- Microwave-assisted synthes is of novel chiral receptors derived from deoxycholic acid and their molecular recognition properties
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Under microwave irradiation (MWI), novel chiral receptors derived from deoxycholic acid were synthesized by using deoxycholic acid methyl ester as the spacer, and arylhydrazine and amino acids as the arm. Selective recognition properties of these receptors for aromatic amines and D/L-amino acids have been investigated by UV-vis spectral titration and 1H NMR spectral study. The results indicate this type of receptors can form a 1:1 supramolecular complex with an aromatic amine and a 1:2 supramolecular complex with D/L-tryptophan.
- Ye, Ying,Suo, Yourui,Yang, Fang,Han, Lijuan
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Read Online
- Antibacterial and Antiviral Activities of 1,3,4-Oxadiazole Thioether 4H-Chromen-4-one Derivatives
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Various 1,3,4-oxadiazole thioether 4H-chromen-4-one derivatives were conceived. The title compounds demonstrated striking inhibitory effects againstXac,Psa, andXoo. EC50data exhibited that A8 (19.7 μg/mL) had better antibacterial activity againstXoothan myricetin, BT, and TC. Simultaneously, the mechanism of action of A8 had been verified by SEM. The results of anti-tobacco mosaic virus indicated that A9 had the bestin vivoantiviral effect compared with ningnanmycin. From the data of MST, it could be seen that A9 (0.003 ± 0.001 μmol/L) exhibited a strong binding capacity, which was far superior to ningnanmycin (2.726 ± 1.301 μmol/L). This study shows that the 1,3,4-oxadiazole thioether 4H-chromen-4-one derivatives may become agricultural drugs with great potential.
- Cao, Xiao,Liu, Fang,Liu, Liwei,Liu, Tingting,Peng, Feng,Wang, Qifan,Xie, Chengwei,Xue, Wei,Yang, Jinsong
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p. 11085 - 11094
(2021/10/01)
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- GPR52 Antagonist Reduces Huntingtin Levels and Ameliorates Huntington's Disease-Related Phenotypes
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GPR52 is an orphan G protein-coupled receptor (GPCR) that has been recently implicated as a potential drug target of Huntington's disease (HD), an incurable monogenic neurodegenerative disorder. In this research, we found that striatal knockdown of GPR52 reduces mHTT levels in adult HdhQ140 mice, validating GPR52 as an HD target. In addition, we discovered a highly potent and specific GPR52 antagonist Comp-43 with an IC50 value of 0.63 μM by a structure-activity relationship (SAR) study. Further studies showed that Comp-43 reduces mHTT levels by targeting GPR52 and promotes survival of mouse primary striatal neurons. Moreover, in vivo study showed that Comp-43 not only reduces mHTT levels but also rescues HD-related phenotypes in HdhQ140 mice. Taken together, our study confirms that inhibition of GPR52 is a promising strategy for HD therapy, and the GPR52 antagonist Comp-43 might serve as a lead compound for further investigation.
- Wang, Congcong,Zhang, Yu-Fang,Guo, Shimeng,Zhao, Quan,Zeng, Yanping,Xie, Zhicheng,Xie, Xin,Lu, Boxun,Hu, Youhong
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p. 941 - 957
(2020/11/30)
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- Development of phenyltriazole thiol-based derivatives as highly potent inhibitors of DCN1-UBC12 interaction
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Defective in cullin neddylation 1(DCN1) is a co-E3 ligase that is important for cullin neddylation. Dysregulation of DCN1 highly correlates with the development of various cancers. Herein, from the initial high-throughput screening, a novel hit compound 5a containing a phenyltriazole thiol core (IC50 value of 0.95 μM for DCN1-UBC12 interaction) was discovered. Further structure-based optimization leads to the development of SK-464 (IC50 value of 26 nM). We found that SK-464 not only directly bound to DCN1 in vitro, but also engaged cellular DCN1, suppressed the neddylation of cullin3, and hindered the migration and invasion of two DCN1-overexpressed squamous carcinoma cell lines (KYSE70 and H2170). These findings indicate that SK-464 may be a novel lead compound targeting DCN1-UBC12 interaction.
- Zhou, Wenjuan,Xu, Chenhao,Dong, Guanjun,Qiao, Hui,Yang, Jing,Liu, Hongmin,Ding, Lina,Sun, Kai,Zhao, Wen
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- Br?nsted acid-catalyzed chlorination of aromatic carboxylic acids
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The chlorination of aromatic carboxylic acids with SOCl2 has been effectively performed by reacting with a Br?nsted acid as the catalyst. Based on this discovery, an efficient catalytic method that is cheaper than traditional catalytic methods was developed. 20 substrates were chlorinated offering excellent yields in a short reaction time. And the SOCl2/Br?nsted acid system has been used in a larger scale preparative reaction. A dual activation mechanism was proposed to prove the irreplaceable system of SOCl2/Br?nsted acid.
- Yu, Zhiqun,Yao, Hongmiao,Xu, Qilin,Liu, Jiming,Le, Xingmao,Ren, Minna
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supporting information
p. 685 - 689
(2021/04/09)
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- Design, synthesis, and biological studies of novel 3-benzamidobenzoic acid derivatives as farnesoid X receptor partial agonist
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Farnesoid X receptor (FXR), a bile acid-activated nuclear receptor, regulates the metabolism of bile acid and lipids as well as maintains the stability of internal environment. FXR was considered as a therapeutic target of liver disorders, such as drug-induced liver injury, fatty liver and cholestasis. The previous reported FXR partial agonist 6 was a suitable lead compound in terms of its high potent and low molecular size, while the docking study of compound 6 suggested a large unoccupied hydrophobic pocket, which might be provided more possibility of structure-activity relationship (SAR) study. In this study, we have performed comprehensive SAR and molecular modeling studies based on lead compound 6. All of these efforts resulted in the identification of a novel series of FXR partial agonists. In this series, compound 41 revealed the best activity and strong interaction with binding pocket of FXR. Moreover, compound 41 protected mice against acetaminophen-induced hepatotoxicity by the regulation of FXR-related gene expression and improving antioxidant capacity. In summary, these results suggest that compound 41 is a promising FXR partial agonist suitable for further investigation.
- Hu, Lijun,Ren, Qiang,Deng, Liming,Zhou, Zongtao,Cai, Zongyu,Wang, Bin,Li, Zheng
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supporting information
(2020/12/25)
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- Method for preparing carboxylic ester compounds by oxidizing and breaking carbon-carbon bonds of secondary alcohol compounds
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The invention discloses a method for preparing carboxylic ester compounds by oxidizing and breaking carbon-carbon bonds of secondary alcohol compounds. The method comprises the following steps: adding a secondary alcohol compound, an additive and a nitrogen-doped mesoporous carbon loaded monatomic catalyst into a fatty primary alcohol solvent, putting into a pressure container, sealing, introducing oxygen source gas with a certain pressure, controlling the pressure of the oxygen source gas to be 0.1-1 MPa and the reaction temperature to be 80-150 DEG C, and obtaining a product after the reaction to be the carboxylic ester compound. The nitrogen-doped mesoporous carbon-loaded monatomic catalyst adopted by the invention is high in activity, the highest separation yield of the carboxylic ester compound as a reaction product reaches 99%, the method is wide in application range, the reaction conditions are easy to control, the catalyst can be recycled, the post-treatment is simple, and the method is suitable for industrial production.
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Paragraph 0046-0047; 0092
(2021/06/02)
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- Methylation with Dimethyl Carbonate/Dimethyl Sulfide Mixtures: An Integrated Process without Addition of Acid/Base and Formation of Residual Salts
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Dimethyl sulfide, a major byproduct of the Kraft pulping process, was used as an inexpensive and sustainable catalyst/co-reagent (methyl donor) for various methylations with dimethyl carbonate (as both reagent and solvent), which afforded excellent yields of O-methylated phenols and benzoic acids, and mono-C-methylated arylacetonitriles. Furthermore, these products could be isolated using a remarkably straightforward workup and purification procedure, realized by dimethyl sulfide‘s neutral and distillable nature and the absence of residual salts. The likely mechanisms of these methylations were elucidated using experimental and theoretical methods, which revealed that the key step involves the generation of a highly reactive trimethylsulfonium methylcarbonate intermediate. The phenol methylation process represents a rare example of a Williamson-type reaction that occurs without the addition of a Br?nsted base.
- Chan, Bun,Lui, Matthew Y.,Lui, Yuen Wai
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- Synthesis, biological evaluation of benzothiazole derivatives bearing a 1,3,4-oxadiazole moiety as potential anti-oxidant and anti-inflammatory agents
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Twenty benzothiazole derivatives bearing a 1,3,4-oxadiazole moiety were synthesized and evaluated for their anti-oxidant and anti-inflammatory activities. Among these compounds, 8h and 8l were appeared to have high radical scavenging efficacies as 0.05 ± 0.02 and 0.07 ± 0.03 mmol/L of IC50 values in ABTS+[rad] bioassay, respectively. In anti-inflammatory tests, compound 8h displayed good activity with 57.35% inhibition after intraperitoneal administration, which was more potent than the reference drug (indomethacin). Molecular modeling studies were performed to investigate the binding mode of the representative compound 8h into COX-2 enzyme. In vitro enzyme study implied that compound 8h exerted its anti-inflammatory activity through COX-2 inhibition.
- Bai, Xue-Qian,Cui, Ming-Yue,Li, Chun-Shi,Liang, Cheng-Wu,Song, Ze-Wen,Wang, Hui-Yan,Zhang, Tian-Yi,Zheng, Xian-Jing
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- Discovery of [1,2,4]triazole derivatives as new metallo-β-lactamase inhibitors
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The emergence and spread of metallo-β-lactamase (MBL)-mediated resistance to β-lactam antibacterials has already threatened the global public health. A clinically useful MBL inhibitor that can reverse β-lactam resistance has not been established yet. We here report a series of [1,2,4]triazole derivatives and analogs, which displayed inhibition to the clinically relevant subclass B1 (Verona integron-encoded MBL-2) VIM-2. 3-(4-Bromophenyl)-6,7-dihydro-5H-[1,2,4]triazolo [3,4-b][1,3]thiazine (5l) manifested the most potent inhibition with an IC50 (half-maximal inhibitory concentration) value of 38.36 μM. Investigations of 5l against other B1 MBLs and the serine β-lactamases (SBLs) revealed the selectivity to VIM-2. Molecular docking analyses suggested that 5l bound to the VIM-2 active site via the triazole involving zinc coordination and made hydrophobic interactions with the residues Phe61 and Tyr67 on the flexible L1 loop. This work provided new triazole-based MBL inhibitors and may aid efforts to develop new types of inhibitors combating MBL-mediated resistance.
- Yuan, Chen,Yan, Jie,Song, Chen,Yang, Fan,Li, Chao,Wang, Cheng,Su, Huiling,Chen, Wei,Wang, Lijiao,Wang, Zhouyu,Qian, Shan,Yang, Lingling
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- Aerobic Oxidative Cleavage and Esterification of C(OH)–C Bonds
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C(OH)–C bonds are widely distributed in naturally renewable biomass, such as carbohydrates, lignin, and their platform molecules. Selective cleavage and functionalization of C(OH)–C bonds is an attractive strategy in terms of producing value-added chemicals from biomass. However, effective transformation of alcohols into esters by activation of C(OH)–C bonds has not been achieved so far. Herein, for the first time, we report selective cleavage and esterification of C(OH)–C bonds, catalyzed by inexpensive copper salts, using environmentally benign oxygen as the oxidant, to afford methyl esters in excellent yields. A diverse range of phenylethanol derivatives that contain C(OH)–C bonds were effectively converted into methyl benzoates. Detailed analysis revealed that the high efficiency and selectivity resulted mainly from the fact that, in addition to the major esterification reaction, the side products (e.g., olefins and acids) were also transformed in situ into esters in the reaction system. C(OH)–C bonds are widely distributed in naturally renewable biomass. In the context of developing future biorefineries, selective cleavage and functionalization of C(OH)–C bonds are crucial and represent an attractive strategy in terms of producing value-added chemical compounds from biomass resources. In the current manuscript, we report, for the first time, an effective and selective method for the cleavage and esterification of C(OH)–C bonds of alcohols to produce esters, by using environmentally benign O2 as the terminal oxidant and inexpensive commercially available copper salts as catalysts. Furthermore, a detailed mechanistic study revealed that, in addition to the major esterification route, side products (e.g., olefins and acids), which are inevitably generated under oxidative and basic conditions, were also simultaneously converted into esters, thus significantly improving the final yields of target ester products. Native lignin represents the only naturally sustainable aromatic resource. Transformation of native lignin into valuable aromatics would make a great contribution to our planet. We report, for the first time, the effective transformation of alcohols into esters by esterification of C(OH)–C bonds, which offers a new way for the simultaneous degradation and functionalization of lignin. This reaction promotes new explorations for biomass valorization.
- Liu, Mingyang,Zhang, Zhanrong,Yan, Jiang,Liu, Shuaishuai,Liu, Huizhen,Liu, Zhaotie,Wang, Weitao,He, Zhenhong,Han, Buxing
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supporting information
p. 3288 - 3296
(2020/10/20)
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- Cobalt Nanoparticles-Catalyzed Widely Applicable Successive C?C Bond Cleavage in Alcohols to Access Esters
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Selective cleavage and functionalization of C?C bonds have important applications in organic synthesis and biomass utilization. However, functionalization of C?C bonds by controlled cleavage remains difficult and challenging because they are inert. Herein, we describe an unprecedented efficient protocol for the breaking of successive C?C bonds in alcohols to form esters with one or multiple carbon atoms less using heterogeneous cobalt nanoparticles as catalyst with dioxygen as the oxidant. A wide range of alcohols including inactive long-chain alkyl aryl alcohols undergo smoothly successive cleavage of adjacent ?(C?C)n? bonds to afford the corresponding esters. The catalyst was used for seven times without any decrease in activity. Characterization and control experiments disclose that cobalt nanoparticles are responsible for the successive cleavage of C?C bonds to achieve excellent catalytic activity, while the presence of Co-Nx has just the opposite effect. Preliminary mechanistic studies reveal that a tandem sequence reaction is involved in this process.
- Dai, Wen,Gao, Shuang,Li, Guosong,Luo, Huihui,Lv, Ying,Shang, Sensen,Wang, Lianyue
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supporting information
p. 19268 - 19274
(2020/08/26)
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- Pd/C-Catalyzed methoxycarbonylation of aryl chlorides
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A new protocol for the methoxycarbonylation of aryl chlorides has been developed. Various methyl benzoates were produced in good to excellent yields. Several parameters are crucial for the success of this procedure: 1) the usage of LiOMe as the base or co-nucleophile which facilitate the carbonylative transformation; 2) employing Pd/C as the catalyst to prevent the palladium reduced by MeOH and subsequent agglomerate; 3) CO concentration, excessive CO concentration will directly lead to the termination of the reaction.
- Ai, Han-Jun,Franke, Robert,Wu, Xiao-Feng
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- Copper-catalyzed oxidative methyl-esterification of 5-hydroxymethylfurfural using TBHP as an oxidizing and methylating reagent: A new approach for the synthesis of furan-2,5-dimethylcarboxylate
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Catalytic conversion of 5-hydroxymethylfurfural (HMF) into furan-2,5-dimethylcarboxylate (FDMC) is of great significance in the production of polyethylene furanoate (PEF), a renewable biomass-derived polymer that can replace the fossil dependent polyethylene terephthalate (PET). Herein, for the first time, we report the synthesis of FDMC from oxidative methyl-esterification of HMF using tert-butyl hydroperoxide (TBHP) as an oxidizing and methylating reagent catalyzed by mesoporous alumina nanospheres-embedded with CuO nanoparticles (CuO/m-Al2O3). The CuO/m-Al2O3 catalysts with different copper contents were prepared by evaporation-induced self-assembly of a structure-directing agent (Pluronic P-123). The decomposition of P-123 during calcination in air results into the formation of a mesoporous structure with highly dispersed CuO nanoparticles. The as-prepared 6-CuO/m-Al2O3 exhibits excellent catalytic activity towards oxidative methyl-esterification of HMF into FDMC with 92% yield and turnover frequency (TOF) of 0.56 h?1. Furthermore, oxidative methyl-esterification of a range of substrates through SP3 C[sbnd]H bond functionalization has also been demonstrated using the same catalyst.
- Gupta, Shyam Sunder R.,Kantam, Mannepalli Lakshmi,Vinu, Ajayan
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p. 259 - 269
(2020/06/27)
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- Exhaustive Reduction of Esters Enabled by Nickel Catalysis
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We report a one-step procedure to directly reduce unactivated aryl esters into their corresponding tolyl derivatives. This is achieved by an organosilane-mediated ester hydrosilylation reaction and subsequent Ni/NHC-catalyzed hydrogenolysis. The resulting conditions provide a direct and efficient alternative to multi-step procedures for this transformation that often require the use of hazardous metal hydrides. Applications in the synthesis of -CD3-containing products, derivatization of bioactive molecules, and chemoselective reduction in the presence of other C-O bonds are demonstrated.
- Cook, Adam,Prakash, Sekar,Zheng, Yan-Long,Newman, Stephen G.
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supporting information
p. 8109 - 8115
(2020/05/20)
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- Palladium-Catalyzed, Copper(I)-Promoted Methoxycarbonylation of Arylboronic Acids with O-Methyl S-Aryl Thiocarbonates
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Here, we report O-methyl S-aryl thiocarbonates as a versatile esterification reagent for palladium-catalyzed methoxycarbonylation of arylboronic acid in the presence of copper(I) thiophene-2-carboxylate (CuTC). The reaction condition is mild, and a variety of substituents including sensitive-Cl,-Br, and free-NH2 could be tolerated. Further applications in the late-stage esterification of some pharmaceutical drugs demonstrate the broad utility of this method.
- Cao, Ya-Fang,Li, Ling-Jun,Liu, Min,Xu, Hui,Dai, Hui-Xiong
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p. 4475 - 4481
(2020/04/10)
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- The synergistic role of the support surface and Au-Cu alloys in a plasmonic Au-Cu?LDH photocatalyst for the oxidative esterification of benzyl alcohol with methanol
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Layered double hydroxide-supported Au-Cu alloy nanoparticles (NPs) were found to be highly efficient catalysts for the oxidative esterification of benzyl alcohol with methanol in the presence of molecular oxygen under visible-light irradiation to prepare methyl benzoate. Here, we report that alloying small amounts of copper into gold nanoparticles can increase the ability to activate oxygen molecules to O2- radicals and display greater charge heterogeneity to promote the cleavage of the C-H bond of benzyl alcohol molecules by reinforcing the coordination of the intermediate with unsaturated metal active sites due to the LSPR effect of alloy NPs, which is the rate-limiting step of the reaction. Besides the Au-Cu alloy NPs, the support also played a pivotal role in the catalytic process. The support with the presence of acid-base pairs, in which the basic sites served as the reactant molecule adsorption sites to provoke the intermediate formation and the acidic sites promoted the recovery of the support surface, showed better performances by affecting the overall reaction rate completely. Moreover, applying this photocatalyst in the cross-esterification of aromatic alcohols and aliphatic alcohols displayed excellent yields.
- Wang, Xiaoyu,Wang, Ruiyi,Wang, Jie,Fan, Chaoyang,Zheng, Zhanfeng
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p. 1655 - 1664
(2020/01/31)
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- Metal-free Synthesis of Spiro-2,2′-benzo[b]furan-3,3′-ones via PhI(OAc)2-Mediated Cascade Spirocyclization
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Treating the benzyl protected 3-hydroxy-1,3-bis(2-hydroxyphenyl)prop-2-en-1-ones solely with PhI(OAc)2 (PIDA) in DCE at room temperature readily furnished the seldom studied spiro-2,2′-benzo[b]furan-3,3′-ones in satisfactory to excellent yields. The hypervalent iodine reagent enables the metal-free cascade spirocyclization resulting in the dual oxidative C?O bond formation. (Figure presented.).
- Xing, Qingyu,Liang, Huiyuan,Bao, Mingmai,Li, Xuemin,Zhang, Jingran,Bi, Tianhao,Zhang, Yilin,Xu, Jun,Du, Yunfei,Zhao, Kang
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supporting information
p. 4669 - 4673
(2019/09/17)
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- Synthesis and biological activities of benzothiazole derivatives bearing a 1,3,4-thiadiazole moiety
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A series of benzothiazole derivatives bearing a 1,3,4-thiadiazole moiety were designed, synthesized and evaluated for their antibacterial, antifungal and antiviral activities. The bioassay results indicated that most of target compounds showed good antiviral activities against tobacco mosaic virus (TMV) and antibacterial activities against Xanthomonas oryzae pv. oryzae (Xoo) and Ralstonia solanacearum (Rs). Especially, the anti-Xoo effect of title compounds 5k (N-(5-methoxybenzo[d]thiazol-2-yl)-2-((5-(2-tolyl)-1,3,4-thiadiazol-2-yl)thio)acetamide) and the anti-Rs effect of title compounds 5a (N-(5-nitrobenzo[d]thiazol-2-yl)-2-((5-(4-(trifluorom ethyl)phenyl)-1,3,4-thiadiazol-2-yl)thio)acetmide) respectively reached 52.4% and 71.6% at 100 μg/mL, which are superior to that of bismerthiazol (32.0% and 52.3%). In addition, the protective and inactivation activities of title compound 5i (N-(5-methoxybenzo [d]thiazol-2-yl)-2-((5-(4-nitrophenyl)-1,3,4-thiadiazol-2-yl)thio)acetamide) against TMV were 79.5% and 88.3%, respectively, which are better than that of ningnanmycin (76.4% and 86.8%). The above research showed that benzothiazole derivatives bearing a 1,3,4-thiadiazole moiety may be used as potential molecular templates in searching for highly-efficient antiviral and antibacterial agents.
- Tang, Xu,Wang, Zhongbo,Zhong, Xinmin,Wang, Xiaobin,Chen, Lijuan,He, Ming,Xue, Wei
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p. 241 - 248
(2019/01/04)
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- 5-Aryl-1,3,4-oxadiazol-2-ylthioalkanoic Acids: A Highly Potent New Class of Inhibitors of Rho/Myocardin-Related Transcription Factor (MRTF)/Serum Response Factor (SRF)-Mediated Gene Transcription as Potential Antifibrotic Agents for Scleroderma
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Through a phenotypic high-throughput screen using a serum response element luciferase promoter, we identified a novel 5-aryl-1,3,4-oxadiazol-2-ylthiopropionic acid lead inhibitor of Rho/myocardin-related transcription factor (MRTF)/serum response factor (SRF)-mediated gene transcription with good potency (IC50 = 180 nM). We were able to rapidly improve the cellular potency by 5 orders of magnitude guided by sharply defined and synergistic SAR. The remarkable potency and depth of the SAR, as well as the relatively low molecular weight of the series, suggests, but does not prove, that binding to the unknown molecular target may be occurring through a covalent mechanism. The series nevertheless has no observable cytotoxicity up to 100 μM. Ensuing pharmacokinetic optimization resulted in the development of two potent and orally bioavailable anti-fibrotic agents that were capable of dose-dependently reducing connective tissue growth factor gene expression in vitro as well as significantly reducing the development of bleomycin-induced dermal fibrosis in mice in vivo.
- Kahl, Dylan J.,Hutchings, Kim M.,Lisabeth, Erika Mathes,Haak, Andrew J.,Leipprandt, Jeffrey R.,Dexheimer, Thomas,Khanna, Dinesh,Tsou, Pei-Suen,Campbell, Phillip L.,Fox, David A.,Wen, Bo,Sun, Duxin,Bailie, Marc,Neubig, Richard R.,Larsen, Scott D.
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p. 4350 - 4369
(2019/05/08)
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- Design, synthesis, and preliminary biological evaluation of 3′,4′,5′-trimethoxy flavonoid salicylate derivatives as potential anti-tumor agents
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According to the pharmacophore combination principle, a set of new 3′,4′,5′-trimethoxy flavonoid salicylate derivatives were designed, synthesized, and evaluated for biological activity. The cytotoxicity evaluation revealed that compound 10v exhibited higher potency than 5-Fu against HCT-116 cells. Preliminary biological activity studies showed that compound 10v could inhibit the colony formation and migration of HCT-116 cells. Besides, the Hoechst 33258 staining assay and flow cytometry revealed that treatment with compound 10v induced the apoptosis of HCT-116 cells in a concentration-dependent manner, while it had no effect on their cell cycle. The WB analysis suggested that HIF-1α, tubulin, HK-2, and PFK might be the potential pharmacophore targets of compound 10v. Tubulin was a potential drug target for compound 10v, which was explained by analyzing the crystal structure of compound 10v complexed with tubulin. These results indicated that compound 10v might be a promising anti-tumor agent candidate, deserving further optimization and evaluation.
- Deng, Xiangping,Liu, Renbo,Li, Junjian,Li, Zhongli,Liu, Juan,Xiong, Runde,Lei, Xiaoyong,Zheng, Xing,Xie, Zhizhong,Tang, Guotao
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p. 1874 - 1884
(2019/01/28)
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- Ligand-free Cu(ii)-catalyzed aerobic etherification of aryl halides with silanes: An experimental and theoretical approach
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Owing to their wide occurrence in nature and immense applications in various fields, the synthesis of aryl alkyl ethers has remained a focus of interest. In contrast to the conventional/traditional methods of etherification, herein, we have reported a more efficient method, which is better yielding and more general in application. The etherification of aryl halides by alkoxy/phenoxy silanes was catalyzed by copper acetate in the presence of cesium carbonate and oxygen in DMF at 145 °C. All the as-synthesized compounds were characterized via the 1H-NMR and 13C-NMR spectroscopic techniques. Density functional theory calculations using the B3LYP functional were performed to elucidate the reaction mechanism. The C-O coupling reaction between 2-nitroiodobenzene and tetramethoxysilane was used as a model reaction. The activation energy barriers for the generation of catalytic species (31.6 kcal mol-1) and the σ-bond metathesis (16.0 kcal mol-1), oxidative addition/reductive elimination (20.3 kcal mol-1), halogen atom transfer (19.2 kcal mol-1) and single electron transfer (SET) (29.5 kcal mol-1) mechanisms for the C-O coupling reaction were calculated. Calculations for the key reaction steps were repeated with the B3PW91, PBEH1PBE, wB97XD, CAM-B3LYP and mPW1LYP functionals. The formation of catalytic species via a single electron transfer reaction between tetramethoxysilane and copper acetate, formation of methoxy radicals and methoxylation of copper showed an overall energy barrier of 31.6 kcal mol-1, and therefore is the rate determining step.
- Ahmed, Muhammad Naeem,Ahmad, Khalil,Yasin, Khawaja Ansar,Farooq, Tayyaba,Khan, Bilal Ahmad,Roy, Soumendra K.
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p. 11316 - 11333
(2019/07/31)
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- Methylation of Aliphatic and Aromatic Carboxylic Acids with Dimethyl Carbonate under the Influence of Manganese and Iron Carbonyls
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The synthesis of methyl esters has been carried out via the reaction of aliphatic and aromatic carboxylic acids with dimethyl carbonate in the presence of manganese and iron carbonyls. The optimal ratio of catalyst and reagents and other conditions for the synthesis of methyl esters of carboxylic acids with high yield have been found.
- Khusnutdinov,Shchadneva,Mayakova, Yu. Yu.
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- Efficient synthesis of esters through oxone-catalyzed dehydrogenation of carboxylic acids and alcohols
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Since esters are important organic synthesis intermediates, an environmentally friendly oxone catalyzed-esterification of carboxylic acids with alcohols has been developed. A series of carboxylic acid esters are obtained in high yield. This strategy requires mild reaction conditions, providing an attractive alternative for the construction of valuable carbonyl esters. Electron-rich and electron-deficient groups are compatible with the standard conditions and a variety of substrates are demonstrated. Moreover, the reaction could easily be adapted to typical prodrugs, drugs and gram-scale synthesis.
- Hou, Fei,Wang, Xi-Cun,Quan, Zheng-Jun
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supporting information
p. 9472 - 9476
(2019/01/03)
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- Preparation method of methyl 5-formyl-2-methoxybenzoate
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The invention discloses a preparation method of methyl 5-formyl-2-methoxybenzoate. The preparation method comprises following steps: (1), preparation of methyl-2-methoxybenzoate; (2), preparation of methyl 5-formyl-2-methoxybenzoate. With the adoption of the method for loading an aldehyde group by urotropine after ester formation, the total yield can be increased to about 90%, the utilization rateof the raw materials is greatly increased, the cost is low, the operation is simple and convenient, and industrialization is facilitated.
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Paragraph 0038; 0039; 0042; 0043
(2019/01/16)
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- One-Step O -Demethyl-Decarboxylation of ortho -Methoxy Aromatic Carboxylic Acids
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A highly selective decarboxydemethylation of o -methoxyarenecarboxylic acids is described. The reaction takes place in DMPU at 170 °C in the presence of TMEDA and iron powder. A similar reaction has not been reported until now.
- Cahiez, Gérard,Moyeux, Alban,Zhou, Edouard,Poizat, Ma?l
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p. 2119 - 2123
(2018/04/12)
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- Synthesis of Hydroxybenzoic Acids and Their Esters by Reaction of Phenols with Carbon Tetrachloride and Alcohols in the Presence of Iron Catalysts
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Alkyl esters of hydroxy-, methoxy-, and ethoxybenzoic and cresotic acids have been synthesized by reaction of phenols, anisole, phenetole, and cresols with carbon tetrachloride and alcohols in the presence of iron catalysts.
- Bayguzina,Tarisova,Khusnutdinov
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p. 208 - 215
(2018/03/26)
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- Development of N-Doped Carbon-Supported Cobalt/Copper Bimetallic Nanoparticle Catalysts for Aerobic Oxidative Esterifications Based on Polymer Incarceration Methods
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Heterogeneous nitrogen-doped carbon-incarcerated cobalt/copper bimetallic nanoparticle (NP) catalysts, prepared from nitrogen-containing polymers, were developed, and an efficient catalytic process for aerobic oxidative esterification was achieved in the presence of a low loading (1 mol %) of catalyst that could be reused and easily reactivated. This protocol enabled diverse conditions for the bimetallic NP formation step to be screened, and significant rate acceleration by inclusion of a copper dopant was discovered. The catalytic activity of the bimetallic Co/Cu catalysts is much higher than that for cobalt catalysts reported to date and is even comparable with noble-metal NP catalysts.
- Yasukawa, Tomohiro,Yang, Xi,Kobayashi, Shu
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supporting information
p. 5172 - 5176
(2018/09/12)
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- Cobalt-entrenched N-, O-, and S-tridoped carbons as efficient multifunctional sustainable catalysts for base-free selective oxidative esterification of alcohols
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We report the synthesis of sustainable and reusable non-noble transition-metal (cobalt) nanocatalysts containing N-, O-, and S-tridoped carbon nanotube (Co@NOSC) composites. The expensive and benign carrageenan served as the source of carbon, oxygen, and sulfur, whereas urea served as the nitrogen source. The material was prepared via direct mixing of precursors and freeze-drying followed by carbonization under nitrogen at 900 °C. Co@NOSC catalysts comprising a Co inner core and outer electron-rich heteroatom-doped carbon shell were thoroughly characterized using various techniques, namely, TEM, HRTEM, STEM elemental mapping, XPS, BET, and ICP-MS. The utility of the Co@NOSC catalyst was explored for base-free selective oxidative esterification of alcohols to the corresponding esters under mild reaction conditions; excellent conversions (up to 97%) and selectivities (up to 99%) were discerned. Furthermore, the substrate scope was explored for the cross-esterification of benzyl alcohol with long-chain alcohols (up to 98%) and lactonization of diols (up to 68%). The heterogeneous nature and stability of the catalyst facilitated by its ease of separation for long-term performance and recycling studies showed that the catalyst was robust and remained active even after six recycling experiments. EPR measurements were performed to deduce the reaction mechanism in the presence of POBN (α-(4-pyridyl-1-oxide)-N-tert-butylnitrone) as a spin-trapping agent, which confirmed the formation of CH2OH radicals and H radicals, wherein the solvent plays an active role in a nonconventional manner. A plausible mechanism was proposed for the oxidative esterification of alcohols on the basis of EPR findings. The presence of a cobalt core along with cobalt oxide and the electron-rich N-, O-, and S-doped carbon shell displayed synergistic effects to afford good to excellent yields of products.
- Nandan, Devaki,Zoppellaro, Giorgio,Med?ík, Ivo,Aparicio, Claudia,Kumar, Pawan,Petr, Martin,Tomanec, Ond?ej,Gawande, Manoj B.,Varma, Rajender S.,Zbo?il, Radek
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p. 3542 - 3556
(2018/08/07)
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- A biocatalytic method for the chemoselective aerobic oxidation of aldehydes to carboxylic acids
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Herein, we present a study on the oxidation of aldehydes to carboxylic acids using three recombinant aldehyde dehydrogenases (ALDHs). The ALDHs were used in purified form with a nicotinamide oxidase (NOx), which recycles the catalytic NAD+ at the expense of dioxygen (air at atmospheric pressure). The reaction was studied also with lyophilised whole cell as well as resting cell biocatalysts for more convenient practical application. The optimised biocatalytic oxidation runs in phosphate buffer at pH 8.5 and at 40 °C. From a set of sixty-one aliphatic, aryl-Aliphatic, benzylic, hetero-Aromatic and bicyclic aldehydes, fifty were converted with elevated yield (up to >99%). The exceptions were a few ortho-substituted benzaldehydes, bicyclic heteroaromatic aldehydes and 2-phenylpropanal. In all cases, the expected carboxylic acid was shown to be the only product (>99% chemoselectivity). Other oxidisable functionalities within the same molecule (e.g. hydroxyl, alkene, and heteroaromatic nitrogen or sulphur atoms) remained untouched. The reaction was scaled for the oxidation of 5-(hydroxymethyl)furfural (2 g), a bio-based starting material, to afford 5-(hydroxymethyl)furoic acid in 61% isolated yield. The new biocatalytic method avoids the use of toxic or unsafe oxidants, strong acids or bases, or undesired solvents. It shows applicability across a wide range of substrates, and retains perfect chemoselectivity. Alternative oxidisable groups were not converted, and other classical side-reactions (e.g. halogenation of unsaturated functionalities, Dakin-Type oxidation) did not occur. In comparison to other established enzymatic methods such as the use of oxidases (where the concomitant oxidation of alcohols and aldehydes is common), ALDHs offer greatly improved selectivity.
- Knaus, Tanja,Tseliou, Vasilis,Humphreys, Luke D.,Scrutton, Nigel S.,Mutti, Francesco G.
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p. 3931 - 3943
(2018/09/11)
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- Oxalic acid as the: In situ carbon monoxide generator in palladium-catalyzed hydroxycarbonylation of arylhalides
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An efficient palladium-catalyzed hydroxycarbonylation reaction of arylhalides using oxalic acid as a CO source has been developed. The reaction features high safety, low catalyst loading, and a broad substrate scope, and provides a safe and tractable approach to access a variety of aromatic carboxylic acid compounds. Mechanistic studies revealed the decomposition pattern of oxalic acid.
- Shao, Changdong,Lu, Ailan,Wang, Xiaoling,Zhou, Bo,Guan, Xiaohong,Zhang, Yanghui
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supporting information
p. 5033 - 5040
(2017/07/10)
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- New highly selective turn-on fluorescence receptor for the detection of copper (II)
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Three new receptors (1a–c) bearing a p-dimethylaminobenzamide fluorophore have been synthesized and evaluated in terms of their fluoroionophoric properties towards various metal ions. Notably, receptors 1a and 1c exhibited dramatic fluorescent enhancement towards Cu2?+ in acetonitrile. Subsequent investigations revealed that the highly selective behavior of these receptors towards Cu2?+ could be attributed to the Cu2?+-mediated oxidative cyclization of these compounds to the corresponding 1,3,4-oxadiazoles. Solvent effects and quantum calculations indicated that 1a and 1c both possessed an intramolecular charge transfer channel, which could be obstructed by the oxidative cyclization of these receptors. Receptor 1a was successfully applied to the determination of the Cu2?+ in drug sample with a low detection limit of 2.2?×?10??8?mol?L??1.
- Nan, Qian,Rong, Pu,Jiang, Yunbao,Yang, Rui
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p. 307 - 315
(2016/12/18)
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- Direct C-H Cyanation of Arenes via Organic Photoredox Catalysis
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Methods for the direct C-H functionalization of aromatic compounds are in demand for a variety of applications, including the synthesis of agrochemicals, pharmaceuticals, and materials. Herein, we disclose the construction of aromatic nitriles via direct C-H functionalization using an acridinium photoredox catalyst and trimethylsilyl cyanide under an aerobic atmosphere. The reaction proceeds at room temperature under mild conditions and has proven to be compatible with a variety of electron-donating and -withdrawing groups, halogens, and nitrogen- and oxygen-containing heterocycles, as well as aromatic-containing pharmaceutical agents.
- McManus, Joshua B.,Nicewicz, David A.
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p. 2880 - 2883
(2017/03/11)
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- Benzene C-H Etherification via Photocatalytic Hydrogen-Evolution Cross-Coupling Reaction
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Aryl ethers can be constructed from the direct coupling between the benzene C-H bond and the alcohol O-H bond with the evolution of hydrogen via the synergistic merger of photocatalysis and cobalt catalysis. Utilizing the dual catalyst system consisting of 3-cyano-1-methylquinolinum photocatalyst and cobaloxime, intermolecular etherification of arenes with various alcohols and intramolecular alkoxylation of 3-phenylpropanols with formation of chromanes are accomplished. These reactions proceed at remarkably mild conditions, and the sole byproduct is equivalent hydrogen gas.
- Zheng, Yi-Wen,Ye, Pan,Chen, Bin,Meng, Qing-Yuan,Feng, Ke,Wang, Wenguang,Wu, Li-Zhu,Tung, Chen-Ho
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supporting information
p. 2206 - 2209
(2017/05/12)
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- Composition FOR PREVENTING ALOPECIA AND ACTIVATING HAIR GROWTH
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The present invention provides a hair growth promoter comprising as an active ingredient, a compound having a chemical structure of general formula (1) or a pharmacologically acceptable salt thereof. In the general formula (1): R_1 is a saturated or unsaturated straight chain or branched C1-C10 alkyl group or hydroxy alkyl group; R_2 is hydrogen or a saturated or unsaturated straight chain or branched C1-C10 alkoxy or hydroxy alkoxy; X is hydrogen, hydroxy, or a saturated or unsaturated straight chain or branched C1-C10 alkyl group, alkoxy or hydroxyl alkoxy; R_3 and R_4 are each independently selected from R_5, hydrogen, aldehyde, and a saturated or unsaturated straight chain or branched alkyl, alkoxy, or hydroxy alkoxy; R_5 has a structure of # AAA #; R_6 is selected from hydrogen, and a saturated or unsaturated straight chain or branched C1-C10 alkyl, alkoxy, or hydroxy alkoxy; and one of R_3 and R_4 is hydrogen.COPYRIGHT KIPO 2017
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Paragraph 0115; 0116
(2018/02/16)
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- Methylation of mono- and dicarboxylic acids with dimethyl carbonate catalyzed with binder-free zeolite NaY
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Synthesis of methyl mono- and dicarboxylates was developed consisting in treating the corresponding acids with dimethyl carbonate in the presence of a heterogenic catalyst, crystalline aluminosilicate whose mechanically strong granules to 90–95% were built of crystal aggregates of zeolite Y with modulus of about 5.0 in the Na-form. Optimum catalyst and reagents ratio and the reaction conditions were found for the preparation in high yields of methyl esters of mono- and dicarboxylic acids.
- Khusnutdinov,Shchadneva,Mayakova, Yu. Yu.,Konovalova, Yu. S.,Khazipova,Kutepov
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p. 163 - 168
(2017/04/24)
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- Activating cobalt nanoparticles via the Mott-Schottky effect in nitrogen-rich carbon shells for base-free aerobic oxidation of alcohols to esters
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Heterogeneous catalysts of inexpensive and reusable transition-metal are attractive alternatives to homogeneous catalysts; the relatively low activity of transition-metal nanoparticles has become the main hurdle for their practical applications. Here, the de novo design of a Mott-Schotfky-type heterogeneous catalyst is reported to boost the activity of a transition-metal nanocatalyst through electron transfer at the metal/nitrogen-doped carbon interface. The Mott-Schottky catalyst of nitrogen-rich carbon-coated cobalt nanoparticles (Co@NC) was prepared through direct polycondensation of simple organic molecules and inorganic metal salts in the presence of g-C3N4 powder. The Co@NC with controllable nitrogen content and thus tunable Fermi energy and catalytic activity exhibited a high turnover frequency (TOF)value (8.12 mol methyl benzoate mol-1 Co h-1) for the direct, base-free, aerobic oxidation of benzyl alcohols to methyl benzoate; this TOF is 30-fold higher than those of the state-of-the-art transitionmetal-based nanocatalysts reported in the literature. The presented efficient Mott-Schottky catalyst can trigger the synthesis of a series of alkyl esters and even diesters in high yields.
- Su, Hui,Zhang, Ke-Xin,Zhang, Bing,Wang, Hong-Hui,Yu, Qiu-Ying,Li, Xin-Hao,Antonietti, Markus,Chen, Jie-Sheng
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p. 811 - 818
(2017/05/17)
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- Direct oxidation of aldehydes to methyl esters with urea hydrogen peroxide and p-toluenesulfonyl chloride
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Combination of urea hydrogen peroxide and p-toluenesulfonyl chloride in methanol was proved to be facile and highly efficient for the oxidative methyl esterification of various aldehydes to the corresponding carboxylic methyl esters.
- Jeong, Deuk Jun,Lee, Su Bin,Lee, Jong Chan
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p. 725 - 728
(2017/12/28)
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- Solvent- and Metal-free Oxidative Esterification of Aromatic Aldehydes Using Urea-2,2-dihydroperoxypropane as a New Solid Oxidant
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Urea-2,2-dihydroperoxypropane as a noble and solid gem-dihydroperoxide derivative was used to transform various aromatic aldehydes to their corresponding benzoate derivatives in the presence of HBr under mild conditions at room temperature in high yields and short reaction times.
- Khosravi, Kaveh,Khalaji, Kobra,Naserifar, Shirin
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p. 303 - 309
(2017/03/27)
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- Synthesis and antiviral activity of novel thioether derivatives containing 1,3,4-oxadiazole/thiadiazole and emodin moieties
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A series of novel thioether derivatives containing 1,3,4-oxadiazole/thiadiazole and emodin moieties were designed and synthesized. The structures of the target compounds were confirmed by 1H NMR, 13C NMR, Infrared, and elemental analysis. The results of bioactivity analysis showed that most of the target compounds exhibited moderate to good antiviral activity against tobacco mosaic virus at a concentration of 500 mg/L. Especially, among the title compounds, Y2, Y8, and Y10 possessed appreciable curative activity in vivo, with inhibition rates of 50.51, 52.08, and 54.62%, respectively, which were similar to that of Ningnanmycin (53.40%).
- Dong, Liangrun,Song, Baojing,Wu, Jian,Wu, Zengxue,Zhu, Yunying,Chen, Xuewen,Hu, Deyu
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p. 904 - 907
(2016/07/06)
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- Antiurease, antiphosphodiesterase and antiglycation studies of Pd(II) complexes with monodentate hydrazides
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The present study was aimed to synthesize and characterize a series of Pd(II)-benzohydrazide complexes with subsequent high throughput screening to seek their effects as enzyme inhibitors and antiglycating agents. Based on complete characterization via elemental (CHN, Pd) analysis, physical (conductivity, magnetic moment) measurements and spectral (FT-IR, 1H-NMR, 13C-NMR) techniques, all Pd(II) complexes were identified as diamagnetic, neutral and orienting in trans square planar geometry with general formula [PdL2Cl2]. The benzohydrazide (L) in these complexes depicts monodentate behavior, providing terminal amino nitrogen as a donor atom. Compared to inactive precursors (free benzohydrazides and Pd2+), almost all Pd(II) complexes showed in vitro antiglycation activity, illustrating the potential role of resulting complexes in the suppression of diabetes and related disorders. The presence of free carbonyl group in complexes has been recognized as possible cause of antiglycation. This study also indicated Pd(II) compounds as far more superior inhibitors of urease and phosphodiesterase-I than parent ligands; many of them exhibited inhibitions equivalent or even greater than the standard inhibitors (thiourea, urease; EDTA, phosphodiesterase), which shows their potential use in future in the control of peptic ulcer and arthritis, respectively. The structure activity relationship (SAR) study demonstrated that complexation, steric hindrance, position of substituents, electron density around metal centre, hydrogen bonding and coordination mode of complexed ligands play prime role in modulating the biological activities of complexes.
- Qurrat-Ul-Ain,Rasheed, Saima,Mahroof-Tahir, Mohammad,Ashiq, Uzma,Jamal, Rifat Ara,Khurshid, Sumaira,Mustafa, Sana
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p. 864 - 881
(2016/11/21)
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- * One derivative containing nitrogen and its preparation method and application (by machine translation)
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The invention discloses a formula (I) of formula (II) containing nitrogen mouth Shan Tong derivative and its preparation method and application, A new synthesis of this invention containing nitrogen mouth Shan Tong derivatives of the salt and its acid salt, increased solubility, active research indicates part of the compound at the same time with treating and/or preventing diabetes and complications from diabetes mellitus the role of the, can further carry out development research as a model for treating and/or preventing diabetes caused by the complications of diabetes medicine. (by machine translation)
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Paragraph 0089-0090
(2017/01/31)
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- Synthesis method of methyl o-anisate
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The invention provides a synthesis method of methyl o-anisate. The method is as below: preparing salicylic acid and potassium hydroxide into an aqueous solution, adding the aqueous solution into a reactor, controlling the temperature at 10-20 DEG C, introducing methyl bromide under stirring, conducting board pointing to trace the extent of reaction; after the reaction, stopping stirring, allowing to stand at room temperature for stratification, separating waste water containing potassium bromide at the lower layer, and concentrating to obtain a by-product potassium bromide; washing the upper product by saturated brine, dying by anhydrous sodium sulfate, conducting vacuum distillation, and collecting fraction at 95-110 DEG C to obtain the methyl o-anisate. The synthesis method of methyl o-anisate has the advantages of shortened process, greatly reduced reaction period, reduction of the amount of three kings of wastes generated, simplified of difficulty in wastewater treatment, and great reduction of power consumption and equipment occupancy for treatment.
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Paragraph 0018; 0019
(2016/10/27)
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- Method for preparing methyl o-anisate
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The invention provides a method Salicylic acid and an alkali liquor with a mol ratio of 1:2-2.5 are prepared into an aqueous solution, the aqueous solution is added in a reaction device, the temperature is controlled at 15-25 DEG C, bromomethane is inputted with stirring, and the reaction degree is tracked through thin layer chromatography; after the reaction is completed, stirring is stopped, the mixture is allowed to stand and layered at a room temperature, bromide-salt-containing waste water at the lower layer is separated, and a side product bromide salt is obtained through condensation processing; the upper layer product is washed in saturated salt solution, dried by anhydrous sodium sulfate, and subjected to reduced pressure distillation, the fraction at the temperature of 95-110 DEG C is collected, and methyl o-anisate is prepared.
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Paragraph 0018
(2016/10/27)
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- Synthetic method of methyl o-anisate
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A synthetic method of methyl o-anisate comprises the following steps: preparing salicylic acid and alkali liquor into a water solution according to a molar ratio of 1:2 to 2:4, adding into a reaction device, controlling a reaction temperature to be 10-20 DEG C, introducing methyl bromide while stirring, and tracking a reaction degree with a point plate; after total reaction, stopping stirring, standing and layering under normal temperature, separating lower layer waste water containing sodium bromide, and performing concentrating treatment to obtain a side product sodium bromide; washing an upper layer product with a saturated saline solution, drying with anhydrous sodium sulfate, then distilling under reduced pressure, collecting a distillate of 95-110 DEG C to obtain the methyl o-anisate. The synthetic method of methyl o-anisate is shortened in a process flow and greatly reduced in reaction time and can reduce output of three wastes, simplifies treatment difficulty of waste water and greatly reduces the treatment power consumption and device occupation amount.
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Paragraph 0022
(2016/11/17)
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- Method for one-step synthesis of methyl o-anisate
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The invention provides a method for one-step synthesis of methyl o-anisate. The method comprises steps as follows: an aqueous solution is prepared from salicylic acid and potassium hydroxide in the mole ratio being 1:(2.1-2.6) and added to a reaction device, the temperature is controlled to range from 15 DEG C to 25 DEG C, methyl bromide is introduced under the condition of stirring, and the reaction degree is traced through thin layer chromatography; after a reaction is completed, stirring is stopped, the mixture is left to stand for layering at the room temperature, lower-layer potassium bromide-containing wastewater is removed, and byproduct potassium bromide is obtained through concentration treatment; an upper-layer product is subjected to reduced pressure distillation after being washed with a saturated salt solution and dried by anhydrous sodium sulfate, fractions at 95-110 DEG C are collected, and methyl o-anisate is obtained. With the adoption of the method for one-step synthesis of methyl o-anisate, the technological process is shortened, the reaction period is substantially shortened, meanwhile, production amounts of three wastes are reduced, the wastewater treatment difficulty is reduced, and treatment power consumption and equipment occupancy are greatly reduced.
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Paragraph 0017; 0018
(2016/12/01)
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- Preparation method of methyl o-methoxybenzoate
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The invention provides a preparation method of methyl o-methoxybenzoate. The method comprises the following steps: preparing salicylic acid and potassium hydroxide in a molar ratio of 1:(2-2.4) into an aqueous solution and adding into a reaction device; controlling the temperature to 10-20 DEG C; introducing bromomethane in a stirring condition while performing point-plate tracking of the reaction degree; after the reaction is complete, stopping stirring and standing for layering at room temperature; separating out the potassium bromide-containing wastewater on the lower layer, and concentrating to obtain a byproduct potassium bromide; washing the upper-layer product with saturated salt solution; drying with anhydrous sodium sulfate and performing reduced-pressure distillation; and collecting the fraction at 95-110 DEG C to obtain methyl o-methoxybenzoate. According to the preparation method of methyl o-methoxybenzoate provided by the invention, the technological process is shortened, the reaction time is remarkably reduced, the generation of three wastes is reduced, the wastewater treatment difficulty is relieved, and the treatment power consumption and equipment occupation are greatly reduced.
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Paragraph 0013; 0017
(2017/03/08)
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- Method for synthesizing methyl o-anisate through methyl bromide
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The invention provides a method for synthesizing methyl o-anisate through methyl bromide. The method comprises the steps that a water solution is prepared from salicylic acid and alkali liquor to be added into a reaction device, the temperature is controlled to range from 10 DEG C to 20 DEG C, methyl bromide is introduced under the condition of stirring, and the reaction degree is tracked in a plate dropping mode; after complete reacting is achieved, stirring is stopped, standing and layering are carried out at room temperature, bromide salt waste water on the lower layer is removed, and by-product bromide salt is obtained through concentration treatment; the product on the upper layer is washed with a saturated saline solution, after anhydrous sodium sulfate is dried, reduced pressure distillation is carried out, and distillate at the temperature of 95 DEG C to 110 DEG C is collected to obtain methyl o-anisate. According to the method for synthesizing methyl o-anisate through methyl bromide, the technological process is shortened, the reaction period is greatly shortened, meanwhile, the quantity of generated three wastes is reduced, the treatment difficulty of waste water is lowered, and treatment power consumption and the quantity of occupied equipment of the method are greatly reduced.
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Page/Page column 4-6
(2017/03/08)
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- N-Doped Sub-3 nm Co Nanoparticles as Highly Efficient and Durable Aerobic Oxidative Coupling Catalysts
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A nano-coating associated with sulfuric acid leaching protocol was developed to prepare N-doped sub-3 nm Co-based nanoparticle catalyst (Co?N/C) using melamine–formaldehyde resin as the N-containing precursor, active carbon as the support, and Co(NO3)2 as the Co-containing precursor. By thermal treatment under nitrogen atmosphere at 800 °C and leached with sulfuric acid solution, a stable and highly dispersive Co?N coordination structure was uniformly dispersed on the formed Co?N/C catalyst with a Co loading of 0.47 wt % and Co nanoparticle size of 2.55 nm. The Co?N/C catalyst was characterized with XRD, XPS, Raman, SEM, TEM, ICP, and elemental analysis. The Co?N/C catalyst showed extremely high catalytic efficiency with a TON of 257 for the aerobic oxidative coupling of aldehydes with methanol to directly synthesize methyl esters with molecular oxygen as the final oxidant. The Co?N/C catalyst also showed broad substrate range and stable recyclability. After recycling for 7 times, no obvious deactivation was detected. It was confirmed that the sub-3 nm Co?N coordination structure formed between metallic Co nanoparticles and pyridinic nitrogen doping into graphitic layers functions as the active site to activate molecular oxygen for the β-H elimination from generated hemiacetal intermediates to produce methyl esters. The nano-coating associated with acid leaching protocol provides a novel strategy to prepare highly efficient non-precious metal-based catalysts.
- Han, Junxing,Gu, Feifei,Li, Yuchao
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p. 2594 - 2601
(2016/09/28)
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- Aerobic Copper-Catalyzed O-Methylation with Methylboronic Acid
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The oxidative coupling of alkylboronic acids with oxygen nucleophiles offers a strategy for replacing toxic, electrophilic alkylating reagents. Although the Chan-Lam reaction has been widely applied in the arylation of heteroatom nucleophiles, O-alkylation with boronic acids is rare. We report a Cu-catalyzed nondecarboxylative methylation of carboxylic acids with methylboronic acid that proceeds in air with no additional oxidant. An isotope-labeling study supports an oxidative cross-coupling mechanism, in analogy to that proposed for Chan-Lam arylation.
- Jacobson, Clare E.,Martinez-Mu?oz, Noelia,Gorin, David J.
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p. 7305 - 7310
(2015/07/28)
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