533-18-6Relevant academic research and scientific papers
Submicron ZnO raspberries as effective catalysts for Fries rearrangement
Ali, Mohammed,Rahaman, Hasimur,Pal, Sudip Kumar,Kar, Nikita,Ghosh, Sujit Kumar
, p. 41780 - 41785 (2015)
o-Xylene-in-water emulsion droplets have been exploited as soft templates for the synthesis of submicrometer-sized raspberry-like ZnO morphologies. The optical properties, structure and morphology of the microstructures have been characterised by absorption and fluorescence spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction and selected area electron diffraction analysis. It has been found that the microstructures could act as an environmentally benign and cost-effective alternative to conventional Lewis acid catalysts for the illustrious Fries rearrangement of o-methylphenyl acetate to 3-methyl-4-hydroxyacetophenone, employed as the model reaction and which has been probed by NMR spectroscopic studies.
Method for promoting acylation of amine or alcohol by carbon dioxide
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Paragraph 0034-0035, (2021/05/29)
The invention relates to a method for promoting acylation of amine or alcohol by carbon dioxide, which comprises the following steps of: mixing an amine compound, carboxylate or thiocarboxylate compound and a reaction solvent under the action of carbon dioxide, and reacting to obtain an amide compound, or under the action of carbon dioxide, mixing the alcohol compound, the thiocarboxylate compound and the reaction solvent [gamma]-valerolactone, and reacting to obtain the ester compound. According to the invention, under the promotion action of carbon dioxide, carboxylate or thiocarboxylate is used as an acylation reagent, and amine and alcohol are converted into amide and ester compounds in the absence of a transition metal catalyst, so that acylation reagents such as acyl chloride or anhydride with irritation and corrosivity are avoided; and the method has the advantages of simple operation, mild reaction conditions, high tolerance of substrate functional groups, strong applicability and high yield, and provides an efficient, reliable and economical preparation method for synthesis of amide and ester compounds.
An efficient method to prepare aryl acetates by the carbonylation of aryl methyl ethers or phenols
Zhang, Dejin,Yang, Guoqiang,Xiong, Junping,Liu, Jia,Hu, Xingbang,Zhang, Zhibing
, p. 2683 - 2687 (2021/02/16)
Synthesis of valuable chemicals from lignin based compounds is critical for the application of biomass. Here, we develop a method of preparing aryl acetates by the carbonylation of aryl methyl ethers or phenols under low CO pressure. Good to excellent yields of aryl acetates were obtained using different substrates, and a possible reaction mechanism was proposed by conducting a series of control experiments. This method may provide a potential way for the utilization of lignin.
Steric effect of NHC ligands in Pd(II)–NHC-catalyzed non-directed C–H acetoxylation of simple arenes
Mandal, Tanmoy,Yadav, Sudha,Choudhury, Joyanta
, (2021/09/06)
Although there has been a lot of progress in oxidative arene C–H functionalization reactions catalyzed by Pd(II/IV) system, the non-directed, site-selective functionalization of arene molecules is still challenging. It has been established that ligands play a pivotal role in controlling rate- as well as selectivity-determining step in a catalytic cycle involving well-defined metal-ligand bonding. N-heterocyclic carbene (NHC) ligands have had a tremendous contribution in the recent extraordinary success of achieving high reactivity and excellent selectivity in many catalytic processes including cross-coupling and olefin-metathesis reactions. However, the immense potential of these NHC ligands in improving site-selectivity of non-directed catalytic C–H functionalization reactions of simple arenes is yet to be realized, where overriding the electronic bias on deciding selectivity is a burdensome task. The presented work demonstrated an initiative step in this regard. Herein, a series of well-defined discrete [Pd(NHCR′R)(py)I2] complexes with systematically varied degree of spatial congestion at the Pd centre, exerted through the R and R’ substituents on the NHC ligand, were explored in controlling the activity as well as the site-selectivity of non-directed acetoxylation of representative monosubstituted and disubstituted simple arenes (such as toluene, iodobenzene and bromobenzene, naphthalene and 1,2-dichlorobenzene). The resulting best yields were found to be 75% for toluene and 65% for bromobenzene with [Pd(NHCMePh)(py)I2], 75% for iodobenzene and 79% for naphthalene with [Pd(NHCMeMe)(py)I2], and 41% for 1,2-dichlorobenzene with [Pd(NHCCyCy)(py)I2]. Most importantly, with increasing the bulkiness of the NHC ligand in the complexes, the selectivity of the distal C-acetoxylated products in comparison to the proximal ones, was enhanced to a great extent in all cases. Considering the vast library of NHC ligands, this study underscores the future opportunity to develop more strategies to improve the activity and the crucial site-selectivity of C–H functionalization reactions in simple as well as complex organic molecules.
Synthetic method of benzofuranone
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Paragraph 0066-0070, (2020/06/16)
The invention provides a synthetic method of benzofuranone. According to the method, o-cresol which is relatively easy to obtain is used as an initial raw material, and the target product benzofuranone is prepared through four-step reaction; and the whole preparation process is mild in condition, high in yield, easy to operate, small in environmental pollution and suitable for large-scale industrial production.
Efficient preparation method of 2'-hydroxyacetophenone compounds
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Paragraph 0029-0031, (2019/05/08)
The invention discloses an efficient preparation method of 2'-hydroxyacetophenone compounds. The method comprises the following steps: substituted phenol and acetic anhydride in a molar ratio of 1:(1-1.1) is subjected to a reaction at 130-150 DEG C in the absent of a solvent, acetic acid substituted phenyl ester as shown in the formula is generated, and acetic acid and acetic acid substituted phenyl ester are separated by rectification; prepared acetic acid substituted phenyl ester is subjected to a transposition reaction under the action of a catalyst in an organic solvent at the temperatureof 50-120 DEG C, and 2'-hydroxyacetophenone compounds as shown in the formula are generated; filtering is performed to remove the catalyst after the reaction is finished, the solvent is removed by evaporation, and the 2'-hydroxyacetophenone compounds are prepared by rectification under vacuum, wherein the catalyst is phosphomolybdic acid, phosphotungstic acid, silicotungstic acid or a mixture of the acid. The preparation method has mild conditions and simple flow, and is environmentally friendly and suitable for industrial production, selectivity is high, and ortho-position selectivity is as high as 99.5%.
Method for synthesizing phenyl acetate derivatives
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Paragraph 0027-0032, (2019/05/08)
The invention discloses a method for synthesizing phenyl acetate derivatives. The method of the invention comprises the following steps: 1, adding a phenol derivative, potassium thioacetate, copper acetate and acetonitrile to a reaction tube, and tightening the bottle stopper of the reaction tube, and magnetically stirring at 80 DEG C and reacting for 4 h; and 2, extracting with ethyl acetate, mixing organic phases, removing most of the solvent by reduced pressure distillation, and carrying out column chromatography separation and purification on residual mixed liquor by using petroleum etherand ethyl acetate at the volume ratio of 10:1 as a leacheate so as to obtain a target product. By using a phenol derivative as the raw material and using stable potassium thioacetate, which is cheap and easily available and is easy to operate, as an acetylation reagent, a series of phenyl acetate derivatives are efficiently synthesized, and the yield is considerable.
Unprecedented acetylation of phenols using a catalytic amount of magnesium powder
Bajracharya, Gan B.,Shrestha, Suryaman Sama
supporting information, p. 1688 - 1693 (2018/06/15)
The acetylation of phenols with acetic anhydride was achieved using a catalytic amount of magnesium metal powder under air and solvent-free conditions to afford corresponding phenyl acetates in excellent yield (up to 98%).
Ultrasound-assisted synthesis and antimicrobial activity of tetrazole-based pyrazole and pyrimidine derivatives
Dofe, Vidya S.,Sarkate, Aniket P.,Shaikh, Zarina M.,Gill, Charansingh H.
, p. 59 - 65 (2018/01/18)
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.
Enhanced shape selective catalysis of mixed cyclic ketones in aerobic Baeyer-Villiger oxidation with magnetic Cu-Fe3O4 supported mesoporous silica microspheres
Zheng, Chunming,Chang, Shubin,Yang, Chuanwu,Lian, Dongying,Ma, Chao,Zhang, Chunrong,Fan, Xiangrui,Xu, Shichao,Sun, Xiaohong
, p. 2608 - 2616 (2018/04/23)
Various strategies have been developed to improve the conversion for the Baeyer-Villiger oxidation. However, the catalytic effects of the Baeyer-Villiger oxidation for the mixed ketones are rarely reported, though it is also important for the natural and industrial separation processes. In this report, magnetite Cu modified Fe3O4 supported mesoporous silica microspheres (Cu-Fe3O4@mSiO2) have been successfully synthesized by two step direct hydrothermal method (DHT). Over 99% of cyclohexanone conversion was obtained with mild air oxidation and benzaldehyde as sacrificing agent over Cu-Fe3O4@mSiO2. The catalytic system also shows higher conversion rates for small molecular ketones in the mixed ketone reactants, which was attributed to the enhanced mass transfer effect and Fe-Cu composite active sites in the magnetite mesoporous silica microspheres. The catalyst could be recycled for four times with similar catalytic performance, which shows enhanced shape selectivity in aerobic Baeyer-Villiger oxidations for mixed cyclic ketones.
