Friendly Protocol Research Articles

Mechanochemical Synthesis ofβ-Sulfenylated Ketones and Esters.

For the first time, ball milling has been employed in the solvent-free synthesis of sulfur-functionalized materials from thiols and α,β-unsaturated ketones and esters, using potassium carbonate as a transition metal-free catalyst. This environmentally friendly protocol makes use of easily accessible reagents to prepare β-sulfenylated carbonyl compounds with yields exceeding 91% under ambient air and solvent-free conditions. Additionally, this innovative synthetic strategy enables the modification of chalcones, compounds with significant medicinal and synthetic potential. The reactions are efficient and easily scalable to gram quantities, offering substantial benefits for practical applications.

Synthesis of Quinolines Catalyzed by Bidentate Terpyridine Mn(I) Complex

ABSTRACTA method for efficient synthesis of quinolines via acceptorless dehydrogenative condensation is presented. A series of quinolines are obtained by the coupling reaction of 2‐aminobenzyl alcohols with secondary alcohols in the presence of bidentate terpyridine Mn(I) complex in good to excellent yields. Pleasantly, various substituted secondary alcohols and substituted aminobenzyl alcohols all provide quinolines with good functional group tolerance. Importantly, this investigation also provides a green and environmentally friendly protocol for constructing heterocyclic compounds.

Wittig Reaction in Deep Eutectic Solvents: Expanding the DES Toolbox in Synthesis.

Wittig reaction between substituted phosphonium salts and (hetero)aromatic and alkyl carbonyl compounds in Deep Eutectic Solvents has been developed under a scalable and friendly protocol. Highly efficient reactions were successfully run with a wide range of bases including organic (DBU, LiTMP, t-BuOK) and inorganic (NaOH, K2CO3) ones in ChCl/Gly 1 : 2 (mol/mol) as solvent under mild conditions, at room temperature and under air. The proposed protocol was applied to a wide range of substrates, including (hetero)aromatic aldehydes with substituents as halogens (I, Br, Cl), EDG (alkoxy, methyl), EWG (NO2, CF3) or reactive groups as CN, esters, and ketones. Vinylic, alkynyl and cycloalkyl, alicyclic and α,β-unsaturated aldehydes can also be used. Highly electrophilic ketones gave good yields. The diastereoselectivity of the reaction is in complete agreement with the E/Z ratio predictable under traditional conditions. We demonstrated that the protocol is scalable to 2 g (5 mmol) of phosphonium salt, furthermore the proposed workup protocol allows to remove TPPO without need of additional chromatographic purification.

Synthesis and crystal structural analysis of bismuth phosphovanadate compounds: An eco-friendly and recyclable catalyst for green synthesis of imidazole derivatives

In this investigation, our primary objective is to synthesize and characterize a bismuth phosphovanadate compound Bi13V0.8-xBa0.1PxO21.55 isotype to γ-Bi2O3 of sillenite type and space group is I23. This compound serves as a catalyst for the environmentally friendly synthesis of imidazole derivatives. These derivatives are produced via the reaction of benzil, ammonium acetate, and aromatic aldehydes, yielding satisfactory yields ranging from 87 % to 96 %. The composite catalyst underwent thorough characterization using a variety of analytical techniques, including Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction analysis (XRD). The investigations revealed the excellent performance of this catalyst system. The findings revealed that this catalyst system exhibited excellent performance, offering advantages such as quick reaction time, high product yields, and a simple workup procedure. Moreover, the catalyst demonstrated high stability and could be recovered for at least five repeated runs, providing cost-effective benefits and aligning with principles of green chemistry. This method has the potential to serve as an environmentally friendly protocol for synthesizing other heterocyclic compounds.

Design and development of a novel Co‐MOF catalyst for sustainable pyrimidine synthesis via the Biginelli reaction

In this study, we introduce a novel porous metal–organic framework named Co2(bbda)2(DMF)2·5H2O, or MOF‐UoR‐1, synthesized via hydrothermal techniques employing a unique Schiff base ligand. The framework underwent comprehensive characterization, confirming its microporous nature through gas‐sorption measurements. MOF‐UoR‐1 demonstrated remarkable efficacy as a catalyst for the one‐step synthesis of pyrimidine analogs. Structural validation of the synthesized pyrimidines was accomplished via 1H‐nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) analyses. Through systematic experimentation, the optimal catalyst dosage (40 mg) was determined, showcasing its effectiveness across various aldehydes, 1,3‐carbonyl compounds, and urea substrates. Noteworthy is the broad applicability of this environmentally friendly protocol, which offers advantages such as high yields (96%), rapid reaction times (90 min), straightforward product isolation, and product purity without necessitating column chromatography. Furthermore, the catalytic integrity of the framework remained intact, enabling its reuse without compromising performance. This research presents a promising approach for the synthesis of pyrimidine derivatives, with significant implications for sustainable and efficient chemical synthesis methodologies.

Synthesis and biological evaluation of 2-(2-hydrazinyl) thiazole derivatives with potential antibacterial and antioxidant activity

Heterocyclic systems containing 2-(2-hydrazinyl) thiazole moieties were synthesized by heterocyclization of thiosemicarbazones with arylglyoxals and Meldrum's acid in ethanol and water 1:1 (v/v) under reflux conditions. The paper reports an efficient, facile, and environmentally friendly protocol via a novel one-pot three-component reaction to access a broad range of 2-(2-Hydrazinyl) thiazole derivatives. Products were isolated by plate chromatography and their structures were established from their spectroscopic data, then the antibacterial and antioxidant activity of synthesized 2-(2-hydrazinyl) thiazole derivatives were evaluated, and demonstrated encouraging antibacterial activity against Staphylococcus aureus as a gram positive bacteria and Escherichia coli as a gram negative bacteria. Furthermore, when representative products were assessed for radical scavenging activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH0), high antioxidant effects were observed, indicating their potential safety for use in pharmacological studies.

Systematic Engineering of Escherichia coli for Efficient Production of Pseudouridine from Glucose and Uracil.

In this study, we proposed a biological approach to efficiently produce pseudouridine (Ψ) from glucose and uracil in vivo using engineered Escherichia coli. By screening host strains and core enzymes, E. coli MG1655 overexpressing Ψ monophosphate (ΨMP) glycosidase and ΨMP phosphatase was obtained, which displayed the highest Ψ concentration. Then, optimization of the RBS sequences, enhancement of ribose 5-phosphate supply in the cells, and overexpression of the membrane transport protein UraA were investigated. Finally, fed-batch fermentation of Ψ in a 5 L fermentor can reach 27.5 g/L with a yield of 89.2 mol % toward uracil and 25.6 mol % toward glucose within 48 h, both of which are the highest to date. In addition, the Ψ product with a high purity of 99.8% can be purified from the fermentation broth after crystallization. This work provides an efficient and environmentally friendly protocol for allowing for the possibility of Ψ bioproduction on an industrial scale.

Green synthesis of cerium oxide nanoparticles using Portulaca oleracea Extract: Photocatalytic activities

This paper presents a novel method for synthesizing cerium oxide nanoparticles (CeO2 NPs) using Portulaca oleracea extract, focusing on their structural, optical, and photocatalytic properties. CeO2 NPs were prepared through a simple, cost-effective, and environmentally friendly protocol, utilizing the reducing and stabilizing properties of Portulaca oleracea. Structural analysis revealed the formation of cubic CeO2 with an average crystallite size of 16 nm. Optical studies using FTIR and Raman spectroscopy confirmed the characteristic absorption bands of Ce-O and O-Ce-O bonds, while HR-TEM imaging showcased quasi-spherical nanoparticles with sizes ranging from 4 nm to 14 nm. The synthesized CeO2 NPs exhibited significant photocatalytic activity towards the degradation of methylene blue (MB) and methyl orange (MO) under visible light irradiation. The degradation efficiencies achieved were 98 % for MB and 95 % for MO. Kinetic analysis indicated pseudo-first-order degradation kinetics, with observed rate constants of 0.018 min−1 for MO and 0.014 min−1 for MB. Furthermore, CeO2 NPs demonstrated stable and reusable photocatalytic performance over five cycles, highlighting their potential for practical applications in wastewater treatment. Overall, this study presents a promising eco-friendly approach for synthesizing CeO2 NPs with enhanced photocatalytic properties, contributing to the advancement of green nanotechnology for environmental remediation.

Room temperature C-O bond cleavage of vinyl cyclic synthons via a metallaphotoredox approach.

Herein, we report visible-light induced C-O bond cleavage of vinyl-appended cyclic synthons via a Co(II)-photoredox dual catalytic approach operating at room temperature. This methodology exhibits a broad scope and is capable of accessing linear as well as branched allyl arenes simply by tuning the ring size of the cyclic motifs, in a mild and environmentally friendly protocol. Mechanistic studies unveil an interesting aspect of the reaction pathway involving a challenging homolytic cleavage of the Co(III)-O bond, 1,5-HAT of an unstable Co(II)-organometallic intermediate, and the key roles of O2 and the photocatalyst. The successful removal of the directing group further adds an important dimension to the methodology.

Microwave-assisted UV digestion of starch and skimmed milk powder: Environmentally friendly protocol for essential and toxic elements determination

The present work evaluated a microwave-assisted wet digestion method using diluted HNO3 with in situ UV radiation for the digestion of starch and skimmed milk powder for further metals determination by spectrometric plasma-based techniques. The sample digestion was conducted using an in situ UV lamp (electrodeless discharge lamp), and the digestion efficiency was improved by employing O2 (20 bar) and 2 mL 30 % H2O2 as auxiliary reagents. The accuracy of the proposed digestion method was evaluated by metals determination (Ca, Cd, Cu, Fe, K, Mg, Mo, Mn, Na, Pb, and Zn) in certificated reference material, which agreed with certified values (Student t-test <0,05). With the use of a UV lamp an environmentally friendly protocol was developed for starch and skimmed milk powder digestion using 0.1 mol L−1 HNO3 with auxiliary reagents (H2O2 or O2). The RCC value ranged from 0.9 to 1.2 % (starch and skimmed milk powder, respectively). The simultaneous cooling approach further improved the digestion efficiency (RCC <0,3 % for both samples), allowing to use milder digestion conditions, or even just water, being environmentally friendly, reducing the waste generation and reagents consumption, allowing food quality control through a greener approach.

Verification of continuous-variable quantum memories

A proper quantum memory is argued to consist in a quantum channel which cannot be simulated with a measurement followed by classical information storage and a final state preparation, i.e. with an entanglement breaking (EB) channel. The verification of quantum memories (non-EB channels) is a task in which an honest user wants to test the quantum memory of an untrusted, remote provider. This task is inherently suited for the class of protocols with trusted quantum inputs, sometimes called measurement-device-independent (MDI) protocols. Here, we study the MDI certification of non-EB channels in continuous variable (CV) systems. We provide a simple witness based on adversarial metrology, and describe an experimentally friendly protocol that can be used to verify all non Gaussian incompatibility breaking quantum memories. Our results can be tested with current technology and can be applied to test other devices resulting in non-EB channels, such as CV quantum transducers and transmission lines.

Fe3O4@SiO2@APTES@MPIB-Mn(II) as an eco-friendly and magnetically recyclable nano catalyst for the green synthesis of various xanthene derivatives

Due to the importance of the magnetic heterogeneous catalysts in the recent advances, especially organic synthesis, in this work, we introduced the new functionalised manganese magnetic nanoparticles as Fe3O4@SiO2@APTES@MPIB-Mn(II). The new magnetic material was studied by analyses, including Fourier-transform infrared spectroscopy (FT-IR), Field emission scanning electron microscope (FE-SEM), energy-dispersive X-ray (EDX), and vibrating sample magnetometer (VSM). The synthesized catalyst was used as a recyclable catalyst in the one-pot multi-component reactions (MCRs) for the preparation of xanthene derivatives (1,8-dioxo-octahydroxanthene, 14-substituted-14H-dibenzo[a,j]xanthene, 12-aryl-tetrahydrobenzo[a]xanthenes-11-one derivatives) under solvent-free conditions at 100 ℃. The studies revealed that this catalyst system exhibited excellent performance. The outstanding advantages in the present work include quick reaction time, high yields of products, and simple workup procedure. Also, no need to use any solvent, escape of the extra steps for separation of product from the catalyst, environmentally benign, high stability, and recovery of the catalyst for at least six repeated runs which provide reasonably-priced rewards are the other advantages of this protocol in the direction of green chemistry. This method can be an environmentally friendly protocol for other heterocyclic syntheses.

Development and validation of an accurate, precise and safe method for the acceptance testing of recovered asphalt binder

With the ever-increasing use of recycled asphalt pavement (RAP) in road construction, extraction and recovery of binders from mixtures as placed becomes a critical aspect of quality assurance testing. However, current extraction and recovery methods are associated with shortcomings, as they are often time consuming, costly, inaccurate and involve toxic solvents. The objective of this study was to develop a practical and more environmentally friendly protocol for the accurate and precise acceptance testing of recovered binder. The process uses a low toxicity solvent for extraction, followed by simple filtration, evaporation and thin film oven aging. Residual solvent is removed from the binder during initial thin film oven aging and fines are found to have an insignificant effect on the rheological properties of importance. Results of this study provide guidance for further optimization of a simplified extraction, recovery, and aging protocol for the acceptance testing of asphalt binder and mixture.

Standardized protocol for reproductive phenology monitoring of fucalean algae of the genus Cystoseira s.l. with potential for restoration

Active marine restoration is strongly encouraged to prevent the loss of the valuable habitats formed by Cystoseira sensu lato species, since they enhance biodiversity and preserve ecosystem functions and services. Current restoration interventions are mainly based on recruitment enhancement methods by deploying bags with fertile receptacles in situ or by outplanting juveniles grown ex situ under laboratory conditions. These methods allow the recovery of endangered species avoiding the depletion of the donor populations. In all cases, a priori knowledge of the reproductive phenology and recruitment periods of the species to be restored is essential, since the success of restoration techniques relies on collecting fertile branches and the obtention and survival of recruits. For their collection, identified donor populations characterized by dense Cystoseira s.l. cover should be studied. Specifically, monitoring the reproductive phenology of populations is crucial to detect the period of the year in which they develop mature reproductive structures and to understand how it might be linked to environmental conditions. Then, these general patterns on the reproductive phenology of Cystoseira s.l. species are essential to determine the most suitable time and conditions to plan for the most effective restoration action. Here, we provide a cost-effective and friendly protocol that can be easily and widely implemented for all Cystoseira s.l. species. We pose that this protocol provides a standardized and useful methodology to understand the environmental factors driving the optimal periods for sampling fertile branches across the Mediterranean Sea, and thus it can be an essential tool to plan future restoration actions.

Novel biogenic preparation of gold nanoparticles decorated on sepiolite clay and evaluation of anti-cancer effect on gastric cancer cell and electrochemical sensing of nitrite

An environmentally friendly strategy was used in this study to synthesize gold nanoparticles decorated on sepiolite clay (GNPs-SC) using Heracleum persicum grass extract. The physicochemical characters of the prepared composite were characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray diffraction (XRD). A GNPs-SC modified carbon pate electrode (CPE) was used to study the electrochemical oxidation of nitrite. The proposed nitrite sensor exhibits excellent performance, including a broad linear range (1.0–150 μM), a low limit of detection (0.4 μM), and acceptable reproducibility (RSD = 2.6%). As well, the prepared GNPs-SC was tested for its effectiveness against human gastric adenocarcinoma (AGS) cell line. The MTT assay protocol revealed that the bio-synthesized product displayed significant cytotoxic activity against gastric cancer in human subjects. The findings of this study indicate that GNPs-SC, synthesized using environmentally friendly protocol, exhibit great potential for use in electrochemical sensing and treatment of human cancer.

Fe3O4@SiO2@(CH2)3N+H3HCOO- Nanoparticles: A Novel and Heterogeneous Nanocatalyst for Preparation of New (Methylsulfonyl)Benzopyranophenazin-3-Amine Derivatives

An efficient synthesis of new (methylsulfonyl)benzopyranophenazin-3-amines via the condensation of 2-hydroxynaphthoquinone, 1,2-phenylenediamine, methylsulfonylacetonitrile, and arylaldehydes derivatives catalyzed by ionic liquid [(EtO)3Si–CH2–CH2–CH2–NH3 +][HCOO−] immobilized on magnetic Fe3O4@SiO2, as a novel heterogeneous nanocatalyst, was described. The novel nanocatalyst was characterized by FE-SEM, XRD, FT-IR, TGA‐DTG, and VSM techniques. The environmentally friendly protocol presented some advantages, such as a simple work-up and excellent yields. This nanocatalyst can be easily reused several times and recovered by an external magnet. The activity of the recoverable nanocatalyst remains intact even after five repeated runs.

Metal- and Photocatalyst-Free, Visible-Light-Initiated C3 α-Aminomethylation of Quinoxalin-2(1H)-ones via Electron Donor-Acceptor Complexes.

We report a metal- and photocatalyst-free C3 α-aminomethylation of quinoxalin-2(1H)-ones with N-alkyl-N-methylanilines. The reaction proceeds through the formation of a photoactivated electron donor-acceptor complex between quinoxalin-2(1H)-ones and N-alkyl-N-methylanilines. The present method provides a mild and environmentally friendly protocol that exhibits good atom economy and excellent functional group tolerance to obtain a library of biologically significant C3 α-aminomethylated quinoxalin-2(1H)-ones in good yields.

Nickel-Imidazolium Low Transition Temperature Mixtures with Lewis-Acidic Character.

Low transition temperature mixtures (LTTMs) are a new generation of solvents that have found extensive application in organic synthesis. The interactions between the components often generate highly activated, catalytically active species, thus opening the possibility of using LTTMs as catalysts, rather than solvents. In this work, we introduce a nickel-based imidazolium LTTM, study its thermal behavior and explore its catalytic activity in the solvent-free allylation of heterocycles with allylic alcohols. This system is effective in this reaction, affording the corresponding products in excellent yield without the need for additional purifications, thus resulting in a very environmentally friendly protocol.

Environmentally friendly protocol for the determination of sitagliptin phosphate in pharmaceutical preparations and biological fluids using l-tyrosine as a fluorescence probe.

A responsive spectrofluorometric method was developed for the determination of sitagliptin phosphate using l-tyrosine as a fluorescence probe. The fluorescence intensity of l-tyrosine was quenched with sitagliptin phosphate. The fluorescence intensity was recorded at 307 nm using a 272 nm excitation wavelength. The calibration plot between fluorescence intensity and the concentration of drug was linear in the range of 0.1 to 2.0mM with a good correlation value of 0.997. The limit of detection and quantification were established to be 3.7×10-4 and 1.23 ×10-3 mM, respectively. Commonly used excipients did not interfere with sitagliptin phosphate measurement. The proposed method was used to measure the sitagliptin phosphate in its standard type, dosage form, and biological samples. The percent recovery ranged from 97.41-103.36%. The static quenching was shown to be responsible for quenching as indicated by the Stern-Volmer plot. The method was validated using ICH guidelines and profitably applied for the content uniformity test, resulting in a high percent recovery and small relative standard deviation. The proposed approach is effortless, susceptible, selective, economic, and provides a high precision and accuracy, and can be used to determine sitagliptin phosphate in the pharmaceutical industry.

A Simple and Effective Protocol for the Pechmann Reaction to Obtain 4-Methylcoumarin Derivatives Using a High-Speed Mixer Ball Mill Process

We hereby report a simple and efficient method for the preparation of 4-methylcoumarins series, including Coumarin 120 (7-amino-4-methylcoumarin) from phenols (or naphthols) and ethyl acetoacetate in the presence of 3 mol% InCl3. Coumarins were obtained in good yields (52–92%) through Pechmann condensation, under a rapid and environmentally friendly protocol using a high-speed ball mill mixer at room temperature, with short reaction times, under solvent-free conditions.