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1.
间二苄胍衍生物的合成 总被引:1,自引:0,他引:1
通过间二苄氯衍生物和二甲酰胺钠的亲核取代及水解方便地制备了相应的间二苄胺. 后者与甲基异硫脲作用生成间二苄胍硫酸盐,经离子交换得到相应的间二苄胍盐酸盐. 相似文献
2.
Brendan P. Orner Andrew D. Hamilton 《Journal of inclusion phenomena and macrocyclic chemistry》2001,41(1-4):141-147
The guanidinium group is found in many natural products and has been extensively incorporated into various drug designs as well as artificial receptor structures. In this paper we critically review the various synthetic routes to guanidiniums and describe a novel approach that allows the mild formation of multi-substituted derivatives. 相似文献
3.
To introduce chirality and functional groups adjacent to guanidiniums to modulate specificity and affinity in recognition, N,N'-bis(Boc)-alpha-guanidino acids were synthesized from alpha-amino acid methyl esters. Protected alpha-guanidino acids coupled to cyclohexylamine and trans-1,4-diaminocyclohexane in good yield and with retention of stereochemistry. Boc deprotection was conducted under mild acidic conditions (0.5 M HCl/EtOAc) to minimize epimerization. The deprotected guanidinium is configurationally stable under more acidic conditions. This approach represents a practical, convergent, stereospecific methodology to introduce chiral alpha-substituted guanidinium groups into molecules. 相似文献
4.
The glucose receptor 1 developed by Shinkai was synthesized by known methods and with modifications involving the final synthetic step, installation of the phenylboronic acid moieties. Binding of the bis(alpha-hydroxycarbolxylate), tartrate, was assessed and compared to the corresponding bis(diol), erythritol, as well as the corresponding mono(alpha-hydoxycarboxylate), malate. These results suggest that bisboronate/bis(alpha-hydoxycarboxylate) interactions are stronger than the corresponding bisboronate/bis(diol) interactions. Furthermore, we report that the receptor is an order of magnitude more selective for tartrate than malate. 相似文献
5.
Alla Sapronova Vladimir Bystrov Michael E. Green 《Journal of Molecular Structure》2003,630(1-3):297-307
A model of ion channel gating has been proposed (J. Biomol. Struct. Dyn. 19 (2002) 725). It includes the following. (1) There is a bacterial channel for which an X-ray structure is known (KcsA) that opens (‘gates’) with a drop in pH. In the proposal, a proton gates this channel by adding a charge to the glutamate residues that form the center of the gating region. It is postulated that two water molecules form a strong short hydrogen bond when the glutamates plus the water have a −2 charge. Adding a proton leads to a normal, weak, hydrogen bond, and the groups can separate, opening the channel.
98 calculations support this part of the proposal (J. Phys. Chem. B 105 (2001) 5298). (2) Voltage gated channels contain six transmembrane (TM) segments in each of four domains. We suggest that the additional four TM segments (KcsA has two) act as a voltage-to-proton current transducer. In the model, the first step in gating is proton tunneling (J. Phys. Chem. A 102 (1998) 7181), followed by a proton cascade. Calculations supporting the latter step are presented here. One of the eukaryotic TM segments, S4, is known to be involved in gating. This segment has arginines (occasionally lysine) at every third amino acid. The arginines appear capable of transmitting a proton, or possibly a proton cascade (three per S4 would produce the observed charge movement (‘gating current’) that precedes gating). We have carried out density functional calculations, using
98, on a system that includes: one pair of guanidinium groups, the side chains of arginines responsible for carrying the proton current; a mobile proton; one, two or three water molecules. Several guanidinium spacings have been tried, all in the range of carbon–carbon distances 4–6 Å. The potential energy surface was computed for each, and a minimum path found for the proton, at B3LYP/6-311G** level. It was found that the proton, under some conditions, could follow a path between guanidiniums that had no barriers greater than a few kT (thermal energy), thereby supporting the proposal that protons could move along the chain of guanidiniums. 相似文献
6.
Two different hydrogen-bonded inclusion compounds, [2,4,6-C5H2N(COO?)3]0.5·[C(NH2) 3 + ]0.5·[(C2H5)4N+]·2H2O (1) and [2,4,6-C5H2N(COO?)3]·[C(NH2) 3 + ]·[(C2H5)4N+]·[(C3H7)4N+]·6H2O (2) are reported in this paper, in which 2,4,6-pyridine-tricarboxylic anions, guanidiniums and water molecules jointly construct host lattices while tetraalkylammonium cations are accommodated as guest species. Both two compounds formed sandwich-like hydrogen-bond inclusion compounds. In compound 1, the dimers composed of 2,4,6-pyridine-tricarboxylic anions and guanidiniums form 2D hydrogen-bonded layers by connecting with water molecules. In compound 2, 2,4,6-pyridine-tricarboxylic anions, guanidiniums and water molecules contribute to generate an undulate rosette hydrogen-bonded architecture. Interestingly, in compound 2, there are two species of guest molecules, tetraethylammonium and tetrapropylammonium, which are alternately arranged between the neighboring layers. Mixed guest cations accommodated in hydrogen-bonded inclusion compounds are seldom seen. 相似文献
7.
Kim DS Miyaji H Chang BY Park SM Ahn KH 《Chemical communications (Cambridge, England)》2006,(31):3314-3316
A ferrocene-based bis(o-trifluoroacetylcarboxanilide) receptor selectively recognizes m-phenylene diacetate through cooperative binding; the receptor also displays a significant negative shift in the oxidation potential of ferrocene upon the guest binding. 相似文献
8.
An online citrate and Ca(2+) sensing system based on sequential injection analysis (SIA) is developed as a safety module for hemodialysis. Host 1 displays high affinity towards citrate, and was selected for this study owing to its unique structural features. The o-aminomethylphenylboronic moiety can effectively interact with the α-hydroxycarboxylate moiety of citrate and the remaining two guanidiniums may further stabilize the complex via hydrogen bonds. Fura-2 chelates to Ca(2+) with a high selectivity and affinity and was utilized in this study for Ca(2+) measurements. The citrate sensing chemistry via an indicator displacement assay is orthogonal to the Ca(2+) sensing chemistry, and the use of sophisticated chemometrics is not required for data analysis. The citrate and Ca(2+) concentrations in dialysate samples are measured with the developed SIA system. The obtained citrate concentrations were verified via a commercially available enzymatic assay and an NMR method, respectively, while the Ca(2+) concentrations were verified via atomic absorption. 相似文献
9.
J D Thomas 《The Analyst》1991,116(12):1211-1215
Researches on prospects for novel ion-selective electrodes, based on organic molecule sensors, are described. The organic molecules are large crown ethers extending from bis(metaphenylene)-26-crown-8 to bis(metaphenylene)-38-crown-12, small crown ethers, bis-crown ethers, and acyclic polyethers consisting of diphenyl ethers of tetraethylene glycol and receptor molecules of planar and tetrahedral tripodal types. 相似文献
10.
New (tetrakis)imidazolium macrocyclic receptor systems of variable cavity size have been synthesised by stepwise alkylation reactions of bis(imidazolium) precursor compounds. Proton NMR titration studies reveal the macrocycles to strongly bind halide and benzoate anions, with two receptor systems displaying notable selectivity for fluoride in competitive acetonitrile-water (9:1) solvent media. 相似文献
11.
12.
Jürgen TeichgräberUlrike Holzgrabe 《Tetrahedron》2003,59(44):8697-8703
The allosteric modulation of receptors has become a widely accepted concept in order to enhance the agonist or antagonist binding to a receptor. Alcuronium, characterized by a high allosteric potency and a positive cooperativity at the muscarinic M2 receptor, was chosen as a template to design a structural novel terphenyl-type of allosteric modulator. The skeleton was build up from 1-bromo-2-methylnaphthalene and 1,4-dibromo-2,5-dimethylbenzene using bis(triphenylphosphine)nickel(II) dichloride as a catalyst. Several amino substituted terphenyls were synthesised and preliminary pharmacological tests were performed. 相似文献
13.
Wang L Wei W Guo Y Xu J Shao S 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,78(2):726-731
A series of nitro-substituted 3,3'-bis-indolyl phenylmethane derivatives were synthesized and their anion binding properties were investigated in detail. The introduction of the electron-withdrawing nitro group into indole unit and/or meso-phenyl ring, which leads to the increased acidity of indole NH and meso-position CH proton, has a positive effect on anion binding. The nitro-substituted bis(indolyl)methane receptors exhibited selective colorimetric sensing of F- anion, as revealed by the notable color and spectral changes, rationally due to the deprotonation of the indole NH of the receptor. Meanwhile, the additive introduction of the nitro substituents on the meso-phenyl ring of bis(indolyl)methane can lead to the deprotonation of the meso-position CH and further induce an irreversible oxidation process obtaining bis(indolyl)methene product in the F- anion sensing system. 相似文献
14.
《Angewandte Chemie (International ed. in English)》2017,56(41):12774-12777
We report a general preparation of arylated bicyclo[1.1.1]pentanes through the opening of [1.1.1]propellane with various arylmagnesium halides. After transmetalation with ZnCl2 and Negishi cross‐coupling with aryl and heteroaryl halides, bis‐arylated bicyclo[1.1.1]pentanes are obtained. These bis‐arylated bicyclo[1.1.1]pentanes may be considered as bioisosteres of internal alkynes. Bioisosteres of tazarotene and the metabotropic glutamate receptor 5 (mGluR5) antagonist 2‐methyl‐6‐(phenylethynyl)pyridine were prepared and their physicochemical properties were evaluated. 相似文献
15.
Tetrakis(bicyclo[2.2.2]oct‐2‐ene)‐fused calix[4]pyrrole, 5 , was obtained starting from (E)‐1,2‐bis(phenylsulfonyl)ethylene. This new calixpyrrole derivative is the prospective precursor of tetrabenzocalix[4]pyrrole, a potential ion‐pair receptor and an attractive species as a possible deep‐walled ‘molecular container’. 相似文献
16.
Arena G Contino A Longo E Sgarlata C Spoto G Zito V 《Chemical communications (Cambridge, England)》2004,(16):1812-1813
The electrochemically switchable Cu(2+) complex of a 1,3 alternate bis(dipyridyl)calix[4]arene derivative forms self-assembled monolayers on Au(111) surfaces. The receptor is patterned on the surface by using microcontact printing procedures and the resulting surface is imaged via SPR. 相似文献
17.
γ-Hydrobutenolides were obtained from the reaction of substituted 2,5- bis(trimethylsiloxy)furans with aldehydes and ketones using titanium tetrachloride activation. Similarly, α,β-unsaturated carbonyl compounds reacted as a Michael receptor with the title compounds to give γ-hydroxybutenolides. 相似文献
18.
Turega SM Lorenz C Sadownik JW Philp D 《Chemical communications (Cambridge, England)》2008,(34):4076-4078
Nitrones undergo dynamic exchange in chloroform at room temperature through two mechanisms-hydrolysis and recombination or hydroxylamine addition/elimination; this dynamic exchange is harnessed to select a nitrone-based bis(amidopyridine) receptor for diacids from a group of four nitrones through its binding to a glutaric acid-based target. 相似文献
19.
Host–Guest Chemistry of a Bis‐Calix[4]pyrrole Derivative Containing a trans/cis‐Switchable Azobenzene Unit with Several Aliphatic Bis‐Carboxylates 下载免费PDF全文
Grazia Cafeo Franz H. Kohnke Giovanni Mezzatesta Aldo Profumo Camillo Rosano Antonino Villari Andrew J. P. White 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(14):5323-5327
The azobenzene unit used as a photochemically and thermally switchable linker in the assembly of a bis‐calix[4]pyrrole receptor provides a means to modulate the binding of bis‐carboxylates of significant biological importance in cancer research. Conversely, the complexation of different bis‐anionic guests has significant kinetic effects on both the photochemical and thermal trans/cis isomerization of the azobenzene unit. 相似文献
20.
Kobayashi S Atuchi N Wakamatsu H Hattori M Kawada A Asano K 《Chemical & pharmaceutical bulletin》2007,55(11):1585-1592
The interaction between growth inhibition and chirality, especially of diastereomers, has an important modifying effect on cancer cell proliferation. Previously, we have reported on the design, synthesis, and chemical properties of a series of novel, double-stranded peptides, (y-AA-x-AA)(2)-(CH(2))(12), with -y-AA-x-AA- and -z-AA-y-AA-x-AA- sequences conjugated to the spacer. Here, we extend those results by showing that (D-, L-) and (L-, D-) diastereomers are more potent inhibitors of tyrosine phosphorylation than (L-, L-). Although the replacement of the L-Phe-L-Phe sequence with L-Tyr-L-Phe produces a less active inhibitor, the double-stranded peptide conjugated with L-Tyr-D-Phe is more active than that conjugated with L-Tyr-L-Phe. In addition, we show that SDS-PAGE gel profiles of tyrosine phosphorylation following treatment with bis(y-Tyr-x-Phe)-N,N-dodecane-1,12-diamine appear very similar to profiles of tyrosine phosphorylation following treatment with an analog of the tyrosine kinase inhibitor, erbstatin. Moreover, the level of autophosphorylation of the epidermal growth factor receptor kinase domain (EGFRKD) treated with bis(L-Tyr-D-Phe)-N,N-dodecane-1,12-diamine was lower than that seen following treatment with bis(L-Phe-D-Phe)-N,N-dodecane-1,12-diamine. These data provide new insights for the control of cancer cell proliferation through drug designs which replace the less active -L-Phe-L-Phe- (and -D-Phe-L-Phe-) with the more active -L-Tyr-L-Phe- (and -L-Tyr-D-Phe-) sequence. 相似文献