Reaction Yield Research Articles

COELENTERAZINE-DEPENDENT LUCIFERASES: PROPERTIES AND APPLICATION

The review presents data on the structure of bioluminescent systems of marine animals that use coelenterazine-dependent luciferases as light-emitting proteins. It has been shown that due to the availability, stability and high quantum yield of reactions, these luciferases, as well as their genetic variants with new useful properties, are successfully applied as reporter molecules in a variety of analytical systems in vitro and in vivo. Their use provides high sensitivity, simple design and fast analysis.

Phosphomolybdic acid supported on magnetic poly calix[4]resorcinarene-EDTA-chitosan network as a recyclable catalyst for the synthesis of 5-aroyl-NH-1,3-oxazolidine-2-ones

In this work, a novel procedure for immobilization of phosphomolybdic acid (PMA) on Magnetic polycalix[4]resorcinarene grafted to chitosan by EDTA (calix-EDTA-Cs) was reported. The heterogeneous nanocomposite (CoFe2O4@calix-EDTA-Cs@PMA) was applied an acid nanocatalyst for the synthesis of 5-aroyl-NH-1,3-oxazolidine-2-ones through the reaction of α-epoxyketones with sodium cyanate (NaOCN) in polyethylene glycol (PEG) as a green solvent under ultrasonic irradiation conditions. Some features of this work include quick reaction time, high reaction yield, easy separation of the catalyst, thermal stability, and eco-friendly.

Porous g-C3N4-based nanoarchitectures by playing with sustainable precursors: Role of urea/melamine ratio on the structure/properties relationship

In this study, porous g-C3N4 based nanoarchitectures were obtained by a facile and effective in-situ synthesis method, that entailed the thermal treatment of different melamine (M) and urea (U) precursor mass ratios (in particular M/U = 50:50, 20:80), which were then compared with g-C3N4 obtained from pure M and U. The role of the melamine/urea mass ratio on morphology, structure, surface area, porosity, optical and vibrational properties of the g-C3N4 -based materials, was analysed in detail by means of many characterization techniques, including FESEM, AFM , XRD, HRTEM, Raman, FTIR, UV and PL spectroscopies, BET and TGA analyses. It will be shown that samples obtained from different M and U precursor mass ratios combine the advantage of high thermal stability and significant reaction yields, which are due to melamine action, and greatly improved surface area and short migration paths, which are due to urea effect, thus providing the suitable conditions for charge transfer within the interfaces. The results may shed light on effective improvements in the structure/properties of g-C3N4 based nanoarchitectures, aiming at peculiar functional materials.

Mechanochemical and Microwave Multistep Organic Reactions

Abstract: The development of more sustainable chemical reactions and processes has been the focus of recent research activities. Advances in the field of organic synthesis have led to the emergence of new methodologies and techniques involving non-conventional energy sources. These include the applications of mechanical energy (mechanochemistry) and microwave radiation (MW) methods. This article reviews the advances in multistep organic synthesis of biologically relevant organic molecules using mechanochemistry and microwave techniques. Among them, various heterocyclic molecules (with nitrogen, oxygen, and sulphur atoms), amides, and peptides have been synthesized by multistep mechanochemical or MW reactions. Performing multiple synthetic steps using more sustainable methods shows cumulative advantages over multistep processes under conventional conditions in terms of reduced solvent use, shorter reaction times, better turnovers, and reaction yields. Simplification of protocols by carrying out two or more reaction steps in the same reaction vessel is another advantage of multistep syntheses.

Eco-synthesis route: Developing bis-hydrazono[1,2,4]-thiadiazoles via a green synthetic approach with calcium oxide-chitosan nanocomposite

Modern environmental organic chemistry is focused on developing cost-efficient, versatile, environmentally acceptable catalytic chemicals that are also highly effective. Herein, hybrid calcium-chitosan nanocomposite films was prepared by doping calcium oxide molecules into a chitosan matrix at weight percentage (15, 20, and 25 % wt. chitosan‑calcium) using an easy and affordable simple co-precipitation process. The CS–CaO nanocomposite's structure was elucidated using analytical techniques such as Fourier transform infrared (FTIR), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). Based on the X ray diffraction (XRD) measurements, the crystallinity was reduced by the incorporation of the CaO molecules. Also, from the calculation of the Debye-Scherrer equation on this X-ray diffraction (XRD) pattern, the crystallite size was found to be 17.2 nm for the nanocomposite film with 20 % wt. The energy dispersive spectroscopy graph demonstrated the presence of the distinctive Ca element signals within the chitosan, with the amount in a sample of 20 % wt. being discovered to be 21.32 % wt. For the synthesis of bis-hydrazono[1,2,4]thiadiazoles, the obtained CS–CaO nanocomposite could be employed as a potent heterogeneous recyclable catalyst. Better reaction yields, quicker reactions, softer reaction conditions, and green reusable efficient biocatalysts for several uses are just a few advantages of this approach.

Modeling and numerical analysis for cylindrical flow-through catalytic membrane reactor with power-law reaction kinetics: Revealing dead-core phenomena

Cylindrical flow-through catalytic membrane reactors, employing porous membranes impregnated with catalysts, offer enhanced selectivity and yield in chemical reactions. This work focuses on the mathematical modeling and numerical analysis of a cylindrical flow-through catalytic membrane reactor. The proposed reactor model addresses a critical gap in research by incorporating realistic geometries of porous catalytic membranes. This model simulates a series of irreversible reactions following power-law kinetics under non-isothermal conditions within the reactor, formulated using a system of non-linear differential equations to account for mass and heat balances.The paper investigates the occurrence of dead zones within the membrane reactor as a result of rapid reactant depletion, a phenomenon that has not been extensively studied in prior literature for cylindrical membrane reactors. Problems with fractional reaction exponents require efficient numerical solvers since conventional iterative solvers encounter difficulties due to the fact that the power-law reaction term with fractional reaction exponent is not differentiable at the vanishing concentration. A novel time-marching scheme specifically designed for the cylindrical catalytic flow-through membrane reactor is developed and applied for simulations to get valuable insights into dead-core phenomena.The effects of dimensionless process parameters, including Thiele modulus, Peclet numbers, reaction exponent, Prater number, and a membrane geometrical parameter on the concentration and temperature profiles, as well as dead zone formation, are extensively investigated. The simulation results demonstrate that these parameters affect the occurrence of dead zones and their size. Finally, the effect of convective flow on the reactor performance indicators is presented.

Triazole-based COF tightly hugging ionic liquids through interactions of hydrogen bonds for enhanced atmospheric CO2 conversion

In the conversion of CO2 into green chemicals, efficient catalysts are urgently needed. Composite catalysts with ionic liquids (ILs) fixed to covalent organic frames (COFs) are considered as ideal materials. However, synthesizing composite materials by modifying ionic liquids on covalent organic frameworks encountered challenges related to the modification process and the easy detachment of functional groups. In this paper, a variety of multifunctional components were combined into composites to tailor catalysts ([TMGVBr]x@COFs) for cycloaddition reaction under mild atmospheric CO2 condition. In the strategy of in-situ encapsulation, triazole-based COF (TT-COF) tightly “hugged” the ionic liquids ([TMGH+][-O2MVIm+][Br-]) through the inductions of hydrogen bonds, resulting in excellent stability. Moreover, owing to the synergy between [TMGH+][-O2MVIm+][Br-] and TT-COF, [TMGVBr]10@COF achieved a good catalytic activity with 96.3 % yield in the cycloaddition reactions under atmospheric CO2, 100 °C and 10 h. Furthermore, the strong hydrogen bonds between ionic liquids and the framework of TT-COF ensured the [TMGVBr]10@COF catalyst’s good catalytic stability. There, a new idea was proposed for the efficient conversion atmospheric CO2 using designed heterogeneous catalysts.

On the optimality of the radical-pair quantum compass

Quantum sensing enables the ultimate precision attainable in parameter estimation. Circumstantial evidence suggests that certain organisms, most notably migratory songbirds, also harness quantum-enhanced magnetic field sensing via a radical-pair-based chemical compass for the precise detection of the weak geomagnetic field. However, what underpins the acuity of such a compass operating in a noisy biological setting, at physiological temperatures, remains an open question. Here, we address the fundamental limits of inferring geomagnetic field directions from radical-pair spin dynamics. Specifically, we compare the compass precision, as derived from the directional dependence of the radical-pair recombination yield, to the ultimate precision potentially realisable by a quantum measurement on the spin system under steady-state conditions. To this end, we probe the quantum Fisher information and associated Cramér–Rao bound in spin models of realistic complexity, accounting for complex inter-radical interactions, a multitude of hyperfine couplings, and asymmetric recombination kinetics, as characteristic for the magnetosensory protein cryptochrome. We compare several models implicated in cryptochrome magnetoreception and unveil their optimality through the precision of measurements ostensibly accessible to nature. Overall, the comparison provides insight into processes honed by nature to realise optimality whilst constrained to operating with mere reaction yields. Generally, the inference of compass orientation from recombination yields approaches optimality in the limits of complexity, yet levels off short of the theoretical optimal precision bounds by up to one or two orders of magnitude, thus underscoring the potential for improving on design principles inherent to natural systems.

Ultrasonic reactor set-ups and applications: A review

Sonochemistry contributes to green science as it uses less hazardous solvents and methods to carry out a reaction. In this review, different reactor designs are discussed in detail providing the necessary knowledge for implementing various processes. The main characteristics of ultrasonic batch systems are their low cost and enhanced mixing; however, they still have immense drawbacks such as their scalability. Continuous flow reactors offer enhanced production yields as the limited cognition which governs the design of these sonoreactors, renders them unusable in industry. In addition, microstructured sonoreactors show improved heat and mass transfer phenomena due to their small size but suffer though from clogging. The optimisation of various conditions of regulations, such as temperature, frequency of ultrasound, intensity of irradiation, sonication time, pressure amplitude and reactor design, it is also discussed to maximise the production rates and yields of reactions taking place in sonoreactors. The optimisation of operating parameters and the selection of the reactor system must be considered to each application’s requirements. A plethora of different applications that ultrasound waves can be implemented are in the biochemical and petrochemical engineering, the chemical synthesis of materials, the crystallisation of organic and inorganic substances, the wastewater treatment, the extraction processes and in medicine. Sonochemistry must overcome challenges that consider the scalability of processes and its embodiment into commercial applications, through extensive studies for understanding the designs and the development of computational tools to implement timesaving and efficient theoretical studies.

Photodecarboxylative Ring Annulation of α‐ and β‐Functionalized Phthaloyl‐GABA Derivatives: Bioactive Pyrroloisoindolinones with High Quantum Efficiency

AbstractThe triplet‐sensitized (by the solvent acetone) as well as the direct (λex=300–320 nm) photochemical decarboxylation of N‐phthaloylated γ‐aminobutyric acid (GABA) derivatives are versatile and high‐yielding routes to benzopyrrolizidines via intramolecular electron transfer initiated decarboxylation followed by radical coupling. The ß‐mono‐ and ß,ß'‐disubstituted N‐phthaloyl GABA derivatives 7 a–7 g, respectively, were applied as substrates. Decarboxylative photocyclization yielded hydroxy benzopyrrolizidines 8 a–8 g in high chemical yields and with moderate diastereoselectivities from the ß‐monosubstituted substrates. The analogous α‐substituted GABA derivatives 11 a–11 c were also applied as potential substrates for memory of chirality effects. The reaction quantum yields of the photodecarboxylation reactions for the parent GABA derivative 13 and for the new substrates 7 h and 11 a were determined by the quantum yield determination system (QYDS) and showed a remarkable concentration dependency indicating aggregation at higher substrate concentrations. Inhibition studies on the atherogenic human serine hydrolase cholesterol esterase showed derivatives 8 a and 8 d to exhibit a hyperbolic mode of inhibition with moderate IC50 values of about 60–80 μM.

Desulfurdioxidative N‐N Coupling of N‐Arylhydroxylamines and N‐Sulfinylanilines: Reaction Development and Mechanism

AbstractA highly efficient and chemoselective approach for the divergent assembling of unsymmetrical hydrazines through an unprecedented intermolecular desulfurdioxidative N−N coupling is developed. This metal free protocol employs readily accessible N‐arylhydroxylamines and N‐sulfinylanilines to provide highly valuable hydrazine products with good reaction yields and excellent functional group tolerance under simple conditions. Computational studies suggest that the in situ generated O‐sulfenylated arylhydroxylamine intermediate undergoes a retro‐[2π+2σ] cycloaddition via a stepwise diradical mechanism to form the N−N bond and release SO2.

Development of a functional catalytic membrane by alkalization of PVA and green synthesis of fuel additive glycerin carbonate with high oxygen content

ABSTRACT Glycerin carbonate with high oxygen content has the potential to be an oxygenated fuel additive that improves fuel properties and reduces harmful gas emissions. Glycerin carbonate was produced from the green solvent dimethyl carbonate and glycerin through a heterogeneous catalytic membrane under environmentally friendly and mild conditions. The PVA/NaOH catalytic membrane was prepared in film form from polyvinyl alcohol (PVA) polymer with good film-forming properties and sodium hydroxide, a strong base. The heterogeneous catalytic membrane obtained by adding sodium hydroxide to the polymer is environmentally friendly with easy recovery. The chemical structure and thermal resistance of the produced catalytic membranes were examined by Fourier-transform infrared spectroscopy and Thermogravimetric analysis. Reaction experiments were carried out in a batch reactor, and the influences of reaction parameters such as time, catalyst amount, DMC/glycerin initial molar ratio, and temperature on the reaction yield were investigated. The maximum glycerin carbonate yield of 93.03% was obtained after 2 h of reaction time, with a NaOH ratio of 7.5% a DMC/Glycerin molar ratio of 3/1, and a reaction temperature of 75°C. Additionally, the influences of reaction variables on glycerin carbonate yield were analyzed and the obtained yield data are supported by the Response surface method (RSM).

Sono-photocatalytic amination of quinoxalin-2(1H)-ones with aliphatic amines

The first example of sono-photocatalytic bond formation was reported. With both visible light and ultrasound wave as the energy, various 3-aminoquinoxalin-2(1H)-ones were efficiently obtained with good functional group tolerance in the absence of any additive or external photocatalyst. Compared with the conventional photocatalysis, sono-photocatalysis not only dramatically improved the reaction rates and yields, but also reduced energy consumption.

Incorporating Synthetic Accessibility in Drug Design: Predicting Reaction Yields of Suzuki Cross-Couplings by Leveraging AbbVie's 15-Year Parallel Library Data Set.

Despite the increased use of computational tools to supplement medicinal chemists' expertise and intuition in drug design, predicting synthetic yields in medicinal chemistry endeavors remains an unsolved challenge. Existing design workflows could profoundly benefit from reaction yield prediction, as precious material waste could be reduced, and a greater number of relevant compounds could be delivered to advance the design, make, test, analyze (DMTA) cycle. In this work, we detail the evaluation of AbbVie's medicinal chemistry library data set to build machine learning models for the prediction of Suzuki coupling reaction yields. The combination of density functional theory (DFT)-derived features and Morgan fingerprints was identified to perform better than one-hot encoded baseline modeling, furnishing encouraging results. Overall, we observe modest generalization to unseen reactant structures within the 15-year retrospective library data set. Additionally, we compare predictions made by the model to those made by expert medicinal chemists, finding that the model can often predict both reaction success and reaction yields with greater accuracy. Finally, we demonstrate the application of this approach to suggest structurally and electronically similar building blocks to replace those predicted or observed to be unsuccessful prior to or after synthesis, respectively. The yield prediction model was used to select similar monomers predicted to have higher yields, resulting in greater synthesis efficiency of relevant drug-like molecules.

Synthesis of Mg2FeH6 by High‐Temperature High‐Pressure Reactive Planetary Ball Milling

Herein, a new approach for the synthesis of metal hydrides using simultaneous high‐temperature and high‐pressure reactive ball milling is demonstrated by preparing ternary magnesium iron hydride. The novelty and uniqueness of this technique are based on its integration of a specially designed and manufactured milling vial, allowing synthesis at controlled elevated temperatures (room temperature [RT]–400 °C) and pressures up to 100 bar. A Mg and Fe (2:1) mixture is used as a substrate for Mg2FeH6 synthesis. The effects of temperature on the synthesis kinetics and their outcomes are examined. An increase in the temperature accelerates the kinetics of hydrogen absorption for MgH2, while Mg2FeH6 formation is observed only above 250 °C. Increasing the reaction temperature not only causes magnesium particle refinement due to the hydrogenation and formation of magnesium hydrides but also leads to the agglomeration of iron caused by plastification due to a lack of strain hardening. The maximum conversion to Mg2FeH6 is observed for the sample premilled at RT. In this work, it is revealed that additional physical variables, e.g., pressure, temperature, time, and milling speed, during mechanochemical synthesis and material properties, need to be evaluated and considered to improve the reaction kinetics and yield of the synthesis.

Sonochemical Synthesis of Copper Borates: Effect of Reaction Conditions on the Characteristic Properties

The effect of ultrasonic treatment on liquid-state production and the characteristic features of synthesized powder were studied in liquid-state conditions. In sonochemical synthesis, the operation parameters of mole ratio, reaction temperature, and time were optimized. The synthesis was achieved in moderate conditions such as mole ratio of copper: sodium: boron (Cu: Na: B) 1:2:1, 70°C and 2.5 minutes. The prepared samples were identified as copper borate (Cu(BO2)2) with the powder diffraction file number "00-001-0472". The reaction yields were also increased from 50% to 71.5% with the modification of the experimental procedure. The specific FT-IR peaks were observed at 1090, 985, 872, 781 and 731 cm-1 band values. In the morphological analyses, the agglomerations of multi-angular particles were seen. The results showed the affirmative effects of the possible use of the ultrasonic treatment on both the practical synthesis and the increase of characteristics.

Progress in Electrochemically Empowered C-O Bond Formation: Unveiling the Pathway of Efficient Green Synthesis.

(C-X) bonds (X=C, N, O) are the main backbone for making different skeleton in the organic synthetic transformations. Among all the sustainable techniques, electro-organic synthesis for C-X bond formation is the advanced tool as it offers a greener and more cost-effective approach to chemical reactions by utilizing electrons as reagents. In this review, we want to explore the recent advancements in electrochemical C-O bond formation. The electrochemically driven C-O bond formation represents an emerging and exciting area of research. In this context, electrochemical techniques offers numerous advantages, including higher yields, cost-efficient production, and simplified work-up procedures. This method enables the continuous and consistent formation of C-O bonds in molecules, significantly enhancing overall reaction yields. Furthermore, both intramolecular and intermolecular C-O bond forming reaction provided valuable products of O-containing acyclic/cyclic analogue. Hence, carbonyl (C=O), ether -O-), and ester (-COOR) functionalization in both cyclic/acyclic analogues have been prepared continuously via this innovative pathway. In this context, we want to discuss one-decade electrochemical synthetic pathways of various C-O bond contains functional group in chronological manner. This review focused on all the synthetic aspects including mechanistic path and has also mentioned overall critical finding regarding the C-O bond formation via electrochemical pathways.

Laser-assisted chemical bath deposition of TiO2 nanoparticles for UV photodetection

Extensive research has been conducted on UV photodetectors employing titanium dioxide nanoparticles (TiO2-NPs), which exhibit numerous advantageous qualities, notably encompassing fascinating switching behaviour and strong photosensitivity. An efficient TiO2 NPs synthesis process is essential for the quality and output of photodetectors. A quick synthesis process can lead to less energy and cost consumption, sustainable production processes, increased reaction rate, and improved homogeneity of the reaction resulting high quality films with low impurities. In this study, we exhibited a simple and quick laser-assisted chemical bath deposition (LACBD) method to synthesize high crystalline TiO2 nanoparticles for UV detection. The TiO2-NPs were synthesized by irradiating the tiny area between aluminium (Al) electrodes submerged in TiO2 precursor (in situ chemical bath) with a blue laser of wavelength (460 nm), power (1 W), and deposition duration (25 minutes). UV photodetector built from TiO2-NPs with (Al/TiO2-NPs/Al)/Glass architecture was examined, and our findings proved that TiO2 synthesized by LACBD has potential UV sensing and detecting properties. TiO2-NPs were examined by FESEM, EDX, and XRD. Measurements of current-voltage, I-V and current-time, I-T were employed to analyze the (Al/TiO2-NPs/Al)/Glass UV photodetector performance. Based on the results, it proved that the synthesis method of TiO2-NPs by LACBD is a promising and viable route, resulting in satisfactory reaction yield and low contamination. The responsivity, specific detectivity, and external quantum efficiency could reach as high as 1.36e-1 A/W, 2.87e+7 Jones and 46.1 % respectively at −5 V bias voltage.

Development and characterization of poly(lactic-co-glycolic acid) (PLGA) nanoparticles with finasteride and in vivo evaluation of their efficacy in hair growth

Introduction: Alopecia is a condition that affects the hair follicle. Currently, a wide variety of treatments are available, including topical, oral and injectable formulations. Oral therapies are the most adhered to; however, they generally present more adverse effects. As a well-established oral drug therapy, finasteride is presented, which inhibits the enzyme 5-α-reductase, and blocks the conversion of testosterone into dihydrotestosterone. This drug is capable of promoting hair growth, however can lead to adverse effects. Therefore, in this study, poly(lactic-co-glycolic acid) nanoparticles with finasteride were developed, aiming to improve the efficiency of this drug and reduce its systemic side effects. Methodology: Nanoparticles without the drug and with the drug at 10, 20 and 30mg were developed. The system was characterized by Dynamic Light Scattering, Zeta Potential, Differential Scanning Calorimetry and Fourier Transform Infrared Spectroscopy. Results and Conclusion: The drug-free nanoparticles had a reaction yield of 91.8%, nanoparticles with 10mg of finasteride showed a yield of 82.6%, with 20mg a yield of 92.9%, and with 30mg a yield of 89.3%. The average diameter ranged from 162.2nm for drug-free nanoparticles, 176.1nm for nanoparticles with 10mg of finasteride, 179.6nm for nanoparticles with 20mg, and 187.7nm for nanoparticles with 30mg. Nanoparticles with 10mg of finasteride showed an encapsulation efficiency of 48.2%, nanoparticles with 20mg an efficiency of 90.7%, and nanoparticles with 30mg an efficiency of 83.2%. The development of nanoparticles and the encapsulation of finasteride were successful. Next, an in vivo study will be conducted to evaluate its efficacy in promoting hair growth orally.

Pd-Catalyzed Miyaura Borylation and Telescopic Borylation/Suzuki-Miyaura Cross-Coupling Processes in Deep-Eutectic Solvents.

We report an efficient procedure to carry out palladium-catalyzed Miyaura borylation reactions of (hetero)aromatic halides and triflates in choline chloride (ChCl)-based deep eutectic solvents (DESs). The procedure employs bis(pinacolato)diboron as a boron source and a catalyst prepared in situ from readily available Pd2(dba)3 and the phosphine ligand XPhos. Reactions proceed well in different ChCl-based DESs, among which the best results were provided by environmentally friendly and biodegradable mixtures with glycerol and glucose. The reaction tolerates both EDG and EWG substituents on the substrates and can be run on different halides (chloride, bromide, iodide) and pseudohalides (triflate). Furthermore, for several substrates, the catalyst loading can be reduced to 1 mol % Pd (0.5% mol Pd2(dba)3) without compromising the reaction yield. Moreover, we show that the Miyaura borylation protocol in DES can be combined with a subsequent Suzuki-Miyaura cross-coupling reaction in a one-pot procedure, allowing access to various biaryl products and demonstrating its synthetic utility by preparing the precursors of two compounds with reported applications in the photovoltaics sector. Finally, two green metrics (E-factor and EcoScale) of the new one-pot procedure in DES were calculated and compared with literature values to assess the potential advantages in terms of waste reduction, safety, and energy consumption.