- Fabrication of Fe3O4- l -dopa-CuII/SnIV@Micro-Mesoporous-SiO2 Catalyst Applied to Baeyer-Villiger Oxidation Reaction
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A Magnetic mFe3O4-l-dopa-CuII/SnIV@micro-mesoporous-SiO2 catalyst was successfully prepared. The catalyst exhibits high and stable catalytic activity for the Baeyer-Villiger oxidation reaction with air as oxidant. Furthermore, the selectivity can reach nearly 100 %. Meanwhile the catalyst can be easily separated by an external magnet and reused at least up to five cycles without any notable loss in catalytic activity. In addition, the effect of Sn and Cu on the oxidation of cyclohexanone is discussed.
- Huo, Hongfei,Wu, Li,Ma, Jianxin,Yang, Honglei,Zhang, Le,Yang, Yuanyuan,Li, Shuwen,Li, Rong
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- Oxidation of p-cresol with ozone in acetic anhydride
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Preparation of aromatic alcohols and aldehydes by oxidation of p-cresol with ozone in acetic anhydride in the presence of sulfuric acid, manganese acetate, and potassium bromide was studied. The optimal oxidation conditions were determined. Pleiades Publishing, Inc., 2006.
- Sedykh,Galstyan
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- Catalysis of reaction between ozone and 4-hydroxytoluene in acetic anhydride
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Kinetics and products of 4-hydroxytoluene oxidation with ozone-air mixture in the presence of transition metal acetates as catalysts have been studied. Main steps of the catalytic series have been considered, and a mechanism of redox catalysis has been proposed which conforms to the experimental data and enables control over the direction, depth, and selectivity of the oxidation. Only manganese(II) acetate has been found to exhibit high catalytic activity in the presence of catalytic amounts of mineral acids. Manganese(II) acetate largely suppresses electrophilic reaction of ozone with the aromatic ring, so that the main reaction direction is oxidation of the methyl group with formation of 4-acetoxybenzyl acetate as the major product (62.6%) and 4-acetoxybenzylidene diacetate as a minor one (10.2%).
- Galstyan, A. G.,Sedykh, A. A.,Galstyan, G. A.
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- Oxidation of 4-hydroxytoluene with an ozone-oxygen mixture in acetic acid
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Liquid-phase oxidation of 4-hydroxytoluene by ozone to 4-hydroxybenzoic acid in the presence of cobalt(II) acetate as a catalyst was studied. The optimal oxidation conditions were found.
- Galstyan,Tarasenko,Shumilova
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- New synthesis of 4-methoxyisophthalic acid
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A new synthetic route to 4-methoxyisophthalic acid, the key intermediate in the synthesis of Picotamide, is reported. The new protocol starts from commercially available and cheap 4-methylphenol and includes four steps: esterification, Fries rearrangement, methylation, and oxidation; the overall yield is 49%. Unlike the traditional Blanc chloromethylation/oxidation scheme, the proposed procedure avoids using volatile and corrosive hydrochloric acid.
- Liu,Yan,Wang,Li,Liu
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- A simple, two-step conversion of various iodoarenes to (diacetoxyiodo)arenes with chromium(VI) oxide as the oxidant
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Chromium(VI) oxide, an inexpensive and easily handled oxidant, dissolved in the anhydrous acetic acid/acetic anhydride/concentrated H2SO4 liquid system effectively oxidizes various iodoarenes ArI to the respective iodine(III) intermediates AxISO4 and/or ArI(OSO3H)2. The resulting solutions were mixed with excess 20% aqueous ammonium acetate solution to give, after filtration and purification, (diacetoxyiodo)arenes ArI(OAc)2 in 58-82% yields.
- Kazmierczak, Pawel,Skulski, Lech
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- Theoretical and experimental studies on selective oxidation of aromatic ketone by performic acid
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The Baeyer-Villiger (B-V) reactions of 3,4-dimethoxy acetophenone (DMOAP), 4-methyl acetophenone (MAP), and acetophenone (AP) with performic acid (PFA) in formic acid (FA) solvent have been studied by density functional theory (DFT) method. The noncatalyzed and the formic acid-catalyzed reaction paths have been calculated at the MPWB1K/6-311++G(d,p)-IEF-PCM// MPWB1K/6-311G(d,p) level of theory. On the basis of the calculations, the attack of peracid to the carbonyl carbon is rate-determining in both the noncatalyzed and acid-catalyzed paths. The selective oxidation of 3,4-dimethoxy acetophenone and 4-methyl acetophenone by performic acid into aromatic esters have been experimentally investigated. The kinetic rate constants were obtained in the temperature range of 303 to 323 K. The selectivity of product was also explained by the NBO electric charge analysis. The calculated activation energy barriers of the B-V reaction of DMOAP and MAP were in good agreement with those of experiment.
- Liu, Bo,Meng, Xiang-Guang,Li, Wei-Yi,Zhou, Liang-Chun,Hu, Chang-Wei
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- Direct Acetoxylation of Arenes
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Acetoxylation of arenes is an important reaction and an unmet need in chemistry. We report a metal-free, direct acetoxylation reaction using sodium nitrate under an anhydrous environment of trifluoroacetic acid, acetic acid, and acetic anhydride. Arenes (31 examples), with oxidation potentials (Eox, in V vs SCE) lower than benzene (2.48 V), were acetoxylated with good yields and regioselectivity. A stepwise, single electron-transfer mechanism is proposed.
- Hong Nguyen, Thi Anh,Hou, Duen-Ren
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supporting information
p. 8127 - 8131
(2021/08/23)
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- An efficient method to prepare aryl acetates by the carbonylation of aryl methyl ethers or phenols
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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.
- Zhang, Dejin,Yang, Guoqiang,Xiong, Junping,Liu, Jia,Hu, Xingbang,Zhang, Zhibing
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p. 2683 - 2687
(2021/02/16)
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- Steric effect of NHC ligands in Pd(II)–NHC-catalyzed non-directed C–H acetoxylation of simple arenes
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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.
- Mandal, Tanmoy,Yadav, Sudha,Choudhury, Joyanta
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- Method for promoting acylation of amine or alcohol by carbon dioxide
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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.
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Paragraph 0034-0035
(2021/05/29)
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- Novel p-functionalized chromen-4-on-3-yl chalcones bearing astonishing boronic acid moiety as MDM2 inhibitor: Synthesis, cytotoxic evaluation and simulation studies
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Background: Novel 4-[3-(6/7/8-Substituted 4-Oxo-4H-chromen-3-yl)acryloyl]phenyl-boronic acid derivatives (5a-h) as well as other 6/7/8-substituted-3-(3-oxo-3-(4-substituted-phenyl)prop-1-enyl)-4H-chromen-4-one derivatives (3a-u) have been designed as p53-MDM2 pathway inhibitors and reported to possess significant cytotoxic properties against several cancer cell lines. Objectives: The current project aims to frame the structure-anticancer activity relationship of chromen-4-on-3-yl chalcones (3a-u/5a-h). In addition, docking studies were performed on these chromeno-chalcones in order to have an insight into their interaction possibilities with MDM2 pro-tein. Methods: Twenty-nine chromen-4-on-3-yl chalcone derivatives (3a-u/5a-h) were prepared by utilizing silica supported-HClO4 (green route with magnificent yield) and tested against four cancer cell lines (HCT116, MCF-7, THP-1, NCIH322). Results: Among the series 3a-u, compound 3b exhibited the highest anticancer activity (with IC50 values ranging from 8.6 to 28.4 μM) overall against tested cancer cell lines. Interestingly, para-Boronic acid derivative (5b) showed selective inhibition against colon cancer cell line, HCT-116 with an IC50 value of 2.35 μM. Besides the emblematic hydrophobic interactions of MDM2 inhibi-tors, derivative 5b was found to exhibit extra hydrogen bonding with GLN59 and GLN72 residues of MDM2 in molecular dynamics (MD) simulation. All the compounds were virtually nontoxic against normal fibroblast cells. Conclusion: Novel compounds were obtained with good anticancer activity especially 6-Chlorochromen-4-one substituted boronic acid derivative 5b. The molecular docking study proposed good activity as a MDM-2 inhibitor suggesting hydrophobic as well as hydrogen bonding interactions with MDM2.
- Bhatia, Richa Kaur,Coutinho, Evans C.,Garg, Ruchika,Kancherla, Satyavathi,Kaur, Maninder,Madan, Jitender,Pissurlenkar, Raghuvir R. S.,Singh, Lakhwinder,Yadav, Manmohan
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p. 212 - 228
(2020/03/10)
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- Synthesis and anti-inflammatory activity of 2-oxo-2H-chromenyl and 2H-chromenyl-5-oxo-2,5-dihydrofuran-3-carboxylates
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Cycloaddition reaction of 4-chloro-2-oxo-2H-chromene-3-carbaldehydes (3a-g) and 4-chloro-2H-chromene-3-carbaldehydes (7a-h) with activated alkynes (4a-b) provided the 2-oxo-2H-chromenyl-5-oxo-2,5-dihydrofuran-3-carboxylates (5a-n) and 2H-chromenyl-5-oxo-2,5-dihydrofuran-3-carboxylates (8a-p). All the prepared compounds were screened for anti-inflammatory activity. In vitro anti-inflammatory activity data demonstrated that the compounds 5g, 5i, 5k-l and 8f are effective among the tested compounds against TNF-α (1.108 ± 0.002, 0.423 ± 0.022, 0.047 ± 0.001, 0.070 ± 0.002 and 0.142 ± 0.001 μM) in comparison with standard compound Prednisolone (0.033 ± 0.002 μM). Based on in vitro results, three compounds (5i, 5k and 8f) have been selected for in vivo experiments and these compounds are identified as better compounds with respect to anti-inflammatory activity in LPS induced mice model. Compound 5i was identified as potent and showed significant reduction in TNF-α and IL-6.
- Bhimapaka, China Raju,Karri, Shailaja,Kuncha, Madhusudana,Kurma, Siva Hariprasad,Sistla, Ramakrishna
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- Substrate substitution effects in the Fries rearrangement of aryl esters over zeolite catalysts
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The catalytic transformation of aryl esters to hydroxyacetophenones via Fries rearrangement over solid acids is of interest to avoid the use of corrosive and toxic Lewis and Br?nsted acids traditionally applied. Microporous zeolites are known to catalyze the reaction of simple substrates such as phenyl acetate, but their application to substituted derivatives has received limited attention. To refine structure-activity relationships, here we examine the impact of various parameters including the solvent polarity, water content, acidic properties, and framework type on the reaction scheme in the Fries rearrangement of p-tolyl acetate over common solid acids. The results confirm the importance of providing a high concentration of accessible Br?nsted acid sites, with beta zeolites exhibiting the best performance. Extension of the substrate scope by substituting methyl groups in multiple positions identifies a framework-dependent effect on the rearrangement chemistry and highlights the potential for the transformation of dimethylphenyl acetates. Kinetic studies show that the major competitive path of cleavage of the ester C-O bond usually occurs in parallel to the Fries rearrangement. The possibility of sequentially acylating the resulting phenol depends on the substrate and reaction conditions.
- Bonrath, Werner,Létinois, Ulla,Lin, Ronghe,Medlock, Jonathan,Mitchell, Sharon,Netscher, Thomas,Pérez-Ramírez, Javier,Stemmler, René T.
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p. 4282 - 4292
(2020/07/30)
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- Preparation method for phenyl acetate compound
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The invention discloses a preparation method for a phenyl acetate compound. The preparation method comprises the following steps: taking substituted phenol shown as formula (I) and acetic anhydride asreaction raw materials, taking a sodium hydroxide aqueous solution as a solvent, and performing esterification reaction in a tubular reactor, thereby acquiring the phenyl acetate compound shown as formula (II). The reaction formula is as follows. In formula (I) and formula (II), substituent group R is hydrogen, C1-C6 alkyl, nitro, cyano group, halogen, carboxyl or C1-C12 alkoxycarbonyl. The manner of approximate plug flow tubular reaction is adopted by the invention, so that materials in tubular reaction almost are free from back mixing, mass and heat transfer efficiency is high, happening ofside reaction is obviously reduced and product yield and purity are both higher.
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Paragraph 0017; 0018
(2019/04/10)
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- Copper-Catalyzed Acetylation of Electron-Rich Phenols and Anilines
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An approach has been developed for the copper-catalyzed acetylation of phenols and anilines with potassium thioacetate as an acetylating reagent. Although only electron-rich phenols and anilines are compatible with this protocol, the reaction can provide moderate to high yields under mild conditions. Compared with other acetylating reagents, the current reagent has certain advantages, such as its low cost, easy availability, stability, insensitivity to water or air, and ease of storage.
- Zhang, Jieyu,Ke, Qiumin,Tian, Feitao,Jiang, Bei,Ji, Chang-An,Zhang, Lingling,Yu, Jian,Huang, Dayun,Yan, Guobing
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supporting information
p. 726 - 730
(2019/03/26)
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- Method for synthesizing phenyl acetate derivatives
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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.
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Paragraph 0039-0044
(2019/05/08)
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- Synthetic process of esmolol intermediate 3-(4-hydroxyphenyl) methyl propionate
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The invention belongs to the field of medicinal chemical industry, and particularly relates to a synthetic process of an esmolol intermediate 3-(4-hydroxyphenyl) methyl propionate. The synthetic process comprises the steps of: adopting p-methyl phenol and acetic anhydride as raw materials, performing an acylation reaction to obtain (4-methyl) phenol acetate, performing a halogenation reaction between the obtained (4-methyl) phenol acetate and a halogenating reagent, then carrying out a substitution reaction between the halogenated product and diethyl malonate, performing hydrolysis decarboxylation, and then carrying out an esterification reaction between the obtained product with methanol to obtain the 3-(4-hydroxyphenyl) methyl propionate. Through the route of the synthetic process, the process conditions are optimized, and the synthetic process has simple operation, easy and available raw materials and low cost; and the 3-(4-hydroxyphenyl) methyl propionate is obtained finally through acylation, halogenation, substitution, hydrolysis decarboxylation and the esterification reaction, and the synthetic process has a good industrial value and a total yield of 48.8%.
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Paragraph 0020; 0023; 0024; 0030
(2018/11/03)
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- Ultrasound-assisted synthesis and antimicrobial activity of tetrazole-based pyrazole and pyrimidine derivatives
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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.
- Dofe, Vidya S.,Sarkate, Aniket P.,Shaikh, Zarina M.,Gill, Charansingh H.
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- Practical and efficient synthesis of hydroxyaryl ketones catalyzed by HF@SiO2 under solvent-free condition
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A wide variety of hydroxyaryl ketones bearing different motifs was successfully synthesized with good yields and excellent selectivities in the presence of HF@SiO2 as an environmental friendly acid under solvent-free condition. Mild and green reaction conditions and excellent yields (50-91%) make this method an attractive method for the efficient synthesis of hydroxyaryl ketones. Fries rearrangement of phenyl benzoate in the presence of HF@SiO2 led to p-hydroxybenzophenone, while phenyl acetate in the same conditions produced o-hydroxyacetophenone as a single isomer.
- Paghandeh, Hossein,Saeidian, Hamid,Ghaffarzadeh, Mohammad
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p. 809 - 814
(2018/09/26)
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- Enhanced shape selective catalysis of mixed cyclic ketones in aerobic Baeyer-Villiger oxidation with magnetic Cu-Fe3O4 supported mesoporous silica microspheres
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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.
- Zheng, Chunming,Chang, Shubin,Yang, Chuanwu,Lian, Dongying,Ma, Chao,Zhang, Chunrong,Fan, Xiangrui,Xu, Shichao,Sun, Xiaohong
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p. 2608 - 2616
(2018/04/23)
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- Efficient Baeyer–Villiger Oxidation Catalysed by Silver Nanoparticles Stabilized on Modified Montmorillonite
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Abstract: Silver nanoparticles supported on modified montmorillonite clay (Ag-NPs@mont), were utilized as catalyst for the Baeyer–Villiger oxidation of various ketones with hydrogen peroxide as an oxidant under solvent free condition at room temperature. The modification of Montmorillonite K10 clay was carried out with HCl under controlled conditions for generating a high surface area porous matrix which acts as support for the in situ generation of Silver nanoparticles. The synthesized nanocomposite material was characterized by UV–Visible spectroscopy, powder XRD, SEM-EDX, TEM and N2 adsorption–desorption analysis. The catalyst can be recycled and reused several times without significant loss of their catalytic activity. Graphical Abstract: [Figure not available: see fulltext.].
- Borah, Subrat Jyoti,Das, Diganta Kumar
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p. 3669 - 3677
(2018/11/21)
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- A PdII Carbene Complex with Anthracene Side-Arms for π-Stacking on Reduced Graphene Oxide (rGO): Activity towards Undirected C–H Oxygenation of Arenes
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An N-heterocyclic carbene palladium(II) complex containing two anthracene side arms was immobilized on the surface of reduced graphene oxide (rGO) by π-stacking. The activity of the homogeneous analogue and the supported complex in undirected C–H acetoxylation reaction of arenes was studied. The results show that the catalytic efficiency in acetoxylation of benzene is improved in the immobilized materials compared to the homogeneous analogue. According to XPS analysis, the immobilized catalyst maintains the original oxidation state of PdII after the catalytic reaction.
- Majeed, Maitham H.,Shayesteh, Payam,Persson, Axel R.,Wallenberg, L. Reine,Schnadt, Joachim,Wendt, Ola F.
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supporting information
p. 4742 - 4746
(2018/11/27)
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- Preparation method of aryl carboxylate compound based on alkenyl carboxylate ester exchange reaction
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The invention provides a preparation method of an aryl carboxylate compound based on alkenyl carboxylate ester exchange reaction and belongs to the technical field of pharmaceutical chemical intermediates and related chemistry. According to the method, phenol and alkenyl carboxylate are used as raw materials and green and efficient synthesis of the aryl carboxylate compound is realized under the catalysis effect of alkali. The method has the advantages of high selectivity, moderate reaction conditions, good functional group compatibility, wide substrate range, environment friendliness and thelike. The aryl carboxylate compound is an important organic synthetic intermediate and has very wide application in the fields of organic synthesis and pharmacology, so that the preparation method hasvery great application value and social economic benefits.
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Paragraph 0052; 0053; 0054
(2018/10/11)
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- Na 2 CO 3-Catalyzed O-Acylation of Phenols for the Synthesis of Aryl Carboxylates with Use of Alkenyl Carboxylates
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Inorganic base-catalyzed O-acylation of phenol and its derivatives has been developed. The procedure provides an efficient catalysis system for the preparation of aryl carboxylates with alkenyl carboxylates as acyl reagents. The reaction proceeded smoothly by using ?-Na 2 CO 3 as the catalyst in MeCN to produce the corresponding aryl carboxylates in good to excellent yields.
- Zhou, Xiao-Yu,Chen, Xia
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supporting information
p. 2321 - 2325
(2018/10/20)
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- Size-selective catalysts in five functionalized porous coordination polymers with unsaturated zinc centers
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The five reported structural isomorphic porous coordination polymers (PCPs) 1-5, namely, [Zn(L)(ip) (1), Zn(L)(aip) (2), Zn(L)(hip) (3), Zn(L)(nip) (4), and Zn(L)(HBTC) (5) (L = N4,N4′-di(pyridine-4-yl)biphenyl-4,4′-dicarboxamide, H2ip = isophthalic acid, H2aip = 5-aminoisophthalic acid, H2hip = 5-hydroxyisophthalic acid, H2nip = 5-nitroisophthalic acid, H3BTC = 1,3,5-benzenetricarboxylic acid)] were used to catalyze the acetylation of phenol. All these heterogeneous catalysts exhibit good catalytic efficiency and size-selectivity toward the acetylation of phenols owing to their unsaturated metal centers, non-coordinated amide, and suitable channel size and shape. Among them, 2 displays the highest catalytic activity and excellent cooperative catalysis due to the presence of basic non-coordinated amide groups.
- Deng, Dongsheng,Guo, Hui,Ji, Baoming,Wang, Weizhou,Ma, Lufang,Luo, Feng
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p. 12611 - 12616
(2017/11/06)
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- "Click Chemistry" Mediated Functional Microporous Organic Nanotube Networks for Heterogeneous Catalysis
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The synthesis of azide functional microporous organic nanotube networks (N3-MONNs) via a Friedel-Crafts hyper-cross-linking reaction is reported. Subsequently, a general method for obtaining heterogeneous catalysts through a Cu-catalyzed alkyne-azide reaction is presented. The small-molecule catalysts such as 2,2,6,6,-tetramethylpiperidine-1-oyl and 4-(N,N-dimethylamino)pyridine can be anchored into the MONNs. Owing to the hierarchically porous structure and high surface area, these catalysts show high activity in selective oxidation of alcohols and acylation reaction, respectively.
- Yu, Wei,Zhou, Minghong,Wang, Tianqi,He, Zidong,Shi, Buyin,Xu, Yang,Huang, Kun
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supporting information
p. 5776 - 5779
(2017/11/10)
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- Diazepinium perchlorate: a neutral catalyst for mild, solvent-free acetylation of carbohydrates and other substances
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Diazepinium perchlorate, an essentially neutral organic salt possessing excellent stability, has been found to be well suited for the acetylation of free as well as partially protected sugars, phenols, thiophenols, thiols and other alcohols as well as amines. The diazepinium perchlorate-catalyzed acetylation is mild, organic and solvent-free and leaves acid sensitive protecting groups such as TBDMS/TBDPS/Tr ethers and isopropylidene/benzylidene acetals present on a substrate unaffected. Regioselective hydroxyl protection in partially protected carbohydrate derivatives/polyhydroxylic compounds was possible and was proved to be a convenient time-saving alternative to the conventional synthesis of such compounds. Easy preparation of the catalyst, mild reaction conditions and an environmentally benign protocol are some of the notable features of this reaction. The results obtained on the acetylation of phenols and thiophenols could be rationalized through their local nucleophilicity index obtained from DFT calculations.
- Giri, Santosh Kumar,Gour, Rajesh,Kartha, K. P. Ravindranathan
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p. 13653 - 13667
(2017/03/11)
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- Synthesis, characterization and antibacterial activity of nanocrystalline Ni(II)-6-methyl-4-oxo-4H-chromene-3-carbaldehyde complex
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The methyl substituted 3-formyl chromones was synthesized by Vilsmeier-Haack reaction. Nickel(II) complex was synthesized by refluxing the mixture of ligand solution taken into ethanol:acetic acid as 1:1 ratio and Ni(II) salt solution. The nature of bonding and geometry of the Ni(II) complex have been characterized from elemental analysis, FTIR, UV-visible spectral studies, thermal methods like TGA, the magnetic susceptibility, XRD, SEM, ESI-MS and molar conductance measurement, etc. Nickel(II) chloride is forming 1:2 (M:L) complex. The FTIR spectrum shows characteristic frequency band at 1614 cm-1 and 1695 cm-1, which belongs to carbonyl of pyron ring and neighboring aldehyde carbonyl in ligand respectively. The Ni(II)-ligand complex shows characteristic frequency of M-O- bonding in 545-466 cm-1 region. The electronic spectrum shows three absorption bands and confirmed complex has octahedral geometry. The formation of nanocrystalline complex and their bird feather like morphology was identified by powder XRD and SEM. Finally, NiO residue was obtained in thermogravimetric study of the complex. The ligand and its Ni(II) complex were screened for antimicrobial activities by the agar well diffusion technique.
- Kolhe,Jadhav,Takate,Aware,Athare
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p. 119 - 123
(2016/12/22)
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- Synthesis, antimicrobial activity and anti-biofilm activity of novel tetrazole derivatives
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In the development of antimicrobial agents, we designed and synthesized novel tetrazole derivatives. The structures of compounds 6a-f and 7a-f were characterized by IR, 1H NMR, 13C NMR, MS and elemental analysis. These compounds were tested for their antimicrobial activity against a series of strains Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa and for antifungal activity against the strains Candida albicans, Candida glabrata, and Candida tropicalis. Compounds 6e, 6f, 7a, and 7f exhibit potent antimicrobial activities compared to the reference drugs streptomycin and miconazole. Tetrazole derivatives 7a-f also inhibit biofilm formation and compound 7f exhibits best anti-biofilm activity with a biofilm inhibitory concentration (BIC) as low as 0.9 μm.
- Dofe, Vidya S.,Sarkate, Aniket P.,Kathwate, Santosh H.,Gill, Charansingh H.
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p. 325 - 330
(2017/08/18)
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- Copper-Catalyzed C-S Bond Formation via the Cleavage of C-O Bonds in the Presence of S8 as the Sulfur Source
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Useful and applicable methods for one-pot and odorless synthesis of unsymmetrical and symmetrical diaryl sulfides via C-O bond activation are presented. First, a new efficient procedure for the synthesis of unsymmetrical sulfides using the cross-coupling reaction of phenolic esters such as acetates, tosylates, and triflates and with arylboronic acid or triphenyltin chloride as the coupling partners is reported. Depending on the reaction, S 8 /KF or S 8 /NaO t -Bu system is found to be an effective source of sulfur in the presence of copper salts and in poly(ethylene glycol) as a green solvent. Then, the synthesis of symmetrical diaryl sulfides from phenolic compounds by using S 8 as the sulfur source and NaO t -Bu in anhydrous DMF at 120 °C under N 2 is described. By these protocols, the synthesis of a variety of unsymmetrical and symmetrical sulfides become easier than the available protocols in which thiols and aryl halides are directly used for the preparation of the sulfides.
- Rostami, Abed,Rostami, Amin,Ghaderi, Arash,Gholinejad, Mohammad,Gheisarzadeh, Sajedeh
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p. 5025 - 5038
(2017/10/06)
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- A process for preparing 5 - substituted benzyl - 2, 4 - diamino pyrimidine and its derivatives (by machine translation)
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The invention discloses a process for preparing 5 - substituted benzyl - 2, 4 - diamino pyrimidine and derivatives thereof, in particular can be used for preparing omay pullin, b a oxygen animal pen amine pyrimidine, such as palestinian kuikui purin. The invention relates to 5 - hydroxymethyl uracil as raw materials, through the electrophilic substitution reaction, chlorinated, amino and hydrolysis step preparation 5 - substituted benzyl - 2, 4 - diamino pyrimidine and its derivatives. The method can be used for preparing various 5 - substituted benzyl - 2, 4 - diaminopyrimidines of the molecule, thereby avoiding the high-pressure reaction step, the safety is high, and is suitable for industrial production. (by machine translation)
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Paragraph 0049; 0053; 0057
(2018/01/11)
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- Regioselective Baeyer-Villiger oxidation of lignin model compounds with tin beta zeolite catalyst and hydrogen peroxide
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Lignin depolymerization represents a promising approach to the sustainable production of aromatic molecules. One potential approach to the stepwise depolymerization of lignin involves oxidation of the benzylic alcohol group in β-O-4 and β-1 linkages, followed by Baeyer-Villiger oxidation (BVO) of the resulting ketones and subsequent ester hydrolysis. Towards this goal, BVO reactions were performed on 2-adamantanone, a series of acetophenone derivatives, and lignin model compounds using a tin beta zeolite/hydrogen peroxide biphasic system. XRD, 119Sn MAS NMR spectroscopy, DRUVS and XPS were used to determine tin speciation in the catalyst, the presence of both framework Sn and extra framework SnO2 being inferred. Conversion of ketones to BVO products was affected by electron donation as well as steric hindrance, 4′-methoxyacetophenone affording the highest yield of ester (81%). As the size and complexity of the ketone increased, excess hydrogen peroxide was typically needed for successful BVO. Yields of ester products derived from β-O-4 and β-1 lignin models were modest due to the formation of polymeric material stemming from direct ring hydroxylation.
- Jennings, John A.,Parkin, Sean,Munson, Eric,Delaney, Sean P.,Calahan, Julie L.,Isaacs, Mark,Hong, Kunlun,Crocker, Mark
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p. 25987 - 25997
(2017/07/07)
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- Continuous Production of Biorenewable, Polymer-Grade Lactone Monomers through Sn-Β-Catalyzed Baeyer–Villiger Oxidation with H2O2
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The Baeyer–Villiger oxidation is a key transformation for sustainable chemical synthesis, especially when H2O2 and solid materials are employed as oxidant and catalyst, respectively. 4-substituted cycloketones, which are readily available from renewables, present excellent platforms for Baeyer–Villiger upgrading. Such substrates exhibit substantially higher levels of activity and produce lactones at higher levels of lactone selectivity at all values of substrate conversion, relative to non-substituted cyclohexanone. For 4-isopropyl cyclohexanone, which is readily available from β-pinene, continuous upgrading was evaluated in a plug-flow reactor. Excellent selectivity (85 % at 65 % conversion), stability, and productivity were observed over 56 h, with over 1000 turnovers (mol product per mol Sn) being achieved with no loss of activity. A maximum space–time yield that was almost twice that for non-substituted cyclohexanone was also obtained for this substrate [1173 vs. 607 g(product) kg(catalyst)?1 cm?3 h?1]. The lactone produced is also shown to be of suitable quality for ring opening polymerization. In addition to demonstrating the viability of the Sn-β/H2O2 system to produce renewable lactone monomers suitable for polymer applications, the substituted alkyl cyclohexanones studied also help to elucidate steric, electronic, and thermodynamic elements of this transformation in greater detail than previously achieved.
- Yakabi, Keiko,Mathieux, Thibault,Milne, Kirstie,López-Vidal, Eva M.,Buchard, Antoine,Hammond, Ceri
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p. 3652 - 3659
(2017/09/13)
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- Preparation of acetates catalyzed by boric acid and/or tungstophosphoric acid-modified zirconia obtained employing polyethylene glycols as pore-forming agents
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Zirconia modified with boric acid and/or tungstophosphoric acid calcined at 320 °C were prepared, characterized and used as catalysts in the production of acetates from diverse alcohols and phenols. Polyethylene glycol (PEG) of different molecular weight (400, 2000, 6000 Da) were added as low cost pore-forming agents during zirconia synthesis using zirconyl chloride as precursor and ammonium hydroxide as precipitating agent. The zirconias were impregnated with aqueous solutions of boric acid and/or tungstophosphoric acid (TPA). The borated zirconias, zirconias modified with TPA and zirconias doped with both boron and TPA were amorphous mesoporous materials with very strong acid sites, and specific surface areas SBET of around 200, 100, and 150 m2/g, respectively. The FT-IR spectra of borated zirconias exhibited the bands of boron species, while the zirconias modified with TPA presented the characteristic bands of tungstophosphate anion, and the zirconias doped with both boron and TPA showed a degradation of the TPA anion, confirmed by 31P MAS-NMR. The borated zirconias and the zirconias modified with TPA gave excellent selectivity and yield in the 2-phenylethanol esterification with acetic acid. The use of these materials allows obtaining higher or similar results than those reported in the literature. Zirconias doped with both boron and TPA gave lower values, due to the transformation of the [PW12O40]3? Keggin anion in to the [P2W21O71]6? and [PW11O39]7? species. The reactivity towards acetylation with acetic acid of different alcohols and phenols using the best catalyst was ordered according to: primary alcohols > secondary alcohols > phenols. The reactivity difference of the alcohols and phenols was correlated with the electronic density on the oxygen atom and steric effects.
- Osiglio, Lilian,Sathicq, Gabriel,Pizzio, Luis,Romanelli, Gustavo,Blanco, Mirta
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- Polymer-Supported Palladium(II) Carbene Complexes: Catalytic Activity, Recyclability, and Selectivity in C?H Acetoxylation of Arenes
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Heterogeneous catalysts for selective oxidation of C?H bonds were synthesized by co-polymerization of new N-heterocyclic carbene-palladium(II) (NHC-PdII) monomers with divinylbenzene. The polymer-supported NHC-PdII-catalysed undirect
- Majeed, Maitham H.,Shayesteh, Payam,Wallenberg, L. Reine,Persson, Axel R.,Johansson, Niclas,Ye, Lei,Schnadt, Joachim,Wendt, Ola F.
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supporting information
p. 8457 - 8465
(2017/06/28)
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- Silanediol-Catalyzed Chromenone Functionalization
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Promising levels of enantiocontrol are observed in the silanediol-catalyzed addition of silyl ketene acetals to benzopyrylium triflates. This rare example of enantioselective, intermolecular chromenone functionalization with carbonyl-containing nucleophiles has potential applications in the synthesis of bioactive chromanones and tetrahydroxanthones.
- Hardman-Baldwin, Andrea M.,Visco, Michael D.,Wieting, Joshua M.,Stern, Charlotte,Kondo, Shin-Ichi,Mattson, Anita E.
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supporting information
p. 3766 - 3769
(2016/08/16)
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- New gas-phase domino processes leading to benzopyranones and benzofurans
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A new domino approach to flavones by gas phase pyrolysis of β,γ-dioxophosphonium ylides containing a 2-methoxyphenyl group is frustrated by unexpected and novel decarbonylation of the intermediate flavon-3-yl radical leading to 2-phenylbenzofuran. Alternative approaches based on dioxolane protection of one carbonyl, or selective elimination in β,β′-dioxo or β-oxo-β′-thioxo ylides were not successful, but pyrolysis of a β-oxo-β′-phenylimino ylide did give the required domino reaction leading to a protected benzopyranone in moderate yield.
- Aitken, R. Alan,Chang, Da
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p. 164 - 184
(2017/03/11)
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- Synthesis, structure and multifunctional catalytic properties of a Cu(i)-coordination polymer with outer-hanging CuBr2
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A 1D Cu(i)-coordination polymer [(CuL1)(CuBr2), 1] carrying external copper bromide moieties was synthesized. The outer-hanging [CuBr2]- moiety is attached to the 1D Cu(i)-CP backbone via a Cu?Cu bonding interaction, which makes it look like a coordination polymer supported CuBr2 species. 1 exhibits excellent multifunctional catalytic activity for phenol acetylation, A3-coupling (aldehyde-alkyne-amine) and styrene oxide methanolysis reactions. Its heterogeneous catalytic nature was confirmed by solution leaching experiment and it can be reused without significant loss of its catalytic activity and selectivity for the above reactions.
- Zhu, Neng-Xiu,Zhao, Chao-Wei,Yang, Jing,Wang, Xue-Ru,Ma, Jian-Ping,Dong, Yu-Bin
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p. 108645 - 108653
(2016/11/30)
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- Highly efficient and recyclable acetylation of phenols and alcohols by nickel zirconium phosphate under solvent-free conditions
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Nickel zirconium phosphate nanoparticles have been used as an efficient catalyst for the acetylation of a wide range of alcohols and phenols with acetic anhydride in good to excellent yields under solvent-free conditions. The steric and electronic properties of the different substrates had a significant influence on the reaction conditions required to achieve the acetylation. The catalyst used in the current study was characterized by inductively coupled plasma optical emission spectroscopy, X-ray diffraction, N2 adsorption-desorption, scanning electron microscopy, and transmission electron microscopy. This nanocatalyst could also be recovered and reused at least six times without any discernible decrease in its catalytic activity.
- Hajipour, Abdol Reza,Karimi, Hirbod,Kohi, Afshin
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- 1,2,3-Triazole tethered acetophenones: Synthesis, bioevaluation and molecular docking study
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A small focused library of eighteen new 1,2,3-triazole tethered acetophenones has been efficiently prepared via click chemistry approach and evaluated for their antifungal and antioxidant activity. The antifungal activity was evaluated against five human pathogenic fungal strains: Candida albicans, Fusarium oxysporum, Aspergillus flavus, Aspergillus niger, and Cryptococcus neoformans. Among the synthesized compounds, 9c, 9i, and 9p found to be more potent antifungal agents that the reference standard. These 1,2,3-triazole based derivatives were also evaluated for antioxidant activity, and compound 9h was found to be the most potent antioxidant as compared to the standard drug. Furthermore, molecular docking study of the newly synthesized compounds was performed and results showed good binding mode in the active site of fungal C. albicans enzyme P450 cytochrome lanosterol 14α-demethylase. Moreover, the synthesized compounds were also analyzed for ADME properties and showed potential as good oral drug candidates.
- Shaikh, Mubarak H.,Subhedar, Dnyaneshwar D.,Khedkar, Vijay M.,Jha, Prakash C.,Khan, Firoz A. Kalam,Sangshetti, Jaiprakash N.,Shingate, Bapurao B.
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supporting information
p. 1058 - 1063
(2016/07/29)
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- P4VPy–CuO nanoparticles as a novel and reusable catalyst: application at the protection of alcohols, phenols and amines
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P4VPy–CuO nanoparticles were synthesized using ultrasound irradiations. Relevant properties of the synthesized nanoparticles were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Fourier transform infrared spectroscopy. After identification, the prepared reagent was used for the promotion of different types of protection reactions of alcohols, phenols and amines. Easy workup, short reaction times, excellent yields, relatively low cost and reusability of the catalyst are the striking features of the reported methods.
- Shirini, Farhad,Fallah-Shojaei, Abdollah,Abedini, Masoumeh,Samavi, Laleh
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p. 1699 - 1712
(2016/07/27)
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- Photochemistry of aroyloxiranes: Substituent effect on oxepinones and hydroxyalkenones formation
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The photo-irradiation of some aroyloxiranes with Pyrex filtered UV-light from 125?W medium pressure Hg lamp has been described. These compounds furnished the 2-aryl-4,10-dihydrofuro[3,2-c][1]benzoxepin-10-ones and the hydroxyalkenones by the photochemical irradiation. The product(s) formation/distribution in terms of oxepinones and the hydroxyalkenones largely depended upon the nature of the substituent: the oxiranes having electron-donating groups in their benzoyl moiety gave the hydroxyalkenones while oxiranes having electron-withdrawing groups furnished the oxepinones as the major products. The formation of oxepinones has been envisaged to occur through the heterolytic [Formula presented] bond cleavage of epoxide to give carbonyl ylide intermediates followed by the furo-oxepinone ring formation via [3+2] cycloaddition and of hydroxyalkenones through the initial β-H abstraction followed by epoxide ring opening. The structures of all the compounds (substrates and photoproducts) have been determined on the basis of their spectral data (IR, NMR and Mass).
- Dalal, Aarti,Khanna, Radhika,Berar, Urmila,Kamboj, Ramesh C.
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p. 238 - 245
(2016/07/22)
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- Stabilized Fe3O4 magnetic nanoparticles into nanopores of modified montmorillonite clay: A highly efficient catalyst for the Baeyer-Villiger oxidation under solvent free conditions
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In situ generation of Fe3O4 magnetic nanoparticles (Fe3O4@AT-mont.) into the nanopores of modified montmorillonite (AT-mont.) clay has been carried out. Modification of the montmorillonite was done by acid (4 M HCl) activation under controlled conditions for generating nanopores, which act as a "host" for the Fe3O4 nanoparticles. The synthesized Fe3O4@AT-mont. was characterized by PXRD, TEM, SEM-EDX, XPS, VSM and surface area analysis. The average particle size of Fe3O4 nanoparticles was found to be around 10 nm and exhibit a face centered cubic (fcc) lattice geometry. Fe3O4@AT-mont. showed efficient catalytic activity for the Baeyer-Villiger oxidation of various cyclic and aromatic ketones in the presence of hydrogen peroxide as an oxidant at room temperature under solvent free conditions and exhibited conversion of up to 98%. The catalyst was magnetically recovered and recycled up to the third run without any significant loss of efficiency.
- Saikia, Pallab Kumar,Sarmah, Podma Pollov,Borah, Bibek Jyoti,Saikia, Lakshi,Saikia, Kokil,Dutta, Dipak Kumar
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p. 2843 - 2850
(2016/06/06)
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- Mesoporous sulfonic acid silicas for pyrolysis bio-oil upgrading via acetic acid esterification
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Propylsulfonic acid derivatised SBA-15 catalysts have been prepared by post modification of SBA-15 with mercaptopropyltrimethoxysilane (MPTMS) for the upgrading of a model pyrolysis bio-oil via acetic acid esterification with benzyl alcohol in toluene. Acetic acid conversion and the rate of benzyl acetate production was proportional to the PrSO3H surface coverage, reaching a maximum for a saturation adlayer. Turnover frequencies for esterification increase with sulfonic acid surface density, suggesting a cooperative effect of adjacent PrSO3H groups. Maximal acetic acid conversion was attained under acid-rich conditions with aromatic alcohols, outperforming Amberlyst or USY zeolites, with additional excellent water tolerance.
- Manayil, Jinesh C.,Inocencio, Carlos V. M.,Lee, Adam F.,Wilson, Karen
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p. 1387 - 1394
(2016/03/09)
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- Ligand-Promoted Palladium-Catalyzed C?H Acetoxylation of Simple Arenes
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The palladium-catalyzed C?H oxidation of simple arenes is an attractive strategy to obtain phenols, which have many applications in the fine chemicals industry. Although some advances have been made in this research area, low reactivity and selectivity are, in general, observed. This report describes a new catalytic system for the efficient C?H acetoxylation of simple arenes based on Pd(OAc)2 and a pyridinecarboxylic acid ligand.
- Valderas, Carolina,Naksomboon, Kananat,Fernández-Ibá?ez, M. ángeles
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p. 3213 - 3217
(2016/10/24)
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- Acetylation of alcohols and phenols under solvent-free conditions using iron zirconium phosphate
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Iron zirconium phosphate (ZPFe) nanoparticles were found to function as an efficient catalyst for the acetylation of a wide range of alcohols and phenols using acetic anhydride, generating good to excellent yields under solvent-free conditions. The steric and electronic properties of various substrates had a significant influence on the reaction conditions required to achieve the acetylation. The catalyst used in the current study was characterized by inductively coupled plasma-optical emission spectrometry, X-ray diffraction, N2 adsorption-desorption, scanning electron microscopy, and transmission electron microscopy. These analyses revealed that the interlayer distance in the catalyst increased from 7.5 to 9.3 ? when Fe3+ was intercalated between the layers, whereas the crystallinity of the material was reduced. This nanocatalyst could also be recovered and reused at least six times without any discernible decrease in its catalytic activity. This new method for the acetylation of alcohols and phenols has several important advantages, including mild and environmentally friendly reaction conditions, as well as good to excellent yields and a facile work-up.
- Hajipour, Abdol R.,Karimi, Hirbod,Masti, Amir
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p. 595 - 602
(2015/09/28)
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- Design, synthesis and docking studies of novel thienopyrimidine derivatives bearing chromone moiety as mTOR/PI3Kα inhibitors
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Two series of thienopyrimidine derivatives (10a-k, 16a-j) bearing chromone moiety were designed and synthesized. All the compounds were evaluated for inhibitory activity against mTOR kinase at a concentration of 10uM. Four selected compounds were further evaluated for the IC50 values against mTOR kinase, PI3Kα kinase and two cancer cell lines. Some of the target compounds exhibited moderate to excellent mTOR/PI3Kα kinase inhibitory activity and cytotoxicity. The most promising compound 16i showed good inhibitory activity against mTOR/PI3Kα kinase and good antitumor potency for H460 and PC-3 cell lines with IC50 values of 0.16 ± 0.03 μM, 2.35 ± 0.19 μM, 1.20 ± 0.23 μM and 0.85 ± 0.04 μM, which were 8.6, >5, 7.9 and 19.1 times more active than compound I (1.37 ± 0.07 μM, >10 μM, 9.52 ± 0.29 μM, 16.27 ± 0.54 μM), respectively. Structure-activity relationships (SARs) and docking studies indicated that the chromone moiety is necessary for the potent antitumor activity and cytotoxicity of these compounds. Substitution of the chromone moiety at the 6-position has a significant impact to the inhibitory activity, in particular a carboxylic acid group, produced the best potency.
- Zhu, Wufu,Chen, Chen,Sun, Chengyu,Xu, Shan,Wu, Chunjiang,Lei, Fei,Xia, Hui,Tu, Qidong,Zheng, Pengwu
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- Magnetically separable γ-Fe2O3 nanoparticles: An efficient catalyst for acylation of alcohols, phenols, and amines using sonication energy under solvent free condition
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This paper reports a facile synthesis of magnetically separable iron oxide (γ-Fe2O3) nanoparticles using thermolysis method. The structural and morphological study of the synthesized γ-Fe2O3 nanoparticles was carried out using X-ray diffraction (XRD), field emission gun-scanning electron microscopy (FEG-SEM), energy dispersive X-ray spectrum (EDS), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS) techniques. The electron microscopy reveals that the γ-Fe2O3 nanoparticles have spherical morphology with a particle size in the range of 40-100 nm. The XPS study confirmed the Fe is in +3 oxidation state. The synthesized γ-Fe2O3 nanoparticles have been used as an efficient heterogeneous catalyst for the organic transformation between phenols, alcohols, and amines with acetic anhydride under sonication using mild reaction conditions. Various electrons withdrawing and electrons donating substrates show an excellent yield of desired products with the advantage of magnetic separation and reusability of γ-Fe2O3 nanocatalyst.
- Bhosale, Manohar A.,Ummineni, Divya,Sasaki, Takehiko,Nishio-Hamane, Daisuke,Bhanage, Bhalchandra M.
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- The Baeyer-Villiger oxidation versus aromatic ring hydroxylation: Competing organic peracid oxidation mechanisms explored by multivariate modelling of designed multi-response experiments
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Peroxy acids can be used as the terminal oxidant for the Baeyer-Villiger oxidation of acetophenones and for direct ring hydroxylation of methoxy-substituted benzenes. An oxidative system involving 3-chloroperbenzoic acid (mCPBA) and 2,6-dimethoxyacetophenone as model substrate was investigated by means of statistical experimental design, multivariate modelling and response surface methodology. The outcome of the organic peracid oxidation experiments was portrayed by a multi-response matrix consisting of the yields of three different compounds; 2,6-dimethoxyphenyl acetate, 1-(4-hydroxy-2,6-dimethoxy-phenyl)ethanone and 3-hydroxy-2,6-dimethoxy-phenyl acetate. The optimized reaction protocol was utilized to investigate a series of various substituted acetophenones. The overall investigation revealed that both the molecular structure of the acetophenone substrate and the experimental conditions exhibited a substantial impact on whether the oxidation reaction follows the oxygen insertion or direct ring hydroxylation mechanism. An improved protocol for the direct ring hydroxylation was also obtained from the experimental and modelling described herein.
- Gambarotti, Cristian,Bj?rsvik, Hans-René
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p. 619 - 628
(2015/09/28)
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- Palladium-Catalyzed Desilylative Acyloxylation of Silicon-Carbon Bonds on (Trimethylsilyl)arenes: Synthesis of Phenol Derivatives from Trimethylsilylarenes
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A strategy for desilylative acetoxylation of (trimethylsilyl)arenes has been developed in which (trimethylsilyl)arenes are converted into acetoxyarenes. The direct acetoxylation is performed in the presence of 5 mol % of Pd(OAc)2 and PhI(OCOCF3)2 (1.5 equiv) in AcOH at 80°C for 17 h. The acetoxyarenes are obtained in good to high yields (67-98%). The synthetic utility is demonstrated with a one-pot transformation of (trimethylsilyl)arenes to phenols by successive acetoxylation and hydrolysis. Furthermore, desilylative acyloxylation of 2-(trimethylsilyl)naphthalene using several carboxylic acids has been conducted.
- Gondo, Keisuke,Oyamada, Juzo,Kitamura, Tsugio
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supporting information
p. 4778 - 4781
(2015/10/12)
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- Chelating Bis-N-heterocyclic Carbene-Palladium(II) Complexes for Oxidative Arene C-H Functionalization
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Bis-N-heterocyclic carbene (NHC)-chelated palladium(II) complexes have been synthesized, characterized fully including single-crystal X-ray structural analyses, and utilized for the first time toward catalytic oxidative C-H functionalization of arenes with PhI(OAc)2 and N-bromosuccinimide. (Figure Presented).
- Desai, Sai Puneet,Mondal, Moumita,Choudhury, Joyanta
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supporting information
p. 2731 - 2736
(2015/06/30)
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- Synthesis of lipase nano-bio-conjugates as an efficient biocatalyst: Characterization and activity-stability studies with potential biocatalytic applications
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In the present study, we have synthesized lipase-nano-bio-conjugates via immobilization of various lipases on multiwall carbon nano-tubes (MCNT), in order to construct an efficient and recyclable biocatalytic system. In a screening study lipase Pseudomonas fluorescens (PFL) acted as an efficient biocatalyst (lipase-nano-bio-conjugates) which showed higher retention of lipase activity and protein loading. Consequently the immobilization support : lipase (MCNT : PFL) composition was screened in which MCNT : PFL (2 : 1) was calculated as a robust biocatalyst composition which showed higher activity retention and protein loading. This nano-bio-conjugate was then characterized in detail with physical and biochemical techniques using SEM, TEM, FTIR, Km, Vmax, catalytic efficiency and (%) water content analysis. This developed biocatalyst was further used for practical biocatalytic applications such as O-acylation reactions. Various reaction parameters were optimized in detail like reactant molar ratio (2 : 3.5), solvent, MCNT : PFL biocatalyst amount (36 mg), temperature (50°C) etc. The developed biocatalytic protocol was then extended to synthesize several (twenty-two) industrially important acylated moieties with an excellent yield, these products are well characterized by 1HNMR, 13CNMR and GCMS analysis. Moreover in the present study, we have reviewed the potential industrial applications of various synthesized compounds. Also, we have studied the thermodynamic aspect which demonstrated more feasibility of use of immobilized MCNT : PFL lipase over free lipase. Interestingly, immobilized MCNT : PFL lipase showed 2.3 fold higher catalytic activity than free PFL. Besides this, the biocatalyst was efficiently recycled for up to five cycles. Thus the present protocol demonstrated, (i) synthesis of nano-bio-conjugates as a bio-catalyst, (ii) detailed physical-biochemical characterization of nano-bio-conjugates, (iii) optimization of the biocatalytic protocol (iv) practical biocatalytic applications along with a mechanistic study (v) a thermodynamic feasibility study and (vi) recyclability study. 2015
- Badgujar, Kirtikumar Chandulal,Sasaki, Takehiko,Bhanage, Bhalchandra Mahadeo
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p. 55238 - 55251
(2015/07/07)
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- Catalytic application of fluorous silica gel in Fries rearrangement
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Commercially available fluorous silica gel (Fluoro Flash) with no further post-modification was successfully investigated and applied merely as a catalyst in Fries rearrangement of various aryl esters under solvent free conditions in 4 h and optimized temperatures. In addition to good yields and recyclability of the catalyst, toxicity of reaction medium, by-products, and wastes were minimized. Also, low catalyst loading was another advantage of this methodology.
- Ghaffarzadeh, Mohammad,Ahmadi, Maryam
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- Acetylation of alcohols and phenols by zinc zirconium phosphate as an efficient heterogeneous catalyst under solvent-free conditions
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An efficient method for the acetylation of a wide range of alcohols as well as phenols with acetic anhydride in good to excellent yields under solvent-free conditions, using zinc zirconium phosphate as the catalyst was investigated. The catalyst was characterized by XRD, inductivity coupled plasma-optical emission spectroscopy, and scanning electron microscope. Products are easily isolated and the protocol is mild and green, compared to the existing methods. Graphical abstract: [Figure not available: see fulltext.]
- Hajipour, Abdol Reza,Karimi, Hirbod,Karimzadeh, Morteza
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p. 1461 - 1472
(2014/09/30)
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