181640-72-2

Methods are described for the selective bromine-lithium exchange reaction of bromine-substituted calix[4]arenes with either n-BuLi or t-BuLi in THF. Quenching of the lithiated calix[4]arenes with MeOH, D2O, CH3SSCH3, B(OCHg3)3, DMF, or CO2 as electrophiles resulted in 5-monosubstituted, 5,17-disubstituted, or 5,11,17,23-tetrasubstituted calix[4]arenes with H, D, SCH3, B(OH)2, CHO, or COOH functionalities.

A series of malonate derivatives-calix[4]arene conjugates were synthesized through Knoevenagel condensation reaction between formyl-tetrapropoxycalix[4]arene and malonate derivatives. The structures of the resulting malonate derivative functionalized calix[4]arenes were characterized by NMR spectroscopy, mass spectrometry and even single crystal X-ray diffraction analysis.

A one-pot procedure, which combines the Ritter and Friedel-Crafts reactions, produced the first members of a new type of calix[4]arene-based receptors. The cavity in these receptors is formed by a calix[4]arene framework fixed in the cone conformation and

The supramolecular capacity of calixarenes towards guests is largely consolidated; in contrast, the synthesis of porous calixarene-based frameworks by covalent bond formation is still a challenge. Our target was to yield 3D polymers and copolymers based on calixarenes for selective gas-capture, endowed with easy pore accessibility and specific sites, and builtviaa straightforward synthetic route. The covalent calixarene frameworks (CXFs) were prepared by the Yamamoto coupling reaction starting from tetrabromo calixarene propoxy- and methoxy-monomers of three stable calixarene (partial cone, effective cone, and 1,3-alternate) conformers and complete post-synthetic deprotection to achieve polar phenolic calixarene derivatives. Moreover, the copolymer of calixarene-based monomers with tetrabromo-tetraphenylmethane exhibited remarkable surface area up to about 3000 m2g?1. Smart architectures endowed with hierarchical porosity from micro- to meso-porosity showed notable sponge-like swellability by CO2, which was captured effectively at room temperature, even in competition with N2, yielding CO2removal in column breakthrough experiments. Indeed, CXFs displayed excellent CO2and CH4energy binding of 35 and 24 kJ mol?1, respectively. Ultramicropore sites were highlighted by Xe capture andin situdetection after a xenon diffusion time of a few milliseconds, by laser-assisted hyperpolarized129Xe NMR, revealing the accessibility of calixarene capsules and the available space. This synthetic route demonstrated the possibility to modulate at will the pore capacity and selectivity, displaying porous frameworks with two distinct pore families, wherein calixarene moieties play the role of small and selective sites. A contractile behavior of the frameworks was observed upon deprotection which produced more polar sites, due to the formation of hydrogen bond networks.

The invention belongs to the technical field of chemical aromatic amide compounds, in particular to a calix[4]arene amide compound and a preparation method and application thereof. The preparation method of the calix[4]arene amide compound comprises the following steps of: (1) preparing 5,11,17,23-tetrabromo-25,26,27,28-tetra-n-propyl calix[4]arene (II) in 1,3-alternate conformation; (2) preparing5,11,17,23-tetrathienyl-25,26,27,28-tetra-n-propyl calix[4]arene (III) in 1,3-alternate conformation; (3) preparing 5,11,17,23-tetra(5- formylthiophen)-25,26,27,28-tetra-n-propyl calix[4]arene (IV) in 1,3-alternate conformation; (4) preparing 5,11,17,23-tetra(5-carboxythienyl)-25,26,27,28-tetra-n-propyl calix[4]arene (V) in 1,3-alternate conformation; and (5) dissolving the 5,11,17,23-tetra(5-carboxythienyl)-25,26,27,28-tetra-n-propyl calix[4]arene (V) in 1,3-alternate conformation in 1,2-dichloroethane, cooling the mixture in an ice-water bath, adding thionyl chloride slowly and dropwise, then raising the temperature for reflux for 5 hours, then cooling the obtained mixture in an ice-water bath, adding a mixed solution of ammonia water and methylene chloride for a reaction at room temperature for 8-12 hours to obtain the product 5,11,17,23-tetra(5-acylaminothienyl)-25,26,27,28-tetra-n-propyl calix[4]arene (I) in 1,3-alternate conformation.

Herein, we describe an improved method to synthesise mono-, di- and tetra-cyanocalix[4]arene and report their crystal structure determinations. We also report our attempts to further functionalise the cyanocalix[4]arenes into dithiadiazolyl-calix[4]arenes

A biomimetic, ion-regulated molecular receptor was synthesized via the Weak-Link Approach (WLA). This structure features both a calix[4]arene moiety which serves as a molecular recognition unit and an activity regulator composed of hemilabile phosphine alkyl thioether ligands (P,S) chelated to a Pt(II) center. The host-guest properties of the ion-regulated receptor were found to be highly dependent upon the coordination of the Pt(II) center, which is controlled through the reversible coordination of small molecule effectors. The environment at the regulatory site dictates the charge and the structural conformation of the entire assembly resulting in three accessible binding configurations: one closed, inactive state and two open, active states. One of the active states, the semiopen state, recognizes a neutral guest molecule, while the other, the fully open state, recognizes a cationic guest molecule. Job plots and 1H NMR spectroscopy titrations were used to study the formation of these inclusion complexes, the receptor binding modes, and the receptor binding affinities (Ka) in solution. Single crystal X-ray diffraction studies provided insight into the solid-state structures of the receptor when complexed with each guest molecule. The dipole moments and electrostatic potential maps of the structures were generated via DFT calculations at the B97D/LANL2DZ level of theory. finally, we describe the reversible capture and release of guests by switching the receptor between the closed and semiopen configurations via elemental anion and small molecule effectors.

Two novel calix[4]arene-based tetrapyrazolyl cavitands with different cavity size were synthesized by multistep reactions. In the solid state, one of the cavitands forms an infinite chain by Aintermolecular hydrogen bonding. The other cavitand undergoes c

The recognition of protein surfaces by designed ligands has become an attractive approach in drug discovery. However, the variable nature and irregular behavior of protein surfaces defy this new area of research. The easy to understand "lock-and-key" model is far from being the ideal paradigm in biomolecular interactions and, hence, any new finding on how proteins and ligands behave in recognition events paves a step of the way. Herein, we illustrate a clear example on how an increase in flexibility of both protein and ligand can result in an increase in the stability of the macromolecular complex. The biophysical study of the interaction between a designed flexible tetraguanidinium-calix[4]arene and the tetramerization domain of protein p53 (p53TD) and its natural mutant p53TD-R337H shows how the floppy mutant domain interacts more tightly with the ligand than the well-packed wild-type protein. Moreover, the flexible calixarene ligand interacts with higher affinity to both wild-type and mutated protein domains than a conformationally rigid calixarene analog previously reported. These findings underscore the crucial role of flexibility in molecular recognition processes, for both small ligands and large biomolecular surfaces. Copyright

Metalation of 5,17-dibromo-25,26,27,28-tetra propoxy calix[4]arene (1) with n-BuLi in THF at -78 °C gave organolithium reagent, which reacted with Me2HSiCl to give 5,17-bis(dimethylsilyl)-25,26,27,28-tetra propoxy calix[4]arene (2). The Si-H gr

Metalation of (RSiMe2)3CH (1a R = H, 1b R = Me, 1c R = Ph) with lithium diisopropylamide (LDA) or methyllithium in THF gave organolithium reagents (RSiMe2)3CLi, which reacted with the formylated calixarene (2),

Calix[4]arenes having multiple silyl groups on the upper (wide) rim were prepared from the corresponding bromocalixarenes by halogen-metal exchange with t-BuLi followed by silylation. The best results were obtained using the clear supernatant from a mixtu

The concept for a new class of nonplanar polyaromatic hydrocarbons - the funnelenes - is presented. Retrosynthetic considerations lead to polyphenyl- and oligophenylcalix[4]-arenes as potential precursors. In this paper we describe the synthesis of these

(Chemical Equation Presented) We have demonstrated a triangular assembly driven by 12 charged hydrogen bonds and π-π interactions. This assembly is stable even in polar solvents because of its charged hydrogen-bond nature. Helical arrangement of the complex is confirmed by its crystal structure. A solution structure is assigned to the D3 isomer corresponding to the solid-state structure by temperature-dependent 1H NMR experiments.

A facile and efficient approach to synthesize tetra-oligothiophene-substituted calix[4]arenes, Calix-OT(n) with n up to 4 using palladium-catalyzed Kumada coupling of thienylmagnesium bromide and bromo-substituted calix[4]arene as a key step has been deve

The solid state structures of seven tetrapropoxycalix[4]arene derivatives immobilised in a 1,3-alternate conformation were determined using single-crystal X-ray crystallography. The cavity shapes of investigated derivatives (upper rim unsubstituted, dista

We have designed and synthesized a modified calixarene derivative (1) that allows, for the first time, the isolation of a stable cation radical salt that binds a single molecule of nitric oxide deep within its cavity with remarkable efficiency (KNO >108 M-1), as demonstrated by isolation of a crystalline complex [1, NO]+ and its characterization by X-ray crystallography as well as by optical spectroscopy. Furthermore, the ready accessibility of the calixarene cation radical will allow the exploration of its use for developing efficient sensing devices for nitric oxide based on the accompanied color changes. Copyright

The regioselective upper-rim functionalization of calix[4]arene have been performed to prepare all the multisubstituted diphenylphosphine derivatives. In addition, the X-ray structures of 5,17-dibromo-11,23-bis(diphenylphosphino)-25,26,27,28-tetra-n-propoxycalix [4]arene and 5,11,17,23-tetrakis(diphenylphosphino)-25,26,27,28-tetra-i-propoxy-calix[4] arene have been determined. Regioselective functionalizations have been achieved using methods that involve appropriate choices of bases, alkyllithium-solvent systems, stoichiometry, and reaction times. A new and convenient method for selectively preparing derivitized calix[4]arenes at proximal positions in relative large scale quantity has been developed and involves a transesterification of the distal diester derivative into the proximal isomer.

Novel highly extended, cone-conformed tetrakis- styrylstyryltetrapropoxycalix[4]arenes and bis- styrylstyryltetrapropoxycalix[4]arenes were synthesized by stereoselective Wadsworth-Emmons reactions. Intramolecular chromophoric interaction of these assemblies resulted in changes to optical properties relative to those of the corresponding monomers with fluorescence enhancement being observed for the assemblies end-capped with methylsulfonyl acceptors. (C) 2000 Elsevier Science Ltd.