Series Of Benzoic Acids Research Articles

Comprehensive effect of water matrix on catalytic ozonation of chloride contained saline wastewater

Chloride ion (Cl−) is one of the most common anions in wastewater and saline wastewater, but its elusive effects on organics degradation are not clear yet in many cases. In this paper, the effect of Cl− on organic compounds degradation is intensively studied in catalytic ozonation of different water matrix. It was found that the effect of Cl− is almost completely reflected by transforming ·OH to reactive chlorine species (RCS), which is simultaneously competitive with organics degradation. The competition between organics and Cl− for ·OH directly determines the ratio of their consumption rate of ·OH, which depends on their concentration and reactivity with ·OH. Especially, the concentration of organics and solution pH may change greatly during organics degradation process, which will correspondingly influence the transformation rate of ·OH to RCS. Therefore, the effect of Cl− on organics degradation is not immutable, and may dynamically change. As the reaction product between Cl− and ·OH, RCS was also expected to affect the degradation of organics. But we found that Cl· had no significant contribution to the degradation of organics in catalytic ozonation, which may due to its reaction with ozone. Catalytic ozonation of a series of benzoic acid (BA) with different substituents in chloride contained wastewater was also investigated, and the results showed that the electron-donating substituents can weaken the inhibition of Cl− on BAs degradation, because they increase the reactivity of organics with ·OH, O3 and RCS.

Thermodynamics of Ligand Exchange with Aromatic Ligands on the Surface of CdSe Quantum Dots

Quantum dots (QDs) have great application prospects in optoelectronic devices because of their excellent optical properties. Nevertheless, the original ligands of the long carbon chain introduced in the synthesis process are not conducive to the application of CdSe QDs in optoelectronic devices due to their insulating nature. Therefore, short-chain and aromatic ligands are employed to replace the original ligands. However, the influences of conjugation structures on ligand exchange have rarely been systematically studied from a thermodynamic perspective. In this work, two types of aromatic ligands, namely, a series of benzoic acid (BA) ligands and cinnamic acid (CA) ligands that introduced electron-donating (methoxy-) and electron-withdrawing groups (fluoro-) at the meta and para positions of the benzene ring of aromatic ligands, were chosen to investigate the ligand exchanges on the surface of QDs from oleic acid (OA) to a series of aromatic ligands by 1H nuclear magnetic resonance (NMR) spectroscopy and isothermal titration calorimetry (ITC). 1H NMR showed that the average exchange ratio of CA ligands to OA was ∼1:1, which made it possible to obtain thermodynamic parameters through the determined ligand exchange model by ITC. Furthermore, thermodynamic results showed that ligand exchange with CA ligands was endothermic (ΔH > 0) and entropy-increasing (ΔS > 0), indicating that the process was entropy-driven. In addition, the equilibrium constants (K) of ligand exchange with CA ligands were larger than those with BA ligands. However, the K values of ligand exchange with BA ligands were ∼1, which resulted in ΔG ∼ 0 kJ/mol, demonstrating that ligand exchange with BA ligands was less favorable at 298.15 K. Finally, the introduction of substituents on meta and para positions of the aromatic ligand benzene ring had no significant effect on the ligand exchange process. This work not only elaborates on the process of exchange with aromatic ligands but also has fundamental significance for the application of aromatic ligand-modified QDs in optoelectronic devices.

Identification and structure-activity relationship exploration of uracil-based benzoic acid and ester derivatives as novel dipeptidyl Peptidase-4 inhibitors for the treatment of type 2 diabetes mellitus.

Our previously reported carboxyl-containing DPP-4 inhibitors were highly potent but were poorly bioavailable. Esters of the carboxyl analogs exhibited a significant DPP-4 potency loss albeit with enhanced oral absorption. Herein, we described identification and structure-activity relationship (SAR) exploration of a novel series of benzoic acid and ester derivatives as low single-digit nanomolar DPP-4 inhibitors. Importantly, the esters displayed comparable activities to the acids counterparts. Molecular simulation revealed that ester adopts a similar binding mode to acid. Moreover, the selected esters and acids demonstrated high selectivity and low cytotoxicity, as well as good metabolic stability. And more importantly, the esters possessed excellent pharmacokinetic profiles for oral administration. The best compound ester 19b demonstrated long DPP-4 inhibition invivo, and robustly improved the glucose tolerance in normal and db/db mice while ensuring glucose-lowering potency in chronic treatment. Our results supported that the compound 19b can be served as a potential candidate for the treatment of type 2 diabetes.

In-silico investigation of optical, thermal and electronic properties for 4-n-alkoxy benzoic acid series (nOBA; n = 1–8)

The homologous series of 4-n-alkoxy benzoic acid (nOBA) has been chosen to study the variation of electro-optical properties, global reactivity descriptors and thermal properties with the homologous number using density functional based calculations at B3LYP/6-31G(d,p) level. The first two homologues of nOBA (n = 1 and 2) are non-mesogenic compounds. This homologous series exhibits nematic behaviour for n = 3 to 6 while smectic behaviour for n = 7, 8 and above. We have calculated electro-optical parameters such as dipole moment, polarizability, anisotropy in polarizability, molar refractivity, which exhibit no odd-even effect but linear dependence on the homologous number. Furthermore, the global reactivity parameters such as ionization potential, electron affinity, electronegativity, global hardness and softness are almost constant, independent on the homologous number of nOBA series. Thermal parameters such as enthalpy, Gibbs' free energy and entropy of nOBA series are in accordance with the experimental findings reported in the literature. The results may offer better insights into the properties of homologues of nOBA system at the molecular level.

Effects of Self-Assembled Monolayer Modification of Nickel Oxide Nanoparticles Layer on the Performance and Application of Inverted Perovskite Solar Cells.

Entirely low-temperature solution-processed (≤100 °C) planar p-i-n perovskite solar cells (PSCs) offer great potential for commercialization of roll-to-roll fabricated photovoltaic devices. However, the stable inorganic hole-transporting layer (HTL) in PSCs is usually processed at high temperature (200-500 °C), which is far beyond the tolerant temperature (≤150 °C) of roll-to-roll fabrication. In this context, inorganic NiOx nanoparticles (NPs) are an excellent candidate to serve as the HTL in PSCs, owing to their excellent solution processability at room temperature. However, the low-temperature processing condition is usually accompanied with defect formation, which deteriorates the film quality and device efficiency to a large extent. To suppress this setback, we used a series of benzoic acid selfassembled monolayers (SAMs) to passivate the surface defects of the NiOx NPs and found that 4-bromobenzoic acid could effectively play the role of the surface passivation. This SAM layer reduces the trap-assisted recombination, minimizes the energy offset between the NiOx NPs and perovskite, and changes the HTL surface wettability, thus enhancing the perovskite crystallization, resulting in more stable PSCs with enhanced power conversion efficiency (PCE) of 18.4 %, exceeding the control device PCE (15.5 %). Also, we incorporated the above-mentioned SAMs into flexible PSCs (F-PSCs) and achieved one of the highest PCE of 16.2 % on a polyethylene terephthalate (PET) substrate with a remarkable power-per-weight of 26.9 W g-1 . This facile interfacial engineering method offers great potential for the large-scale manufacturing and commercialization of PSCs.

Effect of TiO2 modification with amino-based self-assembled monolayer on inverted organic solar cell

The effects of surface modification of titanium dioxide (TiO2) on the performance of inverted type organic solar cells (i-OSCs) was investigated in this study. A series of benzoic acid derivatized self-assembled monolayer (SAM) molecules of 4′-[(hexyloxy)phenyl]amino-3,5-biphenyl dicarboxylic acid (CT17) and 4′-[1-naphthyl (phenyl)amino]biphenyl-4-carboxylic acid (CT19) were utilized to modify the interface between TiO2 buffer layer and poly-3 hexylthiophene (P3HT):[6,6]-phenyl C61 butyric acid methyl ester (PC61BM) active layer having the device structure of ITO/TiO2/SAM/P3HT:PC61BM/MoO3/Ag. The work function and surface wetting properties of TiO2 buffer layer served as electron transporting layer between ITO and PC61BM active layer were tuned by SAM method. The solar cell of the SAM modified devices exhibited better performance. The power conversion efficiency (PCE) of i-OSCs devices with bare TiO2 electrodes enhanced from 2.00% to 2.21% and 2.43% with CT17 and CT19 treated TiO2 electrodes, respectively. The open circuit voltage (Voc) of the SAM treated TiO2 devices reached to 0.60V and 0.61V, respectively, while the Voc of untreated TiO2 was 0.57V. The water contact angle of i-OSCs with CT17 and CT19 SAMs was also higher than the value of the unmodified TiO2 electrode. These results show that inserting a monolayer at the interface between organic and inorganic layers is an useful alternative method to improve the performance of i-OSCs.

Bacterial Cell Growth Inhibitors Targeting Undecaprenyl Diphosphate Synthase and Undecaprenyl Diphosphate Phosphatase.

We synthesized a series of benzoic acids and phenylphosphonic acids and investigated their effects on the growth of Staphylococcus aureus and Bacillus subtilis. One of the most active compounds, 5-fluoro-2-(3-(octyloxy)benzamido)benzoic acid (7, ED50 ∼0.15 μg mL-1 ) acted synergistically with seven antibiotics known to target bacterial cell-wall biosynthesis (a fractional inhibitory concentration index (FICI) of ∼0.35, on average) but had indifferent effects in combinations with six non-cell-wall biosynthesis inhibitors (average FICI∼1.45). The most active compounds were found to inhibit two enzymes involved in isoprenoid/bacterial cell-wall biosynthesis: undecaprenyl diphosphate synthase (UPPS) and undecaprenyl diphosphate phosphatase (UPPP), but not farnesyl diphosphate synthase, and there were good correlations between bacterial cell growth inhibition, UPPS inhibition, and UPPP inhibition.

Synthesis and an angiolytic role of novel piperazine–benzothiazole analogues on neovascularization, a chief tumoral parameter in neoplastic development

A novel series of benzoic acid N′-[2-(4-benzothiazol-2-yl-piperazin-1-yl)-acetyl]-hydrazides 6a–j were synthesized and characterized by IR, 1H, 13C NMR, elemental and mass spectral analyses. The in-vitro cytotoxicity and cell viability assay of the synthesized compounds 6a–j were evaluated against Dalton’s lymphoma ascites (DLA) cells. Our results showed that compound 6c with a bromo group on phenyl ring has showed promising antiproliferative efficacy. Further investigation of compound 6c on in-vivo treatment model depicts the increased tumor suppression through inhibition of angiogenesis.

Antibacterial activity of novel 2-(substituted sulfonamido) benzoic acid derivatives

ObjectivesSulfonamides were the first chemotherapeutic agents to be used in human, systemically for the treatment of bacterial infection. Though, varieties of sulfonamides are currently available, bacteria have developed resistance to them. This prompted to search for the novel sulfonamide based antibacterials. MethodsNovel 2-(substituted sulfonamido) benzoic acid derivatives were tested for their antibacterial activity against 19 Gram −ve and 2 Gram +ve pathogenic bacteria and MIC values were determined by agar dilution method. ResultsThe tested compounds showed moderate to good antibacterial activity against tested bacteria. Compounds, A5, A12, A15, A18 and A19 were showed moderate antibacterial activity against atypical Escherichia coli. Compounds, A13 and A14 showed good antibacterial activity (MIC = 183.81 μg/ml) against Plesiomonas shigelloides and atypical E. coli, respectively. ConclusionThis study concludes that further structural optimization of 2-(substituted sulfonamido) benzoic acid series would bring more potent useful agents to treat infections caused by range of bacteria.

Polarographic study of hydrogen peroxide anodic current and its application to antioxidant activity determination

Behavior of hydrogen peroxide in alkaline medium has been studied by direct current (DC) polarography with dropping mercury electrode (DME) aiming to apply it in antioxidant (AO) activity determination. Development of a peroxide anodic current having form of a peak, instead of common polarographic wave, has been investigated. As a base for this investigation the interaction of H2O2 with anodically dissolved mercury was followed. Formation of mercury complex [Hg(O2H)(OH)] has been confirmed. The relevant experimental conditions, such as temperature, concentration and pH dependence, as well as time stability of hydrogen peroxide anodic current, have been assessed. Development of an AO assay based on decrease of anodic current of hydrogen peroxide in the presence of antioxidants (AOs) has been described. Under optimized working conditions, a series of benzoic acids along with corresponding cinnamate analogues have been tested for hydrogen peroxide scavenging activity. In addition, the assay versatility has been confirmed on various complex samples.

Design, synthesis, and biological evaluation of conformationally constrained glycerol 3-phosphate acyltransferase inhibitors

Glycerol 3-phosphate acyltransferase (GPAT) isozymes are central control points for fat synthesis in mammals. Development of inhibitors of these membrane-bound enzymes could lead to an effective treatment for obesity, but is thwarted by an absence of direct structural information. Based on a highly successful study involving conformationally constrained glycerol 3-phosphate analogs functioning as potent glycerol 3-phosphate dehydrogenase inhibitors, several series of cyclic bisubstrate and transition state analogs were designed, synthesized, and tested as GPAT inhibitors. The weaker in vitro inhibitory activity of these compounds compared to a previously described benzoic acid series was then examined in docking experiments with the soluble squash chloroplast GPAT crystal structure. These in silico experiments indicate that cyclopentyl and cyclohexyl scaffolds prepared in this study may be occluded from the enzyme active site by two protein loops that sterically guard the phosphate binding region. In view of these findings, future GPAT inhibitor design will be driven toward compounds based on planar frameworks able to slide between these loops and enter the active site, resulting in improved inhibitory activity.

Synthesis and antimycobacterial evaluation of new trans-cinnamic acid hydrazide derivatives

In this work, we report the synthesis and the antimycobacterial evaluation of new trans-cinnamic acid derivatives of isonicotinic acid series ( 5) and benzoic acid series ( 6), designed by exploring the molecular hybridization approach between isoniazid ( 1) and trans-cinnamic acid derivative ( 3). The minimum inhibitory concentration (MIC) of the compounds 5a– d and 6c exhibited activity between 3.12 and 12.5 μg/mL and could be a good start point to find new lead compounds against multi-drug resistant tuberculosis.

Modeling Robust QSAR 3: SOM‐4D‐QSAR with Iterative Variable Elimination IVE‐PLS: Application to Steroid, Azo Dye, and Benzoic Acid Series.

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Modeling Robust QSAR 3: SOM-4D-QSAR with Iterative Variable Elimination IVE-PLS: Application to Steroid, Azo Dye, and Benzoic Acid Series

In the current paper we present a receptor-independent 4D-QSAR method based on self-organizing mapping (SOM-4D-QSAR) and in particular focus on its pharmacophore mapping ability. We use a novel stochastic procedure to verify the predictive ability of the method for a large population of 4D-QSAR models generated. This systematic study was conducted on a series of benzoic acids, azo dyes, and steroids that bind aromatase. We show that the 4D-QSAR method coupled with IVE-PLS provides a very stable and predictive modeling technique. The method enables us to identify the molecular motifs contributing the most to the fiber-dye affinity and the aromatase enzyme binding activity of the steroid. However, the method appeared much less effective for the benzoic acid series, in which the efficacy was limited by electronic effects strictly correlated to a single conformer.

Modeling Robust QSAR. 2. Iterative Variable Elimination Schemes for CoMSA: Application for Modeling Benzoic Acid pKaValues

A variety of issues decide the efficiency of 3D QSAR methods, and their practical importance for drug design is still controversial. This refers both to the predictive ability and the possibility for the indication of these areas within 3D molecular representations that are responsible for biological or chemical effects. Technically, the latter comes down to the selection or elimination of the reliable variables during 3D QSAR modeling using the Partial Least-Squares (PLS) method. In this paper we used a series of benzoic acids to test the dependence between the predictive ability and variable selection performance of PLS with Iterative Variable Elimination (IVE-PLS) in the Comparative Molecular Surface Analysis (CoMSA) modeling of Hammett constant which correlates with the pKa values. Modeling this chemical effect allowed us to select the IVE-PLS variant that plots the contour maps indicating a carboxylic function, i.e., the region including the dissociation reaction center that determines the respective pKa values. In fact, it appeared that a novel robust IVE version is capable of the indication of the proper contour plots independent of the method used for the calculation of partial atomic charges (AM1 or Gasteiger-Marsili).

Nitroarene catalyzed oxidation with sodium percarbonate or sodium perborate as the terminal oxidant

A new catalytic oxidation method for the preparation of aromatic carboxylic acids from methyl aryl ketones is reported. The method is an alternative to the haloform reaction; it is benign and affords the desired product without production of any harmful side products. The catalytic cycle is based on the use of an electron-deficient nitroarene as catalyst with either of the two cheap and green oxidants sodium percarbonate or sodium perborate. The method gives a good yield (87%) and shows excellent selectivity when the model substrate (acetophenone) is oxidized. A series of benzoic acids of industrial interest were prepared by means of this method.

Specific antioxidant activity of caffeoyl derivatives and other natural phenolic compounds: LDL protection against oxidation and decrease in the proinflammatory lysophosphatidylcholine production.

Specific antioxidant activity (SAA) (i.e., activity related to the molar or gallic acid equivalent amount of antioxidant) of natural polyphenolic mixtures or pure phenolic compounds was studied using their capacity to delay the conjugated diene production brought about by in vitro LDL copper-mediated or AAPH-mediated oxidation. The cinnamic acid series (caffeic, sinapic, ferulic acids) displayed a constant SAA over a large range of concentrations, whereas the benzoic acid series (gallic and protocatechuic acids) showed much higher SAA at low concentrations. The natural phenolic mixtures had a constant SAA. The highest SAA was obtained with caffeoyl esters (caffeoylquinic, rosmarinic, and caffeoyltartaric acids) and catechin for the copper-oxidation and the AAPH-oxidation system, respectively. Phenolic mixtures and acids delayed vitamin E depletion and decreased proinflammatory lysophosphatidylcholine production. As with polyphenols, probucol delayed lysophosphatidylcholine and conjugated dienes production, at higher concentrations, but was not effective at preventing vitamin E depletion. Polyphenols prevent the oxidation of LDL and its constituents (vitamin E, phosphatidylcholine), which is compatible with an antiinflammatory and antiatherosclerotic role in pathophysiological conditions.

Carboxylic acid anchoring groups for the construction of self-assembled monolayers on organic device electrodes

We have investigated the surface adsorption of carboxylic acid derivatives on both an aluminium cathode and an indium-tin oxide anode, commonly used in light emitting devices. For this purpose, a series of benzoic acids with systematically varying dipole moments were used to form self-assembled monolayers on these electrodes. The work function shifts induced by the adsorbed molecules were measured by the Kelvin probe method, while the surface densities of the adsorbed molecules were inferred from Langmuir isotherm measurements. It appeared that the work function shifts correlate linearly with the molecular dipole moment measured in the gas phase. Furthermore, the dipole moment which is formed upon adsorption depends crucially on the surface acido-basicity of the electrode. The difference of the adsorption dipoles on indium-tin oxide and aluminium is as high as 3.5 D indicating a very different binding mechanism in the two cases.

The comparative molecular surface analysis (COMSA): a novel tool for molecular design

A new method allowing for 3-D QSAR analysis and the prediction of biological activity is presented. Unlike comparative molecular field analysis (CoMFA)-like techniques, it is based not on a comparison of the properties characterizing a discrete set of points but on the mean electrostatic potential (MEP) calculated and labeling specific areas defined on the molecular surface. A Kohonen self-organizing neural network and partial least square (PLS) analysis have been used for performing such an operation. The series of steroids complexing the corticosteroid (CBG) and testosterone (TBG) globulins, which forms a benchmark measuring the performance of the methods in molecular design, and a series of benzoic acids described by the Hammett σ constants is used for testing the method. It is demonstrated that a method can be used efficiently to evaluate the responses determined both by the combination of electrostatic and steric effects or by electrostatic effects alone, therefore, two different schemes were developed. The first one, which involves PLS analysis of the full comparative networks, covers both steric and electrostatic effects. This scheme works well for both the CBG and TBG data. The second scheme takes into account only the properties (MEP) of these regions within molecules that can be superimposed with the template molecule. This scheme provides the best predictive power for the benzoic acids series. Comparison of the results from a CoMFA analysis proves that method is at least as effective for the responses limited by electrostatic effects, although it significantly outperforms CoMFA for CBG affinity which is dominated by steric effects.

Local anesthetics from ester to isomer

The use of chemical substances to prevent or treat local pain had its origin in South America. It was known that central nervous system stimulation occurred among the natives of Peru who chewed the leaves of an indigenous plant (Erythroxylon coca). Circumoral numbness was believed to have occurred as a by-product of this custom. Attempts to isolate the active principle from these leaves finally resulted in the isolation of the alkaloid, cocaine, by Niemann in 1860. The clinical usefulness of cocaine was not appreciated until 1884, when Koller reported upon topical anesthesia of the eye. The chemical identification of cocaine as a benzoic acid ester led to the synthesis of numerous compounds which were basically benzoic ester derivates. In 1905, Einhorn reported the synthesis of procaine. Tetracaine, the most potent ester of the benzoic acid series appeared in 1930. A major breakthrough in the chemistry of local anesthetic agents occurred in 1943 when Loefgren synthesized lidocaine, since it was not an ester but an amide derivate of diethylamino acetic acid. Concerning structure-activity relationships, local anesthetic agents, in general, possess the chemical arrangement of: aromatic portion--intermediate chain--amine portion. Changes in the aromatic or amine portion of a local anesthetic substance will alter its lipid/water distribution coefficient and its protein-binding characteristics which, in turn, will markedly alter the anesthetic profile. The toxic effects of long-acting local anesthetics on brain and heart, firstly reported by Albright, provided the initial stimulus to develop new amide-type local anesthetics. The first of these drugs, which has come into clinical practice was ropivacaine, the S-enantiomer of two possible optical isomers. It is structurally related to bupivacaine and mepivacaine, exerting a different pharmacodynamic profile, specifically on cardiac electrophysiology (less arrhythmogenic than bupivacaine). Studies on the anesthetic activities and toxicity of the individual enantiomers of bupivacaine and mepivacaine generally indicate, that the S-enantiomers are longer-acting and less toxic than the R-enantiomers.