Optimal Reaction Conditions Research Articles

Alkynylation of C(sp3)H Bonds via 1,4‐Palladium Migration

This study presents the successful development of an aryl‐to‐alkyl 1,4‐palladium migration/Sonogashira coupling reaction, enabling the synthesis of migratory alkynylation products in moderate to good yields. The regioselectivity is effectively modulated through extensive optimization of reaction conditions. Mechanistic investigations, supported by stoichiometric experiments with palladium complexes, provide insights into the catalytic cycle and the migratory pathway.

Efficient and Rapid Arylation of NH₂-Unprotected Bromobisindole Ethanamines via Suzuki-Miyaura Coupling: Generating New Leads against Leishmania.

Leishmaniasis is a neglected tropical disease which presents significant global health challenges due to the lack of effective vaccines and the limitations of existing chemotherapeutics in view of their toxicity, resistance, and high costs. In this study, we realized a library of novel bisindole derivatives as potential anti-leishmanial agents through a rapid Suzuki-Miyaura coupling reaction, utilizing NH2-unprotected bromobisindoles ethanamines and boronic acids. Optimization of reaction conditions allowed for the efficient and selective arylation of these substrates, with yields up to 93%. The compounds were screened for their activity against Leishmania infantum promastigotes. Among the tested bisindole derivatives, 3af (bearing a 4-vinylphenyl moiety) demonstrated potent anti-leishmanial activity (IC50 = 1.1 μM) with a higher selectivity index (21.8) compared to the reference drug miltefosine (9.8). A significant activity was also retained against intracellular amastigotes. This study establishes a robust methodology for late-stage functionalization of bisindoles, also highlighting these derivatives' potential as promising leads for antileishmanial drug development.

Unveiling the Multifaceted Role of HP6: A Critical Regulator of Humoral Immunity in Antheraea pernyi (Lepidoptera: Saturniidae)

Serine proteases are widely distributed in both invertebrates and vertebrates, playing critical roles in the regulation of innate immunity. In the insect innate immune system, two pivotal pathways—the prophenoloxidase (PPO) activation cascade and Toll pathway-mediated antimicrobial peptide (AMP) synthesis—are both tightly regulated by serine protease cascades. This study focuses on serine protease–hemolymph protease 6 of A. pernyi (Ap-HP6). Following immune stimulation, the expression of Ap-proHP6 was significantly induced, primarily observed in hemocytes and the fat body. After suppressing Ap-proHP6 expression via RNA interference (RNAi) and infecting larvae with different microbes, the expression levels of AMPs showed a downward trend. When endogenous Ap-proHP6 content in hemolymph was reduced using RNAi technology or anti-rAp-proHP6-His6 polyclonal antibodies, PAMPs/microbe-mediated phenoloxidase (PO) activity significantly decreased. These results suggest that Ap-HP6 has a positive regulatory effect on PPO activation and AMP synthesis. Additionally, the in vitro hydrolysis of rAp-proHP6-Tb-His6 yielded rAp-HP6 with serine protease activity, which exhibited optimal reaction conditions for S-2288 at pH 8.0, 50 °C, and 15 min.

Establishment of a TaqMan Quantitative Real-Time PCR for Detecting Lawsonia intracellularis

Porcine proliferative enteropathy (PPE) is an infectious disease in pigs, caused by Lawsonia intracellularis (LI), affecting their intestines during growth and finishing stages, leading to higher production costs. Current detection methods for LI face two main challenges, delayed results and high costs, making them impractical for large-scale pig farming epidemiological surveys. This study developed a TaqMan-qPCR method using specific probes and primers based on the LI aspartate ammonia lyase genes from GenBank, completing detection in just 45 min. After optimizing reaction conditions, sensitivity analysis revealed that the detection limit of this method was 4.6 copies/μL targeting standard plasmids. The results of the specificity analysis showed no cross-reactivity with other common porcine pathogens, highlighting its specificity. The inter- and intra-group coefficients of variation were both <1%, indicating high reproducibility. Furthermore, the TaqMan-qPCR demonstrated 100% relative sensitivity, and a 92.50% compliance rate compared to conventional PCR, suggesting it could be a complement to the conventional PCR method. In summary, the TaqMan-qPCR method established in this study is not only suitable for epidemiological investigations and early qualitative and quantitative diagnosis of proliferative enteropathy in pigs, but it is also valuable for studying the biological characteristics of LI.

Environmental Remediation of Sulfamethazine Wastewaters by Iron Doped Perylene Diimide Supramolecular Catalysts in a Visible Light Driven Photocatalytic Process: Optimization and Kinetic Approach

The presence of pharmaceutical compounds in water sources threaten the environmental and human health due to their complex molecular structures and persistence. The release of improperly treated pharmaceutical wastewaters into aquatic medium may result in development of drug-resistant microorganisms and endocrine disruption. Sulfamethazine, as a type of sulfonamides is one of the most widely used agents particularly in veterinary medicine. Therefore, the effective removal of sulfamethazine from water is of importance. The main focus of the study is to search for an environmental solution for the removal of recalcitrant organic compounds by testing the performance of iron impregnated perylene diimide supramolecular photocatalysts (Fe/PDI) in photo Fenton-like oxidation of sulfamethazine. The interactive effects of the operating parameters were examined in the presence of Fe/PDI by using Box-Behnken Design. The optimum photo Fenton-like reaction conditions were determined as 0.45 g/L catalyst dosage, pH 3 and 6.46 mM H2O2 dosage. The low iron leaching (1.344 ppm) detected in the treated sulfamethazine solution indicates the stability of the catalyst and its suitability for practical applications. The kinetic studies revealed that fitting is consistent with 1st and 2nd order kinetics but literature suggests that 2nd order is likely to be correct for the sulfamethazine degradation. The activation energy was determined as 11.3 kJ/mol in the presence of Fe/PDI photocatalyst. The radical quenching tests showed that the dominant reactive species is the hydroxyl radicals. The photocatalytic activity of the Fe/PDI was tested for the removal of different pollutants under the same reaction conditions. Complete Procion Red MX-5B decolorization was achieved in 15 min and 71.2% oxytetracycline hydrochloride degradation was obtained in 120 min. Optimization studies and modeling of reaction kinetics are significant for the application of environmentally friendly and effective supramolecular catalysts and industrial wastewater treatment systems.Graphical

Construction of Acid–Base Dual Sites in Heterogeneous Catalysts for Effective Conversion of Biomass Molecules into 5‐Hydroxymethylfurfural

This review presents the latest developments in the field of acid‐base bifunctional catalysts in 5‐hydroxymethylfurfural (5‐HMF) production. It focuses on the design principles of catalysts, the synergistic effects of active sites, and a deeper understanding of reaction mechanisms. We explore the performance of various catalyst systems in hydrolysis, isomerization, and dehydration processes, with a particular focus on the impact of acid and base site interactions on the selectivity and yield of 5‐HMF. The employment of optimized acid‐base bifunctional catalytic systems has been demonstrated to yield fructose‐to‐HMF conversion yields as high as 98.6%, while for glucose substrates, conversion yields can reach 93%. Notably, these catalytic systems can achieve a notable conversion efficiency of 53% when confronted with cellulose substrates characterized by intricate three‐dimensional network structures and pronounced crystallinity. This observation serves to underscore the efficacy of acid‐base bifunctional catalytic strategies. Furthermore, the article addresses the current limitations of catalysts and future development directions, including the development of new catalysts and the optimization of reaction conditions. By summarizing existing research findings, this article aims to provide guidance for the application of acid‐base bifunctional catalysts in the field of biomass conversion, facilitating their transition to industrial applications.

Biocatalytic Synthesis of N-trans-feruloyltyramine Using an Amide Bond Synthetase with an ATP Recycling.

N-trans-feruloyltyramine (FLA) is one kind of phenylpropanoid compound found in various plants. Numerous studies have confirmed that it exhibits a wide range of physiological functions, such as antioxidant, ɑ-glucosidase inhibition, and anti-inflammatory activity. However, the low content of FLA in plants greatly limits its potential use in food and pharmaceutical industries. It is, therefore, very important to establish an effective synthesis of FLA. In this study, a green and efficient method to synthesize FLA was sought using an amide bond synthetase (ABS) biocatalyst. Ten kinds of ABS enzymes, including AlCfaL from Azospirillum lipoferum, were screened as the potential biocatalysts for the production of FLA. To obtain optimum reaction conditions, the effects of various parameters on conversion of FLA were firstly evaluated. Under the optimum conditions using 1mM N-trans-ferulic acid, 50mM tyramine (substrate ratio of 1:50), 10mM MgCl₂, 8mM ATP, and 35µM AlCfaL enzyme at 30°C with a shaking speed of 500 r/min for 48h, maximum conversion rate of 74% was reached. Given that the amidation reaction is mediated by relative expensive ATP, we further optimized reaction systems to incorporate an ATP recycling system consisting of a polyphosphate kinase enzyme (CHU) and an inexpensive polyphosphate (PolyP) as the phosphate donor. Response surface methodology (RSM) based on five-level, five-variable central composite design (CCD) was used to evaluate the optimal parameters for the production of FLA. The effects of AMP, PolyP, AlCfaL, CHU concentrations, and reaction time on the conversion rate of FLA were analyzed. The optimum conditions derived via RSM were 7.12mM AMP, 5.96mg/mL PolyP, 39.72μM AlCfaL, 27.68μM CHU, and a reaction time of 36h. Validation experiments conducted under these optimized conditions yielded an actual conversion rate of 63.5%, which compared well to the maximum predicted value of 64.2%.

Development of Selective Reactions in the Synthesis of Medicines

This review summarizes the contributions to the discovery, evaluation, and functional development of microbial and enzyme catalysts, as well as the rational design of pathways that synergistically integrate chemical and biochemical reactions. In the introduction, the author outlines his strategies and principles: 1) He avoided biosynthetic enzymes and pathways, opting instead for degradative enzymes that offer broader substrate flexibility and a wider range of applications. 2) He focused on commercially available enzymes, prioritizing their reproducibility and accessibility for widespread use. All the microorganisms he identified have been deposited in public institutions, making them available to researchers in both academic and corporate settings. 3) He developed methods to enhance reactivity and selectivity by optimizing reaction conditions and substrate structures, without altering the enzymes themselves. The main body of the review is divided into two parts. Part 1, titled "Chemo-enzymatic Synergistic Synthesis of Medicines," covers the following topics: 1) the synthesis of dihydroxymethylepoxyquinomicin (DHMEQ); 2) the synthesis of sialic acids; 3) the utilization of epoxide hydrolase; and 4) the synthesis of (S)-azetidine-2-carboxylic acid. Part 2, titled "New Selective Reactions for Synthesis of Medicines," includes: 1) the optimization of reaction conditions in lipase-catalyzed transesterification and aminolysis; 2) the conversion of racemates into single enantiomers using hydrolytic enzymes through novel pathways; 3) the use of carbonyl reductases in conjunction with substrate design; 4) nitrile hydratase and amidase in Rhodococcus species; 5) selective acylation and deacylation of alcohols and phenols; and 6) the use of oligosaccharides as protective groups in the synthesis of polyphenol glycosides.

Iodine-Catalyzed Room-Temperature Aerobic Oxidation of C(sp3)-H Bonds and Its Application in the Synthesis of Quinoxaline Derivatives.

An iodine-catalyzed aerobic oxidation reaction of C(sp3)-H bonds was established at room temperature. In this transformation, iodine acts as a Lewis acid catalyst, and the pyridine moiety in the substrate plays a crucial role. Under the optimum reaction conditions, picolyl ketone substrates were smoothly transformed into the corresponding 1,2-dicarbonyl compounds, and the subsequent introduction of 1,2-diaminobenzenes into the reaction mixture led to the formation of various quinoxaline derivatives. This synthetic process does not use transition metals and also features mild reaction conditions, operational simplicity, and gram-scale synthesis.

Identification of a sucrose phosphorylase variant from Streptococcus mutans for production of epigallocatechin gallate glucosides.

Identification of a sucrose phosphorylase variant from Streptococcus mutans for production of epigallocatechin gallate glucosides.

Screening and characterization of thermostable xylose isomerase from Rhodothermus marinus for erythrose production from one-carbon source.

Screening and characterization of thermostable xylose isomerase from Rhodothermus marinus for erythrose production from one-carbon source.

Engineered L-phenylserine aldolase enhances L-norvaline synthesis within an enzyme cascade.

Engineered L-phenylserine aldolase enhances L-norvaline synthesis within an enzyme cascade.

Integrated one-pot green fractionation of Madhuca indica seed: Green fractionation of lignocellulosic macromolecules into value-added products.

Integrated one-pot green fractionation of Madhuca indica seed: Green fractionation of lignocellulosic macromolecules into value-added products.

Module architecture analysis and application of glycoside hydrolase family 148 thermostable β-1,3-1,4-glucanase.

Module architecture analysis and application of glycoside hydrolase family 148 thermostable β-1,3-1,4-glucanase.

A novel GH11 β-1,4-xylanase from Fusarium verticillioides: Its eukaryotic expression, biochemical characterization and synergistic effect with cellulase on lignocellulosic biomass degradation.

A novel GH11 β-1,4-xylanase from Fusarium verticillioides: Its eukaryotic expression, biochemical characterization and synergistic effect with cellulase on lignocellulosic biomass degradation.

Biodegradable sodium alginate-based nanohybrid: Tuning reaction conditions for maximum efficiency in wastewater treatment.

Biodegradable sodium alginate-based nanohybrid: Tuning reaction conditions for maximum efficiency in wastewater treatment.

Biochemical characterization and biocatalytic application of a hyperthermostable tagatose 4-epimerase from Infirmifilum uzonense.

Biochemical characterization and biocatalytic application of a hyperthermostable tagatose 4-epimerase from Infirmifilum uzonense.

Dual DNAzyme amplification-based colorimetric sensing assay for the identification and quantification of tumor-associated miRNAs.

Dual DNAzyme amplification-based colorimetric sensing assay for the identification and quantification of tumor-associated miRNAs.

Preparation of Temperature‐Sensitive Heteropolyacid Catalysts for Efficient Hydrolysis of Polyethylene Terephthalate: Reaction Kinetics Analysis

AbstractThis paper focuses on the green recycling technology of Polyethylene Terephthalate (PET), which, as the most widely consumed textile fiber globally, has become a key area in textile waste recycling research. While traditional acid‐catalyzed methods have demonstrated value in PET depolymerization, the harsh acidic reaction conditions pose significant technical challenges, including catalyst deactivation and severe equipment corrosion. Based on the principles of green chemistry and engineering, this study innovatively develops a temperature‐sensitive heteropolyacid catalyst, (HOCH2CH2N(CH3)3)xH3‐xPW12O40 (ChxH3‐xPW12O40, x = 1, 2, 3), synthesized by ion exchange between choline chloride and phosphotungstic acid. Under optimized reaction conditions (200 °C, 7 h, solid–liquid ratio of 1:10, 0.2 g catalyst), the catalyst achieves a 99% PET conversion rate and a 96% recovery rate of terephthalic acid (rTPA), with product purity reaching 99.7%. Kinetic studies based on first‐order reaction mechanisms reveal an apparent activation energy of Ea = 86.72 kJ/mol for the PET hydrolysis reaction. Notably, through temperature regulation and crystallization techniques, the used ChxH3‐xPW12O40 catalyst can be easily recovered from the product, maintaining its catalytic activity after six consecutive cycles. This innovative system, which combines high catalytic efficiency with excellent recyclability, significantly reduces energy consumption and minimizes acidic waste emissions compared to traditional methods, providing a breakthrough solution for the development of a closed‐loop recycling system for PET.

Zinc Catalyzed Selective C‐N Cross‐Coupling Reaction with Diverse Aryl and Heteroaryl Amines

AbstractIn this study, we describe an efficient synthesis of s‐triazine derivatives using Zn(OTf)2 catalyst under mild conditions. The optimal reaction conditions, catalyst, and solvent system were identified to afford a number of biologically potent compounds with excellent efficiency. This method demonstrates broad compatibility with both heteroaryl amines and arylamine substrates, effectively accommodating electron‐donating, electron‐withdrawing, and sterically hindered groups. The protocol offers excellent yields, a broad substrate scope, and compatibility with large‐scale synthesis, making it highly applicable and attractive.