- PH-Driven Conformational Switching of Quinoxaline Cavitands in Polymer Matrices
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While pH-driven interconversion of tetraquinoxaline cavitands (QxCav) from vase to kite conformation has been extensively studied both in solution and at interfaces, cavitands behavior in solid matrices is still unexplored. Therefore, the synthesis of a new class of quinoxaline cavitand based copolymers is here reported; a soluble linear poly(butyl methacrylate) (PBMA) and an insoluble cross-linked polydimethylsiloxane (PDMS), ensuring a convenient incorporation of the switchable unit, were chosen as polymer matrices. Conformational studies, performed both in solution and at the solid state, confirmed the retention of vase → kite switching behavior when moving from monomeric units to polymeric structures.
- Torelli,Domenichelli,Pedrini,Guagnini,Pinalli,Terenziani,Artoni,Brighenti,Dalcanale
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- Bioorthogonal Ligation and Cleavage by Reactions of Chloroquinoxalines with ortho-Dithiophenols
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A bioorthogonal ligation and cleavage method via reactions of chloroquinoxalines (CQ) and ortho-dithiophenols (DT) is presented. Double nucleophilic substitutions of ortho-dithiophenols to chloroquinoxalines provide conjugates containing tetracyclic benzo[5,6][1,4]dithiino[2,3-b]quinoxaline with strong built-in fluorescence together with release of the other functional molecules. Three cleavable linkers were designed and successfully used in release of the molecules containing biotin from the protein conjugates. The CQ-DT bioorthogonal reactions can be applied for the bioorthogonal ligations, bioorthogonal cleavages, and trans-tagging of proteins, and show advantages of readily accessible unnatural orthogonal groups, appealing reaction kinetics (k2≈1.3 m?1 s?1), excellent biocompatibility of orthogonal groups, and high stability of conjugates. This complements previous bioorthogonal reactions and is a new route for protein-fishing applications and in-gel fluorescence analysis.
- Fu, Hua,Li, Hongyun,Li, Youshan,Lou, Zhenbang,Yang, Haijun,Zhao, Yufen
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p. 3671 - 3677
(2020/02/04)
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- Triketone compound containing quinoxaline structure, and preparation method and application thereof
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The invention belongs to the technical field of medicine synthesis, and particularly relates to a triketone compound containing a quinoxaline structure, and a preparation method and an application thereof. The quinoxaline-containing triketone compound has a structure represented by general formula (I). The preparation method is mainly characterized in that a compound with a structure represented by formula (II) is contacted in the presence of an alkali and a solvent, and R1, R2, R3 and R4 in the formulas are respectively defined in the description. The quinoxaline-containing triketone compoundhas high herbicidal activity, and especially has an excellent effect of preventing and controlling broadleaf weeds and/or gramineous weeds, and the prevention and control effect is even better than that of some commercial herbicides sold in the market.
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- Synthesis and assembly of self-complementary cavitands
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Cavitands with self-complementary shapes (3 and 4) were prepared by the covalent attachment of adamantane guest molecules to the upper rim of the host structures. Relatives of the 'self-folding' cavitands 2, these new structures possess a seam of intramolecular hydrogen bonds that stabilize the folded conformation. Their self-complementary shapes result in the formation of noncovalent dimers of considerable kinetic and thermodynamic stability (- ΔAG295 = 4.5 kcal/mol for 3a and 6.5 kcal/mol for 4a in p-xylene-d10). The dimerization of cavitands 3 and 4 is reversible and subject to control by solvent and temperature. The dimerization process is enthalpically favored and entropy opposed and occurs with significant enthalpy-entropy compensation.
- Renslo, Adam R.,Tucci, Fabio C.,Rudkevich, Dmitry M.,Rebek Jr., Julius
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p. 4573 - 4582
(2007/10/03)
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