386768-13-4

Upstream product

• 157432-87-6 5,11,17,23-tetra-t-butyl-25,26,27,28-tetrahydroxycalix-4-arene 
• 248590-47-8 25,26,27,28-tetrakis(hydroxy)calix[4]arene 
• 98-54-4 para-tert-butylphenol 

Relevant academic research and scientific papers

Spectroscopic studies of brilliant cresyl blue/water-soluble sulfonated calix[4]arene complex

Water-soluble sulfonated calix[4]arene (SCX4) was used as the host molecule for the guest dye(probe), Brilliant Cresyl Blue (BCB), which is commonly employed for studies of various biological systems. Absorption and fluorescence techniques were employed for the analysis of this system. The formation of a complex between the BCB dye and SCX4 results in a decrease in the BCB fluorescence intensity. A study of the changes in absorption and of temperature effects on the fluorescence of BCB/SCX4 was conducted. The binding constant for BCB/SCX4 at room temperature was estimated to be 8.49×103 M-1.

Binding Methylarginines and Methyllysines as Free Amino Acids: A Comparative Study of Multiple Host Classes**

Methylated free amino acids are an important class of targets for host-guest chemistry that have recognition properties distinct from those of methylated peptides and proteins. We present comparative binding studies for three different host classes that are each studied with multiple methylated arginines and lysines to determine fundamental structure-function relationships. The hosts studied are all anionic and include three calixarenes, two acyclic cucurbiturils, and two other cleft-like hosts, a clip and a tweezer. We determined the binding association constants for a panel of methylated amino acids using indicator displacement assays. The acyclic cucurbiturils display stronger binding to the methylated amino acids, and some unique patterns of selectivity. The two other cleft-like hosts follow two different trends, shallow host (clip) following similar trends to the calixarenes, and the other more closed host (tweezer) binding certain less-methylated amino acids stronger than their methylated counterparts. Molecular modelling sheds some light on the different preferences of the various hosts. The results identify hosts with new selectivities and with affinities in a range that could be useful for biomedical applications. The overall selectivity patterns are explained by a common framework that considers the geometry, depth of binding pockets, and functional group participation across all host classes.

Needle-shaped amphoteric calix[4]arene as a magnetic nanocarrier for simultaneous delivery of anticancer drugs to the breast cancer cells

Background: Chemotherapy as an important tool for cancer treatment faces many obstacles such as multidrug resistance and adverse toxic effects on healthy tissues. Drug delivery systems has opened a new window to overcome these problems. There has been a strong interest development of new platform and system for delivof chemotherapeutic agents. Purpose: In the present study, a green synthesis method was chosen and performed for preparation of a novel amphoteric calix[4]arene (Calix) macrocycle with low toxicity to the human body. Materials and methods: The amphoteric Calix was coated on the surface of Fe3O4 magnetic nanoparticles and used as a magnetic nanocarrier for simultaneous delivery of two anticancer agents, doxorubicin and methotrexate, against MCF7 cancer cells. Several chemical characterizations were done for validation of prepared nanocarrier, and in vitro loading and release studies of drugs were performed with good encapsulation efficiency. Results: In vitro biological studies including hemolysis assay, erythrocytes sedimentation rate, red blood cells aggregation, cyto cellular internalization, and apoptosis evaluations were performed. Based on results, the developed nanocarrier has many advantages and capability for an efficient codelivery of DOX and MTX, which has a highly potent ability to kill cancer cells. Conclusion: All these results persuade us, this nanocarrier could be effectively used for cancer therapy of MCF7 breast cancer cells and is suitable for use in further animal studies in future investigations.

Investigation of hydrogen bonding in p-sulfonatocalix[4]arene and its thermal stability by vibrational spectroscopy

The vibrational spectra of p-sulfonatocalix [4] arene were studied. The geometrical parameters, the energies, the frequencies and the intensities of the bands in the IR and Raman spectra are calculated for four conformations. The most stable conformation of the p-sulfonatocalix[4]arene is the cone due to the cooperative cyclic intramolecular hydrogen bonding system. The strength of the hydrogen bonds depends on the type of substituent on the upper rim of the calixarene molecules. We studied the process of destruction of calixarenes using IR spectroscopy and TGA methods. Characteristic bands for each conformation were selected. HOMO covers aromatic units with notable conjugation, and LUMO belongs to sulfonate groups.

A calix[4]arene-based ternary supramolecular nanoassembly with improved fluoroquinolone photostability and enhanced NO photorelease

Micellar-like nanoassemblies of a sulfonate amphiphilic calix[4]arene (1) are able to effectively co-entrap the fluoroquinolone antibacterial norfloxacin (2) and a hydrophobic nitric oxide (NO) photodonor (3), leading to a ternary supramolecular complex having a diameter of ca. 150 nm and a zeta potential of -48 mV. Outstanding photochemical stabilization of the otherwise photolabile fluoroquinolone 2 is observed under UVA excitation. Besides, visible light excitation leads to a remarkable enhancement of the NO photorelease efficiency of 3. Both the results can be explained on the basis of a "cage effect" of the micellar host that, in the case of 2, hinders the formation of the precursor complex responsible for the photodegradation, whereas in the case of 3 it provides a low polarity environment and easily abstractable hydrogens, which facilitate the radical-mediated mechanism involved in NO photorelease. Therefore, this supramolecular ternary nanoassembly simultaneously overcomes the main limitations of the free individual guests such as photolability and low photoreactivity. In view of the well-known antibacterial properties of the NO radical and the biocompatibility of the calixarene host, this nanoassembly represents a suitable bimodal system to be tested in antibacterial research.

Highly branched amine-functionalized: P -sulfonatocalix[4]arene decorated with human plasma proteins as a smart, targeted, and stealthy nano-vehicle for the combination chemotherapy of MCF7 cells

Nanotechnology has recently emerged as a promising field for biomedical applications, especially the targeted delivery of drugs to tumors. Besides, combination chemotherapy is common in cancer treatment and is rapidly evolving. Therefore, the successfully delivery of chemotherapeutic drugs to targeted cancers is a big challenge. In this study, we endeavour to develop a nano-vehicle, based on highly branched amine-functionalized p-sulfonatocalix[4]arene, to act as a dual-drug carrier for the co-delivery of DOX and MTX to MCF7 breast cancer cells with targeting and synergistic effects. After the synthesis and preparation of the nano-vehicle, structural characterization was also conducted (FTIR, AFM, VSM, SEM, EDX, XRD, DLS, and zeta potential analyses). Drug loading and release studies on the prepared drug-loaded nano-vehicle were conducted to optimize the formulation. The designed platform has targeting and pH-triggered drug release capabilities to improve the therapeutic index of DOX and MTX. Hemolysis assay results proved that the nano-vehicle has high blood compatibility, even for high dosage treatment. The protein-particle interactions of the nano-vehicle in human blood circulation systems were simulated via SDS-PAGE assays and the results indicated that a series of proteins were attached to the surface of the nano-vehicle. This feature gives the nano-vehicle stealth properties in the blood circulation system. The cellular uptake, from flow-cytometry and fluorescence microscopy, validated that the human plasma proteins attached to the nano-vehicle surface gave the nano-vehicle high internalization capabilities into cells due to the presence of some protein receptors on the surfaces of cancer cells, improving the tumor cell targeting properties. MTT assays and DAPI staining were also performed to show the viability and DNA fragmentation of treated cells. All results validated one another and confirmed that our designed nano-vehicle is useful for targeted and combination drug delivery systems with stealth properties.

Quinolines: Microwave-assisted synthesis and their antifungal, anticancer and radical scavenger properties

An efficient method for the synthesis of quinolines using microwave irradiation was developed providing 28 quinolines with good yields. The reaction procedures are environmentally friendly, convenient, mild and of easy work-up. Quinolines were evaluated f

P-Sulfonic acid calix[4]arene-functionalized alkyl-bridged organosilica in esterification reactions

Two new p-sulfonic acid calix[4]arene- and p-sulfonic acid calix[6]arene-functionalized organosilica have been synthesized using a sol-gel method and applied as heterogeneous catalysts in esterification reactions. The catalytic performance was evaluated using the esterification of carboxylic acids with ethanol, and good catalytic activity (i.e., 55-88%) was observed under the optimum reaction conditions. This study reports the first promising example of the successful employment of calix[n]arenes as a heterogeneous catalyst for catalytic esterification. The catalyst was easily separated by filtration and reused five times without any significant loss of activity.

Synthesis and investigation of catalytic affinities of water-soluble amphiphilic calix[n]arene surfactants in the coupling reaction of some heteroaromatic compounds

Six water-soluble calix[n]arene-based Br?nsted acid-type catalysts with amphiphilic groups were successfully synthesized by incorporating sulfonic acid moieties. Their structures were characterized using FTIR,1H NMR,13C NMR, APT-NMR, and elemental analysis techniques. Moreover, their catalytic capabilities were evaluated in the coupling reaction of 2-methylfuran and/or N-methylindole with some sec-alcohols in aqueous media. The association of their surfactant abilities, and the effects of water amount used and reaction durations on the catalytic activities of these amphiphilic calix[n]arene derivatives were also investigated. Observations indicated that these amphiphilic calix[n]arene catalysts exhibited high catalytic activities in the coupling reactions of 2-methylfuran and N-methylindole with some alcohols in water.

Calix[n]arenes: Active organocatalysts for the synthesis of densely functionalized piperidines by one-pot multicomponent procedure

An efficient, suitable and high yielding method has been developed for the synthesis of different densely functionalized piperidine derivatives via pseudo-five component, one-pot domino reaction through a combination of β-ketoesters, aromatic aldehydes, and various amines using p-sulfonic acid calix[n]arenes as catalysts. The reaction was carried out in refluxing methanol, affording very good yields of the expected piperidine. Atomic economy, environmentally benign procedure, reuse of catalysts, and short reaction time are some of the important features of this protocol.