- 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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- Discovery of novel furo[2,3-d]pyrimidin-2-one–1,3,4-oxadiazole hybrid derivatives as dual antiviral and anticancer agents that induce apoptosis
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A new series of furo[2,3-d]pyrimidine–1,3,4-oxadiazole hybrid derivatives were synthesized via an environmentally friendly, multistep synthetic tool and a one-pot Songoashira-heterocyclization protocol using, for the first time, nanostructured palladium pyrophosphate (Na2PdP2O7) as a heterogeneous catalyst. Compounds 9a–c exhibited broad-spectrum activity with low micromolar EC50 values toward wild and mutant varicella-zoster virus (VZV) strains. Compound 9b was up to threefold more potent than the reference drug acyclovir against thymidine kinase-deficient VZV strains. Importantly, derivative 9b was not cytostatic at the maximum tested concentration (CC50 > 100 μM) and had an acceptable selectivity index value of up to 7.8. Moreover, all synthesized 1,3,4-oxadiazole hybrids were evaluated for their cytotoxic activity in four human cancer cell lines: fibrosarcoma (HT-1080), breast (MCF-7 and MDA-MB-231), and lung carcinoma (A549). Data showed that compound 8f exhibits moderate cytotoxicity, with IC50 values ranging from 13.89 to 19.43 μM. Besides, compound 8f induced apoptosis through caspase 3/7 activation, cell death independently of the mitochondrial pathway, and cell cycle arrest in the S phase for HT1080 cells and the G1/M phase for A549 cells. Finally, the molecular docking study confirmed that the anticancer activity of the synthesized compounds is mediated by the activation of caspase 3.
- El Mansouri, Az-eddine,Oubella, Ali,Danoun, Karim,Ahmad, Mehdi,Neyts, Johan,Jochmans, Dirk,Snoeck, Robert,Andrei, Graciela,Morjani, Hamid,Zahouily, Mohamed,Lazrek, Hassan B.
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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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- Novel C-C bond cleavage from arylacetonitriles in alcohols to aryl carboxylic esters using potassium iodide and catalytic amount of samarium
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A novel way to cleave the carbon-carbon bond from arylacetonitriles in alcohols to their corresponding aryl carboxylic esters using potassium iodide and a catalytic amount of samarium under mild and neutral conditions is described. Useful yields of the reaction can be obtained with electron-deficient subsistent groups in aromatic rings, and the yields are higher when the subsistent group is an electron-withdrawing group (EWG) rather than an electron-donating group (EDG). Products were characterized by IR, 1H NMR, 13C NMR, and MS. Copyright Taylor & Francis Group, LLC.
- Yu, Mingxin,Wen, Weijiang,Wang, Zhiyuan
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- Modified extra-large mesoporous silica supported Au-Ni as a highly efficient catalyst for oxidative coupling of aldehydes with methanol
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Herein, we report for the first time that a La-Mg composite oxide modified extra-large mesoporous FDU-12 supported Au-Ni bimetallic catalyst exhibits excellent performance for oxidative coupling of aldehydes (including benzyl and aliphatic aldehydes) with methanol to directly produce methyl esters.
- Han, Junxing,Zhang, Suojiang,Zhang, Juan,Yan, Ruiyi
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- Efficient aerobic oxidation of alcohols to esters by acidified carbon nitride photocatalysts
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Photocatalytic aerobic oxidation of alcohols for the direct synthesis of esters has received significant attention in recent years, but the relatively low efficiency and selectivity under visible light irradiation is the main challenge for their practical applications. Here, surface acidic sites were imparted onto metal-free heterogeneous photocatalysts by the protonation of carbon nitride (HMCN) to promote the activity for the esterification reaction through further adsorption and activation of the intermediate aldehyde. The activation of the substrate could be remarkably modulated through tuning the acidic sites on the surface of the photocatalyst, leading to a controllable reactivity of the catalytic reaction. The one-pot process for the direct aerobic oxidative esterification of alcohol exhibits high efficiency and selectivity under mild and additive-free conditions and the apparent quantum yield (AQY) of the photocatalytic esterification reaction is 0.41% at 420 nm. Moreover, a scalable photocatalytic process by the merging of a continuous flow system with the heterogeneous HMCN photocatalyst is demonstrated, combining high catalytic efficiency and stability at ambient temperatures and being promising for larger-scale applications.
- Antonietti, Markus,Cheng, Jiajia,Lin, Sen,Savateev, Aleksandr,Wan, Qiang,Wang, Chong,Wang, Xinchen
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- Design, synthesis, in silico molecular docking and biological evaluation of novel oxadiazole based thiazolidine-2,4-diones bis-heterocycles as PPAR-γ agonists
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A library of novel 1,3,4-oxadiazole and 2-4-thiazolidinedione based bis-heterocycles 7 (a-r) has been synthesized which exhibited significant PPAR-?3 transactivation and blood glucose lowering effect comparable with the standard drugs Pioglitazone and Rosiglitazone. Compounds 7m and 7r did not cause body weight gain and were found to be free from hepatotoxic and cardiotoxic side effects. Compounds 7m and 7r increased PPAR-?3 gene expression by 2.10 and 2.00 folds, respectively in comparison to the standard drugs Pioglitazone (1.5 fold) and Rosiglitazone (1.0 fold). Therefore the compounds 7m and 7r may be considered as potential candidates for development of new antidiabetic agents.
- Nazreen, Syed,Alam, Mohammad Sarwar,Hamid, Hinna,Yar, Mohammad Shahar,Shafi, Syed,Dhulap, Abhijeet,Alam, Perwez,Pasha,Bano, Sameena,Alam, Mohammad Mahboob,Haider, Saqlain,Ali, Yakub,Kharbanda, Chetna,Pillai
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- Natural formation of chlorobenzoic acids (CBA) and distinction between PCB-degraded CBA
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Mono- and dichlorobenzoic acid (CBA) could be found in samples of remote bog pond water and sediment. The 2,4-CBA always had the highest concentrations. In bog water samples the concentrations ranged between 0.11 and 0.48 μg/l. Besides 2,4-CBA most only 2,5-CBA could be found as dichlorobenzoic acid. In all samples we could detect also trichloroacetic acid (TCAA). The TCAA concentrations correlate with the CBA concentrations. As TCAA is known as a naturally produced organohalogen, this correlation can be seen as an indication to a natural formation of CBA. A confirmation of this presumption is our detection CBA in a reaction of benzoic acid with the chlorinating enzyme chloroperoxidase (CPO).
- Niedan,Schoeler
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- Facile Coupling of Aldehydes with Alcohols: An Evolved Tishchenko Process for the Preparation of Unsymmetrical Esters
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A facile coupling process between aldehydes and alcohols to afford unsymmetrical esters is presented herein. This transformation is complementary to the Tishchenko reaction and provides access to unsymmetrical esters under very mild conditions. Various aldehydes and alcohols are suitable in this reaction, and the addition of a sacrificial trifluoromethyl ketone allows the process to take place in a highly selective manner. A plausible mechanism based on details obtained by monitoring the reaction progress and deuterium-labeling studies has been proposed.
- Liu, Heng,Eisen, Moris S.
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- Polymer supported Zn-salen complexes: An effective one-pot oxidative esterification of aldehydes to carboxylic esters
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Polymer-supported Zn-salen (PS-Zn-salen) complexes were synthesized, characterized and used as a catalyst for one-pot oxidative esterification of aldehydes with alcohols. The PS-Zn-salen heterogeneous catalyst exhibited a high-performance for the oxidative esterification of aldehydes to the corresponding methyl/ethyl esters using hydrogen peroxide as a green oxidant. Due to the synergistic effect of polymer support, the heterogeneous catalyst presented superior catalytic activity and afford 100% conversion of 3,4,5-trimethoxybenzaldehyde and 4-chlorobenzaldehyde to corresponding esters under optimized conditions. The different alcohol substrates study (viz. methyl alcohol, ethyl alcohol, allyl alcohol and benzyl alcohol) showed reasonable selectivity for esters, indicating the scope of the catalysts. Significantly, the synthesized complexes possess good hydrophobic/heterogeneous properties, which permit facile reclamation of the catalyst by using mere filtration. Moreover, the effect of counter anions of complex also studied which indicated that there is no appreciable influence on the conversion of product. The catalyst was reused up to 5th successive run with the average conversion of ester 87.4%. Mechanistic studies have recognized that this “one pot” direct oxidative esterification proceeds through acid formation, proven by a GC–MS. The catalyst is also found to be very stable, up to 280?°C, confirmed by the thermo gravimetric study.
- Balinge, Kamlesh Rudreshwar,Khiratkar, Avinash Ganesh,Bhagat, Pundlik Rambhau
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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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- Magnetic gold nanocatalyst (nanocat-Fe-Au): Catalytic applications for the oxidative esterification and hydrogen transfer reactions
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An efficient and sustainable protocol is described for the oxidative esterification of aldehydes and the reduction of aromatic nitro compounds that uses a magnetically separable and reusable maghemite-supported gold nanocatalyst (nanocat-Fe-Au) under mild conditions. The complex chemical, morphological, structural and size analyses, including e.g. XPS, HRTEM, in-field Moessbauer spectroscopy and HRTEM, revealed that the hybrid material is composed of a well-defined stoichiometric maghemite support (20-30 nm) decorated with ultrasmall (5-6 nm) gold nanoparticles. The hybrid catalytic system containing 4 wt% of nanogold has been generated using simple impregnation methods in aqueous medium from readily available starting materials and was recycled five times without any significant loss in catalytic activity; high yields, 40-95% and 83-94% for oxidative esterification and reduction reactions, respectively, were obtained. the Partner Organisations 2014.
- Gawande, Manoj B.,Rathi, Anuj K.,Tucek, Jiri,Safarova, Klara,Bundaleski, Nenad,Teodoro, Orlando M.N.D.,Kvitek, Libor,Varma, Rajender S.,Zboril, Radek
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- One Pot Electrooxidative Conversion of Aromatic 1,2-Diketones into Methyl Carboxylates
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One-pot conversion of several aromatic1,2-diketones into the corresponding methyl carboxylates was performed by indirect electrooxidation using iodide ion as an electron carrier in the presence of catalytic amount of sodium cyanide.
- Okimoto, Mitsuhiro,Nagata, Yuji,Sueda, Satoru,Takahashi, Yukio
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- Controlled immobilization of Keggin-type heteropoly acids on the surface of silica encapsulated γ-Fe2O3 nanoparticles and investigation of catalytic activity in the oxidative esterification of arylaldehydes with methanol
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Preparation, leaching and solid acidity measurements of H 3PW12O40, H3PMo12O 40 and H4SiW12O40 supported on silica-encapsulated γ-Fe2O3 nanoparticles were performed. The impregnating solvent and calcination temperature were optimized using various techniques. Catalytic activity of samples was examined by carrying out oxidative esterification of benzaldehyde with methanol under the same conditions. The acidity of the catalysts that was determined by NH 3-temperature-programmed desorption technique and chemisorption of pyridine. The best catalyst was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy and laser particle size analyzer. Finally, a mild, simple and clean procedure was presented for the one-pot oxidative esterification of arylaldehydes with methanol using magnetically recoverable nanocatalyst and hydrogen peroxide as a green oxidant.
- Rafiee, Ezzat,Eavani, Sara
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- Study of new synthesized ferrocenyl ionic liquids in oxidative esterification reaction
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In this work, novel ferrocene-based ionic liquids, 1-(ferrocenylbutyl)-4-(3-methylimidazolium) Azide and 1-(ferrocenylbutyl)-4-(3-methylimidazolium) Tetrafluoroborate, were synthesized and utilized in the oxidation esterification reaction of aldehydes in the present of different reagents such as NaN3, (K2CO3 and NCS), (KI and KCN), (I2 and K2CO3), (KMnO4). The results were compared with that of [BMIM][X] (X?Cl, BF4) under the same conditions. As expected, ferrocene-based ionic liquids showed better results; It seems, iron nuclear may play a similar role such as iron catalysts in these novel ionic liquids and can facilitated the oxidation esterification reaction with improve the yield and decrease the reaction time.
- Teimuri-Mofrad, Reza,Rahimpour, Keshvar,Rezaei, Hannaneh,Valizadeh, Hassan,Aghaiepour, Alireza
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- Cobalt single atoms anchored on nitrogen-doped porous carbon as an efficient catalyst for oxidation of silanes
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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
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- Chloride-Induced Highly Active Au Catalyst for Methyl Esterification of Alcohols
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Chloride is generally regarded as a harmful species for the heterogeneous catalysts, especially Au catalysts. In this work, a series of active Au/NiOx catalysts were successfully prepared with co-precipitation method by tracking the concentrations of chloride in the re-dispersed aqueous solutions. For methyl esterification of alcohols, the highest active Au/NiOx catalysts could be prepared from aqueous solutions containing 8-13 ppm chloride, the yield of methyl benzoate of catalyst Au/NiOx-9 was 99%. The catalyst structures and the role of chloride in catalysts were explored by ICP, BET, XPS, TEM and EXAFS characterizations. It was found that the appropriate amount of residual chloride in Au catalysts was beneficial to their catalytic activities. Especially for Au/NiOx-9, the appropriate amount of residual chloride had positive effects on the physicochemical properties of Au/NiOx catalyst, the position of Au nanoparticles (NPs) located on NiOx crystallites and the ratio of Auδ+/Au0 in catalyst, which together resulted in its high reactivity.
- Zhang, Chengming,Wang, Yongzhao
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- The effect of indium(III) triflate in oxone-mediated oxidative methyl esterification of aldehydes
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An oxidative methyl esterification of aldehydes was effectively achieved. The trivalent indium reagent, indium(III) triflate, was revealed to accelerate the reactions in many cases. Aromatic aldehydes with various substituents were subjected to this method, and each produced the corresponding methyl esters in good to excellent yields within a relatively short reaction time.
- Mineno, Tomoko,Sakai, Mai,Ubukata, Akira,Nakahara, Kazuhide,Yoshimitsu, Hitoshi,Kansui, Hisao
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- Pharmacological screening of some newly synthesized triazoles for H1 receptor antagonist activity
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The present work deals with the pharmacological screening of some newly synthesized triazoles. A series of 1,2,4-triazoles have been synthesized using benzoic acid or 4-chloro benzoic acid as the starting materials. The synthesized compounds were characterized by physical and spectral analysis viz., Fourier transform infrared spectroscopy, 1H nuclear magnetic resonance, 13C nuclear magnetic resonance, Gas Chromatography-Mass Spectrometry and elemental analysis Carbon, Hydrogen and Nitrogen analysis in order to confirm the structure. Acute toxicity studies were carried out in accordance with the Organization for Economic Co-operation and Development guideline 425. The compounds were not found to be lethal even at a dose level of 2000 mg/kg. Pharmacological evaluation was done following three intact animal experiments and one experiment on the isolated tissue. Results of the study indicated that the compound 7bi and 7bj protected up to 60% against histamine-induced dyspnea. Antihistaminic nature of the test compounds 7bi, 7bj, 7ai, and 7bk were also confirmed by the loss of catalepsy after the administration of clonidine (1%, s.c.). During experiments on isolated tissue, suppression of dose-response curve of histamine indicates a noteworthy denouement in favor of the said effect.
- Gupta, Jeetendra Kumar,Mishra, Pradeep
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- One Pot Electrooxidative Conversion of Benzyl Type Alcohols into the Corresponding Methyl Carboxylates
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One-pot conversion of several benzyl type alcohols into the corresponding methyl carboxylates was carried out by indirect electrooxidation using iodide ion as the electron carrier.
- Okimoto, Mitsuhiro,Nagata, Yuji,Sueda, Satoru,Takahashi, Yukio
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- Synthesis, characterization and anti mycobacterial activity of novel hydrazones
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The hydrazone Schiff base analogues namely benzoic acid (4-allyloxy-benzylidene)-hydrazide and its series were designed and synthesized. The structures of newly synthesized compounds were characterized by analytical methods and spectral analysis and subjected to antibacterial and docking studies. The synthesized molecules were subjected to molecular docking studies using enoyl-acyl-carrier protein reductase (NADH) from mycobacterium tuberculosis as the receptor. The docking results confirm the binding affinity of the synthesized compounds with the selected receptor. Preliminary in-vitro anti bacterial studies were carried out with Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. Benzoic acid (4-allyloxy-benzylidene)-hydrazide was found to be most potent anti tuberculosis agent at 200 and 100μg per ml, the percentage of inhibition was 98.7% and 97.9%. The designed synthesized molecules were considered for evaluation for the molecular docking studies of their binding pattern with enoyl-acyl-carrier protein reductase from Mycobacterium tuberculosis. The antimycobacterial screening was performed against MTB H37Rv an isoniazid-resistant clinical isolate of MTB was used for the study.
- Therese, S Kulandai,Geethamalika
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- NaIO4/LiBr-mediated direct conversion of benzylic alcohols and aromatic aldehydes to aromatic esters
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Aromatic aldehydes or benzylic alcohols are directly converted to the corresponding aromatic esters in high yields on treatment with methanol or ethanol mediated by sodium metaperiodate (NaIO4)/LiBr in an acidic medium. Copyright Taylor & Francis Group, LLC.
- Shaikh, Tanveer Mohammad Ali,Emmanuvel, Lourdusamy,Sudalai, Arumugam
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- Visible-light induced oxidative Csp3-H activation of methyl aromatics to methyl esters
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Direct functionalization of readily available hydrocarbons under mild conditions fulfills the requirements of green and sustainable chemistry. In this work, a mild and green catalytic oxidative Csp3-H activation of methyl aromatics using O2via photocatalysis has been achieved. A lot of methyl aromatics can be tolerated, providing a green route for aromatic methyl carboxylates. In addition, this protocol can be performed on a gram scale.
- Zhang, Lingling,Yi, Hong,Wang, Jue,Lei, Aiwen
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- Aerobic oxidative esterification of benzyl alcohols with catalytic tetrabromomethane under visible light irradiation
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We report a useful method for the facile synthesis of aromatic esters from benzyl alcohols with molecular oxygen and catalytic tetrabromomethane in alcohol under visible light irradiation with a fluorescent lamp. This is the first metal-free reaction using molecular oxygen as the terminal oxidant.
- Nobuta, Tomoya,Fujiya, Akitoshi,Hirashima, Shin-Ichi,Tada, Norihiro,Miura, Tsuyoshi,Itoh, Akichika
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- Gold nanoparticles supported on Ce-Zr oxides for the oxidative esterification of aldehydes to esters
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Au nanoparticles supported on Ce-Zr oxides were prepared and characterized in order to study the role of the support in the oxidative esterification of aldehydes in the presence of molecular oxygen. Ce-Zr solid solutions were synthesized by using (NH4)2Ce(NO3)6 as a precursor, while the mixed oxides were obtained by using a Ce(NO3)3 precursor. The solid solutions exhibited a smaller crystallite size, higher BET surface area, larger amount of H2 consumption, and higher acidity and basicity than the mixed oxides at the same Ce/Zr molar ratio due to the incorporation of Zr4+ into the ceria lattice. The effect of the support was investigated because all the samples presented similar Au particle sizes, as confirmed by the HAADF-STEM study. Supports with higher reducibility showed better performance by activating methanol to methoxy and facilitating the β-H elimination of hemiacetal. We also found that the formation of hemiacetal was enhanced by the acidic sites and basic sites of Au catalysts supported on solid solutions possessing similar reducibility. A plausible reaction mechanism for the oxidative esterification of aldehydes on Ce-Zr solid solution-supported Au nanoparticles was proposed. The screened catalyst was also applicable to the oxidative esterification of different benzylic aldehydes, producing high yields. This catalyst could be reused after a simple separation eight times, keeping a high selectivity of above 99%.
- Li, Yuchao,Wang, Lei,Yan, Ruiyi,Han, Junxing,Zhang, Suojiang
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- Direct oxidative esterification of alcohols and hydration of nitriles catalyzed by a reusable silver nanoparticle grafted onto mesoporous polymelamine formaldehyde (AgNPs@mPMF)
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A nitrogen-rich mesoporous organic polymer was synthesized as a novel support. A silver nanoparticle was synthesized and grafted onto it. The prepared catalyst (AgNPs@mPMF) was characterized by powder X-ray diffraction (XRD), scanning electron microscopy(SEM) and energy dispersive X-ray spectrometry (EDS), thermogravimetric analysis (TGA), high-resolution transmission electron microscopy (HRTEM), UV-vis diffuse reflectance spectroscopy (DRS), N2 adsorption, Raman spectroscopy and EPR study. The catalytic activity was evaluated for the oxidative esterification reaction of alcohols and hydration of nitriles. The oxidative esterification reaction was carried out for various activated alcohols giving excellent yields of the corresponding ester products. The catalyst was also efficient in the hydration of nitriles. Both reactions were optimized by varying the bases, temperatures and solvents. The catalyst can be facilely recovered and reused six times without a significant decrease in its activity and selectivity.
- Ghosh, Kajari,Iqubal, Md. Asif,Molla, Rostam Ali,Mishra, Ashutosh,Kamaluddin,Islam, Sk Manirul
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- Synthesis and antimicrobial activity of piperine analogues containing 1,2,4-triazole ring
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A series 1,2,4-triazole piperine analogues (TP1-TP6) were designed and synthesized. The structures were confirmed using 1H NMR and 13C NMR. Antibacterial study was done using Gram-positive (Staphylococcus aureus and Bacillus cereus) and Gram-negative microorganisms (E. coli and Pseudomonas aeruginosa) by disc diffusion method. Compound containing chloro substitution (TP6) showed the highest effect, while compound TP1, TP3, TP4, TP5 showed the moderate activity.
- Kumar, Kottakki Naveen,Amperayani, Karteek Rao,Ummdi, V. Ravi Sankar,Parimi, Uma Devi
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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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- Carbon-carbon bond cleavage and esterification of phenylacetonitrile and its derivatives affording the corresponding benzoic esters
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Phenylacetonitrile and its derivatives were treated with alcohols in the presence of potassium iodide and iodine affording the corresponding benzoate esters via degradation, oxidation and esterification under mild conditions. The products were characterised by IR, 1H NMR, MS and elemental analysis.
- Wang, Zhiyuan,Kang, Junhui,Yu, Mingxin
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- PHOTOOXYDATION AND PHOTOOXYGENATION OF α-DIAZOKETONE IN ALCOHOL
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The investigation of the mechanism of oxydative-cleavage reaction of azibenzil in alcohol to give benzoates revealed the role of oxygen (either 1O2 or 3O2) in the photolysis of α-diazoketone-
- Tomioka, Hideo,Kondo, Shingo,Misaki, Kiyotsugu,Izawa, Yasuji
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- COBALT-CATALYSED CARBONYLATION OF ARYL HALIDES
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A novel method for carbonylation of aromatic and heteroatomatic halides is described.The catalytic system consists of a combination of alkylcobalt carbonyl complexes, either performed or made "in situ", and bases such as alkoxides, NaOH and K2CO3 in aliphatic alcohols.Under these conditions new anionic cobalt complexes are formed which are characterized by a very high reactivity towards aromatic halides.The latter undergo the carbonylation reaction with high yield under very mild conditions.
- Foa, M.,Francalanci, F.,Bencini, E.,Gardano, A.
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- Potential tuberculostatic agents. Topliss application on benzoic acid [(5-nitro-thiophen-2-yl)-methylene]-hydrazide series.
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Nitroaromatic compounds such as nifuroxazide are used in many human enteropathogenic bacteria infections without causing an increase in the plasmidial antibiotic resistance of the aerobic Gram-negative intestinal Enterobacteriaceae. For these reasons, these compounds have been synthesized using the rational approach of Topliss' decision tree. Generally, this approach allows us to obtain the most active derivative from the series in a few steps. These compounds were tested against Mycobacterium tuberculosis in vitro and the most active of the series identified. A new lead for potential tuberculostatic activity has been predicted and will be used in further QSAR studies.
- Rando, Daniela G,Sato, Dayse N,Siqueira, Leonardo,Malvezzi, Alberto,Leite, Clarice Q F,do Amaral, Antonia T,Ferreira, Elizabeth I,Tavares, Leoberto C
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- Oxidation of benzaldehydes to benzoate esters using household bleach and sodium iodide in alcohol solvents
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Various substituted benzaldehydes were converted into benzoate esters with household bleach and sodium iodide in an alcohol solvent. The reaction works best with methanol. Only 4-chlorobenzaldehyde, 3-nitrobenzaldehyde, and 4-nitrobenzaldehyde reacted completely with 1-propanol under these conditions. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications for the following free supplemental resource(s): Full experimental and spectral details.] Copyright
- Hathaway, Bruce A.,Dekastle, Christopher A. D.,Arnett, Brianna A.
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- Mechanistic investigation of the gold-catalyzed aerobic oxidation of aldehydes: Added insight from Hammett studies and isotopic labelling experiments
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The gold-catalyzed aerobic oxidation of aldehydes proceeds through development of a partial negative charge and has a significant kinetic isotope effect (kH/kD = 2.8-2.9), which illustrates that activation of the C-H bond takes place in the rate-determining step. The Royal Society of Chemistry.
- Fristrup, Peter,Bahn Johansen, Louise,Christensen, Claus Hviid
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- Design, synthesis, antibacterial evaluation, and computational studies of hybrid oxothiazolidin–1,2,4-triazole scaffolds
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Bacterial infections are a serious threat to human health due to the development of resistance against the presently used antibiotics. The problem of growing and widespread antibiotic resistance is only getting worse with the shortage of new classes of antibiotics, creating a substantial unmet medical need in the treatment of serious bacterial infections. Therefore, in the present work, we report 18 novel hybrid thiazolidine–1,2,4-triazole derivatives as DNA gyrase inhibitors. The derivatives were synthesized by multistep organic synthesis and characterized by spectroscopic methods (1H and 13C nuclear magnetic resonance and mass spectroscopy). The derivatives were tested for DNA gyrase inhibition, and the result emphasized that the synthesized derivatives have a tendency to inhibit the function of DNA gyrase. Furthermore, the compounds were also tested for antibacterial activity against three Gram-positive (Bacillus subtilis [NCIM 2063], Bacillus cereus [NCIM 2156], Staphylococcus aureus [NCIM 2079]) and two Gram-negative (Escherichia coli [NCIM 2065], Proteus vulgaris [NCIM 2027]) bacteria. The derivatives showed a significant-to-moderate antibacterial activity with noticeable antibiofilm efficacy. Quantitative structure–activity relationship (QSAR), ADME (absorption, distribution, metabolism, elimination) calculation, molecular docking, radial distribution function, and 2D fingerprinting were also performed to elucidate fundamental structural fragments essential for their bioactivity. These studies suggest that the derivatives 10b and 10n have lead antibacterial properties with significant DNA gyrase inhibitory efficacy, and they can serve as a starting scaffold for the further development of new broad-spectrum antibacterial agents.
- Pathak, Prateek,Novak, Jurica,Shukla, Parjanya K.,Grishina, Maria,Potemkin, Vladimir,Verma, Amita
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- Alkoxycarbonylation and phenoxycarbonylation reactions catalyzed by a palladium(II) organometallic complex encaged in y zeolite
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Catalytic routes for synthesis of alkyl benzoates by alkoxycarbonylation reactions and aryl benzoates by phenoxycarbonylation reactions of aryl iodides are described using a palladium-1,10-phenanthroline complex encaged in Y zeolite. Moderate to excellent yields (40-99 %) of various benzoates were obtained at low Pd loadings of 0.6 mol%. The catalyst could be effectively removed from the reaction mixture by a simple filtration process and was reused four times with only minor loss of activity. Furthermore, its catalytic activity was further highlighted by a comparison with another two supported Pd catalysts. The protocol has the advantages of easy handing, moderate to excellent yield, and catalyst recyclability. Graphical Abstract: [Figure not available: see fulltext.]
- Mei, Hui,Xiao, Se,Zhu, Tianwu,Lei, Yizhu,Li, Guangxing
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- Microwave-assisted esterification of diverse carboxylic acids and chiral amino acids
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A facile and efficient synthetic method of esters from their corresponding carboxylic acids and amino acids is described. The esterification reaction of carboxylic acids and amino acids could be greatly accelerated under microwave irradiation because the reactions described in this article took place in only 5 min with almost quantitative yields, and distinct acidity of catalytic acids was well tolerated. Unlike the racemation problem in microwave-assisted N-acylation reactions, the esters of chiral amino acids could be achieved with retention of configuration under this condition. Copyright Taylor & Francis Group, LLC.
- Yang, Qian,Wang, Xiao-Jian,Li, Zhi-Yu,Sun, Li,You, Qi-Dong
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- The carbonylation of phenyl bromide and its derivatives under visible light irradiation
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The carbonylation of phenyl bromide catalyzed by Co(OAc)2 has been investigated with PhCOPh as a sensitizer under visible light in the presence of basic additive. With strong base CH3ONa, PhCOOCH 3 is produced in 70% yield with 100% selectivity, the similar results are also obtained with a stronger base (CH3)3CONa. However, with another strong base NaOH, the yield of the ester is only 40%. On the other hand, with weak base NaOAc or (n-C4H9) 3N, phenyl bromide cannot be carbonylated. The results of carbonylation of the six substituted phenyl bromides suggest that the activities of o, m, p-BrC6H4CH3 are similar to phenyl bromide, while the activities of o, m, p-BrC6H4Cl are higher with the high yields (≥93%) of the corresponding chloro-esters. In addition, the relative position of bromine and chlorine or methyl on phenyl ring has little effect on the activity of the carbonylation.
- Zhong, Wen Hui,Cui, Ying Na,Li, Shen Min,Jia, Ying Ping,Yin, Jing Mei
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- Calcium and magnesium chlorides-catalyzed oxidative esterification of aromatic aldehydes
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An interesting procedure for the oxidative esterification of aromatic aldehydes has been developed. By using catalytic amount of CaCl2 or MgCl2, various methyl benzoates were isolated in good yields with hydrogen peroxide as the terminal oxidant.
- Feng, Jian-Bo,Gong, Jin-Long,Li, Qin,Wu, Xiao-Feng
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- Mechanistic investigation of the one-pot formation of amides by oxidative coupling of alcohols with amines in methanol
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The one-pot formation of amides by oxidative coupling of alcohols and amines via intermediate formation of methyl ester using supported gold and base as catalysts was studied using the Hammett methodology. Determining the relative reactivity of four different para-substituted benzyl alcohol derivatives showed that the first step of the reaction generates a partial positive charge in the benzylic position (i.e. by hydride abstraction), while the second step of the reaction builds up negative charge in the rate determining step. The aminolysis of the methyl ester intermediate was further investigated by means of DFT/B3LYP. The transition state structures and energies were determined for both a concerted and a neutral two-step reaction mechanism. As expected, the base-promoted two-step mechanism was found to be the most energetically favourable and this reaction mechanism was used to construct a theoretical Hammett plot that was in good agreement with the one obtained experimentally.
- Mielby, Jerrik,Riisager, Anders,Fristrup, Peter,Kegn?s, S?ren
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- Efficient and practical approach to esters from acids/ 2-oxoacids/ 2-oxoaldehydes &/ 2-oxoesters
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An efficient, mild, cost effective and practical method is presented for generation of esters (RCO2R′) from acids (RCO2H)/ 2-oxoacids (RCOCO2H)/ 2-oxoaldehydes (RCOCHO)/ 2-oxoesters (RCOCO2R″) and alcohols by using oxone as catalyst. In addition to deciphering the scope of our process, we propose a mechanism for esterification through a common intermediate IV. Reaction with 2-oxoacids and 2-oxoaldehydes proceed with initial CO-C cleavage followed by oxone mediated esterification with alcohols. In addition, reaction with 2-oxoesters proceeds through CO-CO bond cleavage and trans-esterification.
- Padala, Anil K.,Saikam, Varma,Ali, Asif,Ahmed, Qazi Naveed
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- Ultrasound-assisted, one-pot, three-component synthesis and antibacterial activities of novel indole derivatives containing 1,3,4-oxadiazole and 1,2,4-triazole moieties
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Thirteen novel indole derivatives were efficiently synthesized through ultrasound irradiation by using 4-amino-5-(1H-indol-3-yl)-4H-[1,2,4]triazole-3-thiol (8) and 2-mercapto-5-substituted-1,3,4-oxadiazoles (5a-m). Compared with conventional and microwave methods, yields increased to 82-93%, and reaction times decreased to 15-35 min. The structures of these novel compounds were characterized by spectral data and elemental analysis. Two out of the synthesized compounds (10f and 10l) exhibited excellent activity against Staphylococcus aureus and Escherichia coli, and thus warrant further research.
- Shi, Zhichuan,Zhao, Zhigang,Huang, Meiwei,Fu, Xiaolin
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- SOLVOLYSIS OF BENZOYL CYANIDES IN METHANOL-ACETONITRILE AND METHANOL-ACETONE MIXTURES.
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Rate constants for solvolysis of benzoyl cyanides in methanol-acetonitrile and methanol-acetone mixtures were determined.Effects of substituent and solvent indicated that the reaction preceeds via an associative SN2 mechanism.
- Lee, Ikchoon,Kim, Nam Il,Sohn, Se Chul
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- Eco-efficient preparation of a N-doped graphene equivalent and its application to metal free selective oxidation reaction
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Here, we demonstrate that graphene oxide (GO) can be converted to N-doped reduced GO (rGO) that could become a substitute for N-doped graphene. Simultaneous doping and reduction can be accomplished for this purpose by simply mixing GO with hydrazine and then continuously sonicating the solution at 65 °C. A high level of reduction is realized, as evidenced by a carbon to oxygen ratio of 20.7 that compares with the highest value of 15.3 ever reported in solution (water + hydrazine) methods. Nitrogen doping is possible up to 6.3 wt% and the extent of doping can be increased with increasing sonication time. Notably, the simple tuning process of N-doping in GO greatly enhanced the efficiency of the carbocatalyst for various kinds of metal free oxidation reactions and hence is proposed as a suitable candidate for future industrial applications. This journal is the Partner Organisations 2014.
- Singh, Ajay K.,Basavaraju,Sharma, Siddharth,Jang, Seungwook,Park, Chan Pil,Kim, Dong-Pyo
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- Multi-scale promoting effects of lead for palladium catalyzed aerobic oxidative coupling of methylacrolein with methanol
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A highly efficient Pd2Pb8/alumina catalyst was prepared, which provided the highest turnover number (TON) of 302 for aerobic oxidative coupling of methylacrolein with methanol. The enhanced catalytic efficiency could be attributed to the multi-scale (micron, nano and atom scales) promoting effects of the pre-loaded Pb species. This journal is
- Han, Junxing,Zhang, Suojiang,Li, Yuchao,Yan, Ruiyi
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- Synthesis and antitubercular activity of new N-[5-(4-chlorophenyl)-1,3,4-oxadiazol-2-yl]-(nitroheteroaryl)carboxamides
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Nitro-substituted heteroaromatic carboxamides 1a-e were synthesized and tested against three Mycobacterium tuberculosis cell lines. The activities can be explained in terms of the distribution of the electronic density across the nitro-substituted heteroaromatic ring attached to the amide group. 1,3,5-Oxadiazole derivatives 1c-e are candidates for the development of novel antitubercular agents. Ongoing studies are focused on exploring the mechanism by which these compounds inhibit M. tuberculosis cell growth.
- Martínez, Roberto,Nieves Zamudio, Gladys J.,Pretelin-Castillo, Gustavo,Torres-Ochoa, Rubén O.,Medina-Franco, José L.,Espitia Pinzón, Clara I.,Silva Miranda, Mayra,Hernández, Eugenio,Alanís-Garza, Blanca
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- Hexa-arm star shaped hydrazone derivatives from hexakis(4-formylphenoxy)- cyclotriphosphazene core
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A series of novel hexasubstituted cyclophosphazene hydrazones [N 3P3(OC6H4pCHNNHC(O)C 6H4pX)6] (X = H, Br, Cl, F, OH, OCH 3, CH3, NO2, NH2) were prepared by a sixfold condensation reaction of [N3P3(OC 6H4pCHO)6] with para-substituted benzoic hydrazides [NH2NHC(O)C6H4pX] with excellent yields (91-98%). The structures of the compounds were confirmed by elemental analysis, FT-IR, 1H, 13C, 31P, 2D-HSQC NMR and mass spectrometry (MALDI-TOF). All the synthesized cyclophosphazene hydrazones exhibit high thermal stability. The crystal structure of a homogeneously substituted hexakis(4-formylphenoxy)-cyclotriphosphazene was determined by X-ray diffraction analysis. The compound crystallizes in the monoclinic system, space group P21/n with a = 16.558(3) , b = 10.250(2) , c = 23.429(5) , α = γ = 90.00°, β = 90.461(4)°, V = 3976.5(14) 3 and Z = 4. The R value is 0.0823 for 4290 observed reflections. The conformations of the 4-formylphenoxy-groups are different at the three phosphorus atoms.
- Patil, Basavaraj R.,MacHakanur, Shrinath S.,Badiger, Dayananda S.,Hunoor, Rekha S.,Gudasi, Kalagouda B.,Nethaji, Munirathinam,Annie Bligh
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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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- Photochemical Sandmeyer-type Halogenation of Arenediazonium Salts
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Trihalide salts were found to efficiently promote photochemical dediazotizing halogenations of diazonium salts. In contrast to classical Sandmeyer reactions, no metal catalysts are required to achieve high yields and outstanding selectivities for halogena
- Belitz, Florian,Goo?en, Lukas J.,Manu Martínez, ángel,Schmid, Rochus,Sivendran, Nardana,Sowa Prendes, Daniel
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supporting information
(2022/01/19)
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- Preparation method of methyl benzoate compound
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A preparation method of a methyl benzoate compound comprises the step that the methyl benzoate compound is prepared by carrying out esterification reaction on a benzoic acid compound and methyl alcohol under the catalysis of dihalogen hydantoin, and the molar ratio of the benzoic acid compound to the dihalogen hydantoin to the methyl alcohol is 1: (0.01-0.4): (2-30). According to the preparation method, the methyl benzoate compound can be efficiently prepared under mild conditions, the operation is safe, no acid waste liquid exists, meanwhile, raw materials are easy to obtain, and the production cost is low.
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Paragraph 0019; 0035-0036
(2021/08/14)
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- 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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- 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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- Synthesis, characterization and computational study of N-acylhydrazone derivatives
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The N-Acylhydrazone of benzoic acid and their derivatives are important intermediates in organic synthesis and have widespread applications in the medicinal industry. The N-Acylhydrazone was prepared through the condensing the phenyl hydrazide derivatives which prepared from phenylmethyl ester, with benzaldehyde and then identified by physicochemical properties and spectral analysis; FT-IR and 1HNMR. Computation calculations studies by using Semi-empirical-PM3 method through a molecular structure with optimized geometry showed that there is a high correlation between dipole moment, Electron affinity (EA), ionization potential (IP), electronegativity, ClogP and hardness. To Proof, the stability of N-Acylhydrazone derivatives by using Molecular orbital calculations supported a full description of the orbitals and the contributions of individual atoms. Highest occupied molecular orbital/lowest unoccupied molecular orbital energies and structures are demonstrated, calculation atomic charge and molecular electrostatic potential. Through the data obtained from the computational chemistry program, Hyper Chem 8, we were able to demonstrate that the N-acylhydrazone derivatives have a close values and within the limits of stability.
- Alrubaie, Leaqaa A. Raheem
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p. 5067 - 5075
(2021/08/31)
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- Hydroxyl radical-mediated oxidative cleavage of CC bonds and further esterification reaction by heterogeneous semiconductor photocatalysis
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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
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p. 6591 - 6597
(2021/09/10)
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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 0054-0055; 0092
(2021/06/02)
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- The Highly Effective Cobalt Based Metal–Organic Frameworks Catalyst for One Pot Oxidative Esterification Under Mild Conditions
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The cobalt-based metal organic frameworks (Co-MOFs) catalyst has been prepared with using terephthalic acid and 4,4′-bipyridine as organic linkers by facile solvothermal method for one pot oxidative esterification. The prepared catalyst was pyrolysed at different temperature and then applied for oxidation of aldehyde using molecular oxygen as benign oxidant under mild conditions. The Co-MOFs pyrolysed at 800?°C (denoted as Co-MOFs-800) catalyst exhibited excellent catalytic activity, selectivity and recyclability toward the oxidative esterification of benzaldehydes. Furthermore, it can be reused up to 5 runs without significant loss of activity. Graphic Abstract: [Figure not available: see fulltext.]
- Chindawong, Chakkresit,Mekrattanachai, Pagasukon,Setthaya, Naruemon,Song, Wei Guo,Zhu, Lei
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- Oxidative esterification of alcohols by a single-side organically decorated Anderson-type chrome-based catalyst
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The direct esterification of alcohols with non-noble metal-based catalytic systems faces great challenges. Here, we report a new chrome-based catalyst stabilized by a single pentaerythritol decorated Anderson-type polyoxometalate, [N(C4H9)4]3[CrMo6O18(OH)3C{(OCH2)3CH2OH}], which can realize the efficient transformation from alcohols to esters by H2O2oxidation in good yields and high selectivity without extra organic ligands. A variety of alcohols with different functionalities including some natural products and pharmaceutical intermediates are tolerated in this system. The chrome-based catalyst can be recycled several times and still keep the original configuration and catalytic activity. We also propose a reasonable catalytic mechanism and prove the potential for industrial applications.
- Wang, Jingjing,Jiang, Feng,Tao, Chaofu,Yu, Han,Ruhlmann, Laurent,Wei, Yongge
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supporting information
p. 2652 - 2657
(2021/04/21)
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- Ni-NiO heterojunctions: a versatile nanocatalyst for regioselective halogenation and oxidative esterification of aromatics
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Herein, we report a facile method for the synthesis of Ni-NiO heterojunction nanoparticles, which we utilized for the nuclear halogenation reaction of phenol and substituted phenols usingN-bromosuccinimide (NBS). A remarkablepara-selectivity was achieved for the halogenated products under semi-aqueous conditions. Interestingly, blocking of thepara-position of phenol offeredortho-selective halogenation. In addition, the Ni-NiO nanoparticles catalyzed the oxidative esterification of carbonyl compounds with alcohol, diol or dithiol in the presence of a catalytic amount of NBS. It was observed that the aromatic carbonyls substituted with an electron-donating group favoured nuclear halogenation, whereas an electron-withdrawing group substitution in carbonyl compounds facilitated the oxidation reaction. In addition, the catalyst was magnetically separated and recycled 10 times. The tuned electronic structure at the Ni-NiO heterojunction controlled selectivity and activity as no suchpara-selectivity was observed with commercially available NiO or Ni nanoparticles.
- Bhardwaj, Nivedita,Goel, Bharat,Indra, Arindam,Jain, Shreyans K.,Singh, Ajit Kumar,Tripathi, Nancy
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p. 14177 - 14183
(2021/08/16)
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- Electrochemical esterification via oxidative coupling of aldehydes and alcohols
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An electrolytic method for the direct oxidative coupling of aldehydes with alcohols to produce esters is described. Our method involves anodic oxidation in presence of TBAF as supporting electrolyte in an undivided electrochemical cell equipped with graphite electrodes. This method successfully couples a wide range of alcohols to benzaldehydes with yields ranging from 70 to 90%. The protocol is easy to perform at a constant voltage conditions and offers a sustainable alternative over conventional methods.
- Smeyne, Dylan,Verboom, Katherine,Bryan, Maria,LoBue, James,Shaikh, Abid
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supporting information
(2021/03/26)
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- PCl3-mediated transesterification and aminolysis of tert-butyl esters via acid chloride formation
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A PCl3-mediated conversion of tert-butyl esters into esters and amides in one-pot under air is developed. This novel protocol is highlighted by the synthesis of skeletons of bioactive molecules and gram-scale reactions. Mechanistic studies revealed that this transformation involves the formation of an acid chloride in situ, which is followed by reactions with alcohols or amines to afford the desired products.
- Wu, Xiaofang,Zhou, Lei,Li, Fangshao,Xiao, Jing
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p. 491 - 497
(2021/01/20)
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- Alkali-modified heterogeneous Pd-catalyzed synthesis of acids, amides and esters from aryl halides using formic acid as the CO precursor
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To establish an environmentally friendly green chemical process, we minimized and resolved a significant proportion of waste and hazards associated with conventional organic acids and molecular gases, such as carbon monoxide (CO). Herein, we report a facile and milder reaction procedure, using low temperatures/pressures and shorter reaction time for the carboxyl- and carbonylation of diverse arrays of aryl halides over a newly developed cationic Lewis-acid promoted Pd/Co3O4catalyst. Furthermore, the reaction proceeded in the absence of acid co-catalysts, and anhydrides for CO release. Catalyst reusability was achievedviascalable, safer, and practical reactions that provided moderate to high yields, paving the way for developing a novel environmentally benign method for synthesizing carboxylic acids, amides, and esters.
- Fapojuwo, Dele Peter,Maqunga, Nomathamsanqa Prudence,Meijboom, Reinout,Mogudi, Batsile M.,Molokoane, Pule Petrus,Onisuru, Oluwatayo Racheal,Oseghale, Charles O.
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p. 26937 - 26948
(2021/08/17)
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- Design, synthesis, modelling studies and biological evaluation of 1,3,4-oxadiazole derivatives as potent anticancer agents targeting thymidine phosphorylase enzyme
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A series of novel 1,3,4-oxadiazole derivatives with substituted phenyl ring were designed and synthesized with an objective of discovering newer anti-cancer agents targeting thymidine phosphorylase enzyme (TP). The 1,3,4-oxadiazole derivatives were synthesized by simple and convenient methods in the lab. Chemical structure of the all the synthesized compounds were characterized by IR, 1H NMR and mass spectral methods and evaluated for cytotoxicity by MTT method against two breast cancer cell lines (MCF-7 and MDA-MB-231). Further, results of TP assay identified that 1,3,4-oxadiazole molecules displayed anti-cancer activity partially by inhibition of phosphorylation of thymidine. The TP assay identified SB8 and SB9 as potential inhibitors with anti-cancer activity against both the cell lines. The molecular docking studies recognized the orientation and binding interaction of molecule at the active site amino acid residues of TP (PDB: 1UOU). Acute toxicity studies of compound SB8 at the dose of 5000 mg/kg has identified no signs of clinical toxicity was observed. The SARs study of synthesized derivatives revealed that the substitution of phenyl ring with electron withdrawing group at ortho position showed significant TP inhibitory activity compared to para substitution. The experimental data suggests that 1,3,4-oxadiazole with substituted phenyl can be taken as a lead for the design of efficient TP inhibitors and active compounds which can be taken up for further studies.
- Bajaj, Shalini,Kumar, Maushmi S.,Tinwala, Hussain,YC, Mayur
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- Liquid-phase oxidation of olefins with rare hydronium ion salt of dinuclear dioxido-vanadium(V) complexes and comparative catalytic studies with analogous copper complexes
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Homogeneous liquid-phase oxidation of a number of aromatic and aliphatic olefins was examined using dinuclear anionic vanadium dioxido complexes [(VO2)2(salLH)]? (1) and [(VO2)2(NsalLH)]? (2) and dinuclear copper complexes [(CuCl)2(salLH)]? (3) and [(CuCl)2(NsalLH)]? (4) (reaction of carbohydrazide with salicylaldehyde and 4-diethylamino salicylaldehyde afforded Schiff-base ligands [salLH4] and [NsalLH4], respectively). Anionic vanadium and copper complexes 1, 2, 3, and 4 were isolated in the form of their hydronium ion salt, which is rare. The molecular structure of the hydronium ion salt of anionic dinuclear vanadium dioxido complex [(VO2)2(salLH)]? (1) was established through single-crystal X-ray analysis. The chemical and structural properties were studied using Fourier transform infrared (FT-IR), ultraviolet–visible (UV–Vis), 1H and 13C nuclear magnetic resonance (NMR), electrospray ionization mass spectrometry (ESI-MS), electron paramagnetic resonance (EPR) spectroscopy, and thermogravimetric analysis (TGA). In the presence of hydrogen peroxide, both dinuclear vanadium dioxido complexes were applied for the oxidation of a series of aromatic and aliphatic alkenes. High catalytic activity and efficiency were achieved using catalysts 1 and 2 in the oxidation of olefins. Alkenes with electron-donating groups make the oxidation processes easy. Thus, in general, aromatic olefins show better substrate conversion in comparison to the aliphatic olefins. Under optimized reaction conditions, both copper catalysts 3 and 4 fail to compete with the activity shown by their vanadium counterparts. Irrespective of olefins, metal (vanadium or copper) complexes of the ligand [salLH4] (I) show better substrate conversion(%) compared with the metal complexes of the ligand [NsalLH4] (II).
- Maurya, Abhishek,Haldar, Chanchal
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- Syntheses, biological evaluation of some novel substituted benzoic acid derivatives bearing hydrazone as linker
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On the basis of rational drug design fourteen novel compounds having benzoic acid as acidic head,?hydrazone?as?linker?and?substituted?diaryl?sulfanyl/aryl-cyclohexylsulfanyl?as?a?hydrophobic?tail?were synthesized?and?characterized by physicochemical and spectrophotometric (FTIR, Mass, 1HNMR and 13CNMR) analysis. The spectral data were satisfactory with their structures. The?designed compounds were docked against peroxisome proliferated activated receptors (PPARγ) and further evaluated for in vitro PPARγ agonist activity and in vivo hypoglycemic activity in wistar strain of albino rats.?Compound 3k and 3m exhibited potent?anti-diabetic activity without ulcerogenic toxicity and minimum side effects as weight gain. Therefore these compounds would be considered as promising agents for the development of novel antidiabetic agents.
- Mishra, Ganesh Prasad,Sharma, Rajesh,Jain, Mukul,Bandyopadhyay, Debdutta
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p. 5061 - 5078
(2021/08/03)
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- Design, synthesis, and in vitro evaluation of novel 1,3,4-oxadiazolecarbamothioate derivatives of Rivastigmine as selective inhibitors of BuChE
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Rivastigmine has been prescribed for the therapy of Alzheimer’s disease (AD) symptoms. This drug is classified in the carbamate derivative group that has dual activity against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). According to the structure of Rivastigmine and its performance, a new series of 5-aryl-1,3,4-oxadiazole-2-carbamothioate compounds I–XI was synthesized using structure-based drug discovery approaches. For this purpose a set of these compounds were designed with computational docking method and their interactions with amino acid residues in the active sites of AChE and BuChE checked out. The structures of synthesized compounds were established by physicochemical and spectroscopic methods. The carbamoyl moiety of Rivastigmine structure was modified to carbamothioate and the effects of 1,3,4-oxadiazole heterocycle as a pharmacophoric nucleus were investigated. The potential of the synthesized compounds I–XI was evaluated against two most known agents of AD (AChE and BuChE) to determine their IC50 values. The results of the docking showed the range of binding affinity for the best poses of ten individual conformers for any compounds (I–XI) was between ?7.81 (VI) and ?6.75 (II) kcal/mol. The results of biological experiments displayed that most synthetic compounds (I–VIII) showed moderate to excellent selective activity range against BuChE (0.51–69.44 μM). In vitro cytotoxicity evaluation of these compounds (I–XI) by MTT assay on human dermal fibroblast (HDF) cell line exhibited no activity against HDF. The compound VI [S-(5-(p-tolyl)-1,3,4-oxadiazol-2-yl) ethyl(methyl)carbamothioate] showed the most stable binding affinity (?7.81 kcal/mol) and the lowest IC50 value (0.51 μM) in comparison with Rivastigmine with 7.72 μM and Donepezil with 5.20 μM against BuChE.
- Fallah, Akram,Mohanazadeh, Farajollah,Safavi, Maliheh
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p. 341 - 355
(2019/12/30)
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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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- 6H-THIENO[2,3-E][1,2,4]TRIAZOLO[3,4-C][1,2,4]TRIAZEPINE DERIVATIVE
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The 6H-thieno[2,3-e][1,2,4]triazolo[3,4-c][1,2,4]triazepine derivatives or salts thereof of the present invention have BRD4 inhibitory activity, and thus, they are useful as medicaments, in particular, as prophylaxis and/or therapeutic agents for diseases associated with BRD4.
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Paragraph 0090-0091
(2020/05/07)
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- Modulation of estrogen-related receptors subtype selectivity: Conversion of an ERRβ/γ selective agonist to ERRα/β/γ pan agonists
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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
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- Design, synthesis, and biological evaluation of new challenging thalidomide analogs as potential anticancer immunomodulatory agents
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Thalidomide and its analogs are immunomodulatory drugs that inhibit the production of certain inflammatory mediators associated with cancer. In the present work, a new series of thalidomide analogs was designed and synthesized to obtain new effective antitumor immunomodulatory agents. The synthesized compounds were evaluated for their cytotoxic activities against a panel of four cancer cell lines (HepG-2, HCT-116, PC3 and MCF-7). Compounds 33h, 33i, 42f and 42h showed strong potencies against all tested cell lines with IC50 values ranging from 14.63 to 49.90 μM comparable to that of thalidomide (IC50 values ranging from 32.12 to 76.91 μM). The most active compounds were further evaluated for their in vitro immunomodulatory activities via estimation of human tumor necrosis factor alpha (TNF-α), human caspase-8 (CASP8), human vascular endothelial growth factor (VEGF), and nuclear factor kappa-B P65 (NF-κB P65) in HCT-116 cells. Thalidomide was used as a positive control. Compounds 33h and 42f showed a significant reduction in TNF-α. Furthermore, compounds 33i and 42f exhibited significant elevation in CASP8 levels. Compounds 33i and 42f inhibited VEGF. In addition, compound 42f showed significant decrease in levels of NF-κB p65. Moreover, apoptosis and cell cycle tests of the most active compound 42f, were performed. The results indicated that compound 42f significantly induce apoptosis in HCT-116 cells and arrest cell cycle at the G2/M phase.
- El-Zahabi, Mohamed Ayman,Sakr, Helmy,El-Adl, Khaled.,Zayed, Mohamed,Abdelraheem, Adel S.,Eissa, Sally I.,Elkady, Hazem,Eissa, Ibrahim H.
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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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- Methoxylation of Acyl Fluorides with Tris(2,4,6-trimethoxyphenyl)phosphine via C-OMe Bond Cleavage under Metal-Free Conditions
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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
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p. 7526 - 7533
(2020/06/27)
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- Facile synthesis of a highly efficient Co/Cu@NC catalyst for base-free oxidation of alcohols to esters
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The direct oxidation of alcohols to esters is an environmentally benign and cost-effective organic synthetic strategy, but it is still a great challenge to discover an economic, highly active, and long-term stable catalyst for efficient transformation of alcohols to esters under milder conditions. Herein, we developed cobalt and copper nanoparticle -co-decorated nitrogen-doped carbon catalysts (CoCu@NCn) through two steps of ball milling and calcination. It was found that CoCu@NCn could catalyze the oxidation of alcohols to esters effectively in the absence of basic additives. The catalytic activity was much higher than those of monometallic Co@NC2 and Cu@NC2 samples, and the catalyst can be conveniently recovered and quite steadily reused. Through a series of control experiments and characterizations, it is concluded that the remarkable catalytic performance of CoCu@NC2 was associated with the synergistic effect between the two metal components, the enhanced basic active sites and the active surface area.
- Jiang, Jiusheng,Li, Xiang,Du, Shengyu,Shi, Langchen,Jiang, Pingping,Zhang, Pingbo,Dong, Yuming,Leng, Yan
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p. 7780 - 7785
(2020/06/09)
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- Nickel salt of phosphomolybdic acid as a bi-functional homogeneous recyclable catalyst for base free transformation of aldehyde into ester
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A Ni salt of phosphomolybdic acid (NiHPMA) was synthesized and characterized by various physico-chemical techniques such as EDX, UV-Visible spectroscopy, FT-IR, Raman spectroscopy and XPS. FT-IR and Raman spectroscopy confirm the presence of Ni as a counter cation while UV-Visible and XPS studies to confirm the presence of Ni(ii) in the catalyst. The catalyst was evaluated for its bi-functional activity towards the tandem conversion of benzaldehyde to ethyl benzoate and it was found that very small amounts of Ni (2.64 × 10?3mmol) enhance the selectivity towards benzoate. A detailed mechanistic study was carried out by UV-Visible and Raman spectroscopy to confirm that both intermediate species, Mo-peroxo and Ni-oxo, are responsible for higher selectivity towards esters. Further, a study to determine the effect of addenda atoms (heteropoly acid) was also carried out. The catalyst was also found to be viable for a number of aldehydes under optimized conditions.
- Patel, Anjali,Patel, Jay
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p. 22146 - 22155
(2020/07/03)
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- Sodium pyruvate as a peroxide scavenger in aerobic oxidation under carbene catalysis
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NHC-Catalyzed aerobic oxidative reactions of imines and aldehydes have been developed by using sodium pyruvate as a novel and efficient peroxide scavenger. A structurally diverse set of imidates and amidines has been prepared from imines using this strategy. This general and efficient strategy features the use of sodium pyruvate as a novel and efficient peroxide scavenger and ambient air as the sole oxidant to efficiently control the NHC-catalyzed aerobic reaction pathway (selective realization of the oxidative pathway) under mild and green conditions. This journal is
- Fu, Zhenqian,Hong, Xianfang,Huang, Wei,Wang, Guanjie,Wei, Chenlong
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supporting information
p. 6819 - 6826
(2020/11/09)
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- Palladium-Catalyzed Chlorocarbonylation of Aryl (Pseudo)Halides Through In Situ Generation of Carbon Monoxide
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An efficient palladium-catalyzed chlorocarbonylation of aryl (pseudo)halides that gives access to a wide range of carboxylic acid derivatives has been developed. The use of butyryl chloride as a combined CO and Cl source eludes the need for toxic, gaseous carbon monoxide, thus facilitating the synthesis of high-value products from readily available aryl (pseudo)halides. The combination of palladium(0), Xantphos, and an amine base is essential to promote this broadly applicable catalytic reaction. Overall, this reaction provides access to a great variety of carbonyl-containing products through in situ transformation of the generated aroyl chloride. Combined experimental and computational studies support a reaction mechanism involving in situ generation of CO.
- Bismuto, Alessandro,Boehm, Philip,Morandi, Bill,Roediger, Sven
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supporting information
p. 17887 - 17896
(2020/08/19)
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- Catalytic conversion of ketones to esters: Via C(O)-C bond cleavage under transition-metal free conditions
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The catalytic conversion of ketones to esters via C(O)-C bond cleavage under transition-metal free conditions is reported. This catalytic process proceeds under solvent-free conditions and offers an easy operational procedure, broad substrate scope with excellent selectivity, and reaction scalability. This journal is
- Subaramanian, Murugan,Ramar, Palmurukan M.,Rana, Jagannath,Gupta, Virendra Kumar,Balaraman, Ekambaram
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supporting information
p. 8143 - 8146
(2020/09/09)
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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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- 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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- Ni-catalyzed direct alcoholysis of N-acylpyrrole-type tertiary amides under mild conditions
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N-Acylpyrrole-type amides are a class of versatile building blocks in asymmetric synthesis. We report that by employing Ni(COD)2/2,2′-bipyridine (5 mol%) catalytic system, the direct, catalytic alcoholysis of N-acylpyrrole-type aromatic and aliphatic amides with both primary and secondary alcohols can be achieved efficiently under very mild conditions (rt, 1 h) even at gram scale. By increasing the catalyst loading to 10 mol%, prolonging reaction time (18 h), and/or elevating reaction temperature to 50 °C/80 °C, the reaction could be extended to both complex and hindered N-acylpyrroles as well as to N-acylpyrazoles, Nacylindoles, and to other (functionalized) primary and secondary alcohols. In all cases, only 1.5 equiv. of alcohol were used. The value of the method has been demonstrated by the racemization-free, catalytic alcoholysis of chiral amides yielded from other asymmetric methodologies.
- Chen, Hang,Chen, Dong-Huang,Huang, Pei-Qiang
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p. 370 - 376
(2020/03/03)
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- Visible-light-induced selective aerobic oxidation of sp3 C-H bonds catalyzed by a heterogeneous AgI/BiVO4 catalyst
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An efficient oxidation of sp3 C-H bonds to esters and ketones has been developed using AgI/BiVO4 as the photocatalyst and O2 as the oxidant in water. Various substrates can be transformed into the desired esters and ketones in moderate to good yields. The synthetic utility of this approach has been demonstrated by gram-level experiments and consecutive oxidation experiments. A plausible mechanism has been proposed.
- Jiang, Li-Ya,Ming, Jing-Jing,Wang, Lian-Yue,Jiang, Yuan-Yuan,Ren, Lan-Hui,Wang, Zi-Cheng,Cheng, Wen-Chen
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supporting information
p. 1156 - 1163
(2020/03/11)
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- Palladium-catalyzed aryloxy- and alkoxycarbonylation of aromatic iodides in γ-valerolactone as bio-based solvent
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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.
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- METHOD FOR THE SYNTHESIS AND PURIFICATION OF ARYL ACID ESTERS
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The general inventive concepts are directed to the discovery that certain aryl acids can be esterified under particular conditions to provide the resulting ester as a solid that precipitates in good yield from the reaction mixture. The esters may then be isolated and purified with relative ease. Accordingly, a method for the esterification, isolation, and purification of aryl acids is provided.
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Paragraph 0031-0032
(2019/10/17)
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- Development of novel liver?X?receptor modulators based on a 1,2,4-triazole scaffold
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Liver X Receptor (LXR) agonists have been reported as a potential treatment for atherosclerosis, Alzheimer's disease and hepatitis C virus (HCV) infection. We have designed and synthesized a series of potent compounds based on a 1,2,4-triazole scaffold as novel LXR modulators. In cell-based cotransfection assays these compounds generally functioned as LXR agonists and we observed compounds with selectivity towards LXRα (7-fold) and LXRβ (7-fold) in terms of potency. Assessment of the effects of selected compounds on LXR target gene expression in HepG2 cells revealed that compounds 6a-b and 8a-b behaved as inverse agonists on FASN expression even though they were agonists in the LXRα and LXRβ cotransfection assays. Interestingly, these compounds had no effect on the expression of SREBP-1c confirming a unique LXR modulator pharmacology. Molecular docking studies and evaluation of ADME properties in-silico show that active compounds possess favorable binding modes and ADME profiles. Thus, these compounds may be useful for in vivo characterization of LXR modulators with unique profiles and determination of their potential clinical utility.
- Goher, Shaimaa S.,Griffett, Kristine,Hegazy, Lamees,Elagawany, Mohamed,Arief, Mohamed M.H.,Avdagic, Amer,Banerjee, Subhashis,Burris, Thomas P.,Elgendy, Bahaa
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supporting information
p. 449 - 453
(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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- Discovery of 1,3,4-oxadiazol-2-one-containing benzamide derivatives targeting FtsZ as highly potent agents of killing a variety of MDR bacteria strains
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The spread of infections caused by multidrug-resistant (MDR) pathogens, such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant S. aureus (VRSA), has created a need for new antibiotics with novel mechanisms of action. The bacterial division protein FtsZ has been identified as a novel drug target that can be exploited clinically. As part of an ongoing effort to develop FtsZ-targeting antibacterial agents, we describe herein the design, synthesis and bioactivity of six series of novel 1,3,4-oxadiazol-2-one-containing, 1,2,4-triazol-3-one-containing and pyrazolin-5-one-containing benzamide derivatives. Among them, compound A14 was found to be the most potent antibacterial agent, much better than clinical drugs such as ciprofloxacin, linezolid and erythromycin against all the tested gram-positive strains, particularly methicillin-resistant, penicillin-resistant and clinical isolated S. aureus. Subsequent studies on biological activities and docking analyses proved that A14 functioned as an effective compound targeting FtsZ. Preliminary SAR indicated a general direction for further optimization of these novel analogues. Taken together, this research provides a promising chemotype for developing newer FtsZ-targeting bactericidal agents.
- Bi, Fangchao,Song, Di,Qin, Yinhui,Liu, Xingbang,Teng, Yuetai,Zhang, Na,Zhang, Panpan,Zhang, Nan,Ma, Shutao
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p. 3179 - 3193
(2019/06/17)
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- Method for preparing carboxylic ester by alcohol direct oxidation esterification method
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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.
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Paragraph 0048; 0049
(2019/06/30)
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- Pd-Colloids-Catalyzed/Ag2O-Oxidized General and Selective Esterification of Benzylic Alcohols
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Palladium colloids obtained from the degradation of Hermann–Beller palladacycle proved to be an efficient catalytic system in combination with silver oxide as a selective oxidant for the oxidative esterification of differently substituted benzyl alcohols in MeOH as solvent. Excellent reactivity exhibited by the catalytic system also allowed the alcoholic coupling partner to be changed from MeOH to a wide range of alcohols having diverse functionalities. The mildness of the developed protocol also made it possible to employ propargyl alcohol as the coupling partner without any observation of any interference of the terminal alkyne. Selective oxidative coupling of a primary alcoholic functional group over secondary in the case of glycols and glycerols was also made possible using the developed catalyst system. To test the relevancy of Pd/Ag combined catalysis mixed Pd/Ag colloids were synthesized, characterized by TEM, XRD and XPS and applied to oxidative-esterification successfully.
- Sable, Vaibhav,Shah, Jagrut,Sharma, Anuja,Kapdi, Anant R.
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supporting information
p. 2639 - 2647
(2019/07/08)
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- Dehydrogenative cross-coupling of primary alcohols to form cross-esters catalyzed by a manganese pincer complex
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Base-metal-catalyzed dehydrogenative cross-coupling of primary alcohols to form cross-esters as major products, liberating hydrogen gas, is reported. The reaction is catalyzed by a pincer complex of earth-abundant manganese in the presence of catalytic base, without any hydrogen acceptor or oxidant. Mechanistic insight indicates that a dearomatized complex is the actual catalyst, and indeed this independently prepared dearomatized complex catalyzes the reaction under neutral conditions.
- Das, Uttam Kumar,Ben-David, Yehoshoa,Leitus, Gregory,Diskin-Posner, Yael,Milstein, David
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p. 479 - 484
(2019/01/11)
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- Aldehyde effect and ligand discovery in Ru-catalyzed dehydrogenative cross-coupling of alcohols to esters
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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
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p. 2797 - 2800
(2019/03/27)
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