Organic Chemistry
Nahid Ahmadi; Ali Ramazani; Sobhan Rezayati; Fahimeh Hosseini
Abstract
Silica nanoscale powders were obtained by heat treatment on the waste of laboratory silica gel HF254 available at the warehouse. That white solid was thermally treated at optimal conditions at 700 °C for 4 h and after decomposition of all of the materials, was refluxed with HCl (6 M) for 24 hours. ...
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Silica nanoscale powders were obtained by heat treatment on the waste of laboratory silica gel HF254 available at the warehouse. That white solid was thermally treated at optimal conditions at 700 °C for 4 h and after decomposition of all of the materials, was refluxed with HCl (6 M) for 24 hours. Afterward, the prepared catalyst was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Brunauer–Emmett–Teller (BET) analysis. The average nanoparticle size was measured 25 nm. So the purpose was investigated on the attributes of the catalyst supported by chloro sulfuric acid and its application in the Fisher esterification reaction as an acid solid catalyst under solvent-free conditions. According to this, different parameters such as the types of alcohols and phenols and carbon chain length were studied by both nano-silica sulfuric acid (NSSA) and silica sulfuric acid (SSA) at the same conditions. In this case, the foundings illustrated esterification in the presence of NSSA was performed at reaction time less than SSA and the production yield of NSSA was higher than SSA. The obtained results in the mentioned method proved silica from the wastes of silica gel HF254 can be employed as a catalyst at the more reaction.
Medicinal
Armin Zarei; Saeid Taghavi Fardood; Farzaneh Moradnia; Ali Ramazani
Abstract
The arrival of new types of viral diseases, namely coronavirus family, have posed a serious threat for global health. A new kind of coronavirus (CoV) named intense respiratory syndrome CoV-2 (SARS-CoV-2 or COVID-19) firstly diagnosed in Huanan Seafood Wholesale, Wuhan City, China. The COVID-19 origination ...
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The arrival of new types of viral diseases, namely coronavirus family, have posed a serious threat for global health. A new kind of coronavirus (CoV) named intense respiratory syndrome CoV-2 (SARS-CoV-2 or COVID-19) firstly diagnosed in Huanan Seafood Wholesale, Wuhan City, China. The COVID-19 origination is likely to be from an animal host like bat and followed by person-person transmission unless the other routes possibility should be taken into account. The COVID-19 has been spread so fast all over the world, with more than 1,569,504 infected cases and 95,269 mortality as of April, 11th 2020, regardless of potent control and quarantine policy in more countries. Moreover, the SARS-CoV2 known as a novel coronavirus as it’s initial genomic was less likely to be matched with the former CoV types. The human-human transmission range reported to be 2-14 days and its spread expansions would be comforted by surfaces, infected hands and droplets. This review focused on the persistency of different coronaviruses, like avain H7H9, SARS-CoV, MERS-CoV, Ebola virus and COVID-19, on varied surfaces as well as considering of COVID-19 features such as transmission, preventable policies, symptoms and suggested treatment ways to combat COVID-19.
Hamideh Aghahosseini; Ali Ramazani
Abstract
L-Proline is known as the most favored organocatalyst in enamine-mediated reactions. The unique nucleophilic character of L-proline among other amino acids raised from the secondary amine functionality in its pyrrolidine ring. This simple natural amino acid as a promising catalyst for various kinds of ...
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L-Proline is known as the most favored organocatalyst in enamine-mediated reactions. The unique nucleophilic character of L-proline among other amino acids raised from the secondary amine functionality in its pyrrolidine ring. This simple natural amino acid as a promising catalyst for various kinds of organic reactions can compete with the toxic organometallic catalysts. Magnetic functionalization of this organocatalyst could solve its recovery and reuse problems. Herein we report the use of magnetic L-proline nano-biocatalyst for a simple and efficient one-pot coupling reaction of dimedone, malononitrile and aromatic aldehydes to afford the corresponding tetrahydrobenzo[b]pyrans as a significant class of heterocyclic compounds with great biological and pharmacological importance according to a green protocol. Low cost, facile handling, simple preparation, high stability, reusability and low toxicity of this nano-biocatalyst besides its high efficiency and versatility proposed it as a unique candidate for many of enamine-mediated organic transformations.
![Magnetite L-proline as a reusable nano-biocatalyst for efficient synthesis of 4H-benzo[b]pyrans in water: a green protocol](data/ecc/coversheet/221574626541.png)
