Acylation Reaction Research Articles

Preparation of esculin acetates through transesterification reaction catalyzed by Novozyme 435® and their Purification followed by NMR characterization

In this study, biocatalytic transesterification reaction using Novozyme 435® (N435) lipase was employed to enhance the hydrophobicity of esculin, aiming to improve its solubility for commercial applications and enhance its bioactivity and oral viability. The acylation reaction of esculin with vinyl acetate was conducted at 60 °C and 200 rpm for 24 h. After chromatographic and spectroscopic analysis, two products were identified: the first one was monoacylated at the 6′-OH position of the glucosyl moiety of esculin (TR: 10.3 min and m/z 382.93 [M + H]+), and the second one was diacylated at the 6′-OH and 3′-OH positions (TR: 13.0 min and m/z 424.93 [M + H]+). The latter was the major product, with a conversion rate of 53.550 ± 0.368%, while the monoacetylated one showed 8.715 ± 0.064%. Both products were isolated by high-speed counter-current chromatography (HSCCC) using a two-phase system HEMWat 1:9:1:9 and characterized by NMR. In this way, these results improve the practical application of esculin, through the obtention of esculin mono and diacetates by fast and efficient biocatalysis reaction.

Conversion of waste polystyrene into porous adsorbents for efficient removal of hazardous pollutants: Adsorption properties and adsorption mechanism

Herein, the porous adsorbent material (PS-SAS) was prepared by introducing a large number of carboxyl groups on the benzene ring of waste polystyrene (WPS) by Friedel-Crafts acylation reaction using succinic anhydride as the modifying group, followed by further alkaline modification, and was used for the removal of hazardous dye and heavy metal ion. The chemical structure and surface morphology of the prepared adsorbent were assessed via Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), optical microscope (OM), Brunauer–Emmett–Teller (BET), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The prepared adsorbent gave highly efficient separation performance towards malachite green (MG) and Cu2+ with corresponding maximum sorption capacities of 2231 mg/g and 156 mg/g at 298 K. The experimental data indicated that the sorption process followed the Langmuir adsorption isotherm and the pseudo-second-order kinetic model. Moreover, thermodynamic studies also demonstrated that the sorption process occurred spontaneously. The adsorption mechanisms of the adsorbent for MG include hydrogen bonding, electrostatic attraction, n-π interactions, and π-π interactions, while for Cu2+ via electrostatic attraction, ion exchange, and complexation. Furthermore, the selective adsorption, regeneration, dynamic sorption, and simulated wastewater experiment demonstrated that the adsorbent is a promising adsorbent. And phytotoxicity test proved that the prepared adsorbent can effectively reduce the toxicity of dye and metal ions. In summary, the transformation of waste polystyrene into an adsorbent represents a promising solution for water purification.

Exploring Functional Gene XsPDAT1’s Involvement in Xanthoceras sorbifolium Oil Synthesis and Its Acclimation to Cold Stress

Phospholipid: diacylglycerol acyltransferase (PDAT) is crucial in triacylglycerol (TAG) synthesis as it represents the final rate-limiting step of the acyl-CoA-independent acylation reaction. PDAT not only regulates lipid synthesis in plants, but also plays an important function in improving stress tolerance. In this study, the full-length coding sequence (CDS) of XsPDAT1, totaling 2022 base pairs and encoding 673 amino acids, was cloned from Xanthoceras sorbifolium. The relative expression of XsPDAT1 was significantly and positively correlated with oil accumulation during seed kernel development; there were some differences in the expression patterns under different abiotic stresses. Transgenic Arabidopsis thaliana plants overexpressing XsPDAT1 were obtained using the Agrobacterium-mediated method. Under low-temperature stress, the transgenic plants exhibited a smaller decrease in chlorophyll content, a smaller increase in relative conductivity, and a larger increase in POD enzyme activity and proline content in the leaves compared with the wild type. Additionally, lipid composition analysis revealed a significant increase in unsaturated fatty acids, such as oleic (C18:1) and linoleic (C18:2), in the seeds of transgenic plants compared to the wild type. These results suggest that XsPDAT1 plays a dual role in regulating the ratio of fatty acid composition and low-temperature stress in plants.

Synthesis and antifungal activities of small molecule arylthiazolamine derivatives.

Developing new fungicides to compensate for the deficiencies of existing fungicides resistance in phytopathogenic fungi is a research hotspot in the field of pesticides. Aiming to discover novel template small molecules with excellent antifungal activity, thirty-eight arylthiazolamine derivatives were synthesized through bromination, cyclization, halogenation, and acylation reactions. The synthesized compounds were screened for antifungal activity against ten typical fungal pathogens, and some halogenated arylthiazolamines and amides exhibited excellent broad-spectrum antifungal activity, especially compounds 4m (3.96-47.76μg/mL), 5k (0.10-7.70μg/mL) and 5n (2.08-11.21μg/mL). Among them, compound 5k provided comparable protection and curative effects to chloroticonil and boscalid against B. dothidea and V. mali infection in apple and apple tree branches, respectively, and it could exert antifungal effects by inhibiting the differentiation of mycelium spores, spore germination, and bud tube growth. This study provides high-efficiency and inexpensive candidate compounds for managing of diseases caused by plant pathogenic fungi.

The Acylation of α-Carbonyl Sulfoxonium Ylides with N-Hydroxyphthalimide Esters

AbstractA new method for the synthesis of 1,3-dicarbonyl sulfoxonium ylides is described. This acylation reaction is carried out under mild conditions using inexpensive and bench-stable N-hydroxyphthalimide esters as acylating agents. The reactions proceed via a non-radical, transition-metal-free pathway, and the corresponding products are obtained in yields of up to 85%.

Reactions of Benzyl Phosphine Oxide/Sulfide with (COCl)2: Synthesis of Novel Acyl Chloride-Substituted Chlorophosphonium Ylides.

New reactions of benzyl phosphine oxide/sulfide with oxalyl chloride are presented. The resulting reactive intermediates, acyl chloride-substituted chlorophosphonium ylides, are capable of undergoing esterification and Friedel-Crafts acylation reactions, ultimately yielding either methyl 2-(2-bromophenyl)-2-(diphenylphosphoryl)acetate or β-carbonyl-diarylphosphine oxide derivatives. Additionally, when an alkynyl group is contained in the acyl chloride-substituted chlorophosphonium ylide, intramolecular cyclization occurs, leading to the formation of a pair of trans- and cis-dichlorophosphonyl benzofulvene isomers. The generation process of acyl chloride-substituted chlorophosphonium ylide was carefully monitored by using 31P{1H} NMR spectroscopy, and a plausible reaction mechanism was proposed.

Benzoyl cyanide, a general radical acylating reagent for photoredox-catalyzed benzylic site-selective acylation reactions

Benzoyl cyanide, a general radical acylating reagent for photoredox-catalyzed benzylic site-selective acylation reactions

Catalytic Advantages of SO3H-Modified UiO-66(Zr) Materials Obtained via Microwave Synthesis in Friedel-Crafts Acylation Reaction.

The catalytic activity and stability of sulfonic-based UiO-66(Zr) materials were tested in the Friedel-Crafts acylation of anisole with acetic anhydride. The materials were prepared using microwave-assisted synthesis, producing microporous materials with remarkable crystallinity and physicochemical features as acid catalysts. Different ratios between both organic ligands, terephthalic acid (H2BDC) and monosodium 2-sulfoterephthalic acid (H2BDC-SO3Na), were used for the synthesis to modulate the sulfonic content. The sulfonic-based UiO-66(Zr) material synthesized with a H2BDC/H2BDC-SO3Na molar ratio of 40/60 exhibited the best catalytic performance in the acidic-catalyzed Friedel-Crafts acylation reaction. This ratio balanced the number of sulfonic acid sites and their accessibility within the UiO-66 microporous structure. The catalytic performance of this material increased remarkably at 200 °C, outperforming reference acids and commercial heterogeneous catalysts such as Nafion-SAC-13 and Amberlyst-70. Additionally, the best sulfonic-based UiO-66(Zr) material proved to be stable in four successive reaction cycles, maintaining both its catalytic activity and its structural integrity.

Nanosized Porphyrin-Containing Covalent Organic Polymer to Enhance Ferroptosis in Photodynamic Treatment of Tumor Cells via Glutathione Depletion.

A porphyrin-containing nanoscale covalent organic polymer (COP) was fabricated from 5,10,15,20-tetra(4-carboxyphenyl)porphyrin (TCPP) and cystamine via an acylation reaction. On the one hand, TCPP can induce tumor cell death by laser irradiation. Due to the presence of disulfide bonds of cystamine which can react with glutathione, it exhibits depletion of glutathione and accumulation of peroxides in tumor cells. Ultimately by the hyaluronic acid to encapsulate the COP to get S-COP@HA, the nanoparticle with a size of 168.6 nm also exhibits good tumor accumulation and biosafety. Significant inhibition of tumor cell growth was observed after two consecutive doses of S-COP@HA at relatively low laser densities. This combination therapy was proved to reduce the level of reduced glutathione in tumor cells, where ferroptosis occurs after photodynamic treatment. Overall, this study presents a potent, good therapeutic option for the effective enhancement of photodynamic therapy by glutathione depletion.

Structure Modification of Cinnamic Acid to (E)-1-(3,4-dihydroisoquinoline-2(1H)-yl)-3-phenylprop-2-en-1-one and Antioxidant Activity Test by DPPH Method

Antioxidants can protect cells from free radical damage by stabilizing them. One of the compounds that has antioxidant activity is cinnamic acid. Cinnamic acid and its derivatives have several activities: antibacterial, anticancer, and antioxidant. However, the ability of cinnamic acid to capture free radicals is still relatively low. One of the efforts that can be made to increase the antioxidant activity of cinnamic acid is to modify its structure. Structure modification is an effort to improve the pharmacological activity of a compound through chemical synthesis reactions. The cinnamic acid structure can be modified by changing the carboxylic -OH group into an amine group through an N-atom acylation reaction. This study was conducted by reacting cinnamoyl chloride (1a), which is a cinnamic acid derivative with 1,2,3,4-tetrahydroisoquinoline (2b) which is a compound of isoquinoline group to produce (E)-1-(3,4-dihydroisoquinoline-2(1H)-yl)-3-phenylprop-2-en-1-one (3b) and then tested for antioxidant activity using DPPH method. The resulting product compound was yellow crystals with a yield of 81.56%. The antioxidant activity produced by the product is more significant than that of cinnamic acid compounds at the same concentration.

The methods of synthesis of 2-aminobenzophenones — key precursors of 1,4-benzodiazepines

The review article briefly presents the pharmacological profile and mechanism of action of 1,4-dibenzodiazepines, and the structures of the most important drugs from this class of compounds. The strongest emphasis is placed on presentation of various methods for the synthesis of 2-aminobenzophenones — the most often used precursors in the synthesis of 1,4-benzodiazepines and numerous classes of azaarenes. The reactions or their sequences were grouped according to retrosynthetic strategies based on structural similarities and differences of the reagents used. There were presented not only the most classical methods like Friedel-Crafts acylation or Grignard reaction, but also more advanced transformations utilizing various catalysts and more sophisticated approaches involving the synthesis of heterocyclic systems followed by their reductive or oxidative cleavage. Selected nuances of the presented reactions were discussed, including fragments of mechanisms, limitations of the applicability of a given method, and the advantages of modern solutions over the oldest and more classical methods.

Ratiometric fluorescent probe with AIE characteristics for hypochlorite detection and biological imaging

It is very important and highly valuable to detect ClO− in samples and living cells with accuracy and speed. In this work, a novel fluorescent probe NA was prepared from 4-bromo-1,8-naphthalic anhydride by acylation reaction and Suzuki coupling reaction and used for the detection of ClO−. Thiomethyl serves as the recognition group for probe NA, while naphthalimide serves as fluorescent chromophore. The probe exhibited an extremely pronounced blue shift from yellow to blue fluorescence within 1 min after the addition of hypochlorite (ClO−). The probe demonstrates high sensitivity to ClO− with a limit of detection (LOD) of 1.22 µM. Also, probe NA demonstrates excellent selectivity and immunity to interference. Additionally, simple fluorescent test strips containing probe NA were prepared in this study, enabling rapid detection of ClO− in water samples. And NA had been effectively used to image endogenous and exogenous ClO−fluorescence in living cells. The results suggest that probe NA has significant potential for portable detection and biological applications.

CPGA hydrolase assay of DJ-1 in crude cell lysates: Implications for sensing of oxidative stress

Cyclic 3-phosphosphoglyceric anhydride (cPGA), a side product of glycolysis, acylates cellular amines and thiols to form amides and thioesters, respectively. Since these acylation reactions are harmful, organisms rely on a protein, known as DJ-1 in humans, to inactivate cPGA. Inactivation of cPGA likely plays a significant role in cytoprotection by DJ-1, but further progress in this direction is hampered by the lack of quantitative assays to measure the cPGA hydrolase activity of DJ-1 in biological samples. Here we report an optimized procedure for preparation of cPGA which is then used as a substrate to quantify enzymatic activity of DJ-1. The end-point assay for cPGA hydrolase uses dilute cell lysates to hydrolyze cPGA for 0.5–3.5 min followed by conversion of the remaining cPGA into thioester for spectrophotometric quantitation. We illustrate the utility of this assay by showing that higher levels of cPGA hydrolase activity result in better protection from acylation by cPGA. Moreover, the decrease of cPGA hydrolase activity due to oxidation of the catalytic cysteine of DJ-1 under oxidative stress and its subsequent recovery can be monitored using the assay. This relatively simple assay allows functional characterization of DJ-1 in biological samples through quantitative assessment of its cPGA hydrolase activity.

Molecular Basis of Influence of A501X Mutations in Penicillin-Binding Protein 2 of Neisseria gonorrhoeae Strain 35/02 on Ceftriaxone Resistance.

The increase in the resistance of mutant strains of Neisseria gonorrhoeae to the antibiotic ceftriaxone is pronounced in the decrease in the second-order acylation rate constant, k2/KS, by penicillin-binding protein 2 (PBP2). These changes can be caused by both the decrease in the acylation rate constant, k2, and the weakening of the binding affinity, i.e., an increase in the substrate constant, KS. A501X mutations in PBP2 affect second-order acylation rate constants. The PBP2A501V variant exhibits a higher k2/KS value, whereas for PBP2A501R and PBP2A501P variants, these values are lower. We performed molecular dynamic simulations with both classical and QM/MM potentials to model both acylation energy profiles and conformational dynamics of four PBP2 variants to explain the origin of k2/KS changes. The acylation reaction occurs in two elementary steps, specifically, a nucleophilic attack by the oxygen atom of the Ser310 residue and C-N bond cleavage in the β-lactam ring accompanied by the elimination of the leaving group of ceftriaxone. The energy barrier of the first step increases for PBP2 variants with a decrease in the observed k2/KS value. Submicrosecond classic molecular dynamic trajectories with subsequent cluster analysis reveal that the conformation of the β3-β4 loop switches from open to closed and its flexibility decreases for PBP2 variants with a lower k2/KS value. Thus, the experimentally observed decrease in the k2/KS in A501X variants of PBP2 occurs due to both the decrease in the acylation rate constant, k2, and the increase in KS.

Functional properties and molecular docking of different nanoparticles with ROS-sensitive phenylboronylated chitosan as the carrier

ObjectiveTo prepare chitosan-loaded nanoparticles (NPs) that enhance the oral bioavailability of puerarin (Pur) and render it responsive to reactive oxygen species (ROS). SignificanceThis research makes substantial progress towards the theory of intelligent drug delivery, offering a new reference for combining Pur with other natural medicinal active ingredients. MethodsThe acylation reaction between chitosan and ROS-sensitive 3-carboxyphenylboronic acid (PBA) was used to synthesise ROS-sensitive phenylboronylated chitosan (PBACS). Subsequently, PBACS-PBA-Pur-NPs and PBACS-TPP-Pur-NPs were prepared via ion gelation after the addition of PBA and sodium tripolyphosphate(TPP), respectively. The physicochemical and functional properties of both NPs were compared, and their differences were preliminarily studied through molecular docking. ResultsReactive oxygen species-sensitive PBACS was successfully synthesised. Of the two NPs prepared, PBACS-TPP-Pur-NPs had a size of 127.2 ± 0.80 nm, polydispersity index (PDI) of 0.129 ± 0.0008, and an encapsulation rate of 95.75 ± 0.387 %, whereas PBACS-PBA-Pur-NPs had a size of 149.8 ± 0.1414 nm, PDI of 0.389 ± 0.0012, and an encapsulation rate of 91.77 ± 0.279 %. The micromorphology of the PBACS-TPP-Pur-NPs exhibited better physical properties. However, PBACS-PBA-Pur-NPs demonstrated a faster in vitro release and more significant in vitro anti-inflammatory effects. Pharmacokinetically, the AUC0–24, Tmax, and Cmax of PBACS-PBA-Pur-NPs were 3.485, 2.117, and 3.339 times higher, respectively, than those of Pur. The AUC0–24, Tmax, and Cmax of PBACS-TPP-Pur-NPs were 2.41, 1.33, and 2.03 times higher, respectively, than those of Pur. Molecular simulation revealed that the binding energy of PBACS-PBA-Pur -NPs was approximately −4.34 kcal/mol and that of PBACS-TPP-Pur-NPs was even lower, approximately −5.93 kcal/mol, suggesting that the NPs prepared with TPP are more densely packed than those designed with PBA, resulting in slower and reduced drug release. ConclusionThe NPs constructed in this study effectively reduced inflammatory factors at the disease site, providing a theoretical and experimental basis for the application of nano drugs in inflammatory disease models. In addition, the molecular docking study of the two NPs offered insights into the relationship between the release and structure of subsequent nano drugs.

Tuning the textural properties of biomass-derived nanocrystallized BEA for acetyl functionalization of anisole

The synthesis of a highly active zeolite beta catalyst for acetyl functionalization of anisole by utilizing the silica precursor obtained from rice husk is a promising approach for the mitigation of agricultural waste. The influence of combustion temperature (CT) (300, 500, 700, and 900 °C) on the characteristics of rice husk ash was investigated. The C52H obtained at a medium CT (500 °C) has a high surface area compared to the C72H indicates that, merging of smaller crystals of amorphous silica to form crystalline silica with larger crystallites by applying more thermal energy when CT ≥ 700 °C. The PS-5 catalyst derived from C52H possess high surface area (332 m2/g) and a smaller crystallite size (14.8 nm) compared to the PS-7 obtained from C72H, which shown the lower surface area (131.5 m2/g) with a larger crystallite size (25.6 nm). Solid-state NMR and NH3-TPD analysis reveals that PS-5 catalyst possessing higher acidity compare to both PS and PS-7. The activity studies confirms that the PS-5 catalyst exhibited superior catalytic activity (>98%) compared to PS (conventional) and PS-7 catalysts, making it a potential candidate for continuous production of aromatic ketones. acylation reactions.

Synthesis of antioxidant functionalized nano-TiO2 for improving fire resistance and UV-shielding behavior of intumescent fire-retardant coatings for cable

A unique hybridized antioxidant named TiO2-KH550-PA, of which silane modified nano-TiO2 particles were grafted with 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid by acylation reaction, was applied to intumescent fire-retardant coatings for cable. Through fire protection test, contact angle test, thermogravimetric test and UV-ageing test, the effects of TiO2-KH550-PA on hydrophobicity, flame retardancy, smoke suppression, anti-ageing and charring performance for coatings were evaluated. The obtained results indicate that the TiO2-KH550-PA can enhance the hydrophobicity of the coating, thereby reducing the adhesion of dust on the coating surface. Additionally, TiO2-KH550-PA has a greatly promoting role in strengthening the fire protection abilities of the coating, but an appropriate amount is the key. Compared to coatings without composite, the intumescent fire-resistant coating for cable containing 1 wt% TiO2-KH550-PA (IFRCC2) exhibits excellent fire protection performance, including a prolongation by 2.6 times in failure time, an increase by 1.7 times in char layer height, and an increase by 0.4 times in light transmittance for smoke density test. Furthermore, the presence of TiO2-KH550-PA can also strengthen the oxidation resistance, charring ability and char layer stability of the coating, when the remaining mass of IFRCC2 increases to 49.0 % at 800 °C. The anti-ageing performance test demonstrates that the TiO2-KH550-PA can absorb ultraviolet light, eliminate free radicals, and raise the structural stability of the coating, thus reinforcing the durability of the fire resistance for the coating.

Optimizing telescoped heterogeneous catalysis with noise-resilient multi-objective Bayesian optimization

This study evaluates the noise resilience of multi-objective Bayesian optimization (MOBO) algorithms in chemical synthesis, an aspect critical for processes like telescoped reactions and heterogeneous catalysis but seldom systematically assessed. Through simulation experiments on amidation, acylation, and SNAr reactions under varying noise levels, we identify the qNEHVI acquisition function as notably proficient in handling noise. Subsequently, qNEHVI is employed to optimize a two-step heterogeneous catalysis for the continuous-flow synthesis of hexafluoroisopropanol. Remarkable optimization is achieved within just 29 experimental runs, resulting in an E-factor of 0.125 and a yield of 93.1%. The optimal conditions are established at 5.0 sccm and 120 °C for the first step, and 94.0 sccm and 170 °C for the second step. This research highlights qNEHVI’s potential in noisy multi-objective optimization and its practical utility in refining complex synthesis processes.

New Method for Obtaining Carboxylic Derivatives of Oxazolo[5,4-b]pyridine Based on 3-Aminopyridine-2(1H)-ones

Current methods for synthesis of oxazolo[5,4-b]- and oxazolo[4,5-b]pyridines have several limitations, such as severe reaction conditions, lengthy reaction times, low yields and concurrent formation of side reaction products. This article presents the results of study focused on a one-step method for the synthesis of new derivatives of oxazolo[5,4-b]pyridine incorporating an aliphatic carboxylic group as a linker. During the investigation of acylation reactions of 3-aminopyridine-2(1H)-ones with cyclic anhydrides of dicarboxylic acids (succinic, maleic and glutaric), it was found that the monoamides formed at the initial stage undergo intramolecular cyclization yielding derivatives of oxazolo[5,4-b]pyridine. Subsequently, the reaction conditions were studied and optimized to achieve the target compounds with high yield and purity. The potential anti-inflammatory activity of the obtained derivatives of oxazolo[5,4-b]pyridine was evaluated by molecular docking method using AutoDock Vina software. Compounds 11-14b exhibited higher binding affinity with the selected target protein Prostaglandin synthase-2 (1CX2) compared to the reference anti-inflammatory drug diclofenac. Thus, taking into account the results of in silico analyses, the newly synthesized oxazolo[5,4-b]pyridine derivatives based on 3-aminopyridine-2(1H)-ones are promising candidates for further investigation of their potential anti-inflammatory activity through in vivo methods.

Acquisition of para-(1-methylcyclopentyl)phenol and its acylation reaction with acetyl- and benzoyl chlorides

The article is devoted to the study of phenol cycloalkylation reactions 1-methylcyclopentene in a in periodical action installation in the presence of zeolite-containing catalyst KN-30 and acylation reactions of obtained p-(1-methylcyclopentyl)phenol with acetyl and benzoyl chlorides in the presence of a ZnCl2 catalyst. First of all, the influence kinetic parameters (temperature, time, molar ratios starting components, the amount of catalyst) on the yield and selectivity reactions of cycloalkylation of phenol with 1-methylcyclopentene in the presence of catalyst KN-30 was investigated. In the found optimal conditions for the cycloalkylation reaction: temperature – 110 оС, time – 5 hours, molar ratio of phenol to MCF 1:1, amount of catalyst 12 %, yield of the target product – p-(1-methylcyclopentyl)phenol is 77.3 % (based on phenol), the selectivity of the target product is 92.6 %. Acylation reactions of the obtained p-(1-methylcyclopentyl)phenol with acetyl- and benzoyl chlorides were performed in the presence of anhydrous catalyst ZnCl2. In order to obtain effective conditions for acylation reactions, the influence of the reaction temperature, duration, and molar ratio of the starting components on the yield and selectivity of methylcyclopentylaceto- and benzophenones was studied. As a result, it was found that for acylation reactions of p-(1-methylcyclopentyl)phenol with acetyl and benzoyl chloride in the presence of a ZnCl2 catalyst, the reaction temperature is 140–150 оC, the duration should be 35–40 minutes, and the molar ratio phenol AC(BC) should be 1:2. Under these conditions, the yield of target products is 57.2–61.7 % (based on the taken alkylphenol).