Reaction Of Glyoxal Research Articles

Glyoxal Caging of Nucleoside Antivirals toward Self-Activating, Extended-Release Prodrugs.

Nucleoside antivirals are a leading class of compounds prescribed as a first-line treatment for viral infections. However, inherent limitations such as low solubility and circulation lifetime can necessitate multi-intraday dosing. Here, we deploy the 1,2-dialdehyde glyoxal to generate antiviral nucleoside prodrugs with enhanced pharmacokinetic properties and extended-release activity to combat poor patient adherence. The near-quantitative reaction of glyoxal with acyclovir (ACV) drastically improves ACV solubility and enables subsequent drug release with a half-life of 1.9 h under physiological conditions. Further, glyoxal caging thermoreversibly disrupts ACV activity against HIV-1 reverse transcription in vitro and HSV-1 pathology in cellulo. Finally, the amenability of a panel of nucleoside reverse transcriptase inhibitors to glyoxal caging showcases the potential of this highly versatile method for achieving timed-release activation of a clinically important class of antiviral therapeutics.

Synergistic inhibition against heterocyclic amines by amino acid combinations: Focus on carbonyl-amine reactions of methylglyoxal and glyoxal

In this study, critical reactants were identified in glycine/glucose/creatinine model system to clarify the formation pathways of imidazoquinoxaline-type heterocyclic amines (IQx-type HAs). It has been confirmed that the condensation between pyrazines and creatinine was the critical step to produce IQx-type HAs. There was a conversion between methylglyoxal and glyoxal, and their carbonyl-amine reaction was a route for the production of 2,5-dimethylpyrazine and methylpyrazine. When cysteine was combined with proline at the mass ratio of 4:1 (2 mg/mL in total), the inhibitory rate of MeIQx and IQx in glucose/creatinine/glycine model system increased to 62 % and 55 %, respectively. The synergistic inhibition of cysteine-proline combinations was further assessed in roast yellow croaker, and the total content of IQx-type HAs decreased from 4.99 ± 0.48 ng/g of the control group to 2.46 ± 0.21 ng/g. The carbonyl scavenging rate of corresponding cysteine-proline combinations also increased compared with that of single agents. These findings suggest that scavenging methylglyoxal and glyoxal simultaneously to control the production of pyrazines may be a potential inhibitory strategy to enhance the suppression of IQx-type HAs formation.

Indium-Mediated Preparation of Bis(α-hydroxyallenes) or α,α'-Dihydroxyallenynes and Further Gold-Catalyzed Cyclizations.

We present the regio- and diastereoselective Barbier-type allenylation reaction of glyoxals mediated by indium to furnish highly valuable syn-bis(α-hydroxyallenes) and syn-α,α'-dihydroxyallenynes. The gold-catalyzed controlled cyclization of these unsaturated diols enables the divergent preparation of three types of oxacycles.

Synthesis and characterization of high thermal resistance acetal-containing heterocyclic polyamides

This study synthesized a heterocyclic acetal-containing monomer, 7a,14c-dihydronaphtho[2,1-b] naphtho [1′,2′:4,5] furo[3,2-d] furan (DHNF) with a melting point of 230 °C, through the acidic reaction of 2-naphthol and glyoxal. Two types of heterocyclic polyamides were produced via condensation polymerization of DHNF Diamine with terephthalic acid (aromatic diacid) and sebacic acid (aliphatic diacid), achieving melting points exceeding 400 °C. Spectroscopic methods, including Fourier-transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy (1HNMR), were used to identify the synthesized compounds. Thermal analysis, including Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), demonstrated the thermal stability of the polyamides with acetal functional groups, showing a 10 % weight loss at 193.6 ℃ for PA-1 and 420 ℃ for PA-2, with crystallization temperatures of 155 °C and 180 °C for Types 1 and 2, respectively. The results indicate that the acetal functional group enhances polyamide solubility and processability. Viscometry revealed higher inherent viscosity for PA-2, attributed to its higher molecular weight.

Introduction of aldehyde groups into surface of pine bark via Cannizzaro reaction to improve Urea-formaldehyde resin properties

Pine bark, a natural and renewable forest residue, was modified using a simple interfacial solid-phase chemical method to design a highly chemically reactive additive for urea-formaldehyde (UF) resin. The modification introduced carbonyl groups onto the bark surface during the glyoxal reaction at the bark-solid interface. Thermal properties, including curing temperatures, of UF, UFB, and UFGB were evaluated using DSC and DMA. Glyoxal modification of bark significantly influenced these properties, facilitating the crosslinking and curing of adhesives. Notably, plywood bonded with UFGB resin released approximately half as much formaldehyde (52.89 % less) compared to plywood bonded with UF resin, reducing from 1.38 to 0.65 mg/L. Additionally, the wet shear strength of plywood increased by 197.3 %, from 0.37 MPa to 1.10 MPa, exceeding the minimum requirement (0.7 MPa) defined by the China national standard (GB/T 17657–2013). The study presents a compelling case for the utilization of glyoxal-modified pine bark as a filler in UF adhesive for plywood manufacturing. The demonstrated improvements in plywood properties and formaldehyde emissions, along with the environmentally friendly nature of the approach, make it a promising avenue for sustainable plywood production. Further investigations into the underlying mechanisms and long-term performance are encouraged to solidify the potential of this technology.

Synthesis of Polycyclic Pyrrolopyridine Derivatives via Multicomponent Synthesis of 1,5‐Diketones

AbstractA simple, two‐step process was developed for the easy access of polycyclic pyrrolopyridine derivatives. The first step involves a multicomponent reaction of aryl glyoxal, cyclohexane‐1,3‐dione derivatives and 2‐amino‐1,4‐napthoquinone in AcOH: H2O (1 : 1 v/v) under reflux conditions which led to the formation of 1,5‐diketones in 15 min of reaction time. In the second step, the reaction of ammonium acetate with 1,5‐diketones in AcOH under reflux conditions resulted the formation of polycyclic pyrrolopyridine derivatives. All the products were characterized by FTIR, 1H NMR, 13C NMR and HRMS. The single crystal XRD of one compound was recorded to further confirm the structure of the product. The presence of several bioactive moieties in our product, simple reaction process, metal‐free reaction conditions, easy purification method, and good yields of the products are the notable features of this methodology.

A new gold nanosol SERS method for ultratrace atrazine by a difunctional surface molecular imprinted polymethacrylate probe

A new type of bifunctional nanosurface molecularly imprinted polymer nanoprobe (Au@MIP) was prepared using methacrylic acid as functional monomers respectively, gold nanoparticles (AuNP) as nanosubstrate. The Au@MIP nanoprobe not only has recognition function but also has catalytic function. The findings demonstrate that the AuNP@MIP nanoprobes, prepared with methacrylic acid as the functional monomer, very strongly catalyzed the new nano indicator reaction of glyoxal (GO)-HAuCl4. In situ generated AuNP sol exhibits strong surface-enhanced Raman scattering (SESR) effects. After adding atrazine (ATZ), the signals were significantly boosted. As a result, a new SESR trimode sensor platform was created for ultratrace ATZ. The linear ranges for ATZ was 0.005–0.0625 nmol/L, with detection limits of 0.0012 nmol/L. Moreover, the SERS method was used to determine the content of ATZ in corn samples, achieving relative standard deviations (RSDs) of 6.53–9.57 % and recoveries of 96.4 %–108.2 %.

HFIP-Mediated Multicomponent Reactions: Synthesis of Pyrazole-Linked Thiazole Derivatives.

The development of one-pot, atom, and step-economic new methods avoiding metal, harsh reaction conditions, and toxic reagents for the synthesis of medicinally important hybrid molecules bearing more than one bioactive moieties is currently one of the hot topics in organic synthesis. Herein, we report a green and efficient room temperature multicomponent reaction for the synthesis of novel pyrazole-linked thiazoles involving a one-pot C-C, C-N, and C-S bond-forming process from the reaction of aryl glyoxal, aryl thioamide, and pyrazolones in 1,1,1,3,3,3-hexafluoroisopropanol, a hydrogen bond donating reaction medium. A set of diverse hybrid molecules bearing thiazole and pyrazole moieties were prepared in good to excellent yields by using this method. This methodology can also be extended to prepare thiazole-linked barbiturates as well as imidazole-linked pyrazoles. All the products were fully characterized by spectroscopic techniques. The notable features of this protocol are room temperature, metal as well as additive-free reaction conditions, use of recyclable solvent, water as the byproduct, wide substrate scope, operational simplicity, easy purification, applicability for gram-scale synthesis, high atom economy, and the presence of two bioactive pyrazole and thiazole moieties in the products.

Ammonolysis of Glyoxal at the Air‐Water Nanodroplet Interface

AbstractThe reactions of glyoxal (CHO)2) with amines in cloud processes contribute to the formation of brown carbon and oligomer particles in the atmosphere. However, their molecular mechanisms remain unknown. Herein, we investigate the ammonolysis mechanisms of glyoxal with amines at the air‐water nanodroplet interface. We identified three and two distinct pathways for the ammonolysis of glyoxal with dimethylamine and methylamine by using metadynamics simulations at the air‐water nanodroplet interface, respectively. Notably, the stepwise pathways mediated by the water dimer for the reactions of glyoxal with dimethylamine and methylamine display the lowest free energy barriers of 3.6 and 4.9 kcal ⋅ mol−1, respectively. These results showed that the air‐water nanodroplet ammonolysis reactions of glyoxal with dimethylamine and methylamine were more feasible and occurred at faster rates than the corresponding gas phase ammonolysis, the OH+(CHO)2 reaction, and the aqueous phase reaction of glyoxal, leading to the dominant removal of glyoxal. Our results provide new and important insight into the reactions between carbonyl compounds and amines, which are crucial in forming nitrogen‐containing aerosol particles.

Ammonolysis of Glyoxal at the Air-Water Nanodroplet Interface.

The reactions of glyoxal (CHO)2 ) with amines in cloud processes contribute to the formation of brown carbon and oligomer particles in the atmosphere. However, their molecular mechanisms remain unknown. Herein, we investigate the ammonolysis mechanisms of glyoxal with amines at the air-water nanodroplet interface. We identified three and two distinct pathways for the ammonolysis of glyoxal with dimethylamine and methylamine by using metadynamics simulations at the air-water nanodroplet interface, respectively. Notably, the stepwise pathways mediated by the water dimer for the reactions of glyoxal with dimethylamine and methylamine display the lowest free energy barriers of 3.6 and 4.9 kcal ⋅ mol-1 , respectively. These results showed that the air-water nanodroplet ammonolysis reactions of glyoxal with dimethylamine and methylamine were more feasible and occurred at faster rates than the corresponding gas phase ammonolysis, the OH+(CHO)2 reaction, and the aqueous phase reaction of glyoxal, leading to the dominant removal of glyoxal. Our results provide new and important insight into the reactions between carbonyl compounds and amines, which are crucial in forming nitrogen-containing aerosol particles.

Glyoxalase-based toolbox for the enantioselective synthesis of α-hydroxy carboxylic acids.

We report highly enantioselective synthesis of L-α-hydroxy carboxylic acids (L-αHCAs) via enzymatic intramolecular Cannizzaro reaction of (hetero)aryl glyoxals in the presence of glutathione-independent human glyoxalase DJ-1. Combined with the optimized synthesis of D-αHCAs using glyoxalases I and II, this approach offers a general, scalable and operationally simple access to both enantiomers of α-hydroxy acids in moderate to excellent yields with uniformly high enantioselectivity.

SYNTHESIS, BIOCHEMICAL AND IN SILICO EXPLORATION OF NOVEL IMIDAZOLE BASED 1,2,3-TRIAZOLES AS POTENTIAL HIT AGAINST CARBONIC ANHYDRASE II ISOZYME

This study aimed to synthesize novel compounds as more effective carbonic anhydrase II inhibitors. For this purpose, 2-(3-methoxy4-(prop-2-yn-1-yloxy)phenyl)-4,5-diphenyl-1H-imidazole (3) was reacted with 3-methoxy-4-(prop-2-yn-1-yloxy)benzaldehyde through the glyoxal reaction to produce a series of imidazole-based 1,2,3-triazoles 5a-f. The synthesized compounds were structurally confirmed using IR, 1H, and 13C NMR techniques. To evaluate their potential as inhibitors of carbonic anhydrase II enzyme, the synthesized compounds were tested via in vitro enzyme inhibition assay. Among the derivatives, compounds 5f and 5a exhibited the most promising inhibitory potential, with IC50 values of 0.025 ± 0.001 and 0.032 ± 0.003 µM, respectively. Both 5a and 5f derivatives have comparable inhibitory potential but 5f was found to be more potent than 5a. Molecular docking analysis revealed that compounds 5a and 5f displayed excellent binding scores of −8.0 and −8.4 kcal mol-1, respectively. The results were further validated by MD simulations. The RMSD analysis revealed the average values of 3.20 Å for the ligand-protein complex, 1.38 Å for the apoprotein, and 7.15 Å for the ligand molecule. Based on the chemical stability and biological importance, the compound 5f was identified as potential lead candidates for the development of more effective carbonic anhydrase II inhibitors.

Product-oriented thermodynamic function construction of wheat straw and thermodynamic analysis for rapid pyrolysis

Given the complexity of the rapid pyrolysis reaction system of wheat straw and the difficulty in product regulation, this paper investigated the feasible range for high-value product formation. It determined the conditions for product regulation of wheat straw pyrolysis through thermodynamic analysis. The research constructed the standard enthalpy of formation ΔHf0, standard entropy ΔSm0, and standard Gibbs free energy of formation ΔGf0 of wheat straw molecules. Based on the pyrolysis characteristics of cellulose, hemicellulose, and lignin, which were the main components of wheat straw, 34 reactions were constructed to produce high-valued components such as 2-furfural, acetone, and guaiacol. With Gibbs free energy and equilibrium constant as evaluation indexes, the relationship between the feasible region of the reaction and temperature and pressure at 200–800 °C and 0.1–10 MPa was explored. The results showed that ΔHf0 was-115.86 kJ mol−1, ΔSm0 was 66.34 J mol−1 K−1 and ΔGf0 was-135.64 kJ mol−1. The temperature was conducive to a spontaneous endothermic reaction, whereas pressure was not conducive to a spontaneous reaction. As the pressure increases, the temperature required for spontaneous reaction also increases. At 10 MPa, the thermodynamic temperature at which the reaction of glyoxal and acrolein could proceed spontaneously was increased by 318 °C and 87 °C, respectively. At 0.5 MPa, the range of 3- hydroxy -2- butanone could be spontaneous was 200–388 °C. By adjusting the temperature and pressure, the product's production process could be directed.

Magnetically retrievable nanocatalyst Fe3O4@CPTMO@dithizone-Ni for the fabrication of 4H-benzo[h]chromenes under green medium

In the research, the core–shell procedure synthesized a novel magnetically separable heterogeneous nanocatalyst with high stability named Fe3O4@CPTMO@dithizone-Ni. In this method, Fe3O4 was modified as a magnetic core using surfactant (SDS) and polyethylene glycol (PEG) coating; after functionalizing the magnetic nanoparticles with 3-chloropropyl-tri-methoxysilane and dithizone, Ni metal was immobilized. The prepared catalyst was identified and specified utilizing diverse physicochemical techniques involving FT-IR, XRD, SEM, EMA, BET, ICP, EDS, TGA, Raman, and TEM. In the following, to vouch for the efficiency of the obtaining catalyst for the green synthesis of 4H-benzo[h]chromenes utilizing the three-component, one-pot condensation reaction of α-naphthol, aryl glyoxal, and malononitrile as precursors were evaluated. The catalyst exhibited high recyclability with a slight reduction in activity at least eight series without a substantial decrease in stability and efficiency. The synthesized nanocatalyst was evaluated in various conditions such as different solvents, etc. the best of these conditions is the initial concentration of 30 mg of nanocatalyst with water as a solvent in 3 min with 98% yield. The prominent merits of the present research include easy separation of the catalyst without centrifugation, high-accessible raw precursors, cost-effectiveness, environmental friendliness, green reaction status, quick reaction, and excellent product yields.

Kinetics of glyoxal oxidation by nitric acid in a capillary microreactor

Aiming at solving the problems of long operation periods, low selectivity, and low safety in the traditional batch reactor, a method of oxidation reaction of glyoxal with nitric acid through a continuous flow microreactor is proposed, with high selectivity. The method utilizes the excellent performance of mass and heat transfer in the microreactor, to improve the reaction efficiency, selectivity, and safety. The effects of the mixing performance, the molar ratio of reactants, temperature, residence time, and mass fraction of nitric acid on the oxidation of glyoxal with nitric acid are investigated, and the optimum reaction conditions are determined. The glyoxylic acid yield can reach 81.6% while the selectivity is 92.4% with the set residence time of only 7.9 min at 68 ℃ (the molar ratio of nitric acid to glyoxal is 1.4, sodium nitrite to glyoxal is 0.15, hydrochloric acid to glyoxal is 0.2, and the mass concentration of nitric acid is 35%). The apparent kinetic model of the oxidation reaction of glyoxal with nitric acid in a microchannel reactor is established. By precisely controlling the reaction temperature and residence time of the continuous flow microreactor system, the apparent reaction rate constants, pre-exponential factor, and activation energy of glyoxal oxidation to glyoxylic acid by nitric acid are obtained. This work paves the way for the promotion of the synthesis of glyoxylic acid in a microreactor by the continuous flow chemistry system.

Synthesis and study of the protective properties of the product of the reaction of glyoxal, ammonia, and acetaldehyde against hydrogen sulfide corrosion of carbon steel in model stratum waters

Synthesis and study of the protective properties of the product of the reaction of glyoxal, ammonia, and acetaldehyde against hydrogen sulfide corrosion of carbon steel in model stratum waters

Imidazole: Synthesis, Functionalization and Physicochemical Properties of a Privileged Structure in Medicinal Chemistry.

Imidazole was first synthesized by Heinrich Debus in 1858 and was obtained by the reaction of glyoxal and formaldehyde in ammonia, initially called glyoxaline. The current literature provides much information about the synthesis, functionalization, physicochemical characteristics and biological role of imidazole. Imidazole is a structure that, despite being small, has a unique chemical complexity. It is a nucleus that is very practical and versatile in its construction/functionalization and can be considered a rich source of chemical diversity. Imidazole acts in extremely important processes for the maintenance of living organisms, such as catalysis in enzymatic processes. Imidazole-based compounds with antibacterial, anti-inflammatory, antidiabetic, antiparasitic, antituberculosis, antifungal, antioxidant, antitumor, antimalarial, anticancer, antidepressant and many others make up the therapeutic arsenal and new bioactive compounds proposed in the most diverse works. The interest and importance of imidazole-containing analogs in the field of medicinal chemistry is remarkable, and the understanding from the development of the first blockbuster drug cimetidine explores all the chemical and biological concepts of imidazole in the context of research and development of new drugs.

HFIP-mediated multicomponent reactions for the synthesis of fluorescent quinoline-fused pyrroles

Herein we report a metal-free multicomponent reaction for the synthesis of diverse quinoline-fused pyrroles using 1,1,1,3,3,3-hexafluoro isopropanol (HFIP) as a reaction medium cum promoter. The reaction of aryl glyoxals, 4-hydroxycoumarin or other cyclic 1,3-dicarbonyl compounds, and 6/5-aminoquinoline or 5-aminoisoquinoline in the HFIP medium under reflux conditions provide regioselective corresponding quinoline/isoquinoline-fused pyrroles. This methodology is applicable to a wide range of substrates and provided quinoline/isoquinoline-fused pyrroles in good to very good yields. The notable features of this protocol are metal-free conditions, operational simplicity, easy purification, and the presence of bioactive pyrrole, quinoline/isoquinoline and cyclic 1,3-dicarbonyl moieties in the products. Most of the synthesized fused pyrroles exhibit fluorescence properties. The photophysical properties of all the synthesized fused pyrroles were studied by recording UV–Visible and steady-state fluorescence spectroscopy. Compounds 4a, 4e, 4f, 4h, 4i and 4s showed very good fluorescence quantum yields.

Theoretical study on atmospheric gaseous reactions of glyoxal with sulfuric acid and ammonia

The reaction mechanisms and rate constants of the gaseous reactions of glyoxal with H2SO4, NH3-catalyzed glyoxal with H2SO4, glyoxal with NH3, and H2SO4-catalyzed glyoxal with NH3 are studied detailedly using M06-2X followed by CCSD(T) calculations and conventional transition state theory in current study. The results show that NH3 has a certain catalytic ability to reduce the barrier for reaction of glyoxal with H2SO4, and increases their rate constant by 103 times to 2.66 × 10-15 cm3 molecule-1 s−1 under atmospheric condition ·NH3 can facilitate the formation of organosulfates at high concentration and low temperature. H2SO4 has a strong catalytic ability, significantly reduces the barrier of glyoxal with NH3, and increases their rate constant to 4.52 × 10-12 cm3 molecule-1 s−1, which is slightly less than the rate coefficient of OH radicals and glyoxal. These provide the basis for clarifying the characteristic mechanism of gaseous reaction of glyoxal to form organosulfates and carbinolamine.

Reaction of Glyoxal and Ammonium as a Potential Contributor to Protein-like Fluorescence in Atmospheric Measurements

Reaction of Glyoxal and Ammonium as a Potential Contributor to Protein-like Fluorescence in Atmospheric Measurements