- Investigating the influence of a CrO42?/Cr2O72? template in the formation of a series of silver-chalcogenide clusters
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Three new silver-chalcogenide clusters protected by naphthyl ligands are described in this work, namely [Ag14(SCH2C10H7)6(CF3COO)8(DMAc)6] (1), [Ag30(SCH2C10H7)18(CrO4)2(DMAc)2 (CF3COO)8] (DMAc = dimethylacetamide) (2) and {Ag12(SCH2C10H7)6(CF3COO)4(CH3CN)6(Cr2O7)}n (3). Their crystal structures were studied by X-ray crystallography, and they show hollow-core-shell (1), template-core-shell (2) and 1D infinite (3) structures, respectively. The luminescence properties of cluster 1 were investigated, which showed interesting thermochromic variation from red to bright yellow. Moreover, the chromate ions were proven to act as templates in forming the silver clusters through a series of experiments to prepare compounds 2 and 3, which could be considered as derivatives of cluster 1.
- Li, Yan-Ling,Xu, Qing-Qing,Li, Si,Huang, Ren-Wu,Liu, Xiao-Fei,Wei, Yong-Li,Zang, Shuang-Quan
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- 2,3,3,3-Tetrafluoropropene (HFO-1234yf) as a CF3-Building Block: Synthesis of Enol Ethers and Vinyl Sulfides
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2,3,3,3-Tetrafluoropropene (HFO-1234yf) is an inexpensive and readily available fluorinated building block, owing to its growing use as a low global warming potential 4th generation refrigerant, but there have so far been few reported uses of this fluoroalkene in organic synthesis. Herein, we report our investigations into nucleophilic substitution reactions of HFO-1234yf with alkoxide and thiolate derivatives. The regiochemistry of these transformations varies with conditions and we propose these reactions proceed through addition–elimination with reversible formation of a carbanion intermediate. The regioselectivity is dictated by hard/soft nucleophile/electrophile control. This is supported by deuterium trapping of the proposed reactive intermediate. The effect of solvent and base choice was examined and the substrate scope for the synthesis of α-trifluoromethyl enol ethers was expanded.
- Murray, Ben J.,Ball, Ellis D.,Harsanyi, Antal,Sandford, Graham
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p. 7666 - 7672
(2019/12/24)
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- Nonenzymatic Dynamic Kinetic Resolution of in situ Generated Hemithioacetals: Access to 1,3-Disubstituted Phthalans
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The first nonenzymatic DKR reaction of hemithioacetals is developed. Hemithioacetals were formed in situ via thiol addition and subsequently underwent an intramolecular oxa-Michael reaction. The scope of the reaction was quite broad ranging from aliphatic to aromatic substituents and 1,3-disubstituted-1,3-dihyroisobenzofuran products were obtained in good yields with moderate diastereoselectivities and high enantioselectivities. (Figure presented.).
- Nath, Utpal,Chowdhury, Deepan,Pan, Subhas Chandra
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p. 1628 - 1633
(2018/03/21)
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- Two-step three-component process for one-pot synthesis of 8-alkylmercaptocaffeine derivatives
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A highly efficient, odourless and two-step three-component process for one-pot synthesis of some 8-alkylmercaptocaffeine derivatives has been described. The catalyst-free three-component reaction of alkyl bromides, thiourea, and 8-bromocaffeine gave 8-alkylmercaptocaffeine products in excellent to quantitative yields. In addition, the impact of parameters on sample reaction is discussed.
- Rad, M. N. Soltani,Maghsoudi
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p. 70335 - 70342
(2016/08/06)
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- PYRAZOLE COMPOUNDS AS CRTH2 ANTAGONISTS
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The present invention relates to pyrazole compounds of formula (I) and pharmaceutically acceptable salts thereof having CRTH2-activity, wherein W, L1, L2, X, L3, Y, R1 and R2 are as defined in the spe
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Page/Page column 72
(2012/02/06)
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- PYRAZOLE COMPOUNDS AS CRTH2 ANTAGONISTS
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The present invention relates to pyrazole compounds of formula (I) and pharmaceutically acceptable salts thereof having CRTH2-activity, wherein W, L1, L2, X, L3, Y, R1 and R2 are as defined in the spe
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Page/Page column 122-123
(2011/08/21)
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- Structure-activity relationships in the binding of chemically derivatized CD4 to gp120 from human immunodeficiency virus
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The first step in HIV infection is the binding of the envelope glycoprotein gp120 to the host cell receptor CD4. An interfacial "Phe43 cavity" in gp120, adjacent to residue Phe43 of gp120-bound CD4, has been suggested as a potential target for therapeutic intervention. We designed a CD4 mutant (D1D2F43C) for site-specific coupling of compounds for screening against the cavity. Altogether, 81 cysteine-reactive compounds were designed, synthesized, and tested. Eight derivatives exceeded the affinity of native D1D2 for gp120. Structure-activity relationships (SAR) for derivatized CD4 binding to gp120 revealed significant plasticity of the Phe43 cavity and a narrow entrance. The primary contacts for compound recognition inside the cavity were found to be van der Waals interactions, whereas hydrophilic interactions were detected in the entrance. This first SAR on ligand binding to an interior cavity of gp120 may provide a starting point for structure-based assembly of small molecules targeting gp120-CD4 interaction.
- Xie, Hui,Ng, Danny,Savinov, Sergey N.,Dey, Barna,Kwong, Peter D.,Wyatt, Richard,Smith III, Amos B.,Hendrickson, Wayne A.
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p. 4898 - 4908
(2008/03/11)
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- Synthesis and Biological Activity of trans-(+/-)-N-Methyl-2-(3-pirydyl)-2-tetrahydrothiopyrancarbothioamide 1-Oxide (RP 49356) and Analogues: A New Class of Potassium Channel Opener
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The synthesis and biological activity of trans-(+/-)-N-methyl-2-(3-pyridyl)-2-tetrahydrothiopyrancarbothioamide 1-oxide (8a, RP 49356) and analoques is reported.These compounds constitute a new structural class of K+-channel opener.The effects of changes in the pyridyl group, thioamide, and thiane ring on in vitro K+-channel opening activity are discussed.A 3-pyridyl or 3-quinolyl group, a small N-alkyl thioamide function, and a thiane oxide ring, in which the sulfoxide is in a trans relationship to thioamide, are preferred for activity.Selected compounds were tested intravenously in the normotensive anaesthetized rat for hypotensive effects, and the activities reflect their in vitro K+-channel opening activity.This led to further evaluation of compound 8a and the selection of the (-)-enantiomer 8b (RP 52891) for development as an antihypertensive and antianginal agent.
- Brown, Thomas J.,Chapman, Robert F.,Cook, David C.,Hart, Terance W.,McLay, Iain M.,et al.
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p. 3613 - 3624
(2007/10/02)
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- 5-[(1- and 2-naphthalenyl) sulfonyl]-2,4-thiazolidinediones and derivatives thereof
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Disclosed herein are 1- or 2-thio, thiomethylene, and sulfonylnaphthalene derivatives of formulas I and II STR1 or a pharmaceutically acceptable catonic salt thereof, wherein n is 0 or 1 R5 is hydrogen, bromo, chloro, trifluoromethyl or difluoroethyl; R6 is hydrogen, hydroxy, methoxy or ethoxy; and R7 is hydrogen or R7 and R6 are both methyl or ethyl carbonate, provided that, when S(O)2 is in the 2 position of the naphthalene ring, R5, R6 and R7 are each hydrogen. The disclosed compounds possess blood-glucose lowering actions and are useful in the treatment of diabetes mellitus.
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- Photoextrusion of SO2 from Arylmethyl Sulfones: Exploration of the Mechanism by Chemical Trapping, Chiral, and CIDNP Probes
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The photochemistry of eight benzylic sulfones, all of which efficiently extrude sulfur dioxide, was studied by a variety of methods.Optically active sulfones (S)-(-)-8, (S)-(-)-11, (S)-(-)-12, (S)-(+)-13, and (R)-(+)-14 were employed to measure the extent of the "hidden" return of the initial photogenerated intermediates by the stereoequilibration of the chiral center.By comparison of the regioisomeric methyl sulfones 11 vs. 13 and 12 vs. 14, preferential C-S bond fragmentation on the naphthyl side was established for the singlet excited sulfones.Added nucleophilic and proton trapping agents had no effect on the course of the reaction, ruling out ionic intermediates.The three hydrocarbon products of photodesulfonation from the unsymmetrical sulfones 8-14 provided a measure of the cage effects, which were highly structure and multiplicity dependent.Rate constants for reaction, and fluorescence, as well as the energy transfer rates from benzophenone were determined.The reaction rate constant for singlet reactivity from the 1-naphthyl sulfones was about three times greater than that for the 2-naphthyl derivatives.CIDNP studies showed a strong product signal for the 1-naphthyl sulfones from desulfonation of a triplet caged radical pair.Naphthaldehyde formation, a very minor, triplet process, was also detected by the CIDNP study of sulfones 9-12.
- Givens, Richard S.,Hrinczenko, Borys,Liu, Jerry H.-S.,Matuszewski, Bogdan,Tholen-Collison, Joan
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p. 1779 - 1789
(2007/10/02)
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