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1.
Ivachtchenko AV Tkachenko SE Sandulenko YB Vvedensky VY Khvat AV 《Journal of combinatorial chemistry》2004,6(5):828-834
The parallel solution-phase synthesis of a series of building blocks and combinatorial libraries based on natural bispidine scaffold has been accomplished. Key reactions include catalytic hydrogenation of the (-)-cytisine heterocyclic system, followed by alkali-mediated ring cleavage. Using this approach, a series of new bispidine core building blocks for combinatorial synthesis with three points of diversity were effectively synthesized. The libraries from libraries were then obtained in good yields and purities using solution-phase acylation reactions. Obtained combinatorial libraries of 3,4,7-trisubstituted bispidines are potentially useful in the discovery of novel physiologically active compounds. 相似文献
2.
Alexandre V Ivachtchenko Alexander V Khvat Vladimir V Kobak Volodymir M Kysil Caroline T Williams 《Tetrahedron letters》2004,45(28):5473-5476
The unusual formation of 6-sulfamoylquinoline-4-carboxylic acids from 5-sulfamoylisatins under the conditions of Pfitzinger reaction is described. Key step in the suggested mechanism is the reaction of in situ generated acetaldehyde with the hydrolytically cleaved isatin ring. The suggested mechanism has been confirmed by dynamic LCMS measurements and by reactions with isotopically labeled reactants. 相似文献
3.
Ilyn AP Loseva MV Vvedensky VY Putsykina EB Tkachenko SE Kravchenko DV Khvat AV Krasavin MY Ivachtchenko AV 《The Journal of organic chemistry》2006,71(7):2811-2819
We present a convenient synthesis of novel heteroaryl-fused 3-oxo-1,4-thiazepine-5-carboxamides and 5-oxo-1,4-thiazepine-3-carboxamides using a modification of four-component Ugi condensation. We demonstrate the usefulness and versatility of the developed approach for the synthesis of variously substituted compounds and discuss the scope and limitations of the chemistry involved. 相似文献
4.
R Nirmala V Sankaranarayanan K Sethupathi AV Morozkin T Geethakumary Y Hariharan 《Pramana》2002,58(5-6):1101-1104
New R
2Ti3Ge4 (R=Dy, Ho and Er) intermetallic compounds have been synthesized and characterized by X-ray diffraction and low temperature ac
magnetic susceptibility, electrical resistivity and thermoelectric power measurements were carried out. The compounds crystallize
in the parent, Sm5Ge4-type orthorhombic structure (space group Pnma) and lanthanide contraction is observed as one moves along the rare-earth series.
The changeover from paramagnetic to antiferromagnetic phase happens at low temperatures and the ordering temperature scales
with the de Gennes factor. The electrical resistivity is metallic with a negative curvature above 100 K. Thermopower displays
a weak maximum at temperatures less than 50 K signifying the possible phonon and magnon drag effects. 相似文献
5.
6.
Ivachtchenko AV Kobak VV Ilyn AP Khvat AV Kysil VM Williams CT Kuzovkova JA Kravchenko DV 《Journal of combinatorial chemistry》2005,7(2):227-235
Two efficient strategies for solution-phase parallel synthesis of libraries of quinoline derivatives are described. The first synthetic pathway features the Pfitzinger reaction of isatin with diethyl malonate and sulfochlorination of the resulting 2-oxo-1,2-dihydroquinoline-4-carboxylate followed by generation of sulfonamide library. The second strategy employs the unusual behavior of 5-sulfamoylisatins in Pfitzinger reactions, which results in formation of 6-sulfamoyl-4-carboxyquinolines instead of the anticipated 2-oxo-1,2-dihydroquinoline structures. The obtained carboxylates appeared to be convenient synthetic intermediates for the generation of the corresponding carboxamide libraries. Using these reagents, the parallel solution-phase synthesis of more than 500 substituted quinoline and 2-oxo-1,2-dihydroquinoline derivatives has been accomplished on the 50-100-mg scale. Simple manual techniques for parallel reactions using special CombiSyn synthesizers were coupled with easy purification procedures to give high-purity final products. The scope and limitations of the developed approaches are discussed. 相似文献
7.
Trifilenkov AS Kobak VV Salina MA Kusovkova JA Ilyin AP Khvat AV Tkachenko SE Ivachtchenko AV 《Journal of combinatorial chemistry》2006,8(4):469-479
In this work, we explored several original combinatorial derivatization patterns for the 3,4-dihydro-2H-1,4-benzothiazine scaffold. The synthesis begins with commercially available 4-chloro- and 4-fluoro-3-nitrobenzoates and employs a sequence of moderate and high-yielding reactions that display a relatively high substituent tolerance. Simple manual techniques for parallel reactions were coupled with easy workup and purification procedures to give high-purity final products. The developed approach was easily adaptable for parallel synthesis of more than 2600 novel 2H-benzo[1,4]thiazine-6-carboxylic acid amides, which were efficiently prepared in a semiautomatic fashion using special CombiSyn synthesizers. 相似文献
8.
Alexandre V. Ivachtchenko Alexandre Khvat Sergey E. Tkachenko Yuri B. Sandulenko Vladimir Y. Vvedensky 《Tetrahedron letters》2004,45(36):6733-6736
Novel 1,3-diazaadamantane structures 3 and 6 were prepared from tetrahydro(−)-cytisine 1 using intermolecular conversions within the bispidine moiety. 2-Oxo derivative 6 was synthesized using a microwave-assisted procedure, which reduces the reaction time and increases the purity of the crude reaction mixture. Alternative possibilities of intermolecular cyclizations were also explored. Though less successful, they provided interesting insights into the chemistry of bispidine systems. 相似文献
9.
Resonant ultrasound spectroscopy was used to measure the elastic constants of bcc Ta0.33V0.67 over the temperature range 3.5–300?K; the results were compared to earlier measurements on C15 TaV2. The temperature dependence of the polycrystalline shear modulus is completely different in the two phases; that of the bcc phase decreases with temperature whereas that of the C15 phases increases in an anomalous fashion. This difference is consistent with a model involving doubly-degenerate levels at the X point of the Brillouin zone in the C15 phase with the Fermi level lying near the doubly degenerate level. This model accounted for the unusual behaviour of the C15 phase. Debye temperatures were determined from the ultrasonic measurements: 295?K for the C15 phase and 315?K for the bcc phase. 相似文献
10.
Isocyanide-based multicomponent reaction (IMCR) of 1,3-diaminopropane with carbonyl compounds has been developed as an efficient strategy for the synthesis of 1,4-diazepine-2-amines. Brønsted and Lewis acids are able to promote the reaction, and TMSCl has been found to be the most efficient among them. The IMCR is applicable to a variety of carbonyl compounds and isocyanides. 相似文献