Cholesteric liquid crystalline polysiloxanes containing furan ring with selective reflection – synthesis and properties

Zn-based metal-organic-framework as a multifunctional fluorescent sensor for HSO4−, acidic and basic amino acids

High molecular weight, fully biobased random copolymers of 2,5-furandicarboxylic acid (2,5-FDCA) containing different amounts of (1R, 3S)-(+)-Camphoric Acid (CA) have been successfully synthesized by two-stage melt polycondensation and compression molding in the form of films. The synthesized copolyesters have been first subjected to molecular characterization by nuclear magnetic resonance spectroscopy and gel-permeation chromatography. Afterward, the samples have been characterized from a thermal and structural point of view by means of differential scanning calorimetry, thermogravimetric analysis, and wide-angle X-ray scattering, respectively. Mechanical and barrier properties to oxygen and carbon dioxide were also tested. The results obtained revealed that chemical modification permitted a modulation of the abovementioned properties depending on the amount of camphoric co-units present in the copolymers. The outstanding functional properties promoted by camphor moieties addition could be associated with improved interchain interactions (π-π ring stacking and hydrogen bonds).

Efficient conditions for the synthesis of nitrogen-containing heterocyclic derivatives of (1R,3S)(+)-camphoric acid were selected. A series of heterocyclic compounds based on (+)-camphoric acid bearing pharmacophoric fragments was synthesized using the developed methodology. The compounds were tested for their antiviral activity against SARS-CoV-2 and H1N1 influenza viruses, and efficient inhibitors were identified that are of significant interest for further studies. The stability of the compounds and pharmaco-kinetics of the leader compound were studied when administered intragastrically and intramuscularly to mice at a dose of 200 mg kg-1 using the HPLC-MS/MS method.

Electrical, thermal, and spectral characterizations of ferroelectric liquid crystal obtained from the precursors namely camphoric acid and heptyloxy benzoic acid abbreviated as CA + 7BAO. This mesogen exhibits two phases smectic C* and smectic G* in its exothermic run. DSC thermograms reveals the phase transition temperatures and enthalpy values of those phases. The spectral information recorded through Fourier transform infrared spectroscope reveals the possession of hydrogen bond. An interesting feature of this work lies in realizing the constant current device with variation to both temperature as well as potential. The same observation shall be utilized for the sensitive biomedical instruments where the current rating above few µA increment do have significant effect. Furthermore, the research work also reveals the information about the linearity of the thermo-electric graph with respect to phase transition temperatures. Thermoelectric Plot.

The generation and regulation of chirality are closely related to the origin of life. Using achiral precursors to spontaneously build chiral MOFs remains a major challenge. Here, a method to synthesize chiral MOFs from achiral precursors by utilizing chiral fragments was achieved. The transformation from chiral fragments of 1 to chiral frameworks of 2 and 3 was realized by modifying the substituents, and the enantiomer resolution of 3-P41212 and 3-P43212 was achieved by d/l camphoric acid. 3 was then further studied in applications.

Abstract The reaction of dioxygen with copper(I) complexes containing camphor‐derived ligands was investigated. Stopped‐flow measurements revealed the formation of bis(μ‐oxido) copper complexes at low temperatures. However, these intermediates were not stable enough to be isolated and decomposed quickly. Sterically more demanding alkyl groups slowed the formation of the bis(μ‐oxido) copper complexes. A kinetic analysis was performed and showed ‐ in line with previous reports ‐ that the rate‐determining step could be assigned to forming a mononuclear superoxido copper complex. For one of the reactions investigated, a product could be structurally characterized and turned out to be a copper(II) complex with an additional hydroxide as a ligand (most likely caused by a C−H abstraction from the solvent acetone). One of the complexes oxidized thioanisole to the corresponding sulfoxide (conversion of 34 % according to GC‐MS) with no byproducts. Chiral GC gave an enantiomeric excess of 14 %.

Synthesis and characterization of Liquid crystalline Cholesteric polysiloxane derivatives

Multiple aspects of chirality in coordination polymers formed by the uranyl ion with (1R,3S)-(+)-camphorate ligands

Novel 1,3-diamine-derived bifunctional thiourea and squaramide organocatalysts were synthesized from (+)-camphoric acid. These catalysts were easily obtained in up to two to five synthetic steps, in a flexible approach that facilitates their structure variation. Their catalytic activity was examined in the asymmetric Michael addition of 1,3-dicarbonyl compounds to several trans-β-nitrostyrenes. Yields up to 98% and enantiomeric excesses up to 74% and high diastereoselectivities when applicable (dr up to 93:7) were obtained in these reactions showing that 1,3-diamine-derived bifunctional thioureas are efficient organocatalysts.

The drugs, their active ingredients under conditions of manufacture and pharmaceutical waste at the ingress in the environment can be hazardous to the human health. The toxicological examination enables to predict the risk of their adverse effects on the organism with a determination of the prior criteria of hazard. Objectives: We defined the probable toxic effects and the mechanism of their formation under various conditions of the exposure of the original anti-diabetic drug based on a camphoric acid derivative (Diacamph - DCMPh) under various conditions of its exposure. Methods: The peculiarities of DCMPh effect on the organism were studied in the acute, sub-acute, and chronic experiments under different conditions of the drug introduction to animals by the indicators characterizing a state of the organism in a whole and the separate organs and systems of the organism and individual organs and systems, including prooxidant- antioxidant and immune systems. Its possible allergenic and mutagenic effects were studied in a separate run of the experiments. Results: Our studies showed that DCMPh is virtually non-toxic in terms of an acute toxicity, does not accumulate, has no local irritant, mutagenic and allergenic effects, but is capable of the skin resorption. Adverse effect of DCMPh on the organism under its oral and inhalation introduction are realized through the disturbance of the prooxidant-antioxidant balance and cellular components of the immunological resistance. We determined a high sensitivity of lungs to the inhalation impact of DCMPh, taking into account an increase of the free radical oxidation in the organ tissue on the background of the weakening of the antioxidant system and a decrease of the functional reserve of neutrophils manifested in the aftereffect period. The high sensitivity of the lungs to the inhalation effect of DCMPh was determined taking into account the increase in free radical oxidation in the organ tissue on the background of the weakening of the antioxidant system and the decrease in the functional reserve of neutrophils, which manifests itself during the aftereffect period. Conclusions: Taking into account the mechanism of toxic action, the maximum permissible concentration of DCMPh in the air of the working area was substantiated at the level of 0.4 mg / m3, hazard class II.

Employing the dicarboxylate ligand of D-H2cam to react with Gd2O3 and Cu(NO3)2·3H2O under hydrothermal conditions, we successfully prepared a new heterometallic compound, namely [Gd2Cu(D-cam)4(H2O)]n (1, D-H2cam is d -(+)-camphoric acid). Moreover, the photocatalytic performance was also explored for the methylene blue (MB) solution degradation under the irradiation of ultraviolet light. Its application values on the pancreatitis treatment were examined and the corresponding mechanism was tested in meantime. Firstly, the cell counting kit-8 (CCK-8) assay was conducted and the compound’s inhibitory effect against the pancreatitis cells viability was detected. Besides, the detection of the inflammatory cytokines content released into plasma was performed enzyme-linked immunosorbent assay (ELISA) detection.

RETRACTED: Two new Cd(II)/Co(II) compounds: Luminescent and photocatalytic property, and treatment activity on coronary artery atherosclerosis

Aqueous OH kinetics of saturated C6–C10 dicarboxylic acids under acidic and basic conditions between 283 and 318 K; new structure-activity relationship parameters

Among the several actions contributing to the development of a sustainable society, there is the eco-design of new plastic materials with zero environmental impact but that are possibly characterized by properties comparable to those of the traditional fossil-based plastics. This action is particularly urgent for food packaging sector, which involves large volumes of plastic products that quickly become waste. This work aims to contribute to the achievement of this important goal, proposing new bio-based cycloaliphatic polymers based on trans-1,4-cyclohexanedicarboxylic acid and containing different amount of camphoric acid (from 0 to 15 mol %), a cheap and bio-based building block. Such chemical modification was conducted in the melt by avoiding the use of solvents. The so-obtained polymers were processed in the form of films by compression molding. Afterwards, the new and successfully synthesized random copolymers were characterized by molecular (NMR spectroscopy and GPC analysis), thermal (DSC and TGA analyses), diffractometric (wide angle X-ray scattering), mechanical (through tensile tests), and O2 and CO2 barrier point of view together with the parent homopolymer. The article aims to relate the results obtained with the amount of camphoric moiety introduced and to present, the different microstructure in the copolymers in more detail; indeed, in these samples, a different crystalline form developed (the so-called β-PBCE). This latter form was the kinetically favored and less packed one, as proven by the lower equilibrium melting temperature determined for the first time by Baur’s equation.

The Front Cover shows the reaction of dioxygen with a copper(I) complex containing a tetramethylated diamine ligand that is related to camphor. The formation of a short-lived bis(μ-oxido) copper complex was observed spectroscopically by low temperature stopped-flow kinetics. Deuteration of the methyl groups enabled crystallization and structural characterization of this reactive intermediate. More information can be found in the Full Paper by R. Göttlich, S. Schindler and co-workers.

Abstract Generally, high‐performance epoxy resins, which are derived from aromatic compounds have two major disadvantages of yellowing and brittleness, and thus it presently remains a challenge for the facile synthesis of epoxy resin with excellent ultraviolet resistance and superior strength and toughness. Herein, a novel bio‐based epoxy resin diglycidyl ester of camphoric acid (DGECA) was synthesized from the renewable camphoric acid via an efficient and scalable route. The chemical structure of DGECA was carefully characterized by Fourier transform infrared (FT‐IR), nuclear magnetic resonance (NMR), and mass spectrometry before being cured with methylhexahydrophthalic anhydride (MHHPA). Compared with the cured diglycidyl ether of bisphenol A (DGEBA)/MHHPA, the cured DGECA/MHHPA system achieved 11.5%, 16.7%, and 109.4% increment in flexural strength (126 MPa vs. 113 MPa), modulus (2.8 GPa vs. 2.4 GPa), and impact strength (6.7 kJ/m2vs. 3.2 kJ/m2), respectively. Moreover, cured DGECA exhibited extremely lower ultraviolet absorption (0.038A) and better ultraviolet resistance than that of cured DGEBA. This work provides a new strategy to synthesize epoxy resin with excellent ultraviolet resistance and high toughness by using the unique structure of renewable feedstock.

Abstract Amine derivatives prepared from camphoric acid were used as ligands for the synthesis of corresponding copper(I) complexes. Their reactivity towards dioxygen was analyzed. The formation of a short‐lived bis(μ‐oxido)copper complex was spectroscopically observed during the reaction of the copper(I) complex with (1R, 3S)‐N1,N1,N3,N3‐Tetramethyl‐1,2,2‐trimethylcyclopentane‐1,3‐diamine as a ligand. Furthermore, a regioselective demethylation of the ligand system was detected. Deuteration of the methyl groups of the ligand allowed crystallization and characterization of the bis(μ‐oxido)copper complex. Derivatives of the ligand with pyridine residues caused suppression of the reactivity of the corresponding copper(I) complexes towards dioxygen. Additionally, the ligand system could be modified for intramolecular oxygenation reactions with benzaldehyde that led to the formation of salicylaldehyde, a selective hydroxylation in ortho position.

Camphoric acid as renewable cyclic building block for bio-based UV-curing polyhexylene itaconate

Cyclic products can be obtained through the intramolecular version of the Nicholas reaction, which requires having the nucleophile connected to the alkyne unit. Here, we report the synthesis of 1-oxa-3-cyclooctynes starting from commercially available (1R,3S)-camphoric acid. The strategy is based on the initial preparation of propargylic alcohols, complexation of the triple bond with Co2(CO)8, and treatment with BF3·Et2O to induce an intramolecular Nicholas reaction with the free hydroxyl group as nucleophile. Finally, oxidative deprotection of the alkyne afforded the cyclooctynes in good yields. Notably, large-sized R substituents at the chiral center connected to the O atom were oriented in such a way that steric interactions were minimized in the cyclization, allowing the formation of cyclooctynes exclusively with (R) configuration, in good agreement with theoretical predictions. Moreover, preliminary studies demonstrated that these cyclooctynes were reactive in the presence of azides yielding substituted triazoles.