Refernces
10.1007/s10593-010-0647-2
The study focuses on the intramolecular cyclization of 1-[1-alkylsulfanyl-2-phenyl-2-(phenylhydrazono)ethylidene]pyrrolidinium salts, which are synthesized by the alkylation of thioamide with benzyl, allyl, and propargylsulfanyl groups in the presence of cesium carbonate in DMF at room temperature. These pyrrolidinium salts can be efficiently converted into 1,3-diphenyl-6,7,8,8a-tetrahydro-1H-pyrrolo[2,1-c]-1,2,4-triazine-4-thione derivatives in good yields. The research demonstrates that this cyclization method is general for alkyl derivatives of arylhydrazonothioacetamides, expanding the scope of this reaction type. The synthesized pyrrolotriazines are of practical interest due to their potential high antitumor activity, making them promising candidates for biological investigation. The study was financially supported by the Russian Basic Research Fund and includes detailed experimental procedures, characterization data, and comparison of the reaction outcomes with different bases and solvents.
10.1016/j.tet.2009.07.021
The study presents the synthesis and characterization of a new class of fluorescent nucleosides with 2-aryl-3-hydroxychromone (3-HC) as base analogues. These nucleosides, specifically 1a and 1b, were designed to incorporate into DNA oligonucleotides for sensitive fluorescence-based detection and imaging. The synthesis involved key steps like aryl-aldol condensation, cycloetherification, Friedel-Crafts glycosylation, and 1,3-dipolar cycloaddition. The resulting nucleosides exhibited dual emission sensitivity to polarity changes, with 1a showing high sensitivity, making it promising for nucleic acid labeling and tracking environmental changes within DNA structures. The study provides a foundation for developing more advanced fluorescent probes for biological applications.
10.1016/j.ejmech.2010.11.020
The research focuses on the synthesis and anti-mycobacterial activities of triazoloquinolones, a class of quinolone derivatives with potential as anti-tuberculosis agents. The study confirms that these compounds exhibit selective anti-mycobacterial activity without cytotoxicity. The synthetic route involved the alkylation of 4-nitrobenzotriazole with benzyl bromide to form benzyl benzotriazoles, which were then reduced and reacted to form quinolone derivatives. The synthesized compounds were evaluated for their activity against Mycobacterium tuberculosis, including multi-drug resistant strains, as well as a range of Gram-positive and Gram-negative bacteria and Candida species. The most promising compounds were also tested for cytotoxicity in human hematological tumor cell cultures. The results showed that specific triazoloquinolones had potent anti-mycobacterial activity comparable to reference drugs, with a narrow spectrum of activity and favorable cytotoxicity profiles. The research utilized various analytical techniques, including NMR spectroscopy and mass spectrometry, to characterize the synthesized compounds.
10.1016/S0040-4020(98)01096-5
The research aimed to develop a simple, direct, and efficient method for converting thioamides into thioesters, which are activated carboxylic acid derivatives with applications in synthetic chemistry. The study addressed the need for a reliable, multi-gram synthesis of thioesters and proposed a new route from thioamides that is mild, inexpensive, and experimentally straightforward. The method involved warming thioamides in an aqueous tetrahydrofuran (THF) solution containing an alkylating agent, leading to high yields and being scalable to multi-gram levels. The reactions were found to be tolerant of aryl ethers and acetals, and when volatile alkyl halides were used, products of approximately 95% purity could be obtained without chromatographic purification. Key chemicals used in the process included various thioamides, alkyl iodides, dialkyl sulfates, and activated alkyl bromides as alkylating agents, with methyl iodide (MeI), ethyl iodide (EtI), allyl bromide (allyl-Br), and benzyl bromide (BnBr) being specific examples. The study concluded that the developed method was effective for preparing thioesters from thioamides, offering a practical alternative to existing methods.
10.1023/A:1026191021119
The research focuses on the reaction of zinc and sodium enolates of 3-alkyl-6-aryl-5,5-dimethyl-2,3,5,6-tetrahydropyrane-2,4-diones with acyl chlorides or benzyl bromides. The purpose of the study was to investigate the synthetic possibilities of these reactions and to extend the understanding of the reaction mechanisms. The conclusions drawn from the research indicate that zinc enolates react with acyl chlorides to form O-acylation products, specifically 4-acyloxy-3-alkyl-6-aryl-5,5-dimethyl-5,6-dihydropyrane-2-ones, while sodium enolates react with substituted benzyl bromides to primarily yield C-alkylation products, 3-alkyl-6-aryl-3-(4-R-benzyl)-5,5-dimethyl-2,3,5,6-tetrahydropyrane-2,4-diones, as single geometric isomers. In some cases, O-alkylation products were formed as by-products. The chemicals used in the process include acyl chlorides, benzyl bromides, ethyl 2-alkyl-2,4-dibromo-4-methyl-3-oxopentanoate, aldehydes, and various substituted aromatic compounds.
10.1016/j.tetlet.2010.10.133
The study explores an efficient method for preparing benzyl bromides from corresponding alcohols using hexabromoacetone (HBA) and triphenylphosphine (PPh3) under neutral conditions at low temperatures. This method serves as a milder alternative to traditional harsh and corrosive chlorinating agents like SOCl2. The researchers found that the protocol is applicable to a wide range of benzyl alcohols, including those with electron-withdrawing and electron-releasing groups, as well as heterocyclic analogues. The study also successfully synthesized the precursor of the antiulcer drug omeprazole, demonstrating the method's potential for preparing drug intermediates. The reaction mechanism involves the formation of an intermediate with PPh3 and HBA, followed by an SN2 displacement to yield the bromide. The study highlights the importance of steric factors influencing the reaction rates and yields, with para-substituted compounds generally converting more efficiently than ortho-substituted ones at room temperature. The use of acetonitrile as a solvent and the optimization of HBA equivalents were key to achieving high reproducibility and yields.
10.1016/j.bmcl.2015.06.009
The research focuses on the synthesis and biological evaluation of 3,5-disubstituted-4-alkynylisoxazoles as a novel class of HSP90 inhibitors. The study involves the design and synthesis of these derivatives through a palladium(II)-copper(I) catalyzed Sonogashira cross-coupling reaction, aiming to develop new potent inhibitors with improved specificity for HSP90, a molecular chaperone overexpressed in tumors. The synthesized compounds were tested for their binding affinity to HSP90 proteins using a fluorescence polarization assay and their anti-proliferative activities against various cancer cell lines. Key reactants in the synthesis include 4-dihydroxyphenylmethylketone, which undergoes a series of transformations, and terminal alkynyl compounds used in the cross-coupling reaction. Benzyl bromide (BnBr) was used for protection of the hydroxyl groups in the synthesis process. The analyses used to evaluate the compounds include molecular docking, binding free energy calculations, and cytotoxic activity assays. The results showed that some compounds demonstrated similar or better binding affinity and inhibitory activity against cancer cell lines compared to the known HSP90 inhibitor NVP-AUY922.
10.1021/jo801665k
The research focuses on the π-facial stereoselective alkylation of chiral bicyclic lactams, specifically examining the reversal of diastereoselectivity in the benzyl bromide alkylation of phenylglycinol-derived oxazolopiperidone enolates. The study employs a combination of theoretical calculations and experimental assays to explore this reversal, attributing it to the formation of a C-H···π hydrogen bond between the C-H unit of the C8a angular position and the benzene ring of the alkylating reagent. The experiments involve the generation of enolates from chiral bicyclic lactams using lithium bis(trimethylsilyl)amide as the base, followed by the addition of alkylating reagents such as benzyl bromide. The reaction products are analyzed using techniques like gas chromatography/mass spectrometry (GC/MS), infrared (IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, and high-resolution mass spectrometry (HRMS) to determine the diastereoisomeric ratios and confirm the structures of the products. The research provides valuable insights into the factors influencing diastereoselectivity in alkylation reactions, which is crucial for the selective preparation of enantiopure bioorganic and pharmaceutical compounds.
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