability, we have designed sequentially heterogenous modified oligonucleotides, which can be prepared using a modified dinuleoside block. In this paper we report on the synthesis of the dithymidine phosphoramidite block with the triazole linker, its utilization in oligonucleotide synthesis and hybridization data of thus obtained oligonucleotide analogs. The effect of single and multiple modifications on stability of irregular sequence duplexes is assessed and compared with published data for the oligo(T)/oligo(A) duplex. We also compare the effect of the linker concerned with that of a shorter triazole linker.

Oxalyl chloride (1) has been known to be involved as C1 synthon for ketone synthesis,¹ as an alternative route for carbonylation with CO gas. Given the importance of ketones in pharmaceutical and industrial applications,there is a permanent interest in finding new ways for their synthesis. Based on the exceptional leaving group ability of the trialkylstannyl group in EAS, we have recently proposed efficient catalyst-free and regioselective synthesis of unsymmetrical ketones using different acyl chlorides.² Driven by these results we initiated studies on the reaction of arylstannanes with 1. Now, we describe a novel regioselective synthesis of symmetrical diaryl ketones using 1 as C1 carbonyl synthon, under catalyst-free conditions. These results are significant from the point of view of its simplicity, the wide range of synthetically³ or commercially available arylstannanes and the associated convenience in the utilization of 1 as carbonyl synthon, instead of specific acyl chlorides. All the reactions studied went, exclusively, through an ipso-substitution independently whether the directing influences of the aryl substituents and the trialkylstannyl group are either matched or mismatched. We suggest a mechanism by which 1 acts as C1 synthon on these reactions. In addition, a special work up is proposed in order to recover the trialkyltin chlorides generated. ¹ Rao, M. L. N.; Venkatesh, V.; Dasgupta, P. Tetrahedron Lett. 2010, 51, 4975-4980. ²Lo Fiego, M. J.; Silbestri, G. F.; Lockhart, M. T.; Chopa, A. B. J. Org. Chem. 2011, 76, 1707-1714. ³ Silbestri, G. F.; Lo Fiego, M. J.; Lockhart, M. T.; Chopa, A. B. J. Organometal. Chem. 2010, 695, 2578-2585.

Some new nitrogen bridge-head pyrido[1,2-b][1,2,4]triazepines incorporating 6-methylchromone moiety have been synthesized from the reaction of 1,6-diamino-4-(6-methyl-4-oxo-4H-chromen-3-yl)-2-oxo-1,2-dihydropyridine-3,5-dicarbonitrile (4) with some 1,3-bifunctional electrophiles including 2-cyano-3,3-bis(methylthio)acrylonitrile, 2-cyano-3,3-bis(methylthio)prop-2-enamide, 5-chloro-3-methyl-1-phenylpyrazol-4-carboxaldehyde, 2-chloro-3-formylquinoline, p-methoxybenzylidenemalononitrile, ethyl 2-cyano-3-(4-methoxyphenyl)prop-2-enoate and chromone-3-carbonitrile. Structure of the newly synthesized compounds have been establised on the basis of elemental analysis and spectral data. All compounds were screened in vitro for their antimicrobial activity.

Phenolic compounds are bioactive substances widely distributed in the vegetable kingdom. They act as natural antioxidants, and their presence contributes to the color, flavor and aroma of food. This group of micronutrients is composed of one or more aromatic benzene rings with one or more hydroxyl groups and their redox properties are related with their chemical structure characteristics. The knowledge of their redox potentials may help the food industry, because when phenolic compounds are oxidized they could affect the quality of the wines, beers, grape juices, etc. Coumarins are a large family of compounds, of natural and synthetic origin, that show important biological activities. Therefore, they occupy an important place in the study of natural products and synthetic organic chemistry. Recent studies pay special attention to their antioxidative, anticarcinogenic and enzymatic inhibition properties. Their preparation, and the versatility of the synthetic methodology, allowed us obtaining a wide family of compounds with substituent in different positions in the molecule. The election of these derivatives has considered the later pharmacological evaluation. The investigation of the properties of these compounds, the study of the structural pattern and the elucidation of their biological role is of great interest for further development of coumarin-like antioxidant drugs. The electrochemical behaviour of a group of differently substituted hydroxycoumarins was investigated using cyclic, differential pulse and square wave voltammetry, in aqueous media at a glassy carbon electrode over the whole pH range. The antioxidant reactivity and capacity were also evaluated through a competition assay with hydroxyl radical (OH•) and DMPO like ORAC-FL methodology. Number and positions of the hydroxyl groups were important factors in the antioxidant activities against peroxyl radical of both types of coumarins derivatives.