- Analogues of the Herbicide, N-Hydroxy- N-isopropyloxamate, Inhibit Mycobacterium tuberculosis Ketol-Acid Reductoisomerase and Their Prodrugs Are Promising Anti-TB Drug Leads
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New drugs to treat tuberculosis (TB) are urgently needed to combat the increase in resistance observed among the current first-line and second-line treatments. Here, we propose ketol-acid reductoisomerase (KARI) as a target for anti-TB drug discovery. Twenty-two analogues of IpOHA, an inhibitor of plant KARI, were evaluated as antimycobacterial agents. The strongest inhibitor of Mycobacterium tuberculosis (Mt) KARI has a Ki value of 19.7 nM, fivefold more potent than IpOHA (Ki = 97.7 nM). This and four other potent analogues are slow- and tight-binding inhibitors of MtKARI. Three compounds were cocrystallized with Staphylococcus aureus KARI and yielded crystals that diffracted to 1.6-2.0 ? resolution. Prodrugs of these compounds possess antimycobacterial activity against H37Rv, a virulent strain of human TB, with the most active compound having an MIC90 of 2.32 ± 0.04 μM. This compound demonstrates a very favorable selectivity window and represents a highly promising lead as an anti-TB agent.
- Kandale, Ajit,Patel, Khushboo,Hussein, Waleed M.,Wun, Shun Jie,Zheng, Shan,Tan, Lendl,West, Nicholas P.,Schenk, Gerhard,Guddat, Luke W.,McGeary, Ross P.
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p. 1670 - 1684
(2021/02/27)
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- Site-specific catalytic activities to facilitate solvent-free aerobic oxidation of cyclohexylamine to cyclohexanone oxime over highly efficient Nb-modified SBA-15 catalysts
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The development of highly active and selective heterogeneous catalysts for efficient oxidation of cyclohexylamine to cyclohexanone oxime is a challenge associated with the highly sensitive nitrogen center of cyclohexylamine. In this work, dispersed Nb oxide supported on SBA-15 catalysts are disclosed to efficiently catalyze the selective oxidation of cyclohexylamine with high conversion (>75%) and selectivity (>84%) to cyclohexanone oxime by O2without any addition of solvent (TOF = 469.8 h?1, based on the molar amount of Nb sites). The role of the active-site structure identity in dictating the site-specific catalytic activities is probed with the help of different reaction and control conditions and multiple spectroscopy methods. Complementary to the experimental results, further poisoning tests (with KSCN or dehydroxylation reagents) and DFT computational studies clearly unveil that the surface exposed active centers toward activation of the reactants are quite different: the surface -OH groups can catch the NH2group from cyclohexylamine by forming a hydrogen bond and lead to a more facile cyclohexylamine oxidation to desired products, while the monomeric or oligomeric Nb sites with a highly distorted structure play a key role in the dissociation of O2molecules beneficial for insertion of active oxygen species into cyclohexylamine. These catalysts exhibit not only satisfactory recyclability for cyclohexylamine oxidation but also efficiently catalyze the aerobic oxidation of a wide range of amines under solvent-free conditions.
- Ding, Wei,Mao, Liqiu,Peng, Haoyu,Yin, Dulin,Zhong, Wenzhou
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p. 3409 - 3422
(2020/06/09)
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- Functional panchromatic BODIPY dyes with near-infrared absorption: Design, synthesis, characterization and use in dye-sensitized solar cells
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We report two novel functional dyes based on a boron-dipyrromethene (BODIPY) core displaying a panchromatic absorption with an extension to the near-infrared (NIR) range. An innovative synthetic approach for preparing the 2,3,5,6-tetramethyl-BODIPY unit is disclosed, and a versatile way to further functionalize this unit has been developed. The optoelectronic properties of the two dyes were computed by density functional theory modelling (DFT) and characterized through UV-vis spectroscopy and cyclic voltammetry (CV) measurements. Finally, we report preliminary results obtained using these functional dyes as photosensitizers in dyesensitized solar cells (DSSCs).
- Huaulmé, Quentin,Aumaitre, Cyril,Kontkanen, Outi Vilhelmiina,Beljonne, David,Sutter, Alexandra,Ulrich, Gilles,Demadrille, Renaud,Leclerc, Nicolas
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supporting information
p. 1758 - 1768
(2019/08/07)
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- Octamolybdate-based hybrids for direct conversion of aldehydes and ketones to oximes
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Two inorganic-organic hybrid materials, [Co(L)2]2Na2[β-Mo8O26]·9H2O (1) and [Fe(L)2]2Na2[β-Mo8O26]·9H2O (2) (HL = 2-acetylpyrazine N4-methyl thiosemicarbazone) have been synthesized and characterized by elemental analyses, infrared (IR) spectroscopy, thermal gravimetric analysis (TGA), powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction. The hybrids 1 and 2 were explored in the oximation of aldehydes and ketones with in situ generated hydroxylamine by a one-pot procedure. In the crystal structures of 1 and 2, N-containing thiosemicarbazide ligands, Lewis acid, and oxidation catalyst octamolybdate coexist within a confined space providing a promising synergistic catalytic way. Hybrids 1 and 2 displayed high catalytic activity and selectivity for the oximation of aldehydes and ketones.
- Han, Pei Pei,Li, Jie,Xing, Cui Li,Zhao, Meng,Han, Qiu Xia,Li, Ming Xue
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- High add valued application of turpentine in crop production through structural modification and qsar analysis
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Turpentine is a volatile component of resin, which is an abundant forest resource in Southern China. As one of the most important components, the integrated application of-pinene has been studied. The broad-spectrum evaluation of -pinene and its analogues has, therefore, been necessary. In an attempt to expand the scope of agro-activity trials, the preparation and the evaluation of the herbicidal activity of a series of -pinene analogues against three agricultural herbs were carried out. In accordance with the overall herbicidal activity, it is noteworthy that compounds 6k, 6l, and 6m demonstrated extreme activity with IC50 values of 0.065, 0.065, and 0.052 mol active ingredients/hectare against E. crus-galli. The preliminary structure-activity relationship (SAR) was analyzed and the compounds with the appropriate volatility and substituent type that had beneficial herbicidal activity were analyzed. Simultaneously, the quantitative structure-activity relationship (QSAR) model was built and the most important structural features were indicated, which was, to a certain extent, in line with the SAR study. The study aimed to study the application of the forest resource turpentine in agriculture as a potential and alternative approach for comprehensive utilization.
- Gao, Yanqing,Li, Jingjing,Li, Jian,Song, Zhanqian,Shang, Shibin,Rao, Xiaoping
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- AMMOXMATION CATALYST AND PROCESS FOR PRODUCING OXIME
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Disclosed is an ammoximation catalyst useful in producing oximes from ketones with high yield and high selectivity by ammoximation reaction using hydrogen, oxygen and ammonia. The ammoximation catalyst contains (a) a titanosilicate and (b) a metal supported on the titanosilicate and/or another support that is different from the titanosilicate; the metal comprising palladium and gold.
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Paragraph 0088
(2018/05/27)
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- Method for preparing oxime
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The invention discloses a method for preparing oxime. The method is characterized in that catalytic reaction for oxime synthesis is performed by using a titanium silicate molecular sieve of a MSE topological structure as a catalyst and using ketone or aldehyde, ammonia and hydrogen peroxide as a reaction system, wherein in the reaction system, the weight ratio of ketone or aldehyde to the catalystto a solvent is 1:(0.03 to 0.15):(1 to 15); the molar ratio of the ketone or aldehyde to the ammonia is 1:(1 to 4); the catalyst is Ti-MSE or a combination body of Ti-MSE and silicon dioxide or a titanium-containing molecular sieve. Compared with the prior art, the method has the advantages that the selectivity is high; the catalytic activity is high; the aftertreatment is simple and convenient;the conversion rate of reactants of ketone or aldehyde reaches up to 99 percent; the product oxime selectivity reaches up to 99 percent, so that the molecular sieve shows excellent catalytic activityin the specific catalysis field; the application field of the molecular sieve is expanded; a novel and environment-friendly ammoxidation oxime preparation path is provided; certain industrial popularization and application prospects and prominent economic values are realized.
- -
-
Paragraph 0031; 0032; 0033
(2018/09/08)
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- Green synthesis of low-carbon chain nitroalkanes via a novel tandem reaction of ketones catalyzed by TS-1
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A green and efficient one-pot method has been developed for the synthesis of low-carbon chain nitroalkanes via a novel TS-1 catalyzed tandem oxidation of ketones with H2O2 and NH3. The tandem reaction including ammoxidation, oximation and oxidation of oximes, afforded up to 88% yield and 98% chemo-selectivity requiring only 90 min, at 70 °C and atmospheric pressure. Moreover, this method was even amenable to 100-fold scale-up without loss of chemical efficiency with 87% yield, represents a significant advance towards industrial production of nitroalkanes. Furthermore, the plausible mechanism of TS-1 catalyzed tandem oxidation of ketones to prepare nitroalkanes was proposed.
- Chu, Qingyan,He, Guangke,Xi, Yang,Wang, Ping,Yu, Haoxuan,Liu, Rui,Zhu, Hongjun
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- One-pot conversion of cyclohexanol to ?-caprolactam using a multifunctional Na2WO4-acidic ionic liquid catalytic system
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Na2WO4-acidic ionic liquid was used as a simple, ecofriendly, recyclable and efficient catalytic system for the one-pot conversion of cyclohexanol to ?-caprolactam. The effect of the structure of the ionic liquid on the catalytic activity of this system was investigated, and the results revealed that sulfonic acid-functionalized ionic liquids with HSO4?as an anion gave the best results. The highly efficient performance of this catalyst system was attributed to the phase-transfer behavior of the cation of the ionic liquid, the improved coordination of the substrate to bisperoxotungstate during the oxidation reaction, and the stabilization of the intermediate formed during the Beckmann rearrangement.
- Wang, Hefang,Jia, Liyuan,Hu, Rongbin,Gao, Meidan,Wang, Yanji
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- Novel process for synthesizing oxime through in-situ generated ammonia
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The invention discloses a novel process for synthesizing oxime through in-situ generated ammonia. The novel process is characterized in that ammonium salt and strong alkali and weak acid salt generate ammonia in situ, and then the ammonia reacts with ketone and hydrogen peroxide under catalysis of a titanium silicalite molecular sieve. The synthetic process has the advantages of simple oximation reaction, mild reaction conditions, few by-products, high product yield and environmentally friendliness. The synthesizing method is simple, an aftertreatment process is simple and convenient and has very strong operability and repeatability, and industrial production is promoted.
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-
Paragraph 0030; 0031; 0034; 0035; 0036-0041; 0044; 0045
(2017/07/19)
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- A process for synthesizing of cyclohexanone oxime (by machine translation)
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The invention discloses a process for synthesizing of cyclohexanone oxime, in carbonate aqueous solution is in the system, in order to titanium-silicon molecular sieve as the catalyst, ketone, ammonia and hydrogen peroxide produced by the reaction of oxime; and, in the reaction process through the pH value of the reaction system to determine the real-time monitoring of the reaction process and to determine the optimal reaction mixture ratio. By monitoring the reaction system pH value to judge in the reaction process to determine the optimal reaction ratio, further through the carbonate aqueous solution to adjust the pH value of the system in order to improve the reaction speed and ammonia conversion rate. (by machine translation)
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Paragraph 0035; 0036
(2017/08/29)
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- A hydrophilic inorganic framework based on a sandwich polyoxometalate: Unusual chemoselectivity for aldehydes/ketones with in situ generated hydroxylamine
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A hydrophilic inorganic porous catalyst was prepared via the hydrothermal method. The combination of [WZn3(H2O)2(ZnW9O34)2]12- and Co(ii) provides a synergistical catalytic way to promote oximation of aldehyde/ketone with in situ generated hydroxylamine that initially produces an oxime, which further either dehydrates into a nitrile or undergoes a Beckmann rearrangement to form an amide.
- Xing, Songzhu,Han, Qiuxia,Shi, Zhuolin,Wang, Shugai,Yang, Peipei,Wu, Qiang,Li, Mingxue
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supporting information
p. 11537 - 11541
(2017/09/18)
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- Method of preparing a butanone
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The invention provides a method for preparing diacetylmonoxime. The method mainly comprises the following five procedures: a raw material procedure, a reaction procedure, a membrane filtration procedure, a sewage separation procedure and a refining procedure.
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-
Paragraph 0109-0117
(2016/10/08)
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- Preparation method of ketoxime and/or aldoxime
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The invention provides a preparation method of ketoxime and/or aldoxime. The method includes a step of performing an ammoximation reaction to ketone and/or aldehyde, ammonia and hydrogen peroxide at 50-200 DEG C in a water solution in the presence of an oximation catalyst without any organic solvent. The method has high conversion rate of ketone and/or aldehyde and high selectivity of ketoxime and/or aldoxime, is simple in subsequent separation and purification, and has great industrial application prospect.
- -
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Paragraph 0031-0033
(2017/06/27)
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- M-CPBA mediated metal free, rapid oxidation of aliphatic amines to oximes
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An efficient, rapid oxidation of various aliphatic amines to oximes using m-CPBA as an oxidant in ethyl acetate is described. High conversion (100%) with >90% oxime selectivity is achieved at room temperature under catalyst-free conditions. Mild reaction conditions along with an easy work up procedure offer lower byproduct formation and high selectivity for oximes in good yield and purity.
- Patil, Vilas V.,Gayakwad, Eknath M.,Shankarling, Ganapati S.
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p. 781 - 786
(2016/02/18)
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- Direct catalytic synthesis of ε-caprolactam from cyclohexanol using [n-C16H33N (CH3)3]H2PW12O40 as a catalyst
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ε-Caprolactam was synthesized directly from cyclohexanol via a tandem catalytic process using [n-C16H33N(CH3)3]H2PW12O40 as a catalyst. The highly efficient performance of the catalysts is due to the phase-transfer function of cation, improved coordination with peroxotungsten during oxidation and stabilization function of heteropoly anion on the intermediate formed during Beckmann rearrangement. A ε-caprolactam yield of 73.9% was obtained with a cyclohexanol conversion of 97.1% under optimized conditions.
- Wang, Hefang,Hu, Rongbin,Yang, Yongfang,Gao, Meidan,Wang, Yanji
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- A value-added use of volatile turpentine: antifungal activity and QSAR study of β-pinene derivatives against three agricultural fungi
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In consideration of turpentine and its analogues possessing some agricultural biological activity, persistent efforts to take advantage of renewable, abundant natural resources have been made. Three series of derivatives from β-pinene were synthesized and their fungicidal activities against Rhizoctonia solani, Fusarium graminearum, and Botrytis cinerea were investigated. Most of the synthesized compounds exhibited moderate to significant fungicidal activity. Among them, the acylthiourea derivatives from β-pinene showed more promising results than the other compounds. It was worth noting that compounds 7b and 7d displayed excellent fungicidal activity against Rhizoctonia solani, with IC50 values of 2.439 and 1.857 μg mL-1, which was close to or even better than the control triadimenol (1.945 μg mL-1, a commercial fungicide). The structure-activity relationship (SAR) analysis indicated that the compounds with more net positive charge possessed better fungicidal activity. The quantitative structure-activity relationship (QSAR) model (R2 = 0.9879, F = 348.41, S2 = 0.0047) was obtained through the best multi-linear regression. The built model revealed a strong correlation of fungicidal activity against Rhizoctonia solani with the molecular features of the title compounds. Additionally, the SAR and QSAR studies showed that the introduction of an electron-withdrawing group, which can increase the positive charge, was favorable towards the fungicidal activity. These encouraging results may provide an alternative, promising use of β-pinene through the design and exploration of eco-friendly fungicides with low toxicity and high efficiency.
- Li, Jian,Tian, Xiangrong,Gao, Yanqing,Shang, Shibin,Feng, Juntao,Zhang, Xing
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p. 66947 - 66955
(2015/08/24)
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- Highly efficient and stable peracid for rapid and selective oxidation of aliphatic amines to oximes
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A novel, transition-metal free, rapid approach for selective oxidation of aliphatic and benzylic amines to oximes is described. The dodecanebis(peroxoic acid)-DMF combination efficiently oxidizes various aliphatic amines at 50 °C temperature to give 100% conversion in 20 min with high oxime selectivity. The peroxy acid used here shows exceptional stability at room temperature and is non-shock sensitive in nature, which was confirmed by differential scanning colorimetric (DSC) analysis.
- Patil, Vilas V.,Gayakwad, Eknath M.,Shankarling, Ganapati S.
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p. 6677 - 6682
(2015/08/06)
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- Dual nature of polyethylene glycol under microwave irradiation for the clean synthesis of oximes
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Polyethylene glycol (PEG-400 and PEG-600) is an efficient, inexpensive, and recyclable homogeneous medium and catalyst (dual nature) for the clean synthesis of oximes (and aldoximes) under microwave irradiation in the absence of acid and base catalysts. Both aliphatic and aromatic aldehydes/ketones give satisfactory results under microwave irradiation within a short time. Graphical abstract: [Figure not available: see fulltext.]
- Dutta, Papia,Dutta, Arup Kumar,Sarma, Parishmita,Borah, Ruli
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p. 505 - 508
(2014/03/21)
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- Lewis acidic strength controlled highly selective synthesis of oxime via liquid-phase ammoximation over titanosilicates
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The Lewis acidity of titanosilicates determines the selectivity of the oxime in ammoximation. Higher Lewis acidic strength of Ti active sites could promote free H2O2 to participate in the highly efficient formation of NH2OH by lowering the reaction activation energy for the formation of Ti-OOH species, and thus fundamentally suppress the side reactions of deep oxidation.
- Zhuo, Zuoxi,Wu, Lizhi,Wang, Lei,Ding, Yichun,Zhang, Xiaoqian,Liu, Yueming,He, Mingyuan
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p. 55685 - 55688
(2015/02/19)
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- Influences of fluorine implantation on catalytic performance and porosity of MOR-type titanosilicate
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Fluorine species were implanted into the framework of Ti-MOR by post-treatment with fluorides in order to modify the microenvironment around Ti active sites and then to improve their catalytic activity in liquid-phase oxidation. The effects of NH4F amount, fluorination temperature, and solvent on the catalytic performance of F-Ti-MOR were investigated in detail. Methanol was found to be superior to water in fluorination. Fluorine implantation increased the electropositivity of Ti active sites through forming SiO3/2F units in the neighborhood, which enhanced the catalytic performance in the ammoximation of cyclohexanone remarkably. F-Ti-MOR prepared under optimized fluorination conditions showed a cyclohexanone conversion of 99% in comparison to only 30% conversion given by primitive Ti-MOR. Meanwhile, the implanted fluorine species captured the organic molecules with a relatively large dimension tightly, creating enormous steric hindrances that prevented other molecules, in particular those with bulky molecular dimensions, from diffusing into channels freely. Thus, F-Ti-MOR showed much lower activity than Ti-MOR in the hydroxylation of aromatics.
- Yang, Yulin,Ding, Jianghong,Wang, Binshen,Wu, Jing,Zhao, Chen,Gao, Guohua,Wu, Peng
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p. 160 - 169
(2015/03/31)
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- Selective ammoximation of ketones and aldehydes catalyzed by a trivanadium-substituted polyoxometalate with H2O2 and ammonia
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The ammoximation of different ketones and aldehydes to their corresponding oximes catalyzed by K6[PW9 V3O 40]·4H2O was carried out with hydrogen peroxide and ammonia in isopropanol at room temperature. High yields of oximes were obtained in this catalytic system. This catalytic system was proved to be heterogeneous by the ammoximation activity of removal of catalyst and the elemental analysis of the filtrate after reaction. A possible procedure for the ammoximation catalyzed by K6[PW9V3O40] ·4H2O with H2O2 and NH 3·H2O was proposed. The fresh and used catalysts were characterized by IR and 31P MAS NMR, which revealed the good stability of the catalyst.
- Xue, Xiaoling,Song, Fangyuan,Ma, Baochun,Yu, Yongze,Li, Cheng,Ding, Yong
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-
- Synthesis and antibacterial activity of oxime ester derivatives from dehydroabietic acid
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A series of oxime ester derivatives containing dehydroabietyl group were synthesized from dehydroabietic acid. Their structures were characterized by IR, 1HNMR, MS, and elemental analysis. The preliminary antibacterial activity results indicate that these compounds display extensive anti-bacterial activity against Escherichia coli, Staphyloccocus aureu, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia aerogenes and Staphyloccocus epidermidis. Compounds (5a, 5b, 5c, 5d, 5e, 5f) exhibit excellent anti-bacterial activity against Escherichia coli with the diameter of inhibition zone is 10.91mm, 11.03mm, 12.92mm, 13.48mm, 11.59mm and 11.58mm respectively, compared with the diameter of inhibition zone of 9.66mm of the commercial compound bromogeramine. Furthermore, Compounds(5d) exhibited the same level of antibacterial activity against Staphyloccocus epidermidis when compared with bromogeramine and Ampicillin Na.
- Yan-Jie, Cui,Xiao-Ping, Rao,Shi-Bin, Shang,Jie, Song,Yan-Qing, Gao
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p. 102 - 110
(2013/05/09)
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- Oxidative coupling of 1,7,8-unsubstituted BODIPYs: Synthesis and electrochemical and spectroscopic properties
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We report the synthesis of BODIPYs with unsubstituted 1,7,8-positions and their dimerization by oxidative coupling with phenyliodine(III)- bis(trifluoroacetate) (PIFA). This dimerization was achieved for BODIPYs substituted in the 3,5-positions with either methyl or thienyl groups. The position and the type of the linkage in the resulting dimers depended on the nature of the substituent. The 3,5-dimethyl-BODIPY dyes were linked either via direct 1,1′-pyrrole-pyrrole coupling or via a 1,3′-methylene bridge. The 3,5-dithienyl-BODIPY dyes provided, in excellent yields, unique compounds linked exclusively via the α-thienyl positions. All dyes were unreactive in the 8-position. Electrochemical and spectroscopic measurements on the monomers and dimers provided evidence of interactions between the two halves of the dimers. Thus, oxidation and reduction potentials were split by up to 210 mV, and modest excitonic coupling and an internal charge transfer were observed in some cases.
- Poirel, Arnaud,De Nicola, Antoinette,Retailleau, Pascal,Ziessel, Raymond
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p. 7512 - 7525
(2012/11/13)
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- Regioselective synthesis of heterocycles containing nitrogen neighboring an aromatic ring by reductive ring expansion using diisobutylaluminum hydride and studies on the reaction mechanism
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(Chemical Equation Presented) A systematic investigation of the reductive ring-expansion reaction of cyclic ketoximes fused to aromatic ringswith diisobutylaluminum hydride (DIBALH) is described. This reaction regioselectively afforded a variety of five- to eight-membered bicyclic heterocycles or tricyclic heterocycles containing nitrogen neighboring an aromatic ring, including indoline, 1,2,3,4,5,6-hexahydrobenz[b]azocine, 3,4-dihydro-2H-benzo[b] [1,4]oxazine, 2,3,4,5-tetrahydrobenzo[b][1,4]thiazepine, 1,2,3,4,5,6- hexahydroazepino[3,2-b]-indole, 2,3,4,5-tetrahydro-1H-benzothieno[2,3-b]azepine, 2,3,4,5-tetrahydro-1H-benzothieno[3,2-b]-azepine, 5,6-dihydrophenanthridine, and 5,6,11,12-tetrahydrodibenz[b, f]azocine. The reaction mechanism leading to the rearrangement was investigated on the basis of the restricted Becke three-parameter plus Lee-Yang-Parr (B3LYP) density functional theory (DFT) with the 6-31G (d) basis set. It was found that the reaction proceeds through a three-centered transition state via a stepwise mechanism because the potential energy curve along the intrinsic reaction coordinate (IRC) had twomaxima (saddle points; TS1 and TS2) and the partial phenonium cation intermediate C. In addition to cyclic ketoximes fused to aromatic rings, the reactions of various cyclic and acyclic ketoximeswere examined to investigate preference of migrating group. It was found that themore electron-rich group migrated preferentially to give the corresponding secondary amines.
- Cho, Hidetsura,Iwama, Yusuke,Sugimoto, Kenji,Mori, Seiji,Tokuyama, Hidetoshi
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scheme or table
p. 627 - 636
(2010/04/29)
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- Metalloporphyrin and heteropoly acid catalyzed oxidation of C=NOH bonds in an ionic liquid: Biomimetic models of nitric oxide synthase
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Water soluble iron(III) porphyrins and phosphotungstic acid in an ionic liquid are effective catalysts for the H2O2 mediated oxidation of the CNOH bond in N-hydroxyarginine and other oximes. The carbonyl compounds generated as the oxidation products can be easily isolated from the reaction media. These systems serve as biomimetic models of nitric oxide synthase (NOS) and the catalyst immobilized in an ionic liquid can be easily recycled and reused.
- Jain, Nidhi,Kumar, Anil,Chauhan, Shive M.S.
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p. 2599 - 2602
(2007/10/03)
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- A convenient one-pot method of converting alcohols into oximes
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The one-pot conversion of primary and secondary alcohols into oximes is reported using chromium trioxide supported on alumina and hydroxylamine hydrochloride under solvent free condition. This oxidation-oxime formation reaction has been applied to a range of aliphatic and benzylic alcohols.
- Kiasat, Ali Reza,Kazemi, Foad,Nourbakhsh, Kazem
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p. 1809 - 1812
(2007/10/03)
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- A clean conversion of carbonyl compounds to oximes using silica gel supported hydroxylamine hydrochloride
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The efficient condensation of carbonyl compounds with hydroxylamine hydrochloride under solvent free conditions is described.
- Kiasat, Ali Reza,Kazemi, Foad,Nourbakhsh, Kazem
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p. 1193 - 1196
(2007/10/03)
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- Mono-deoxygenation of nitroalkanes, nitrones, and heterocyclic N-oxides by hexamethyldisilane through 1,2-elimination: Concept of 'counterattack reagent'
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Transformation of secondary nitroalkanes to ketoximes was achieved in 40-73% yields by treatment of the corresponding nitronate anions with hexamethyldisilane. In this new mono-deoxygenation process, hexamethyldisilane acted as a 'counterattack reagent'. The conversion of nitrones to imines was also achieved in 82-88% yields by use of trimethylsilyllithium. Similarly, heterocyclic N-oxides were converted to the corresponding N-heterocycles in 73-86% yields. These deoxygenation processes presumably involve a 1,2-elimination.
- Hwu, Jih Ru,Tseng, Wen Nan,Patel, Himatkumar V.,Wong, Fong Fuh,Horng, Den-Nan,Liaw, Ben Ruey,Lung Ching, Lin
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p. 2211 - 2218
(2007/10/03)
-
- REACTION D'OXIMATION DES CETONES V. MECANISME ET EFFETS DE STRUCTURE DANS LA REACTION DE DESHYDRATATION ACIDO-CATALYSEE DES CARBINOLAMINES
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The equilibrium constants of formation and the rate constants of dehydratation of carbinolamines resulting from the addition of hydroxylamine to 19 ketones, - 5 aliphatic, 5 aromatic and 9 cyclanic -, have been measured at 25 deg C in water/methanol 60/40 v/v.We show that the acid catalyzed process predominates in the range of pH 6 to 7 for acetophenones or pH 7 to 8.5 for saturated ketones.The rate constants ratios and Hammett ρ constant of the reaction suggest an sp3 (early) transition state.The changes in rate constant are discussed in terms of torsional and non-bonding steric effects.For several hindered ketones, e.g. 3,3,5,5-tetramethylcyclohexanone, we show the existence of a steric hindrance to the approach of the catalyst; in that case the result is a strong decrease of the rate of the dehydratation.
- Lamaty, G.,Roque, J. P.,Natat, A.,Silou, T.
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p. 2667 - 2676
(2007/10/02)
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- Producing alkoxysilanes and alkoxy-oximinosilanes
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A silicon halide such as methyl trichlorosilane is reacted with an alcohol such as isopropanol and an oxime such as methyl ethyl ketone oxime. Byproduct oxime hydrohalide is formed in all cases. With higher amounts of alcohol, alkoxysilane (e.g. methyl triisopropoxysilane) is the sole or major product. With lower amounts of alcohol, alkoxy-oxminosilanes (e.g. methyl diisopropoxy(methyl ethyl ketoximo)silane and methyl isopropoxy bis(methyl ethyl ketoximo)silane) are the major products.
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-
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- Alkylwanderungen bei Sextettumlagerungen
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The migration aptitude of alkyl groups in the Beckmann-, the Criegee-, and the isonitrile-nitrile rearrangements were investigated.The relative rearrangement rates of substituted benzyl groups are an expression of the charge on the migrating carbon at transition state.From the relative rates of migration of exo- and endo-2-norbornyl groups the geometrical changes at the migrating carbon is estimated.Finally, the different influence of α-branching in the migrating group is discussed for these and some other rearrangements.
- Langhals, Heinz,Range, Guenter,Wistuba, Eckehardt,Ruechardt, Christoph
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p. 3813 - 3830
(2007/10/02)
-
- PYRROLES FROM KETOXIMES AND ACETYLENE. XII. ANOMALOUS REACTIONS OF α- AND β-HYDROXY KETOXIMES
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In reaction with acetylene (80 - 110 deg C, potassium hydroxide, dimethyl sulfoxide) the oximes of α- and β-hydroxy ketones R(Me)C=NOH, where R = HOCH2 (I), EtOCH2 (II), HOCH2(Me)CH (III), CH2=CHOCH2(Me)CH (IV), and Me(Me)(OH)CCH2 (V), give low yields mainly of a mixture of pyrroles not containing an oxygen atom.The following compounds were identified in the mixtures by GLC, TLC, and PMR and IR spectroscopy (compound No. of oxime and the pyrroles from which it was obtained): (II), 1-vinyl-2-methylpyrrole and 1-vinyl-2-ethoxymethylpyrrole; (III), 1-vinyl-2,3-dimethylpyrrole and 1-vinyl-2-(2-propenyl)pyrrole; (IV), 1-vinyl-2-(2-propenyl)pyrrole; (V), 1-vinyl-2-methylpyrrole.In the case of oxime (I) it was not possible to identify the pyrroles in the reaction mixture.The structures of the anomalous products are consistent with the theories that α-carbanions play an important role in the formation of the pyrrole ring from ketoximes and acetylene in the potassium hydroxide - DMSO system.
- Trofimov, B. A.,Oleinikova, E. B.,Sigalov, M. V.,Skvortsov, Yu. M.,Mikhaleva, A. I.
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p. 366 - 370
(2007/10/02)
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- Synthesis and β-Adrenergic Blocking Activity of New Aliphatic Oxime Ethers
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New β-adrenergic blocking agents, most of which do not contain an aromatic nucleus, were synthesized.They were derived either from alkylamino-aliphatic oxime ethers, or alkylamino-aliphatic ethers.Most active among these are O-acetoxime (8; trachea pA2=7.65) and 1-isobutoxy-3-(tert-butylamino)-2-propanol (15, trachea pA2=7.49), both of which displayed bronchoselectivity (β2/β1 ratio ca. 15).The role and importance of the aromatic nucleus in this class of compounds are discussed
- Leclerc, Gerard,Bieth, Nicole,Schwartz, Jean
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p. 620 - 624
(2007/10/02)
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