共查询到19条相似文献,搜索用时 109 毫秒
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设计合成了一系列3,3′-双吲哚烯类受体分子,应用紫外-可见吸收光谱研究了该类受体对二十种天然氨基酸分子的识别作用. 结果表明,在乙腈-水溶液中,双吲哚烯受体分子可以通过其氢键受体位点的质子化作用比色识别天冬氨酸、谷氨酸等酸性氨基酸;而硝基取代的双吲哚烯受体分子则通过其氢键供体位点的去质子化作用比色识别精氨酸、赖氨酸等碱性氨基酸. 在乙腈-水的中性缓冲溶液体系中,硝基取代的双吲哚烯类受体分子通过与巯基发生亲核加成反应高选择性比色识别半胱氨酸和同型半胱氨酸. 相似文献
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由于在蛋白质分离,生物传感器,疾病诊断和治疗以及基础的生物医药研究等领域的潜在重要应用,合成受体与短肽(3-20氨基酸残基)相互作用的研究已引起了人们的关注。本文综述了近年来合成受体与短肽相互作用的研究进展,介绍了小分子受体与个别氨基酸残基的相互作用,小分子受体对短肽的序列选择性识别,小分子受体对短肽二级结构的诱导与识别以及高分子受体与短肽的相互作用,并对短肽受体的设计进行了建议与展望。 相似文献
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A pair of artificial enantiotopic receptors la and lb composed of ( S, S) or (R,R) chiral bicyclic guanidinium, azacrown ether and (t-butyldiphenylsilyloxy) methyl group for amino acid zwitterions have been synthesized. The liquid-liquid competition extraction experiments and 1H NMR studies indicate that the receptor 1a with (S, S) configuration and lb with (R,R) configuration selectively recognize L- and Z)-aromatic amino acids respectively. 相似文献
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The p‐tetra‐tert‐butyl calix[4] arene derivatives (3 and 4) with (5,5) chiral bicyclic guanidinium, as the receptors of amino acid zwitterions, have been synthesized via a O‐alkylation reaction of p‐tetra‐tert‐butyl calix [4] arene with cbJoromethyl chiral bicyclic guanidinium 2 in the presence of anhydrous K2CO3 in acetonitrile. The results obtained from liquid‐liquid competitive extraction experiments indicate that the two receptors may selectively recognize L‐aromatic amino acids, and that the enantioselective recognizability of the receptor 4 with two chiral bicyclic guanidinium units reachs up to about 90% for L‐Phe. 相似文献
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Breccia P Van Gool M Pérez-Fernández R Martín-Santamaría S Gago F Prados P de Mendoza J 《Journal of the American Chemical Society》2003,125(27):8270-8284
A number of artificial carriers for the transport of zwitterionic aromatic amino acids across bulk model membranes (U-tube type) have been prepared and evaluated. 1,2-Dichloroethane and dichloromethane were employed in the organic phase. All compounds are based on a bicyclic chiral guanidinium scaffold that ideally complements the carboxylate function. The guanidinium central moiety was attached to crown ethers or lasalocid A as specific subunits for ammonium recognition as well as to aromatic or hydrophobic residues to evaluate their potential interaction with the side chains of the guest amino acids. The subunits were linked to the guanidinium through ester or amide connectors. Amides were found to be better carriers than esters, though less enantioselective. On the other hand, crown ethers were superior to lasalocid derivatives. As expected, transport rates were dependent on the carrier concentration in the liquid membrane. Reciprocally, enantioselectivities were much higher at lower carrier concentrations. The results show that our previously proposed three-point binding model (J. Am. Chem. Soc. 1992, 114, 1511-1512), involving the participation of the aromatic or hydrophobic residue to interact with the side chains of the amino acid guest, is unnecessary to explain the high enantioselectivities observed. Molecular dynamics fully support a two-point model involving only the guanidinium and crown ether moieties. These molecules constitute the first examples of chiral selectors for underivatized amino acids acting as carriers under neutral conditions. 相似文献
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Edith J. Banner 《Tetrahedron letters》2004,45(22):4411-4414
The Diels-Alder precursor was constructed from readily available d-glutamic acid utilizing a series of functional group transformations. The stereocenter of the amino acid provided the desired stereochemistry at C2 and diastereoselectively directed the intramolecular Diels-Alder cyclization. This simultaneously generated the three remaining stereocenters and yielded a bicyclic intermediate with all four stereocenters of the target decahydroquinoline 275B. 相似文献
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A series of three, new artificial receptors for guanidinium and ammonium guests has been synthesized. All three receptors have highly preorganized clefts bearing two carboxylate groups. They differ in the number of nitrogen atoms contained in their clefts, as follows: four N atoms in receptor 3, three N atoms in 4, and two nitrogens in 5. Crystallographic studies have produced the solid-state structures of the following guanidinium complexes of each receptor: 3.2CH(3)CH(2)NHC(NH(2))(2)(+), 4.2CH(3)NHC(NH(2))(2)(+), and 5.2C(NH(2))(3)(+). The conformations of the receptor molecules in all three complexes are very similar. N-Alkylguanidinium guests are bound in the clefts of 3 and 4 in similar manners, despite the loss of one hydrogen-bond acceptor nitrogen in 4 and the possible hindrance of the cavity by a CH group. In the guanidinium complex of 5, neither guest enters the cavity containing two CH groups. Complexation studies were conducted in methanol by (1)H NMR titration for several guanidinium and ammonium guests, including derivatives of the amino acids arginine and lysine. Receptor 5 binds all such guests weakly (K(s) < 4000), while 3 binds most guests very strongly (K(s) > 100 000). Receptor 3 is selective for arginine versus lysine, while 4 binds lysine better than does 3. The results generally underscore the importance of receptor preorganization and hydrogen-bonding complementarity in the design of receptors that can serve as probes for biomolecules. 相似文献
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Cuevas F Di Stefano S Magrans JO Prados P Mandolini L de Mendoza J 《Chemistry (Weinheim an der Bergstrasse, Germany)》2000,6(17):3228-3234
The methanolysis of choline p-nitrophenylcarbonate in chloroform containing 1% methanol is catalyzed with turnover by ditopic receptors 1 and 2, consisting of a calix[6]arene connected to a bicyclic guanidinium by means of a short spacer. The calix[6]arene subunit strongly binds to the trimethylammonium head group through cation-pi interactions, whereas the guanidinium moiety is deputed to stabilize through hydrogen bonding reinforced by electrostatic attraction the anionic tetrahedral intermediate resulting from methoxide addition to the ester carbonyl. The observed cholinesterase activity had been anticipated on the basis of the ability of the ditopic receptors 1 and 2 to bind strongly to the choline phosphate DOPC, which is a transition state analogue for the BAc2-type cleavage of choline esters. 相似文献
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The ionic composition of a cation-exchange membrane in solutions of amino acids of three types is studied by measuring its conductivity. The concentration constants of equilibrium of the protonation of zwitterions of these acids in the membrane are estimated. The membrane's ionic composition substantially depends on the type of amino acid. 相似文献
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The synthesis of seven peptidomimetics of RGD is presented. The indolizidine building block was obtained by condensation of allylglycine with dimethoxydihydrofuran followed by an intermolecular cyclization. The bicyclic ring was functionalised with a carboxylic acid and a guanidinium appendage. The seven peptidomimetics were evaluated by cell-adhesion assays. 相似文献
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Ong TT Kavuru P Nguyen T Cantwell R Wojtas Ł Zaworotko MJ 《Journal of the American Chemical Society》2011,133(24):9224-9227
Eight 2:1 cocrystals of amino acid zwitterions and Li(+) salts were crystallized from hot water to afford cationic networks based on tetrahedral lithium cations: square grids, an ABW topology net, and diamondoid nets. 相似文献