- Hydroxyl radical-mediated oxidative cleavage of CC bonds and further esterification reaction by heterogeneous semiconductor photocatalysis
-
A hydroxyl radical-mediated aerobic cleavage of alkenes and further sequence esterification reaction for the preparation of carbonyl compounds have been developed by using tubular carbon nitride (TCN) as a general heterogeneous photocatalyst under an oxygen atmosphere with visible light irradiation. This protocol has an excellent substrate scope and gives the desired aldehydes, ketones and esters in moderate to high yields. Importantly, this metal-free procedure employed photogenerated hydroxyl radicals in situ as green oxidation active species, avoiding the present additional initiators. The reaction could be carried out under solar light irradiation and was applicable to large-scale reactions. Furthermore, the recyclable TCN catalyst could be used several times without a significant loss of activities.
- Hong, Mei,Jia, Rui,Miao, Hongyan,Ni, Bangqing,Niu, Tengfei,Wang, Hui
-
p. 6591 - 6597
(2021/09/10)
-
- Photo-induced thiolate catalytic activation of inert Caryl-hetero bonds for radical borylation
-
Substantial effort is currently being devoted to obtaining photoredox catalysts with high redox power. Yet, it remains challenging to apply the currently established methods to the activation of bonds with high bond dissociation energy and to substrates with high reduction potentials. Herein, we introduce a novel photocatalytic strategy for the activation of inert substituted arenes for aryl borylation by using thiolate as a catalyst. This catalytic system exhibits strong reducing ability and engages non-activated Caryl–F, Caryl–X, Caryl–O, Caryl–N, and Caryl–S bonds in productive radical borylation reactions, thus expanding the available aryl radical precursor scope. Despite its high reducing power, the method has a broad substrate scope and good functional-group tolerance. Spectroscopic investigations and control experiments suggest the formation of a charge-transfer complex as the key step to activate the substrates.
- K?nig, Burkhard,Wang, Hua,Wang, Shun
-
supporting information
p. 1653 - 1665
(2021/06/17)
-
- Method for preparing carboxylic ester compounds by oxidizing and breaking carbon-carbon bonds of secondary alcohol compounds
-
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.
- -
-
Paragraph 0040-0041; 0092
(2021/06/02)
-
- Mild Copper-Catalyzed Addition of Arylboronic Esters to Di- tert -butyl Dicarbonate: An Easy Access to Methyl Arylcarboxylates
-
An efficient copper-catalyzed addition of arylboronic esters to (Boc) 2O was developed. The reaction can be conducted under exceedingly mild conditions and is compatible with a variety of synthetically relevant functional groups. It therefore represents a useful alternative route for the synthesis of methyl arylcarboxylates. A preliminary mechanistic study indicated the involvement of an addition-elimination mechanism.
- Xu, Jin-Di,Su, Xiao-Bo,Wang, Cai,Yao, Li-Wei,Liu, Jing-Hui,Hu, Guo-Qin
-
supporting information
p. 833 - 837
(2021/02/26)
-
- Method for coproducing methyl benzoic acid Process for the production of methyl benzoates and diesters of phthalic acids
-
The invention discloses a coproduction method of methylbenzoic acid, methyl benzoate and benzenedicarboxylic acid diester. The method comprises the following steps: (1) continuously introducing xylene, a catalyst and oxygen-containing gas into an oxidation reactor for a reaction, and controlling oxygenic concentration in the tail gas to not exceed 5% by controlling introduction amount of the oxygen-containing gas to obtain an oxidation reaction liquid; (2) feeding the obtained oxidation reaction liquid into a predistillation tower for distillation separation to obtain a low-boiling-point component and a predistillation tower bottom liquid; (3) feeding the predistillation tower bottom liquid into a distillation tower for distillation to obtain a methylbenzoic acid product and a distillationtower bottom liquid; (4) mixing the distillation tower bottom liquid and alcohol for an esterification reaction, and controlling the reaction endpoint to be lower than 0.5wt% of the content of methylbenzoic acid to obtain an esterification reaction liquid; (5) performing distillation separation on the obtained esterification reaction liquid to obtain methyl benzoate and benzenedicarboxylic acid diester products. The method has the advantages that the process is simple, equipment investment is low, and the method is environmentally friendly and has good comprehensive economic benefits.
- -
-
Paragraph 0176-0192
(2021/02/09)
-
- Light-induced carboxylation of aryl derivatives with cooperative COF as an active photocatalyst and Ni(ii) co-catalyst
-
The photocatalytic carboxylation of aryl derivatives was demonstrated under CO2at atmospheric pressure using a mesoporous covalent organic framework (COF) as the active photocatalyst with triethylamine (TEA) as a sacrificial electron source under visible light. A yield of greater than 91% of the isolated product was achieved with 5 mg of catalyst. The reaction cycle is dependent on the use of the Ni(dmg)2co-catalyst and the sacrificial electron donor (TEA). The reaction does not occur in the absence of light (445 nm) even at elevated reaction temperature. We have also demonstrated that a yield of 32% of the isolated product could be obtained with the use of sunlight in the catalytic cycle. Additionally, this heterogeneous catalytic system was recyclable and reusable for several cycles.
- Chakrabortty, Pekham,Das, Anjan,Chowdhury, Arpita Hazra,Ghosh, Swarbhanu,Khan, Aslam,Islam, Sk. Manirul
-
p. 4738 - 4745
(2021/03/22)
-
- Br?nsted acid-catalyzed chlorination of aromatic carboxylic acids
-
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
-
supporting information
p. 685 - 689
(2021/04/09)
-
- Phosphine-free ruthenium complex-catalyzed synthesis of mono- Or dialkylated acyl hydrazides via the borrowing hydrogen strategy
-
Herein, we report a diaminocyclopentadienone ruthenium tricarbonyl complex-catalyzed synthesis of mono- or dialkylated acyl hydrazide compounds using the borrowing hydrogen strategy in the presence of various substituted primary and secondary alcohols as alkylating reagents. Deuterium labeling experiments confirm that the alcohols were the hydride source in this cascade process. Density functional theory (DFT) calculations unveil the origin and the threshold between the mono- and dialkylation.
- Joly, Nicolas,Bettoni, Léo,Gaillard, Sylvain,Poater, Albert,Renaud, Jean-Luc
-
p. 6813 - 6825
(2021/05/29)
-
- Cobalt single atoms anchored on nitrogen-doped porous carbon as an efficient catalyst for oxidation of silanes
-
The oxidation reactions of organic compounds are important transformations for the fine and bulk chemical industry. However, they usually involve the use of noble metal catalysts and suffer from toxic or environmental issues. Here, an efficient, environmentally friendly, and atomically dispersed Co catalyst (Co-N-C) was preparedviaa simple, porous MgO template and etching method using 1,10-phenanthroline as C and N sources, and CoCl2·6H2O as the metal source. The obtained Co-N-C catalyst exhibits excellent catalytic performance for the oxidation of silanes with 97% isolated yield of organosilanol under mild conditions (room temperature, H2O as an oxidant, 1.8 h), and good stability with 95% isolated yield after nine consecutive reactions. The turnover frequency (TOF) is as high as 381 h?1, exceeding those of most non-noble metal catalysts and some noble metal catalysts. Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), extended X-ray absorption fine structure (EXAFS), and wavelet transform (WT) spectroscopy corroborate the existence of atomically dispersed Co. The coordination numbers of Co affected by the pyrolysis temperature in Co-N-C-700, Co-N-C-800, and Co-N-C-900 are 4.1, 3.6, and 2.2, respectively. Owing to a higher Co-N3content, Co-N-C-800 shows more outstanding catalytic performance than Co-N-C-700 and Co-N-C-800. Moreover, density functional theory (DFT) calculations reveal that the Co-N3structure exhibits more activity compared with Co-N4and Co-N2, which is because the Co atom in Co-N3was bound with both H atom and Si atom, and it induced the longest Si-H bond.
- Yang, Fan,Liu, Zhihui,Liu, Xiaodong,Feng, Andong,Zhang, Bing,Yang, Wang,Li, Yongfeng
-
supporting information
p. 1026 - 1035
(2021/02/09)
-
- GPR52 Antagonist Reduces Huntingtin Levels and Ameliorates Huntington's Disease-Related Phenotypes
-
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
-
p. 941 - 957
(2020/11/30)
-
- Development of phenyltriazole thiol-based derivatives as highly potent inhibitors of DCN1-UBC12 interaction
-
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
-
-
- Ruthenium-Catalyzed Three-Component Alkylation: A Tandem Approach to the Synthesis of Nonsymmetric N,N-Dialkyl Acyl Hydrazides with Alcohols
-
The borrowing hydrogen strategy has been applied in the synthesis of nonsymmetric N,N-dialkylated acyl hydrazides via a tandem three-component reaction catalyzed by a phosphine free diaminocyclopentadienone ruthenium tricarbonyl complex. This strategy represents the first direct one-pot approach to nonsymmetric functionalized acyl hydrazides. Different aromatic acyl hydrazides underwent dialkylation with a variety of primary or secondary alcohols and methanol or ethanol as alkylating agents in mild reaction conditions and good yields. Deuterium labelling experiments suggested that the primary or secondary alcohol was the hydrogen source in this tandem process. DFT calculations show that the combination of the tandem mixed product cannot be perfectly explained neither structurally nor electronically, but might be dependent of the physical state of the aldehyde or ketone intermediate (gaz vs. liquid) at the reaction temperature. (Figure presented.).
- Bettoni, Léo,Joly, Nicolas,Lohier, Jean-Fran?ois,Gaillard, Sylvain,Poater, Albert,Renaud, Jean-Luc
-
supporting information
p. 4009 - 4017
(2021/07/02)
-
- Copper-promoted direct amidation of isoindolinone scaffolds by sodium persulfate
-
Isoindolinones are ubiquitous structural motifs in natural products and pharmaceuticals. Establishing an efficient method for structural modification of isoindolinones could significantly facilitate new drug development. Herein, we describe copper-promoted direct amidation of isoindolinone scaffolds mediated by sodium persulfate. The method exhibits mild reaction conditions and high site-selectivity, and enables the structural modification of the drug indobufen ester with various amides with yields of 49 to 98%. It is also gram-scalable. Additionally, the reaction mechanism appears to involve a radical and a carbocationic pathway.
- Lai, Huifang,Lin, Jin,Xu, Jiexin,Zha, Daijun
-
supporting information
p. 7621 - 7626
(2021/09/22)
-
- Pd/C-Catalyzed methoxycarbonylation of aryl chlorides
-
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
-
-
- Methoxylation of Acyl Fluorides with Tris(2,4,6-trimethoxyphenyl)phosphine via C-OMe Bond Cleavage under Metal-Free Conditions
-
Acyl fluorides are subjected to methoxylation with tris(2,4,6-trimethoxyphenyl)phosphine (TMPP) to afford the corresponding methyl esters in good to excellent yields. This transformation is featured by C(sp2)-OMe bond cleavage under metal-free conditions. Unprecedented utilization of TMPP as a methoxylating agent realized the installation of an OMe group into the desired products.
- Ishida, Takumi,Nishihara, Yasushi,Wang, Xiu,Wang, Zhenhua
-
p. 7526 - 7533
(2020/06/27)
-
- Palladium-Catalyzed, Copper(I)-Promoted Methoxycarbonylation of Arylboronic Acids with O-Methyl S-Aryl Thiocarbonates
-
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
-
p. 4475 - 4481
(2020/04/10)
-
- Palladium-catalyzed aryloxy- and alkoxycarbonylation of aromatic iodides in γ-valerolactone as bio-based solvent
-
Fossil-based solvents and triethylamine as a toxic and volatile base were successfully replaced with γ-valerolactone as a non-volatile solvent and K2CO3 as inorganic base in the alkoxy- and aryloxycarbonylation of aryl iodides using phosphine-free Pd catalyst systems. By this, the traditional systems were not simply replaced but also significantly improved. In the study, the effects of different reaction parameters, i.e. the use of several other solvents, the temperature, the carbon monoxide pressure, the base and the catalyst concentrations, were evaluated in details on the efficiency of the carbonylations. To gather some information on the mechanism of these reactions, the effects of the electronic parameters (σ) of various aromatic substituents of the aryl iodides as well as the influence of para-substitution of phenol were investigated on the activity. For a comparison, the aryl-substituted aryl iodides were also reacted with methanol and aryl iodide was also alkoxycarbonylated using several different lower alcohols. From the observed correlations between the electronic parameters of the aromatic substituents and the rates, it appears that the rate determining step is the oxidative addition of Ar–I to Pd0, provided that sufficient amounts of nucleophiles are present for the ester formation. If this is not the case, the rate of nucleophile attack might determine the overall rate.
- Tukacs, József M.,Marton, Bálint,Albert, Eszter,Tóth, Imre,Mika, László T.
-
-
- Synthesis, biological evaluation of benzothiazole derivatives bearing a 1,3,4-oxadiazole moiety as potential anti-oxidant and anti-inflammatory agents
-
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
-
-
- Discovery of [1,2,4]triazole derivatives as new metallo-β-lactamase inhibitors
-
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
-
-
- Efficient C-H Amination Catalysis Using Nickel-Dipyrrin Complexes
-
A dipyrrin-supported nickel catalyst (AdFL)Ni(py) (AdFL: 1,9-di(1-adamantyl)-5-perfluorophenyldipyrrin; py: pyridine) displays productive intramolecular C-H bond amination to afford N-heterocyclic products using aliphatic azide substrates. The catalytic amination conditions are mild, requiring 0.1-2 mol% catalyst loading and operational at room temperature. The scope of C-H bond substrates was explored and benzylic, tertiary, secondary, and primary C-H bonds are successfully aminated. The amination chemoselectivity was examined using substrates featuring multiple activatable C-H bonds. Uniformly, the catalyst showcases high chemoselectivity favoring C-H bonds with lower bond dissociation energy as well as a wide range of functional group tolerance (e.g., ethers, halides, thioetheres, esters, etc.). Sequential cyclization of substrates with ester groups could be achieved, providing facile preparation of an indolizidine framework commonly found in a variety of alkaloids. The amination cyclization reaction mechanism was examined employing nuclear magnetic resonance (NMR) spectroscopy to determine the reaction kinetic profile. A large, primary intermolecular kinetic isotope effect (KIE = 31.9 ± 1.0) suggests H-atom abstraction (HAA) is the rate-determining step, indicative of H-atom tunneling being operative. The reaction rate has first order dependence in the catalyst and zeroth order in substrate, consistent with the resting state of the catalyst as the corresponding nickel iminyl radical. The presence of the nickel iminyl was determined by multinuclear NMR spectroscopy observed during catalysis. The activation parameters (ΔH? = 13.4 ± 0.5 kcal/mol; ΔS?= -24.3 ± 1.7 cal/mol·K) were measured using Eyring analysis, implying a highly ordered transition state during the HAA step. The proposed mechanism of rapid iminyl formation, rate-determining HAA, and subsequent radical recombination was corroborated by intramolecular isotope labeling experiments and theoretical calculations.
- Betley, Theodore A.,Clarke, Ryan M.,Dong, Yuyang,Porter, Gerard J.
-
supporting information
p. 10996 - 11005
(2020/07/08)
-
- Modulation of estrogen-related receptors subtype selectivity: Conversion of an ERRβ/γ selective agonist to ERRα/β/γ pan agonists
-
Estrogen Related Receptors (ERRs) are key regulators of energy homeostasis and play important role in the etiology of metabolic disorders, skeletal muscle related disorders, and neurodegenerative diseases. Among the three ERR isoforms, ERRα emerged as a potential drug target for metabolic and neurodegenerative diseases. Although ERRβ/γ selective agonist chemical tools have been identified, there are no chemical tools that effectively target ERRα agonism. We successfully engineered high affinity ERRα agonism into a chemical scaffold that displays selective ERRβ/γ agonist activity (GSK4716), providing novel ERRα/β/γ pan agonists that can be used as tools to probe the physiological roles of these nuclear receptors. We identified the structural requirements to enhance selectivity toward ERRα. Molecular modeling shows that our novel modulators have favorable binding modes in the LBP of ERRα and can induce conformational changes where Phe328 that originally occupies the pocket is dislocated to accommodate the ligands in a rather small cavity. The best agonists up-regulated the expression of target genes PGC-1α and PGC-1β, which are necessary to achieve maximal mitochondrial biogenesis. Moreover, they increased the mRNA levels of PDK4, which play an important role in energy homeostasis.
- Avdagic, Amer,Billon, Cyrielle,Burris, Sheryl L.,Burris, Thomas P.,Elagawany, Mohamed,Elgendy, Bahaa,Goher, Shaimaa S.,Hegazy, Lamees,Sanders, Ryan,Shahien, Mohamed,Sitaula, Sadichha
-
-
- Method for preparing carboxylic ester by alcohol direct oxidation esterification method
-
The invention discloses a method for preparing a carboxylic ester by an alcohol direct oxidation esterification method. The method comprises the following steps: taking an aromatic alcohol compound ora saturated linear aliphatic alcohol as a reaction substrate, taking an Au-Co composite particle carrier as a catalyst, adding a low catalytic amount of alkali, reacting for 0.5-15 h in a methanol solvent at the temperature of 25-150 DEG C in air or oxygen or a mixed atmosphere of the air or the oxygen, and performing aftertreatment to obtain a target product carboxylic ester. According to the preparation method disclosed by the invention, the process steps are reduced, conditions are mild, catalyst consumption is less, atom economy is high, the method is simple to operate, the application range of the substrate is wide, and industrial practicability is achieved.
- -
-
Paragraph 0038; 0039
(2019/06/30)
-
- Aldehyde effect and ligand discovery in Ru-catalyzed dehydrogenative cross-coupling of alcohols to esters
-
The presence of different aldehydes is found to have a significant influence on the catalytic performance when using PN(H)P type ligands for dehydrogenation of alcohols. Accordingly, hybrid multi-dentate ligands were discovered based on an oxygen-transfer alkylation of PNP ligands by aldehydes. The relevant Ru-PNN(PO) system provided the desired unsymmetrical esters in good yields via acceptorless dehydrogenation of alcohols. Hydrogen bonding interactions between the phosphine oxide moieties and alcohol substrates likely assisted the observed high chemoselectivity.
- Jiang, Xiaolin,Zhang, Jiahui,Zhao, Dongmei,Li, Yuehui
-
p. 2797 - 2800
(2019/03/27)
-
- 1,3-Dibromo-5,5-dimethylhydantoin as a Precatalyst for Activation of Carbonyl Functionality
-
Activation of carbonyl moiety is one of the most rudimentary approaches in organic synthesis and is crucial for a plethora of industrial-scale condensation reactions. In esterification and aldol condensation, which represent two of the most important reactions, the susceptibility of the carbonyl group to nucleophile attack allows the construction of a variety of useful organic compounds. In this context, there is a constant need for development of and improvement in the methods for addition-elimination reactions via activation of carbonyl functionality. In this paper, an advanced methodology for the direct esterification of carboxylic acids and alcohols, and for aldol condensation of aldehydes using widely available, inexpensive, and metal-free 1,3-dibromo-5,5-dimethylhydantoin under neat reaction conditions is reported. The method is air- and moisture-tolerant, allowing simple synthetic and isolation procedures for both reactions presented in this paper. The reaction pathway for esterification is proposed and a scale-up of certain industrially important derivatives is performed.
- ?ebular, Klara,Bo?i?, Bojan ?.,Stavber, Stojan
-
supporting information
(2019/08/01)
-
- Synthesis and biological activities of benzothiazole derivatives bearing a 1,3,4-thiadiazole moiety
-
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
-
p. 241 - 248
(2019/01/04)
-
- 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
-
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.
-
p. 4350 - 4369
(2019/05/08)
-
- 1,1,2,2-Tetrahydroperoxy-1,2-Diphenylethane: An efficient and high oxygen content oxidant in various oxidative reactions
-
Several oxidative approaches namely thiocyanation of aromatic compounds, epoxidation of alkenes, amidation of aromatic aldehydes, epoxidation of α β-unsaturated ketones, oxidation of sulfides to sulfoxides and sulfones, bayer-villeger reaction, bromination and iodation of aniline and phenol derivatives oxidative esterification, oxidation of pyridines and oxidation of secondary, allylic and benzyllic alcohols were carried out using 1,1,2,2-Tetrahydroperoxy-1,2-Diphenylethane as the potential solid oxidant which can be stored for several months without any loss in its activity. All of the procedures were accomplished via mild reaction conditions and the products were afforded in high yields and short reaction times.
- Khosravi, Kaveh,Naserifar, Shirin
-
supporting information
p. 6584 - 6592
(2018/10/05)
-
- A biocatalytic method for the chemoselective aerobic oxidation of aldehydes to carboxylic acids
-
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.
-
p. 3931 - 3943
(2018/09/11)
-
- Cobalt-entrenched N-, O-, and S-tridoped carbons as efficient multifunctional sustainable catalysts for base-free selective oxidative esterification of alcohols
-
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
-
p. 3542 - 3556
(2018/08/07)
-
- Superior performance of Co-N/m-C for direct oxidation of alcohols to esters under air
-
A convenient, expeditious, and high-efficiency protocol for the transformation of alcohols into esters using a Co-modified N-doped mesoporous carbon material (Co-N/m-C) as the catalyst is proposed. The catalyst was prepared through direct pyrolysis of a macromolecular precursor. The catalyst prepared using a pyrolysis temperature of 900 °C (labeled Co-N/m-C-900) exhibited the best performance. The strong coordination between the ultra-dispersed cobalt species and the pyridine nitrogen as well as the large area of the mesoporous surface resulted in a high turnover frequency value (107.6 mol methyl benzoate mol?1 Co h?1) for the direct aerobic oxidation of benzyl alcohol to methyl benzoate. This value is much higher than those of state-of-the-art transition-metal-based nanocatalysts reported in the literature. Moreover, the catalyst exhibited general applicability to various structurally diverse alcohols, including benzylic, allylic, and heterocyclic alcohols, achieving the target esters in high yields. In addition, a preliminary evaluation revealed that Co-N/m-C-900 can be used six times without significant activity loss. In general, the process was rapid, simple, and cost-effective.
- Li, Ning,Shang, Sensen,Wang, Lianyue,Niu, Jingyang,Lv, Ying,Gao, Shuang
-
p. 1249 - 1257
(2018/06/14)
-
- Design, Synthesis and Evaluation of Antitubercular Activity of Novel 1,2,4-Triazoles Against MDR Strain of Mycobacterium tuberculosis
-
Emergence of various forms of resistant strains of Mycobacterium tuberculosis led to the exploration of drugs with novel mechanism of action. Recently econazole, an azole based antitubercular agent, attracted major attention for targeting mycobacterial cytochrome P450. In the present study, we designed novel 1,2,4-triazole derivatives based on econazole moiety and evaluated them for in vitro antitubercular activity against M. tuberculosis H37Rv and multi-drug resistant (MDR) strains of Mycobacterium.
- Ganesh Kumar,Gautham Shenoy,Kar, Sidhartha Sankar,Shenoy, Vishnu,Bairy, Indira
-
p. 907 - 917
(2018/02/07)
-
- Structural design, synthesis and substituent effect of hydrazone-N-acylhydrazones reveal potent immunomodulatory agents
-
4-(Nitrophenyl)hydrazone derivatives of N-acylhydrazone were synthesized and screened for suppress lymphocyte proliferation and nitrite inhibition in macrophages. Compared to an unsubstituted N-acylhydrazone, active compounds were identified within initial series when hydroxyl, chloride and nitro substituents were employed. Structure-activity relationship was further developed by varying the position of these substituents as well as attaching structurally-related substituents. Changing substituent position revealed a more promising compound series of anti-inflammatory agents. In contrast, an N-methyl group appended to the 4-(nitrophenyl)hydrazone moiety reduced activity. Anti-inflammatory activity of compounds is achieved by modulating IL-1β secretion and prostaglandin E2 synthesis in macrophages and by inhibiting calcineurin phosphatase activity in lymphocytes. Compound SintMed65 was advanced into an acute model of peritonitis in mice, where it inhibited the neutrophil infiltration after being orally administered. In summary, we demonstrated in great details the structural requirements and the underlying mechanism for anti-inflammatory activity of a new family of hydrazone-N-acylhydrazone, which may represent a valuable medicinal chemistry direction for the anti-inflammatory drug development in general.
- Meira, Cássio S.,dos Santos Filho, José Maurício,Sousa, Caroline C.,Anjos, Pamela S.,Cerqueira, Jéssica V.,Dias Neto, Humberto A.,da Silveira, Rafael G.,Russo, Helena M.,Wolfender, Jean-Luc,Queiroz, Emerson F.,Moreira, Diogo R.M.,Soares, Milena B.P.
-
p. 1971 - 1985
(2018/03/12)
-
- Continuous Flow Synthesis under High-Temperature/High-Pressure Conditions Using a Resistively Heated Flow Reactor
-
A cheap, easy-to-build, and effective resistively heated reactor for continuous flow synthesis at high temperature and pressure is herein presented. The reactor is rapidly heated directly using an electric current and is capable of rapidly delivering temperatures and pressures up to 400 °C and 200 bar, respectively. High-temperature and high-pressure applications of this reactor were safely performed and demonstrated by selected transformations such as esterifications, transesterifications, and direct carboxylic acid to nitrile reactions using supercritical ethanol, methanol, and acetonitrile. Reaction temperatures were between 300 and 400 °C with excellent conversions and good to excellent isolated product yields. Examples of Diels-Alder reactions were also carried out at temperatures up to 300 °C in high yield. No additives or catalysts were used in the reactions.
- Adeyemi, Ahmed,Bergman, Joakim,Br?nalt, Jonas,S?vmarker, Jonas,Larhed, Mats
-
supporting information
p. 947 - 955
(2017/07/26)
-
- Direct oxidation of aldehydes to methyl esters with urea hydrogen peroxide and p-toluenesulfonyl chloride
-
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
-
p. 725 - 728
(2017/12/28)
-
- Amberlyst-15 catalysed oxidative esterification of aldehydes using a H2O2 trapped oxidant as a terminal oxidant
-
A simple and efficient method has been developed for the selective oxidative esterification of aldehydes using commercially available Amberlyst-15 as a catalyst. H2O2 released from a clathrate structured 4Na2SO4·2H2O2·NaCl oxidant serves as an efficient source of terminal oxidants. Various aromatic, heteroaromatic, and aliphatic aldehydes undergo selective esterification to give good to excellent yield. The heterogeneous catalyst, Amberlyst-15, exhibits high reactivity and can be recycled over several runs. The 4Na2SO4·2H2O2·NaCl oxidant was found to be superior to commonly used oxidizing agents providing an anhydrous, easy to handle and stable form of H2O2
- Gayakwad, Eknath M.,Patil, Vilas V.,Shankarling, Ganapati S.
-
p. 2695 - 2701
(2017/04/03)
-
- Selective Actinide-Catalyzed Tandem Proton-Transfer Esterification of Aldehydes with Alcohols for the Production of Asymmetric Esters
-
Actinide-catalyzed tandem proton-transfer esterification between aldehydes and alcohols is presented herein for the first time. It represents a novel convenient and external-oxidant-free methodology in the preparation of asymmetric ester compounds. Various kinds of aldehydes and alcohols can be applied to this reaction, affording the corresponding ester product in moderate to high yields. A plausible mechanism was proposed on the basis of the kinetic, stoichiometric, and deuterium-labeling studies.
- Liu, Heng,Eisen, Moris S.
-
supporting information
p. 1461 - 1464
(2017/04/28)
-
- An electrochemical method for carboxylic ester synthesis from N-alkoxyamides
-
An electrochemical method for the synthesis of carboxylic as well as hindered esters from N-alkoxyamides has been reported. The electrochemical reaction proceeds through constant current electrolysis (CCE) by taking advantage of the dual role of n-Bu4NI (TBAI) as the redox catalyst as well as the supporting electrolyte. Besides providing mild reaction conditions, the present protocol is free from external oxidants and conducting salts, thereby generating nitrogen as the nonhazardous side product. Additionally, the developed procedure is highly advantageous due to its short reaction time, wide substrate scope, and gram-scale synthesis.
- Subramanian, Kripa,Yedage, Subhash L.,Bhanage, Bhalchandra M.
-
p. 10025 - 10032
(2018/05/31)
-
- Nickel-catalyzed methylation of aryl halides/tosylates with methyl tosylate
-
This work describes the cross-electrophile methylation of aryl bromides and aryl tosylates with methyl tosylate. The mild reaction conditions allow effective methylation of a wide set of heteroaryl electrophiles and dimethylation of dibromoarenes.
- Wang, Jiawang,Zhao, Jianhong,Gong, Hegui
-
supporting information
p. 10180 - 10183
(2017/09/23)
-
- Visible-Light-Driven Carboxylation of Aryl Halides by the Combined Use of Palladium and Photoredox Catalysts
-
A highly useful, visible-light-driven carboxylation of aryl bromides and chlorides with CO2 was realized using a combination of Pd(OAc)2 as a carboxylation catalyst and Ir(ppy)2(dtbpy)(PF6) as a photoredox catalyst. This carboxylation reaction proceeded in high yields under 1 atm of CO2 with a variety of functionalized aryl bromides and chlorides without the necessity of using stoichiometric metallic reductants.
- Shimomaki, Katsuya,Murata, Kei,Martin, Ruben,Iwasawa, Nobuharu
-
supporting information
p. 9467 - 9470
(2017/07/24)
-
- Oxalic acid as the: In situ carbon monoxide generator in palladium-catalyzed hydroxycarbonylation of arylhalides
-
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
-
p. 5033 - 5040
(2017/07/10)
-
- Heterogeneous cobalt catalysts for selective oxygenation of alcohols to aldehydes, esters and nitriles
-
Efficient and green oxygenation of alcohols to the corresponding aldehydes, esters and nitriles was developed with high selectivity. Functional alcohols, including some heterocyclic and allylic alcohols can be oxygenated to the corresponding aldehydes, esters and nitriles respectively. Moreover, the catalyst can be recycled and reused without significant deactivation. Noteworthy, the Co@NC (800-2h) catalyzed oxygenation of alcohols can be regulated easily by changing the reaction conditions, and then the corresponding aldehydes, esters and nitriles can be obtained in high yields respectively.
- Mao, Fei,Qi, Zhengliang,Fan, Haipeng,Sui, Dejun,Chen, Rizhi,Huang, Jun
-
p. 1498 - 1503
(2017/01/18)
-
- Efficient and selective palladium-catalyzed direct oxidative esterification of benzylic alcohols under aerobic conditions
-
A highly efficient palladium-catalyzed approach for the direct oxidative esterification of benzylic alcohols with methanol and long-chain aliphatic alcohols under mild conditions has been achieved. This practical catalyst system exhibits a broad substrate scope and good functional group tolerance. Catalytic amount of Bi(OTf)3 is used as co-catalyst to improve the activity and selectivity of the reactions. A variety of esters are obtained in yields of 43–96%.
- Hu, Yongke,Li, Bindong
-
p. 7301 - 7307
(2017/11/29)
-
- Selective Oxidative Esterification from Two Different Alcohols via Photoredox Catalysis
-
Esters functionalities are important building blocks that are extensively used in the chemical industry and academic laboratories. Direct oxidative esterification from easy-available alcohols to esters would be a much more appealing approach, especially using O2as terminal oxidant. Inputting external energy by photocatalysis for dioxygen activation, a mild and simple method for ester synthesis from two different alcohols has been achieved in this work. This reaction is performed under neutral conditions using O2as the terminal oxidant. A variety of primary alcohols, especially long chain alcohols and secondary alcohols are tolerated in this system.
- Yi, Hong,Hu, Xia,Bian, Changliang,Lei, Aiwen
-
-
- Activating cobalt nanoparticles via the Mott-Schottky effect in nitrogen-rich carbon shells for base-free aerobic oxidation of alcohols to esters
-
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
-
p. 811 - 818
(2017/05/17)
-
- Design, synthesis, and negative inotropic evaluation of 4-phenyl-1H-1,2,4-triazol-5(4H)-one derivatives containing triazole or piperazine moieties
-
In this study, four novel series of 4-phenyl-1H-1,2,4-triazol-5(4H)-one derivatives containing triazole or piperazine moieties were designed, synthesized, and evaluated for negative inotropic activity by measuring the left atrium stroke volume in isolated rabbit heart preparations. Almost all of the compounds showed an ability to moderate the cardiac workload by decreasing the heart rate and contractility. Among them, 7h was found to be the most potent with a change in stroke volume of ?48.22?±?0.36% at a concentration of 3?×?10?5?mol/L (metoprolol: ?9.74?±?0.14%). The cytotoxicity of these compounds was evaluated using the human cervical cancer cell line HeLa, the liver cancer cell line Hep3B, and the human normal hepatic cell line LO2. A preliminary study of the mechanism of action for the compound 7h on the regulation of atrial dynamics with ATP-sensitive K+ channel and L-type Ca2+ channel blockers glibenclamide and nifedipine was performed in the isolated perfused beating rabbit atria.
- Wei, Zhi-Yu,Cui, Bai-Ri,Cui, Xun,Wu, Yan-Ling,Fu, Yang,Liu, Li-Ping,Piao, Hu-Ri
-
-
- Iron(III)/TEMPO-Catalyzed Synthesis of 2,5-Disubstituted 1,3,4-Oxadiazoles by Oxidative Cyclization under Mild Conditions
-
A simple and efficient cationic Fe(III)/TEMPO-catalyzed oxidative cyclization of aroyl hydrazones has been developed for the synthesis of 2,5-disubstituted 1,3,4-oxadiazole derivatives. The reaction offers a broad scope, good functional-group tolerance, and high yields under mild conditions in the presence of O 2.
- Zhang, Guofu,Yu, Yidong,Zhao, Yiyong,Xie, Xiaoqiang,Ding, Chengrong
-
supporting information
p. 1373 - 1377
(2017/06/27)
-
- Method for synthesizing aromatic acid ester
-
The invention relates to a method for synthesizing aromatic acid ester. Corresponding aromatic acid ester is synthesized from aromatic acid and lower carbon alcohol used as raw materials with a catalytic esterification means through an esterification reaction performed by efficiently catalyzing aromatic acid and lower carbon alcohol with a solid acid catalyst with the surface modified with a sulfonic acid group and immobilized with an imidazole acid ionic liquid at a certain temperature. The catalytic reaction operation is simple, the selectivity of the aromatic ester product can reach 99% or above when aromatic acid is completely converted, and the catalyst has good hydrothermal stability and reusability.
- -
-
Paragraph 0031; 0032; 0042
(2017/09/05)
-
- N-Doped Sub-3 nm Co Nanoparticles as Highly Efficient and Durable Aerobic Oxidative Coupling Catalysts
-
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
-
p. 2594 - 2601
(2016/09/28)
-
- Chemoselective dehydrogenative esterification of aldehydes and alcohols with a dimeric rhodium(II) catalyst
-
Dehydrogenative cross-coupling of aldehydes with alcohols as well as dehydrogentive cross-coupling of primary alcohols to produce esters have been developed using a Rh-terpyridine catalyst. The catalyst demonstrates broad substrate scope and good functional group tolerance, affording esters highly selectively. The high chemoselectivity of the catalyst stems from its preference for dehydrogenation of benzylic alcohols over aliphatic ones. Preliminary mechanistic studies suggest that the active catalyst is a dimeric Rh(ii) species, operating via a mechanism involving metal-base-metal cooperativity.
- Cheng, Junjie,Zhu, Meijuan,Wang, Chao,Li, Junjun,Jiang, Xue,Wei, Yawen,Tang, Weijun,Xue, Dong,Xiao, Jianliang
-
p. 4428 - 4434
(2016/07/07)
-
- Efficient Baeyer-Villiger electro-oxidation of ketones with molecular oxygen using an activated carbon fiber electrode in ionic liquid [bmim][OTf]
-
A new and efficient method for the synthesis of lactones and esters involving the application of an molecular oxygen-based electro-catalytic oxidation system and ionic liquid [bmim][OTf] as electrolyte has been developed. The reaction between various ketones with molecular oxygen proceeds in a three-electrode cell under constant current conditions in [bmim][OTf] at room temperature to give the corresponding esters and lactones in good to excellent isolated yield. Additionally, the possible mechanism of Baeyer-Villiger oxidation of ketones in the electro-catalytic system is proposed.
- Hu, Yu Lin,Xie, Yi Bi,Li, De Jiang
-
p. 297 - 306
(2016/08/05)
-