Synthesis Of Esters Research Articles

An improved synthesis of alkyl AMP esters

Enzymes belonging to the Acyl-CoA/NRPS/Luciferase (ANL) superfamily of enzymes, are significant targets in drug development. One member of this superfamily is Acetyl-CoA Synthetase (ACS). This enzyme is an emerging target for the treatment of various infectious diseases and cancer. Alkyl AMP esters have emerged as potent inhibitors of ACS. Previous methods for synthesizing these esters often involved water-based reactions or necessitate purification through reverse phase prep-HPLC or ion-exchange chromatography. To address these challenges, we developed a new approach utilizing 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC·HCl) to couple 5′-adenylic acid to the corresponding alcohol, utilizing triethylamine as the base. This method yielded primary, secondary, unsaturated, and cyclic alcohols in excellent yields. Importantly, we optimized the reaction conditions to achieve excellent yield and purity without the need for reverse phase prep-HPLC or ion exchange chromatography. Instead, purification was achieved through silica gel chromatography using Biotage ® Sfar spherical silica gel.

Axially chiral α-boryl-homoallenyl boronic esters as versatile toolbox for accessing centrally and axially chiral molecules

Axially chiral allenes bearing organoboron groups are highly sought-after building blocks in organic synthesis due to their potential for generating a wide range of axially and centrally chiral molecules. However, the existing methods for preparing axially chiral allenes containing boron group are primarily limited to the synthesis of allenyl boronic esters, and strategies for accessing axially chiral homoallenyl boronic esters are still scarce. Here, we report the general method for synthesizing axially chiral α-boryl-homoallenyl boronic esters through a highly regio- and stereoselective copper-mediated SN2’-addition of newly prepared (diborylalkyl)copper species to chiral propargyl electrophiles. The reaction conditions were optimized to achieve high yields and excellent stereospecificity. The obtained products were successfully transformed into various axially chiral allenes and other chiral molecules by transforming diboron units. The potential for axial-to-central chirality transfer of axially chiral α-boryl-homoallenyl boronic esters is also demonstrated through the stereospecific addition to aldehydes and N-H aldimines, yielding enantioenriched 1,2-oxaborinin-3,5-dienes and 2-aminomethyl-1,3-dienes.

Enhanced stereodivergent evolution of carboxylesterase for efficient kinetic resolution of near-symmetric esters through machine learning

Carboxylesterases serve as potent biocatalysts in the enantioselective synthesis of chiral carboxylic acids and esters. However, naturally occurring carboxylesterases exhibit limited enantioselectivity, particularly toward ethyl 3-cyclohexene-1-carboxylate (CHCE, S1), due to its nearly symmetric structure. While machine learning effectively expedites directed evolution, the lack of models for predicting the enantioselectivity for carboxylesterases has hindered progress, primarily due to challenges in obtaining high-quality training datasets. In this study, we devise a high-throughput method by coupling alcohol dehydrogenase to determine the apparent enantioselectivity of the carboxylesterase AcEst1 from Acinetobacter sp. JNU9335, generating a high-quality dataset. Leveraging seven features derived from biochemical considerations, we quantitively describe the steric, hydrophobic, hydrophilic, electrostatic, hydrogen bonding, and π-π interaction effects of residues within AcEst1. A robust gradient boosting regression tree model is trained to facilitate stereodivergent evolution, resulting in the enhanced enantioselectivity of AcEst1 toward S1. Through this approach, we successfully obtain two stereocomplementary variants, DR3 and DS6, demonstrating significantly increased and reversed enantioselectivity. Notably, DR3 and DS6 exhibit utility in the enantioselective hydrolysis of various symmetric esters. Comprehensive kinetic parameter analysis, molecular dynamics simulations, and QM/MM calculations offer insights into the kinetic and thermodynamic features underlying the manipulated enantioselectivity of DR3 and DS6.

Preparation and Charcterisation of Acetate Cellulose Laurate Ester in Sodium Acetate/Zinc Chloride Systems

The objective of this study was to explore the preparation and characterisation of acetate cellulose laurate ester in sodium acetate/zinc chloride systems. The cellulose used in the study was obtained from oil palm empty fruit bunch and oil palm frond. The characterization of both the isolated cellulose and the acetate cellulose laurate ester was carried out using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Differential thermogravimetric (DTG), and Thermogravimetric analysis (TGA). The FT-IR analysis of the acetate cellulose laurate ester revealed the presence of C=O, confirming its modification. The crystallinity of the isolated cellulose and the acetate cellulose laurate ester was found to be 67-72% and 51-54%, respectively. The thermal stability of the isolated and modified cellulose esters was found to be 360-340 ℃ and 380-365 ℃, respectively. The solubility test showed that the prepared acetate cellulose laurate esters were soluble in different solvents. However, this study found that the synthesis of acetate cellulose laurate ester in an aqueous medium is not feasible. The improved hydrophobic character, good thermal stability, water retention value, and excellent solubility in different solvents of the acetate cellulose laurate ester reported in this study make it a potential material for applications in bioplastics, and packaging materials.

Screening appropriate lactic acid bacteria as adjunct starter to enhance characteristic flavor and sensory profiles of Huangjiu (Chinese rice wine)

Lactic acid bacteria (LAB) are crucial for enhancing Huangjiu flavor, yet no standardized criteria exist for selecting LAB strains for this purpose. This study aimed to investigate the suitability of screening appropriate LAB strains as adjunct starters for Huangjiu fermentation. Twenty-five LAB strains were assessed for their stress resistance and fermentation characteristics. Co-fermentation with Saccharomyces cerevisiae was conducted to explore its role in flavor development, as this yeast greatly contribute to desirable flavor profiles. Notably, Lactiplantibacillus plantarum AR1018, AR1026 and Weissella confusa AR1038 significantly reduced 3-methyl-1-butanol production while increasing levels of ethyl hexanoate and ethyl octanoate. These strains were selected for further analysis of their impact on the physicochemical properties, volatile organic compounds, and sensory attributes of Huangjiu. The LAB starters enhanced total acidity, sugar and protein utilization and ester synthesis, while reducing ethanol and alcohol levels. AR1018 achieved a 16.51% reduction in 3-methyl-1-butanol, whereas AR1038 exhibited a 27.32% increase in ester content compared to the control. Principal component analysis revealed distinct flavor characteristic between Huangjiu produced with AR1018 and AR1038, and sensory evaluation confirmed enhanced desirable attributes, especially for AR1038. This study highlights the potential of LAB starters in improving the flavor quality of rice wine and similar fermented beverages.

Silica‐Mediated Incorporation of Lipase Into The Bulk of a Deep Eutectic Solvent: An Efficient Biocatalytic Phase for Esters Synthesis

Aiming at sustainable solutions suitable for industrial‐scale catalysis catalytic phase containing lipase and Deep Eutectic Solvent (DES) was designed. To achieve this, both physical and chemical immobilizations of lipases were performed on the surface of silica and carbon materials. The catalytic activity of developed biosystem was tested in biotransformation of α‐angelica lactone into butyl levulinate at 60°C. The best results were achieved for Candida antarctica lipase B adsorbed on fumed silica suspended in choline chloride: glycerol (1:2) with the addition of 20 wt% of water. Under these conditions 99.9% conversion of α‐angelica lactone and 100% selectivity to butyl levulinate were obtained after 45 min. The biocatalytic system maintained its activity for up to five consecutive reaction cycles with full conversion of lactone to ester. The heterogenization of the enzyme allowed the biocatalyst to be integrated into the bulk of the DES, which includes essential water. This combination resulted in the formation of a stable and easy‐to‐operate catalytic phase where reagents formed a second organic phase. The integration of cost‐effective biocatalyst with process efficiency provides a greener alternative with significant potential for industrial use.

Synthesis of the Fatty Acid Ethyl Esters (FAEE) from Krabok (Irvingia malayana) Seed Oil for Use as the Main Ingredient in the Production of Herbal Massage Oil

This study focused on synthesizing fatty acid ethyl esters (FAEE) from Krabok (Irvingia malayana) seed oil via transesterification for use as the primary ingredient in herbal massage oil production. Optimal conditions included 5 wt.% of KOH catalyst compared to the oil weight, 15:1 molar ratio of ethanol to Krabok seed oil, 60 min for reaction time and reaction temperature of 78 ± 3 °C, resulting in FAEE yields as high as 99.83 ± 0.17 %. Analysis using FT-IR, 1H and 13C-NMR, and GC techniques revealed FAEE as ester-type compounds, primarily comprising lauric acid (C12:0) and myristic acid (C14:0), constituting 97 wt.% saturated fatty acids and 3 wt.% unsaturated fatty acids. Physicochemical properties indicated clear yellow liquids with viscosity of 1.73 ± 0.03 cSt/s, density of 0.8199 ± 0.0049 g/cm3, cloud point of +4 °C, and pour point of –1 °C. Acid value, free fatty acid content, iodine value, water content and oxidation stability were measured at 0.703 ± 0.001 mg KOH/g of oil, 0.354 ± 0.001 wt.%, 0.59 ± 0.04 g I2/100 g of oil, 1482.3 ± 6.15 ppm, and greater than 12 h, respectively. When the synthesized FAEE was used to produce herbal massage oil products, the results showed that the herbal massage oil products were characterized as a clear yellow liquid with no sediment, low viscosity, and pH in the range of 5 - 6, meeting standard criteria. Thus, FAEE derived from Krabok seed oil is suitable as a primary ingredient for herbal massage oil production, enhancing the value of local resources within the community. HIGHLIGHTS Under optimal conditions of 5 wt.% KOH catalyst, 15:1 ethanol to oil ratio, 60 min at 78 ± 3 °C, FAEE was synthesized from Krabok seed oil for herbal massage oil, yielding 99.83 ± 0.17 %. FAEE, identified via FT-IR, 1H and 13C-NMR, and GC, comprises 97 wt.% saturated fatty acids (lauric acid and myristic acid) and 3 wt.% unsaturated. The herbal massage oil derived from FAEE as the primary ingredient meets clarity, low viscosity, and pH 5 - 6 standards. FAEE from Krabok seed oil enhances the value of local resources. GRAPHICAL ABSTRACT

Bcwf regulates the white petal color in pak choi [Brassica campestris (syn. Brassica rapa) ssp. chinensis]

Flower color is important in determining the ornamental value of Brassica species. However, our knowledge about the regulation of flower color in pak choi [Brassica campestris (syn. Brassica rapa) ssp. chinensis] is limited. In this study, we investigated the molecular mechanism underlying white flower traits in pak choi by analyzing a genetic population with white and yellow flowers. Our genetic analysis revealed that the white trait is controlled by a single recessive gene called Bcwf. Through BSA-Seq and fine mapping, we identified a candidate gene, BraC02g039450.1, which is similar to Arabidopsis AtPES2 involved in carotenoid ester synthesis. Sequence analysis showed some mutations in the promoter region of Bcwf in white flowers. Tobacco transient assay confirmed that these mutations reduce the promoter's activity, leading to downregulation of Bcwf expression in white flowers. Furthermore, the silencing of Bcwf in pak choi resulted in lighter petal color and reduced carotenoid content. These findings provide new insights into the molecular regulation of white flower traits in pak choi and highlight the importance of Bcwf in petal coloring and carotenoid accumulation.

Lipase Substrate Anchoring Dynamics Guided the Rational Design of Novel Deep Eutectic Solvents for Glucose Ester Synthesis.

Glucose esters, heralded for their emulsifying and solubilizing properties, have found increasing application in food, pharmaceutical, and cosmetic sectors. However, the environmental impact of chemical synthesis and the problem of enzyme inactivation in enzymatic synthesis have hindered their application. To this end, deep eutectic solvents (DESs) with stabilized enzyme activity and better solubility properties are considered a promising solution. In the study, 12 kinds of hydrophilic DESs and 22 kinds of hydrophobic DESs were screened, and we examined their efficiency in the synthesis of glucose esters. The results indicated that d,l-menthol-based DESs have excellent performance, with the highest yield of 92.85%. The molecular dynamics simulations suggested that it can be attributed to DESs changing the size of substrate binding pocket, which in turn affects the substrate anchoring ability and the catalytic efficiency of lipase. To further evaluate the effects of the solvent on the substrate anchoring ability of enzymes, a novel strategy, namely, substrate anchoring index, which is based on the stability of the tetrahedral intermediate, was proposed and used for the designing of more efficient DESs. Fortunately, novel DESs based on cyclohexanone (menthol analogues) were successfully developed with a yield of 98.85%.

Amino-Alkyl Group Dual-Functional Modification Synergistically Regulated Lipase-Carrier Interactions and Enhanced Phytosterol Ester Synthesis Efficiency.

Precisely controlling enzyme conformation to enhance catalytic performance is a highly sought-after yet challenging goal in the immobilization of biocatalysts. Excessively strong enzyme-carrier interactions can restrict enzyme dynamics and reduce catalytic efficiency, while excessively weak interactions may lead to enzyme leakage, thereby reducing reusability. In this study, we developed a novel strategy to finely regulate the interaction between the carrier and the enzyme through the adjustment of the ratio of amino and octadecyl functional groups. The expressed activity of the novel immobilized lipase, CRL@AOMR, was 1.32- and 2.34-fold higher than that of the monofunctional macroporous resin. Moreover, the synthesis of various phytosterol esters in solvent-free systems was conducted as a model reaction to investigate the utilization of CRL@AOMR in different reactions. Under optimized conditions, an impressive yield of 96.1% for phytosterol oleate was achieved and a yield of 76.2% was maintained even after six cycles of utilization (288 h). This study demonstrates the potential feasibility of developing immobilization strategies via dual modification of amino and alkyl groups, which is a potential general strategy for other enzymes with surface lysine.

Exploring Community Succession, Assembly Patterns, and Metabolic Functions of Ester-Producing-Related Microbiota during the Production of Nongxiangxing baijiu.

Esters are vital flavor compounds in Chinese Nongxiangxing baijiu and greatly affect the quality of baijiu. Microbial communities inhabiting fermented grains (FGs) have a marked impact on esters. However, the specific microorganisms and their assembly patterns remain unclear. This study utilized high-throughput sequencing and a culture-based method to reveal ester-producing microorganisms. A total of 33 esters were detected, including 19 ethyl esters, 9 linear chain esters, and 2 branched chain esters. A correlation analysis indicated that the bacterial genus Lactobacillus (relative abundance in average: 69.05%) and fungal genera Pichia (2.40%), Aspergillus (11.84%), Wickerhamomyces (0.60%), Thermomyces (3.57%), Saccharomycopsis (7.87%), Issatchenkia (0.96%), and Thermoascus (10.83%) were dominant and associated with esters production and their precursors. The numbers of esters positively correlated with them were 1, 17, 3, 2, 1, 1, 1, and 1, respectively. The modified stochasticity ratio (MST) index and Sloan neutral model revealed that bacteria were predominantly governed by deterministic processes while fungal assemblies were more stochastic. Saturnispora silvae and Zygosaccharomyces bailii were isolated and identified with ester synthesis potential. PICRUSt2 analysis showed that fungi in FG had a high potential for synthesizing ethanol, while 14 enzymes related to esters synthesis were all produced by bacteria, especially enzymes catalyzing the synthesis of acyl-CoA. In addition, ester synthesis was mainly catalyzed by carboxylesterase, acylglycerol lipase and triacylglycerol lipase. These findings may provide insights into ester production mechanism and potential strategies to improve the quality of Nongxiangxing baijiu.

Synthesis and evaluation of esters obtained from phenols and phenoxyacetic acid with significant phytotoxic and cytogenotoxic activities.

There is a growing demand for herbicides that are more effective than conventional ones yet less harmful to ecosystems. In light of this, this study aimed to synthesize esters from phenols and phenoxyacetic acid, using compounds with known phytotoxic potential as starting materials. Phenoxyacetic acid was first synthesized and then utilized in the synthesis of seven esters through Steglich esterification, employing N,N'-dicyclohexylcarboimide and N,N-dimethylpyridin-4-amine in the presence of phenols (thymol, vanillin, eugenol, carvacrol, guaiacol, p-cresol, and β-naphthol), yielding esters 1-7. All synthesized compounds were characterized using mass spectrometry, 1H, and 13C NMR. These compounds were tested for phytotoxicity to evaluate their effects on the germination and root development of Sorghum bicolor and Lactuca sativa seeds, and for the induction of alterations in the mitotic cycle of meristematic cells of L. sativa roots. Esters 1, 3, 4, and 5 exhibited the most significant phytotoxic activity in both L. sativa and S. bicolor. Alterations in the mitotic index and frequency of chromosomal alterations in L. sativa roots revealed the cytotoxic, genotoxic effects, and the aneugenic mode of action of the tested molecules. These findings suggest that these compounds could serve as inspiration for the synthesis of new semi-synthetic herbicides.

Lawesson’s reagent in the synthesis of a malic ester of dithiophosphonate salts with antifungal activity

Lawesson’s reagent reacted with racemic diethyl malate to yield O-(1,2-bis(ethylcarboxylate)ethyl-1 4-methoxyphenyl dithiophosphonic acid. The acid formed pyridinium dithiophosphonate salts with 3-(hydroxymethyl)pyridine, pyridoxine, and (S)-(–)-nicotine. The salts revealed antifungal activity against Candida albicans.

Enzymatic synthesis of vanillyl fatty acid esters from salmon oil in a solvent-free medium

This study hypothesizes that the solvent-free alcoholysis of oil recovered from salmon heads using vanillyl alcohol (VA) and immobilized lipase B can efficiently produce esters with enhanced stability and antioxidant properties. The objective was to investigate the selectivity and resulting ester profile, which may provide nutritional and functional advantages compared to supplementing oil with vanillyl alcohol. After 24 h, nearly complete conversion of vanillyl alcohol was achieved, leading to the production of various esters reflective of the oil's original fatty acid composition. The synthesis of esters like oleoyl and linolenoyl was favored over docosahexaenoyl and linoleoyl esters, influenced by fatty acid distribution and enzyme specificity, along with potential intra-molecular acyl transfer isomerization. The reaction medium demonstrated significant stability and antioxidant activity, highlighting the potential benefits of vanillyl esters over traditional supplementation methods. These findings suggest that the phenolic alcohol-based alcoholysis of fish oil offers a promising approach to generating stable, nutritionally valuable extracts with potent antioxidant capabilities.

Ethyl esters synthesis catalyzed by lipase B from Candida antarctica immobilized on NiFe2O4 magnetic nanoparticles

Ethyl esters synthesis catalyzed by lipase B from Candida antarctica immobilized on NiFe2O4 magnetic nanoparticles

200 Years of The Haloform Reaction: Methods and Applications.

Discovered in 1822, the haloform reaction is one of the oldest synthetic organic reactions. The haloform reaction enables the synthesis of carboxylic acids, esters or amides from methyl ketones. The reaction proceeds via exhaustive a-halogenation and then substitution by a nucleophile to liberate a haloform. The methyl group therefore behaves as a masked leaving group. The reaction methodology has undergone several important developments in the last 200 years, transitioning from a diagnostic test of methyl ketones to a synthetically useful tool for accessing complex esters and amides. The success of the general approach has been exhibited through the use of the reaction in the synthesis of many different complex molecules in fields ranging from natural product synthesis, pharmaceuticals, agrochemicals, fragrants and flavouring. The reaction has not been extensively reviewed since 1934. Therefore, herein we provide details of the history and mechanism of the haloform reaction, as well as an overview of the developments in the methodology and a survey of examples, particularly in natural product synthesis, in which the haloform reaction has been used.

In situ Product Recovery of Microbially Synthesized Ethyl Acetate from the Exhaust Gas of a Bioreactor by Membrane Technology

ABSTRACTEthyl acetate is at present exclusively produced from fossil resources. Microbial synthesis of this ester from sugar‐rich waste as an alternative is an aerobic process. Ethyl acetate is highly volatile and therefore stripped with the exhaust gas from the bioreactor which enables in situ product recovery. Previous research on microbial formation of ethyl acetate has focused on the kinetics of ester synthesis and in part on the ester stripping, while the separation of the ester from the exhaust gas has hardly been investigated. A mixed matrix membrane was developed consisting of Silikalite‐1 embedded in polydimethylsiloxane which was installed in a radial–symmetrical membrane module. Evaluation of the separation of ethyl acetate was based on the analysis of the composition of the feed and retentate gas by mass spectrometry. The separation efficiency of the membrane was first tested with varied flows of artificial exhaust gas, containing defined amounts of ethyl acetate. A model for describing the separation process was parametrized by the measured data and used to design a real separation experiment. Ethyl acetate produced from delactosed whey permeate by Kluyveromyces marxianus DSM 5422 in a stirred bioreactor gassed with 0.5 vvm air was successfully separated from the exhaust gas by membranes; 93.6% of the stripped ester was separated. Liquid ethyl acetate was recovered by cooling the permeate gas to ‒78°C, whereby 99.75% of the condensed organic compounds were ethyl acetate. This study demonstrates for the first time that microbially produced and stripped ethyl acetate can be effectively separated from the exhaust gas of bioreactors by membrane technology to obtain the ester in high yield and purity.

Development of polyols analogous to neopentyl glycol and trimethylolpropane for the production of oleic acid-based biolubricants

Vegetable oils and animal fats have been known and used as lubricants and fuels since ancient times. However, the chain structure of the triacylglycerols (TAGs) generate limitations that discourage the use of these raw materials as lubricants. As an alternative to improve the physicochemical and thermo-oxidative characteristics of natural oils, the use of polyols without the β-hydrogens in the triacylglycerols structure is an efficient solution for the production of biolubricants. In this context, a series of polyols, analogous to trimethylolpropane (TMP) and neopentyl glycol (NPG) was synthesised and applied in the synthesis of polyol esters based on oleic acid. These esters were prepared by homogeneous catalysis using p-toluenesulfonic acid (p-TSA) and are intended for use as biolubricants. The synthesised polyols were characterized by one and two-dimensional NMR. The derived polyol esters were purified and had their structure confirmed by 1H and 13C NMR, infrared spectroscopy, and mass spectrometry. The polyol esters showed high viscosity index (189 – 222), thermo-oxidative stability (Tonset between 258 and 285 °C), and low melting points (between –19.4 and –47.6 °C). Furthermore, polyol esters showed reduced friction coefficients (0.021 – 0.041) and scar wear diameter on the metallic surface (0.274 – 0.448 mm). In addition to the satisfactory results of thermal stability and lubricity, which suggest the potential of these molecules as lubricants, all molecules were considered environmentally safe when evaluated through the Zebrafish toxicity model.

Biocatalytic Synthesis of α-Amino Esters via Nitrene C-H Insertion.

α-Amino esters are precursors to noncanonical amino acids used in developing small-molecule therapeutics, biologics, and tools in chemical biology. α-C-H amination of abundant and inexpensive carboxylic acid esters through nitrene transfer presents a direct approach to α-amino esters. Methods for nitrene-mediated amination of the protic α-C-H bonds in carboxylic acid esters, however, are underdeveloped. This gap arises because hydrogen atom abstraction (HAA) of protic C-H bonds by electrophilic metal-nitrenoids is slow: metal-nitrenoids preferentially react with polarity-matched, hydridic C-H bonds, even when weaker protic C-H bonds are present. This study describes the discovery and evolution of highly stable protoglobin nitrene transferases that catalyze the enantioselective intermolecular amination of the α-C-H bonds in carboxylic acid esters. We developed a high-throughput assay to evaluate the activity and enantioselectivity of mutant enzymes together with their sequences using the Every Variant Sequencing (evSeq) method. The assay enabled the identification of enantiodivergent enzymes that function at ambient conditions in Escherichia coli whole cells and whose activities can be enhanced by directed evolution for the amination of a range of substrates.

Synthesis of bioactive quercetin-boronate esters as a novel biological agent: Enzyme inhibition, anti-microbial properties, computational insights and anti-cancer activity

This study introduces a novel synthesis for the quercetin-boronate esters (QB1-QB4) for some biological applications. The structure of low-cost, easily synthesized, and functionalizable trigonal planar quercetin-boronate esters was characterized by 1H, 13C, and 11B NMR spectra, FT-IR spectra, UV–Vis spectra, LC-MS/MS spectrometry, elemental analysis, and melting point measurement. Following the successful synthesis studies, quercetin-boronate esters have been tested over glucosidase enzyme inhibition, antimicrobial studies, computational insights, and in vitro anti-cancer activity against pancreatic cancer cells, respectively. QB1 significantly decreased cell viability at a 50 µM concentration compared to other boron compounds. The enzyme inhibition studies on quercetin-boronate esters demonstrated that α-glucosidase enzyme inhibitions were higher than the reference compound. IC50 values of QB1-QB4 against α-glucosidase were 5.92, 5.54, 5.68, and 6.79 μM, repsectivey. As expected, quercetin-boronate esters exhibited respectable activity against the biofilms of some bacteria. The MIC values of QB1-QB4 were 32.5 μg/mL against Enterococcus faecalis. In addition, the binding parameter values and binding sites were determined as a result of docking studies of quercetin-boronate esters. As a result of the scientific findings, quercetin-boronate ester compounds will certainly become important building blocks used in the future from organic synthesis to materials science and medicine.