scholarly journals Ultrasound-assisted synthesis of dihydropyrimidine-2-thiones

2011 ◽  
Vol 76 (5) ◽  
pp. 679-684 ◽  
Author(s):  
Javad Safaei-Ghomi ◽  
Ali Ghasemzadeh
Keyword(s):  
High Efficiency ◽  
Chemical Processes ◽  
Structural Elucidation ◽  
Spectral Analyses ◽  
Chalcone Derivatives ◽  
Aryl Aldehydes ◽  
Ultrasound Assisted ◽  
High Yields ◽  
Ultrasonic Conditions ◽  
Ultrasound Effect

Chalcone derivatives were prepared by the condensation of various substituted aryl aldehydes and acetophenone in alkaline ethanol, while pyrimidine-2-thione derivatives were prepared by the combination of chalcones and thiourea under conventional and ultrasonic conditions. Advantages of the ultrasound effect were observed and high yields of the products were obtained after 20-30 min sonication. Characterization and structural elucidation of the products was realized based on chemical, analytical and spectral analyses. The results clearly demonstrated a high efficiency of the ultrasonic systems was achieved in the chemical processes.

Synthesis and Characterization of a Novel Ionic Liquid Based on N,N,N,N-tetramethylethylenediamine and its Application in the Synthesis of 1,8-dioxo-octahydro Xanthenes

2018 ◽  
Vol 21 (7) ◽  
pp. 526-532 ◽  
Author(s):  
Zahra Abdi Piralghar ◽  
Mohammad Mahmoodi Hashemi ◽  
Ali Ezabadi
Keyword(s):  
Ionic Liquid ◽  
Chlorosulfonic Acid ◽  
Solvent Free ◽  
Aryl Aldehydes ◽  
Acidic Ionic Liquid ◽  
Brønsted Acidic Ionic Liquid ◽  
Solvent Free Conditions ◽  
Aryl Aldehyde ◽  
High Yields

Aim and Objective: In this work, we synthesized and characterized a novel Brönsted acidic ionic liquid from the reaction of N, N, N’, N’-tetramethylethylenediamine with chlorosulfonic acid and explored its catalytic activity in 1, 8-dioxo-octahydroxanthenes synthesis. Materials and Methods: Dimedone, aryl aldehydes, and the ionic liquid as the catalyst were reacted under solvent-free conditions. The progressive of the reaction was monitored by a thin layer of chromatography (ethyl acetate/n-hexane = 1/5). All products were characterized as the basis of their spectra data and melting point by comparison with those reported in the literature. Results: The prepared ionic liquid was successfully applied in the synthesis of 1, 8-dioxooctahydroxanthenes in good to high yields on the reaction of aryl aldehyde and dimedone at 120oC under solvent-free conditions. Conclusion: This research demonstrates that the catalyst is impressive for 1, 8-dioxo-octahydroxanthenes synthesis under solvent-free conditions.

Solid-state regioselective nitration of activated hydroxyaromatics and hydroxycoumarins with cerium (IV) ammonium nitrate

2005 ◽  
Vol 2005 (11) ◽  
pp. 733-735 ◽  
Author(s):  
Nemai C. Ganguly ◽  
Sanjoy Dutta ◽  
Mrityunjoy Datta ◽  
Prithwiraj De
Keyword(s):  
Solid State ◽  
Ammonium Nitrate ◽  
High Efficiency ◽  
Solvent Free ◽  
High Melting ◽  
Microwave Assisted ◽  
Solvent Free Conditions ◽  
High Yields ◽  
Regioselective Nitration ◽  
Cerium Iv Ammonium Nitrate

Predominant ortho-selective mononitration of low-melting and liquid phenols and hydroxycoumarins in moderate to high yields has been accomplished upon grinding with solid cerium (IV) ammonium nitrate (CAN). Microwave-assisted expeditious CAN-mediated nitration of relatively high melting phenols and hydroxycoumarins with high efficiency and selectively under solvent-free conditions has been also developed to address the problems of sluggishness and low yield for these reluctant substrates.

High yield and greener C–H difluoromethylation reactions using copper iodide nanoparticles/boron nitride nanosheets as a versatile and recyclable heterogeneous catalyst

2021 ◽  
Author(s):  
Udayakumar Veerabagu ◽  
Gowsika Jaikumar ◽  
Fushen Lu ◽  
Franck Quero
Keyword(s):  
Boron Nitride ◽  
Heterogeneous Catalyst ◽  
High Efficiency ◽  
High Yield ◽  
Copper Iodide ◽  
Boron Nitride Nanosheets ◽  
Greener Synthesis ◽  
High Yields ◽  
Recyclable Heterogeneous Catalyst

The 3 wt% CuI/BNNS catalyst exhibited high efficiency for C–H difluoromethylation reactions and enabled greener synthesis at high yields using cyrene as a solvent. Furthermore, the catalyst could be easily recovered and recycled for at least five cycles.

From elementary reactions to chemical relevance in the photodynamic therapy of cancer

2013 ◽  
Vol 85 (7) ◽  
pp. 1389-1403 ◽  
Author(s):  
Luis G. Arnaut ◽  
Sebastião J. Formosinho
Keyword(s):  
Photodynamic Therapy ◽  
Theoretical Prediction ◽  
Near Infrared ◽  
Chemical Processes ◽  
Triplet States ◽  
Biological Screening ◽  
Elementary Reactions ◽  
Photodynamic Therapy Of Cancer ◽  
Intense Absorption ◽  
High Yields

Theories of radiationless conversions and of chemical processes were employed to design better photosensitizers for photodynamic therapy (PDT). In addition to photostability and intense absorption in the near infrared, these photosensitizers were required to generate high yields of long-lived triplet states that could efficiently transfer their energy, or an electron, to molecular oxygen. The guidance provided by the theories was combined with the ability to synthesize large quantities of pure photosensitizers and with the biological screening of graded hydrophilicities/lipophilicities. The theoretical prediction that halogenated sulfonamide tetraphenylbacteriochlorins could satisfy all the criteria for ideal PDT photosensitizers was verified experimentally.

scholarly journals Ebb-and-flow Subirrigation Strategies Increase Biomass and Nutrient Contents and Reduce Nitrate Levels in Lettuce

HortScience ◽  
2018 ◽  
Vol 53 (7) ◽  
pp. 1056-1061
Author(s):  
Leqi Yang ◽  
Xiao Yang ◽  
Hong Zhao ◽  
Danfeng Huang ◽  
Dongqin Tang
Keyword(s):  
Nutritional Value ◽  
High Efficiency ◽  
Growth Parameters ◽  
Nitrate Content ◽  
Nutrient Contents ◽  
Overhead Irrigation ◽  
Lettuce Growth ◽  
High Yields ◽  
Lettuce Cultivar ◽  
Ebb And Flow

Overhead irrigation is widely used to water lettuce during commercial production in China but exerts potential water wastage and pollution. Subirrigation is thought as a water-saving, high-efficiency fertigation strategy. However, few studies have compared the nutritional value and nitrate content of lettuce grown using subirrigation with plants cultivated with overhead irrigation. Therefore, this study explored the ability of ebb-and-flow subirrigation strategies to produce high yields of a leafy lettuce (cultivar Biscia Rossa) with high nutritional value and low nitrate content. Lettuce plants were cultivated in an ebb-and-flow subirrigation system with different irrigation frequencies (every 2 or 3 days) and immersion times (5, 10 or 15 minutes); overhead irrigation was used as control. Ebb-and-flow subirrigation significantly enhanced several lettuce growth parameters, significantly increased the level of vitamin C, and significantly decreased the nitrate content of lettuce leaves compared with overhead irrigation. The optimal subirrigation strategy for lettuce production was irrigation every 3 days with 15 minutes immersion; this ebb-and-flow subirrigation protocol could potentially be used to save water and resources, improve yield and nutrient contents and reduce nitrate content in commercial greenhouse lettuce production.

Synthesis of 2-Chromanone-fused [3.2.0] Bicycles through a Phosphine-mediated Tandem [3+2] Cyclization/Intramolecular Wittig Reaction

2021 ◽  
Author(s):  
Junfeng Fu ◽  
Ingrid Rakielle Tsapy Takia ◽  
Peng Chen ◽  
Wei Liu ◽  
Chengjun Jiang ◽  
...  
Keyword(s):  
Wittig Reaction ◽  
High Efficiency ◽  
Intramolecular Wittig Reaction ◽  
Tandem Process ◽  
High Yields

A phosphine-mediated tandem [3+2] cyclization/intramolecular Wittig reaction of 3-aroylcoumarin with alkynone is described. The high efficiency of tandem process allows the synthesis of 2-chromanone-fused bicyclo[3.2.0]heptenones in moderate to high yields...

Ionic liquid promoted and mediated green preparation of arylbispyranylmethane and pyran derivatives and their hybrid with a pyrimidine nucleoside

2009 ◽  
Vol 2009 (8) ◽  
pp. 473-477 ◽  
Author(s):  
Xinying Zhang ◽  
Yingying Qu ◽  
Xuesen Fan ◽  
Xia Wang ◽  
Jianji Wang
Keyword(s):  
Ionic Liquid ◽  
High Efficiency ◽  
Reaction Medium ◽  
Environmentally Benign ◽  
Pyrimidine Nucleoside ◽  
Reaction Conditions ◽  
Operation Process ◽  
Antiviral Activities ◽  
Benign Nature ◽  
High Yields

The utilisation of an ionic liquid-[bmim][BF4] as both reaction medium and promoter for the reaction between aldehyde and 4-hydroxy-6-methylpyran-2-one is described. Without any added catalyst, this reaction was realised efficiently to give arylbispyranylmethane derivatives in high yields. Alternatively, when this reaction was carried out in the presence of acetic anhydride, fused pyran derivatives were obtained. These two novel procedures have advantages such as an environmentally benign nature, high efficiency, simple operation process and mild reaction conditions. As an application, these procedures were used in the preparation of novel 5-substituted pyrimidine nucleoside derivatives with potential antiviral activities.

TiO2–SiO2 nanocomposite as a highly efficient catalyst for the solvent-free cyclocondensation reaction of isatins, cyclohexanones, and urea

2019 ◽  
Vol 74 (7-8) ◽  
pp. 559-564
Author(s):  
Simin Janitabar-Darzi ◽  
Shahrzad Abdolmohammadi
Keyword(s):  
Present Method ◽  
High Efficiency ◽  
Solvent Free ◽  
High Catalytic Activity ◽  
One Pot ◽  
Efficient Catalyst ◽  
Solvent Free Conditions ◽  
Cyclocondensation Reaction ◽  
The One ◽  
High Yields

AbstractA TiO2–SiO2 nanocomposite catalyzes the one-pot cyclocondensation reaction of 1H-indole-2,3-diones (isatins), 1,3-cyclohexanediones, and urea at T = 70°C under solvent-free conditions with high efficiency. The present method affords the corresponding spiro products in high yields and short reaction time. The unique features of the TiO2–SiO2 nanocomposite are high catalytic activity, ease of preparation, non-toxicity, low loading, and recyclability.

Catalytic activity of dithioic acid copper complexes in the alkyne–azide cycloaddition

2013 ◽  
Vol 91 (4) ◽  
pp. 292-299 ◽  
Author(s):  
Bayardo E. Velasco ◽  
Gustavo López-Téllez ◽  
Nelly González-Rivas ◽  
Iván García-Orozco ◽  
Erick Cuevas-Yañez
Keyword(s):  
Catalytic Activity ◽  
Copper Complex ◽  
Copper Complexes ◽  
Functional Group ◽  
High Efficiency ◽  
High Catalytic Activity ◽  
Different Temperatures ◽  
High Yields

Diverse dithioic acid copper complexes exhibit a high catalytic activity in the copper-catalyzed alkyne–azide cycloaddition using several solvents under different temperatures, showing a high efficiency with only 0.005 mmol catalyst/mmol alkyne or less. A dithioic acid copper complex derived from acetophenone was selected and used as the catalyst in the preparation of a library of 1,4-disubstituted-1,2,3-triazoles. This process occurred in high yields and good functional group tolerance.

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