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Molecules (Basel, Switzerland) Jan 2024In this paper, the green synthesis of isoeugenol methyl ether (IEME) from eugenol by -methylation and isomerization is completed using a one-step green process. In the...
In this paper, the green synthesis of isoeugenol methyl ether (IEME) from eugenol by -methylation and isomerization is completed using a one-step green process. In the methylation reaction, dimethyl carbonate (DMC) was used as a green chemistry reagent instead of the traditional harmful methylation reagents, in accordance with the current concept of green chemistry. The phase transfer catalyst (PTC) polyethylene glycol 800 (PEG-800) was introduced into the isomerization reaction to break the barrier of difficult contact between solid and liquid phases and drastically reduce the reaction conditions by shortening the reaction time and reducing the alkalinity of the reaction system. The catalytic systems for the one-step green synthesis of IEME were screened, and it was shown that the catalytic system "KCO + PEG-800" was the most effective. The effects of reaction temperature, n(DMC):n(eugenol) ratio, n(PEG-800):n(eugenol) ratio, and n(KCO):n(eugenol) ratio on eugenol conversion, IEME yield, and IEME selectivity were investigated. The results showed that the best reaction was achieved at a reaction temperature of 140 °C, a reaction time of 3 h, a DMC drip rate of 0.09 mL/min, and n(eugenol):n(DMC):n(KCO):n(PEG-800) = 1:3:0.09:0.08. As a result of the conversion of 93.1% of eugenol to IEME, a yield of 86.1% IEME as well as 91.6% IEME selectivity were obtained.
PubMed: 38276627
DOI: 10.3390/molecules29020551 -
Molecules (Basel, Switzerland) Jun 2016Green is the future of chemistry. Catalysts with high selectivity are the key to green chemistry. Polymer-supported Raney catalysts have been found to have outstanding... (Review)
Review
Green is the future of chemistry. Catalysts with high selectivity are the key to green chemistry. Polymer-supported Raney catalysts have been found to have outstanding performance in the clean preparation of some chemicals. For example, a polyamide 6-supported Raney nickel catalyst provided a 100.0% conversion of n-butyraldehyde without producing any detectable n-butyl ether, the main byproduct in industry, and eliminated the two main byproducts (isopropyl ether and methyl-iso-butylcarbinol) in the hydrogenation of acetone to isopropanol. Meanwhile, a model for how the polymer support brought about the elimination of byproducts is proposed and confirmed. In this account the preparation and applications of polymer-supported Raney catalysts along with the corresponding models will be reviewed.
Topics: 2-Propanol; Acetone; Butanols; Catalysis; Green Chemistry Technology; Hydrogenation; Nickel; Oxidation-Reduction; Polymers; Propylamines
PubMed: 27347922
DOI: 10.3390/molecules21070833 -
Bioresource Technology May 2022The present study explored the use of mannitol and mannitol-rich agro-industrial wastes as substrates for PHB production by Cobetia amphilecti isolated from the green...
The present study explored the use of mannitol and mannitol-rich agro-industrial wastes as substrates for PHB production by Cobetia amphilecti isolated from the green Ulva sp. seaweed. Cultivation of C. amphilecti on mannitol, celery, and olive leaves (OLs) waste led to 4.20, 6.00, and 5.16 g L of cell dry mass (CDM), 76.3, 25.5, and 12.0% of PHB content in CDM and 3.2, 1.53, and 0.62 g L of PHB concentration, respectively; which suggested that they can be exploited as carbon substrates for the production of PHB. Extraction of PHB from C. amphilecti cultures by solubilization in the green solvent methyl levulinate (ML) (2% w/w, 140 °C, 1 h) indicated that the recovery yield and purity of PHB are above 97 and 90% w/w, respectively. The use of ML could be an attractive method for the recovery of PHB when safe and non-toxic solvents are required.
Topics: 3-Hydroxybutyric Acid; Fermentation; Halomonadaceae; Hydroxybutyrates; Levulinic Acids; Mannitol; Polyesters; Solvents
PubMed: 35346815
DOI: 10.1016/j.biortech.2022.127075 -
Letters in Applied Microbiology May 2022Artocarpin-rich extract (ARE) was prepared using a green technology and standardized to contain 49·6% w/w artocarpin, while lawsone methyl ether was prepared using a...
Artocarpin-rich extract (ARE) was prepared using a green technology and standardized to contain 49·6% w/w artocarpin, while lawsone methyl ether was prepared using a green semi-synthesis. ARE, LME and ampicillin exhibited weak anti-MRSA activity with the MICs of 31·2-62·5 µg/ml. Based on the checkerboard assay, the synergistic interaction between ARE (0·03 µg/ml) and LME (0·49 µg/ml) against four MRSA isolates were observed with the fractional inhibitory concentration index (FICI) value of 0·008, while those of ARE (1·95-7·81 µg/ml) and ampicillin (0·49 µg/ml) as well as LME (0·49-1·95 µg/ml) and ampicillin (0·49 µg/ml) were 0·016-0·257. The time kill confirmed the synergistic interactions against MRSA with different degrees. The combination of ARE and LME as well as its combinations with ampicillin altered the membrane permeability of MRSA, which led to release of the intracellular materials. In addition, each compound inhibited the biofilm formation of standard MRSA (DMST 20654) and the clinical isolate (MRSA 1096). These findings suggested that cocktails containing ARE and LME might be used to overcome problems associated with MRSA. Additionally, the results implied that combination of either ARE or LME with available conventional antibiotic agents might be effective in countering these perilous pathogens.
Topics: Ampicillin; Anti-Bacterial Agents; Biofilms; Drug Synergism; Mannose-Binding Lectins; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Naphthoquinones; Plant Extracts; Plant Lectins
PubMed: 35100449
DOI: 10.1111/lam.13662 -
Journal of Oral and Maxillofacial... 2020The diagnosis and grading of epithelial dysplasia is based on a combination of architectural and cytological changes. A gradual increase in quantitative DNA aberrations...
Comparative analysis of nucleomorphometric parameters in methyl green-pyronin-stained sections of oral epithelial dysplasia, oral submucous fibrosis and oral squamous cell carcinoma.
CONTEXT
The diagnosis and grading of epithelial dysplasia is based on a combination of architectural and cytological changes. A gradual increase in quantitative DNA aberrations has been found to correlate with increasing degree of dysplasia in oral mucous membranes.
AIMS
The aim of this study is to assess nuclear parameters in potentially malignant and malignant lesions of the oral cavity and to assess cytomorphometric changes in the nucleus and nucleolus in oral epithelial dysplasia (OED), oral submucous fibrosis (OSMF), oral squamous cell carcinoma (OSCC) and normal oral mucosa using methyl green-pyronin staining to determine its suitability for detecting potentially malignant lesions and the stage of carcinogenesis.
METHODS
Forty-five archival sections of OED, OSMF and OSCC and 5 cases of normal oral mucosa as the control group were stained according to methyl green-pyronin-staining protocol. Cytomorphometric parameters such as nuclear diameter, nucleolar diameter, number of nucleoli and cytoplasmic RNA were assessed.
STATISTICAL ANALYSIS USED
The study was subjected to statistical analysis to evaluate the association between morphometric parameters using analysis of variance test, followed by Bonferroni's analysis.
RESULTS
A progressive increase in the nuclear parameters as well as cytoplasmic RNA content was observed between normal mucosa through dysplasia and OSMF to OSCC.
CONCLUSION
This study serves as an effective diagnostic aid in assessing nuclear parameters in potentially malignant and malignant epithelial lesions affecting oral cavity.
PubMed: 33456260
DOI: 10.4103/jomfp.JOMFP_360_19 -
Nanotechnology May 2022Herein we describe an effective route for the degradation of methyl green (MG) dye under visible light illumination by pristine and strontium (Sr)-doped zinc oxide (ZnO)...
Herein we describe an effective route for the degradation of methyl green (MG) dye under visible light illumination by pristine and strontium (Sr)-doped zinc oxide (ZnO) photocatalysts (synthesized by the simple chemical precipitation method). The x-ray diffraction structural analysis has confirmed that both photocatalysts exhibit the hexagonal wurtzite structure; without any additional phase formation in Sr-doped ZnO, in particular. The optical properties of the synthesized photocatalysts have been investigated using UV-vis absorption spectroscopy in the wavelength range of 250-800 nm. Through Tauc's plot, the slight decrease from 3.3 to 3.2 eV in band gap energy has been elucidated (in the case of Sr-doped ZnO), which has been further confirmed by the quenching in the intensity of Photoluminescence (PL) emission spectrum. This may be due to sub-band level formation between valence and conduction band, caused by the impregnation of Srions into ZnO host. The morphological study has also been performed using Field Emission Scanning Electron Microscope, which indicates nanoparticles (NPs) based surface texture for both photocatalysts. During the photocatalytic activity study, after 30 min irradiation of visible light, ∼65.7% and ∼84.8% photocatalytic degradation of MG dye has been achieved for pristine and Sr-doped (2 wt%) ZnO photocatalysts, respectively. The rate of photocatalytic reaction () has been observed to be ∼0.06399 minfor Sr-doped (2 wt%), whereas nearly half magnitude ∼0.03403 minhas been observed for pristine ZnO, respectively. The significantly improved photodegradation activity may be ascribed to the relatively broader optical absorption capability, surface defects and the enhanced charge separation efficiency of the Sr-doped ZnO photocatalyst.
PubMed: 35504008
DOI: 10.1088/1361-6528/ac6760 -
BMC Chemistry Nov 2022A precise, sensitive eco-friendly, simple, rapid, and derivative spectrofluorimetric method was developed to quantify edoxaban tosylate monohydrate in pure form and...
Development and validation of a novel Spectrofluorimetric method of oral anticoagulant Edoxaban via derivatization with 9-fluorenyl methyl chloroformate: green assessment of the method by Eco-Scale and ComplexGAPI.
A precise, sensitive eco-friendly, simple, rapid, and derivative spectrofluorimetric method was developed to quantify edoxaban tosylate monohydrate in pure form and pharmaceutical dosage form. Sudden death due to pulmonary embolism as a consequence of coronavirus infection (covid-19) is an emerging problem. As a result, the world health organization introduced new guidelines to treat patients with COVID-19 with oral anticoagulants. Edoxaban tosylate monohydrate is an oral anticoagulant that doesn't require hospitalization after dose adjustment. This spectrofluorimetric method relies on the derivatization by 9-fluorenyl methyl chloroformate at room temperature in borate buffer pH 9.0. After excitation at 265 nm, the product is highly fluorescent at 309 nm. Many experimental factors influencing the reaction's stability and development were thoroughly investigated and optimized. The method validation was evaluated by using ICH guidelines and showed high precision and accuracy with an average percent recovery of 101.46% ± 1.02. The linear range was 5.0-50.0 ng/mL with a correlation coefficient of 0.9999, the LOD was 1.5 ng/mL, and the LOQ was 4.5 ng/mL. The green assessment of the method was achieved utilizing the eco-scale and the Green Analytical Procedure Index. There was no significant difference between the results of the suggested method and those of the reported method according to Statistical analysis.
PubMed: 36424617
DOI: 10.1186/s13065-022-00890-2 -
ACS Omega May 2023The synthesis of kynurenic acid derivatives with potential biological effect was investigated and optimized for one-batch, two-step microwave-assisted reactions....
The synthesis of kynurenic acid derivatives with potential biological effect was investigated and optimized for one-batch, two-step microwave-assisted reactions. Utilizing both chemically and biologically representative non-, methyl-, methoxy-, and chlorosubstituted aniline derivatives, in catalyst-free conditions, syntheses of seven kynurenic acid derivatives were achieved in a time frame of 2-3.5 h. In place of halogenated reaction media, tuneable green solvents were introduced for each analogue. The potential of green solvent mixtures to replace traditional solvents and to alter the regioisomeric ratio regarding the Conrad-Limpach method was highlighted. The advantages of the fast, eco-friendly, inexpensive analytic technique of TLC densitometry were emphasized for reaction monitoring and conversion determination in comparison to quantitative NMR. Moreover, the developed 2-3.5 h syntheses were scaled-up to achieve gram-scale products of KYNA derivatives, without altering the reaction time in the halogenated solvent DCB and more importantly in its green substitutes.
PubMed: 37251176
DOI: 10.1021/acsomega.3c01170 -
Molecules (Basel, Switzerland) Nov 2022Dimethindene is a selective histamine H antagonist and is commercially available as a racemate. Upon analyzing the synthetic pathways currently available for the...
Dimethindene is a selective histamine H antagonist and is commercially available as a racemate. Upon analyzing the synthetic pathways currently available for the industrial preparation of dimethindene, we set up a sustainable approach for the synthesis of this drug, switching from petroleum-based volatile organic compounds (VOCs) to eco-friendly solvents, such as 2-methyltetrahydrofuran (2-MeTHF) and cyclopentyl methyl ether (CPME) belonging to classes 3 and 2, respectively. Beyond decreasing the environmental impact of the synthesis (E-factor: 24.1-54.9 with VOCs; 12.2-22.1 with 2-MeTHF or CPME), this switch also improved the overall yield of the process (from 10% with VOCs to 21-22% with 2-MeTHF or CPME) and remarkably simplified the manual operations, working under milder conditions. Typical metrics applied at the first and second pass, according to the CHEM21 metrics toolkit, were also calculated for the whole synthetic procedure of dimethindene, and the results were compared with those of the classical procedure.
Topics: Dimethindene; Solvents; Methyl Ethers; Histamine
PubMed: 36364422
DOI: 10.3390/molecules27217594 -
RSC Advances May 2022Four magnetite nanoparticle (NP) samples have been greenly synthesized using four aqueous plant extracts, which are (L), (L), (L), and (L). The pH of these extracts...
Preferential and enhanced adsorption of methyl green on different greenly synthesized magnetite nanoparticles: investigation of the influence of the mediating plant extract's acidity.
Four magnetite nanoparticle (NP) samples have been greenly synthesized using four aqueous plant extracts, which are (L), (L), (L), and (L). The pH of these extracts are acidic (5.25, 5.05, 4.63, and 3.69, respectively). The synthesized samples were characterized by XRD, SEM, ATR-FTIR, and UV-Vis. This work aimed to study the preferential and enhanced adsorption of methyl green (MG) on the four greenly synthesized FeO surfaces by coupling three processes: MG adsorption in ambient dark conditions as the first process, followed by the thermocatalysis of the MG/FeO residual solution in the second process, and finally photocatalysis by the UV irradiation of MG/FeO residual solution after carrying out thermocatalysis. The novelty of this study lies in highlighting the influence of the mediating plant extract's acidity on the magnetite NPs' physicochemical characteristics, which impact the preferential and enhanced MG adsorption. The studied physicochemical characteristics are the functional hydroxyl group density on the magnetite surface, grain size, and band gap energy. It was found that the plant extract's acidity has a clear effect on the studied physicochemical properties. The analysis of the FTIR spectra showed that the hydroxyl group densities differ on the four magnetite samples. Furthermore, the calculated grain sizes of the magnetite samples based on XRD spectra data vary from 29.27 to 41.49 nm. The analysis of the UV-Vis spectra of the four magnetite samples showed that the estimated direct band gap energies vary from 2.87 to 2.97 eV. The obtained results showed that the decrease of the mediating plant extract's acidity leads to an increase in the hydroxyl group density on magnetite surfaces, which resulted in an increase in the MG adsorption capacities and yields in the first process of adsorption. Thus, MG adsorption was more preferred on greenly synthesized magnetite surfaces mediated by plant extracts with low acidity ( (L) and (L)). Furthermore, the increase of the plant extract's acidity leads to a decrease in the particle size and an increase in the band gap energy and, therefore, to the decrease of the electron/hole pair recombination speed upon electron excitation. So, magnetite greenly synthesized from a more acidic mediating plant extract showed higher thermo- and photocatalytic activities for MG adsorption ( (L) and (L)). However, under photocatalysis, the enhancement is even more significant compared to thermocatalysis.
PubMed: 35702240
DOI: 10.1039/d2ra01085b