共查询到20条相似文献,搜索用时 15 毫秒
1.
Photoswitchable calix[4]resorcinarenes with different numbers of azo groups in the upper rim were synthesised by the reaction of bromomethylcavitand with 4-aminoazobenzene. UV-vis, 1H and 13C NMR, MALDI TOF-MS spectral data have been used to elucidate the structures of compounds. 相似文献
2.
Hideaki Hioki Yumiko Ohnishi Miwa Kubo Emi Nashimoto Yukinori Kinoshita Miho Samejima Mitsuaki Kodama 《Tetrahedron letters》2004,45(3):561-564
A fluorescence-labeled calix[4]arene library substituted with peptides at the upper rim was synthesized. Screening of the library for binding a dye-labeled oligopeptide indicated that some peptidocalix[4]arenes selectively bind the oligopeptide. The chemosensitivity of the library members for a target peptide was also investigated. 相似文献
3.
Highly regio- and stereoselective Diels-Alder reactions of bis(spirodienone) derivatives of calix[4]arene with acetylenes that provide easy access to bisbicyclo[2.2.2]octenones are described. 相似文献
4.
Har Mohindra Chawla Jyotsna Rani Kar Weqar Ahmad Siddiqui Naresh Kumar David StC Black 《Tetrahedron letters》2014
A novel calix[4]arene linked nucleobase molecular receptor bearing two adenine moieties has been synthesized and characterized by UV, IR, NMR and ESI–MS analyses. The synthesized receptor can recognize biologically important Zn2+ and Mn2+ ions through 1:1 binding stoichiometry. The evaluation of binding constants suggests that adenine alone, in an appropriate supramolecular network, can exhibit efficient binding for Zn2+ ions without the presence of any phosphate or sugar unit. 相似文献
5.
Matthias H. DükerRafael Gómez Christophe M.L. Vande VeldeVladimir A. Azov 《Tetrahedron letters》2011,52(22):2881-2884
The synthesis of novel upper rim calix[4]arene-tetrathiafulvalene conjugates 1a-d has been performed by bridging the tetrachloromethylated calix[4]arene derivative 4 with the corresponding tetrathiafulvalene-dithiolates. The cyclic voltammetry of 1a-d shows a two-step oxidation behavior, whereas NMR binding titrations showed their binding affinity to pyridinium salts. X-ray structure of 4 features calixarene fixed in the pinched cone conformation; its crystal packing is defined by the network of C-H···Cl weak hydrogen bonds. 相似文献
6.
Walysson Ferreira de Paiva Ingredy Bastos Braga João Vitor de Assis Sandra Milena Bonilla Castañeda Ángel Gabriel Sathicq Valeria Palermo Gustavo Pablo Romanelli Ricardo Natalino Marcio José da Silva Felipe Terra Martins Gustavo Senra Gonçalves de Carvalho Giovanni Wilson Amarante Sergio Antonio Fernandes 《Tetrahedron》2019,75(27):3740-3750
The application of immobilizing calixarene onto the surface of silica using a sol-gel method, as an efficient heterogeneous catalyst (CX4SO3HSi(n)) for multicomponent Povarov reaction has been described. Catalytic activity of the CX4SO3HSi(n) for the synthesis of julolidines under greener and environmentally benign conditions in simple and efficient method was explored. Notably, only 0.5 mol% of the catalyst is sufficient to catalyze the Povarov solvent-free reaction under microwave-assistance. Besides, this protocol allows the construction of four new C–C bonds and two C–N bonds in a single step. To the best of our knowledge, this consists the first silica support calix[4]arene as a heterogeneous catalyst for multicomponent synthesis of julolidines. 相似文献
7.
Paul D. Beer Anthony D. Keefe 《Journal of inclusion phenomena and macrocyclic chemistry》1987,5(4):499-504
The condensation of 1,1-bis(chlorocarbonyl)metallocenes andp-tert-butylcalix[4]arene in toluene leads to novel metallocene calix[4]arenes in which the metallocene subunit bridges the opposite hydroxy groups of the parent calixarene.Presented at the Fourth International Symposium on Inclusion Phenomena and the Third International Symposium on cyclodextrins, Lancaster, U.K., 20–25 July 1986. 相似文献
8.
Anion complexation. A ditriphenylphosphonium calix[4]arene derivative as a novel receptor for anions
A novel anionic receptor 2 consisting of a calix[4]arene bearing two alkytriphenylphosphonium has been prepared by two different procedures. The complexation occurred at the phosphonium sites probably due to electrostatic and/or π-anion forces. 相似文献
9.
The facile preparation of N(H)-bridged azacalix[4]arenes has been achieved by stepwise nucleophilic aromatic substitutions assisted by hydrogen bonding interactions. The synthesis is uncatalyzed and affords previously unknown tetranitroazacalix[4]arenes. 相似文献
10.
Thiacalix[4]arenes bearing two or four carboxylic functions on the lower rim served as starting compounds for the synthesis of novel calixarene oligomers connected by amidic functions. The cone conformers react smoothly with four molecules of 5-amino-calix[4]arene to yield the corresponding pentakis-calixarenes. On the other hand, because steric hindrance, the 1,3-alternate condenses only with two molecules leading thus to tris-calixarene, possessing a novel type of inherent chirality based on the 25,26-substitution pattern. The title compounds, which connect together ‘classical’ calixarene and thiacalixarene building blocks, represent a first step towards calixarene-based dendritic structures. 相似文献
11.
Chuqiao Tu 《Tetrahedron》2007,63(19):4184-4189
Di-ionizable calix[4]arene-1,2-crown-4 ethers in the cone conformation were synthesized and their conformation and regioselectivity verified by NMR spectroscopy. These new ligands exhibited high Ba2+ selectivity in competitive solvent extraction of alkaline earth metal cations from aqueous solutions into chloroform. The selectivity order was Ba2+>>Sr2+>Ca2+>Mg2+ with Ba2+/Sr2+ selectivity exceeding 100. The ligands also exhibited high extraction ability for Pb2+ and for Hg2+ in single species extraction. With variation of proton-ionizable groups, which are oxyacetic acid moieties and N-(X)sulfonyl oxyacetamide units with X=methyl, phenyl, 4-nitrophenyl, and trifluoromethyl, ‘tunable’ ligand acidity was obtained. 相似文献
12.
Pallavi Srivastava 《Tetrahedron letters》2007,48(26):4489-4493
Calix[4]arene scaffold based quaternary ammonium salts as multi-site phase transfer catalysts were prepared and their catalytic activities were investigated for Darzens condensation, O/N-alkylation reactions and ethyl benzene oxidation. These calix[4]arene based multi-site phase transfer catalysts showed significant high catalytic activity as compared to single-site phase transfer catalysts. 相似文献
13.
Preferential crystallization from a mixture of C-methylresorcin[4]arene (RsC1) and calix[6]arene (Calix6) in the presence of different bases has been investigated. In the presence of pyridine, a boat conformer of RsC1 crystallizes, whereas in the presence of triethylamine, Calix6 crystallizes in a symmetrically distorted conformation. The packing arrangements of the macrocycles show discrete solvent pockets for calixarenes and channels for resorcinarenes. 相似文献
14.
Four novel calix[4]arene derivatives 5-8 bearing four fluorogenic coumarin units attached via imino group acting also as binding sites at the upper rim have been prepared and characterized by IR, IH NMR and MS. Compounds 5-8 adopt a cone conformation. Their complexation properties to different heavy and transition metal ions have been studied by UV-vis spectroscopy. Compounds 5, 6, 8 show selective recognition to Fe^3+ and Cr^3+. 相似文献
15.
Heavy atom substituted Bodipy compounds, unlike the parent chromophore, undergo rapid intersystem crossing to generate singlet oxygen, which is the primary cytotoxic agent exploited in PDT. In this work, we show that an organic soluble calix[4]arene can be functionalized by Knoevenagel reaction and then converted into an amphiphilic photosensitizer in a few steps. In addition to generating a potentially useful photosensitizer, the sequence of reactions is the first use of a Bodipy dye as a chromophoric/fluorogenic label without the typical reactive functional groups. 相似文献
16.
17.
Oleg V. Surov Nugzar Zh. Mamardashvili Gennadiy P. Shaposhnikov Oskar I. Koifman 《Journal of inclusion phenomena and macrocyclic chemistry》2007,58(3-4):329-335
The inclusion of small neutral organic guests (C6H14, CH2Cl2, CH3OH) by calix[4]arene receptors was found by 1H NMR spectroscopy and microanalysis. The studied calix[4]arenes can form stable intramolecular complexes with solvent molecules
which keep the stoichiometric composition without changing under conditions of the sublimation experiment. The saturated vapour
pressures of calix[4]arenes and complexes of calix[4]arenes with solvent molecules were determinated for the first time by
the Knudsen’s effusion method in the wide temperature range. The changing of standard thermodynamic parameters of complexation
by transfer process from condensed state to vapour phase was estimated. It was shown that the large flexibility of the calixarene
ligand structure corresponds to a strongly negative entropic contribution as well as negative enthalpy term to the Gibbs energy
of formation of host–guest complexes in the gas phase. 相似文献
18.
Yuya Inaba Jian Yang Yu Kakibayashi Dr. Tomoki Yoneda Dr. Yuki Ide Dr. Yuh Hijikata Dr. Jenny Pirillo Dr. Ranajit Saha Prof. Dr. Jonathan L. Sessler Prof. Dr. Yasuhide Inokuma 《Angewandte Chemie (International ed. in English)》2023,62(15):e202301460
Chiral pyrrolic macrocycles continue to attract interest. However, their molecular design remains challenging. Here, we report a calixpyrrole-based chiral macrocyclic system, calix[1]furan[1]pyrrole[1]thiophene ( 1 ), synthesized from an oligoketone. Macrocycle 1 adopts a partial cone conformation in the solid state, and undergoes racemization via ring inversion. Molecular dynamics simulations revealed that inversion of the thiophene is the rate determining step. Pyrrole N-methylation suppressed racemization and permitted chiral resolution. Enantioselective N-methylation also occurred in the presence of a chiral ammonium salt, although the stereoselectivity is modest. A unique feature of 1 is that it acts as a useful synthetic precursor to yield several calix[n]furan[n]pyrrole[n]thiophene products (n=2–4), including a calix[12]pyrrole analogue that to our knowledge constitutes the largest calix[n]pyrrole-like species to be structurally characterized. 相似文献
19.
20.
Microwave-assisted synthesis of calix[4]resorcinarenes by cyclocondensation of various aldehydes and resorcinol catalysed by 12-tungstophosphoric acid type Keggin (H3PW12O40·13H2O) or concentrated HCl is described. Excellent isolated yields (up to 90%) were attained within short reaction times (typically, 3-5 min) when the reaction was performed under microwaves irradiation. 相似文献