scholarly journals Ultrasound-Assisted Metal-Mediated Method for the Formation of Tetrahydro-3,3′-Disubstituted Biscoumarins

Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2810 ◽  
Author(s):  
Ana Koleva ◽  
Nevena Petkova-Yankova ◽  
Rositca Nikolova
Keyword(s):  
Ultrasound Irradiation ◽  
New Method ◽  
Experimental Setup ◽  
Simple Preparation ◽  
Ultrasound Assisted ◽  
Excellent Reproducibility ◽  
Organozinc Reagent

A new method for faster and simple preparation of 3,3′,4,4′-tetrahydro-3,3′-disubstituted-4,4′-biscoumarins with participation of an organozinc reagent is reported. The reaction is promoted by ultrasound irradiation and it offers a simple experimental setup and excellent reproducibility of the results. Moreover, homodimers were isolated in yields of 45–92%. The dimerization conditions are applicable to coumarins with electron-withdrawing groups at third position.

scholarly journals Optimization of an Ultrasound-Assisted Extraction Condition for Flavonoid Compounds from Cocoa Shells (Theobroma cacao) Using Response Surface Methodology

Molecules ◽  
2019 ◽  
Vol 24 (4) ◽  
pp. 711 ◽  
Author(s):  
Arief Md Yusof ◽  
Siti Abd Gani ◽  
Uswatun Zaidan ◽  
Mohd Halmi ◽  
Badrul Zainudin
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Ethanol Concentration ◽  
Irradiation Time ◽  
Ultrasound Irradiation ◽  
Coefficient Of Determination ◽  
Ultrasound Assisted Extraction ◽  
Assisted Extraction ◽  
Ultrasound Assisted ◽  
Experimental Values

This study investigates the ultrasound-assisted extraction of flavonoids from Malaysian cocoa shell extracts, and optimization using response surface methodology. There are three variables involved in this study, namely: ethanol concentration (70–90 v/v %), temperature (45–65 °C), and ultrasound irradiation time (30–60 min). All of the data were collected and analyzed for variance (ANOVA). The coefficient of determination (R2) and the model was significant in interaction between all variables (98% and p < 0.0001, respectively). In addition, the lack of fit test for the model was not of significance, with p > 0.0684. The ethanol concentration, temperature, and ultrasound irradiation time that yielded the maximum value of the total flavonoid content (TFC; 7.47 mg RE/g dried weight (DW)) was 80%, 55 °C, and 45 min, respectively. The optimum value from the validation of the experimental TFC was 7.23 ± 0.15 mg of rutin, equivalent per gram of extract with ethanol concentration, temperature, and ultrasound irradiation time values of 74.20%, 49.99 °C, and 42.82 min, respectively. While the modelled equation fits the data, the T-test is not significant, suggesting that the experimental values agree with those predicted by the response surface methodology models.

scholarly journals Intensifying the synthesis of starch nanoparticles using ultrasound-assisted acid hydrolysis method

2021 ◽  
Author(s):  
Vikas S Hakke ◽  
Shirish Sonawane ◽  
Sivakumar Manickam ◽  
Sami Boufi ◽  
Dipak V Pinjari ◽  
...  
Keyword(s):  
Acid Hydrolysis ◽  
Acid Concentration ◽  
Ultrasound Irradiation ◽  
Starch Granules ◽  
Surface Charges ◽  
Hydrolysis Method ◽  
Starch Nanoparticles ◽  
Ultrasound Assisted ◽  
Size And Morphology ◽  
Time Required

Abstract In the present study, an intensified approach for the synthesis of starch nanoparticles (SNPs) was demonstrated by using ultrasound-assisted acid hydrolysis method. The conventional acid hydrolysis for the synthesis of SNPs was intensified using ultrasound. The overall time required to convert starch granules to SNPs in the conventional acid hydrolysis method (48 h) was significantly reduced to 45 min by simultaneous acid hydrolysis and ultrasound irradiation. The acid concentration was found to be an important parameter for obtaining the desired size and morphology of the synthesized SNPs. The variation in the surface charges associated with the SNPs was confirmed through measuring their zeta potential. These potential charges on the surface of SNPs induce crystal growth among the synthesized nanoparticles. The irregular crystal morphology at higher acid concentration clearly shows SNPs' attachment with each other by coalescence. The higher crystallinity for SNPs was observed at low acid concentration; however, the lower acid concentration (0.5 M) leads to the smaller particle size of SNPs from 40 to 60 nm, with the overall yield of 23%. The proposed ultrasound method is more efficient and reproducible for the synthesis of SNPs for various applications.

Tissue characterization with ballistic photons: counting scattering and/or absorption centres

2015 ◽  
Vol 23 (1) ◽  
Author(s):  
F. Corral ◽  
M. Strojnik ◽  
G. Paez
Keyword(s):  
Piezoelectric Actuator ◽  
Tissue Characterization ◽  
Total Concentration ◽  
Phase Delay ◽  
New Method ◽  
Experimental Setup ◽  
Transmission Attenuation ◽  
Pass Through ◽  
Integrated Or ◽  
Ballistic Photons

AbstractWe describe a new method to separate ballistic from the scattered photons for optical tissue characterization. It is based on the hypothesis that the scattered photons acquire a phase delay. The photons passing through the sample without scattering or absorption preserve their coherence so they may participate in interference. We implement a Mach−Zehnder experimental setup where the ballistic photons pass through the sample with the delay caused uniquely by the sample indices of refraction. We incorporate a movable mirror on the piezoelectric actuator in the sample arm to detect the amplitude of the modulation term. We present the theory that predicts the path−integrated (or total) concentration of the scattering and absorption centres. The proposed technique may characterize samples with transmission attenuation of ballistic photons by a factor of 10

scholarly journals Comparative Study on Conventional and Ultrasound Irradiation Promoted Synthesis of 2,3-Disubstitutedquinoxaline Derivatives

2018 ◽  
Vol 28 (3) ◽  
pp. 141
Author(s):  
Ahmed Mutanabbi Abdula ◽  
Ghazwan Ali Salman ◽  
Hamid H. Mohammed
Keyword(s):  
13C Nmr ◽  
Ultrasonic Irradiation ◽  
Reaction Times ◽  
Ultrasound Irradiation ◽  
Conventional Heating ◽  
Heating Method ◽  
Quinoxaline Derivatives ◽  
Ft Ir ◽  
Ultrasound Assisted ◽  
Good Percentage

A series of ten chalcone-substituted quinoxalines (4a-e), (3a-e) starting from 1-(phenylquinoxalin-2-yl)ethanone and 1-(3-methylquinoxalin-2-yl)ethanone have been synthesized using conventional heating and ultrasound-assisted methods. Furthermore, novel of five quinoxaline derivatives including pyrazoline, isoxazole, pyrimidin-2-one, N-acylpyrazoline and pyridin-2-one moieties were also prepared from the reaction of chalcone compound 4a with different cyclization reagents using the same strategy. The structures of all synthesized compounds were established on the basis of FT-IR, 1H-NMR and 13C-NMR. The ultrasonic irradiation method provide several advantages over conventional heating method, including shorter reaction times (30-90 min.) and good percentage yields (65% - 88%), comparing with conventional protocol (5 to 20 hrs. with 30% to 55% reaction yields).

An ultrasound-assisted solvent and catalyst-free synthesis of structurally diverse pyrazole centered 1,5-disubstituted tetrazoles via one-pot four-component reaction

2021 ◽  
Vol 19 ◽  
Author(s):  
Suman Swami ◽  
Rahul Shrivastava ◽  
Neelam Sharma ◽  
Arunava Agarwala ◽  
Ved Prakash Verma ◽  
...  
Keyword(s):  
Reaction Time ◽  
Ultrasound Irradiation ◽  
Amide Bond ◽  
High Yield ◽  
Spectroscopic Techniques ◽  
Mass Analysis ◽  
One Pot ◽  
Green Protocol ◽  
Ultrasound Assisted ◽  
Solvent Free Reaction

Abstract: 1,5-Disubstituted tetrazoles are vital drug-like scaffold usually encountered as valuable bioisosteres of cis-amide bond. In this article, we reported synthesis of some novel medicinally relevant pyrazole centered 1,5-disubstituted tetrazoles using ultrasound irradiation via a one-pot 4-C reaction from various pyrazole originated aldehyde, amine, isocyanide, and sodium azide. All the synthesized derivatives were characterized by IR, 1H NMR, 13C NMR, spectroscopic techniques, and mass analysis. This ultrasound-assisted green protocol has several advantages like mild reaction condition, high yield, catalyst and solvent-free reaction protocol, 15 minutes reaction time and easy workup.

Ultrasound-assisted synthesis of β-enaminone derivatives via Tin(Ⅳ)-catalyzed addition reaction from β-dicarbonyl compounds with nitriles

2021 ◽  
Vol 19 ◽  
Author(s):  
Shuchen Pei ◽  
Jinhua Yang ◽  
Jieyu Wang ◽  
Kangyao Yuan ◽  
Ziqiang Li
Keyword(s):  
Room Temperature ◽  
Addition Reaction ◽  
Ultrasound Irradiation ◽  
Irradiation Condition ◽  
Efficient Synthesis ◽  
Dicarbonyl Compounds ◽  
Ultrasound Assisted

Abstract: An efficient and eco-friendly approach for the synthesis of β-enaminone derivatives is described, which is through the addition of nitriles with β-dicarbonyl compounds under ultrasound irradiation condition at room temperature. The scope and limitation of this strategy are also discussed. A variety of substituted amides can be obtained in moderate to good yields. We hope that this protocol for the efficient synthesis of β-enaminones will offer insights in further investigations.

Ultrasound-assisted synthesis and antimicrobial activity of tetrazole-based pyrazole and pyrimidine derivatives

2018 ◽  
Vol 24 (1) ◽  
pp. 59-65 ◽  
Author(s):  
Vidya S. Dofe ◽  
Aniket P. Sarkate ◽  
Zarina M. Shaikh ◽  
Charansingh H. Gill
Keyword(s):  
Mass Spectrometry ◽  
Escherichia Coli ◽  
Nuclear Magnetic Resonance ◽  
Antimicrobial Activity ◽  
Antimicrobial Agents ◽  
Ultrasound Irradiation ◽  
Pyrimidine Derivatives ◽  
Ultrasound Assisted ◽  
C Nmr

Abstract New tetrazole-based pyrazole and pyrimidine derivatives were synthesized by an ultrasound irradiation method. All compounds were characterized by infrared spectroscopy (IR), 1H nuclear magnetic resonance (NMR), 13C NMR, mass spectrometry (MS) and elemental analysis and assessed in vitro for their efficacy as antimicrobial agents against four bacteria (Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa) and two fungi (Candida albicans, Aspergillus niger). Compounds 8a, 8e, 9a, 9b and 9e show potent activity against the tested strains compared to the reference drugs chloramphenicol and clotrimazole.

scholarly journals ULTRASOUND ASSISTED GREEN SYNTHESIS OF 2-FURAN-2-YL-4H-CHROMEN-4-ONES FROM CHALCONES

2020 ◽  
pp. 84-86
Author(s):  
GOPAL K. KAKADE ◽  
SURESH G. VEDPATHAK
Keyword(s):  
Reaction Time ◽  
Green Synthesis ◽  
Dimethyl Sulfoxide ◽  
Ultrasound Irradiation ◽  
Oxidative Cyclization ◽  
Reaction Conditions ◽  
Ultrasound Assisted ◽  
Conventional Methods

Objective: To report the ultrasound-assisted synthesis of some bioactive 2-furan-2-yl-4H-chromen-4-one derivatives Methods: Oxidative cyclization of chalcones using iodine in dimethyl sulfoxide for the synthesis. Results: Some bioactive 2-furan-2-yl-4H-chromen-4-one derivatives were synthesized from corresponding chalcones in the presence of iodine in dimethyl sulfoxide under ultrasound irradiation at ambient reaction conditions. Conclusion: The use of ultrasound irradiation gave the advantages of higher yields, lower reaction time and simplicity compared to conventional methods for the synthesis of 2-furan-2-yl-4H-chromen-4-one derivatives.

Fast determination of five chiral antipsychotic drugs using dispersive liquid–liquid microextraction combined with capillary electrophoresis

2020 ◽  
Vol 12 (15) ◽  
pp. 2002-2008
Author(s):  
Ming-Mu Hsieh ◽  
Tai-Chia Chiu ◽  
Szu-Hua Chen
Keyword(s):  
Capillary Electrophoresis ◽  
Chiral Separation ◽  
Antipsychotic Drugs ◽  
New Method ◽  
Fast Determination ◽  
Ultrasound Assisted ◽  
Dispersive Liquid Liquid Microextraction ◽  
Phenothiazine Drugs ◽  
Liquid Microextraction

This study developed a new method for the extraction, clean up, chiral separation, and determination of five pairs of phenothiazine drugs using ultrasound-assisted dispersive liquid–liquid microextraction combined with capillary electrophoresis.

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