- Metal-Free Oxidative Esterification of Ketones and Potassium Xanthates: Selective Synthesis of α-Ketoesters and Esters
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A novel and efficient oxidative esterification for the selective synthesis of α-ketoesters and esters has been developed under metal-free conditions. In the protocol, various α-ketoesters and esters are available in high yields from commercially available ketones and potassium xanthates. Mechanistic studies have proven that potassium xanthate not only promotes oxidative esterification but also provides an alkoxy moiety for the reaction, which involves the cleavage and reconstruction of C-O bonds.
- Luo, Xianglin,He, Runfa,Liu, Qiang,Gao, Yanping,Li, Jingqing,Chen, Xiuwen,Zhu, Zhongzhi,Huang, Yubing,Li, Yibiao
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p. 5220 - 5230
(2020/05/18)
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- A heterocyclic compound and use thereof
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The invention discloses a compound of a general formula I and application of the compound serving as a plant disease-resistance activator. In the formula, a substituent group R1 and 0-3 substituent groups R2 exist on the 4th, 5th, 6th and 7th sites; R1 is independently selected from -R3OOH, -R4OOR5, -R6OH and -R7-O-R8; R2 is independently selected from C1-C6 alkyl, C1-6 halogenated alkyl, C1-C6 alkoxy, C1-C6 halogenated alkoxy, hydroxyl, halogen, nitro, amino and C1-C6 alkylamino; R3, R4, R5, R6, R7 and R8 are independently selected from C1-C6 alkyl and C1-6 halogenated alkyl. The compound induces plants to generate disease resistance so as to inhibit pathogens instead of directly killing or inhibiting the pathogens. The compound has the advantages of systematicness, durability, broad spectrum, high safety and the like, so the amount of highly toxic pesticides can be reduced, and the compound is environmentally friendly and has huge industrialized and commercial prospects and market values.
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Paragraph 0103-0106; 0111-0113
(2018/05/24)
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- SO2F2-Mediated One-Pot Synthesis of Aryl Carboxylic Acids and Esters from Phenols through a Pd-Catalyzed Insertion of Carbon Monoxide
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A one-pot Pd-catalyzed carbonylation of phenols into their corresponding aryl carboxylic acids and esters through the insertion of carbon monoxide has been developed. This procedure offers a direct synthesis of aryl carboxylic acids and esters from inexpensive and abundant starting materials (phenols, SO2F2 and CO) under mild conditions. This method tolerates a broad range of functional groups and is also applicable for the modification of complicated natural products.
- Fang, Wan-Yin,Leng, Jing,Qin, Hua-Li
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supporting information
p. 2323 - 2331
(2017/09/06)
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- Accessing N-Acyl Azoles via Oxoammonium Salt-Mediated Oxidative Amidation
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An operationally simple, robust, metal-free approach to the synthesis of N-acyl azoles from both alcohols and aldehydes is described. Oxidative amidation is facilitated by a commercially available organic oxidant (4-acetamido-2,2,6,6-tetramethylpiperidine-1-oxoammonium tetrafluoroborate) and proceeds under very mild conditions for an array of structurally diverse substrates. Tandem reactions of these activated amides, such as transamidation and esterification, enable further elaboration. Also, the spent oxidant can be recovered and used to regenerate the oxoammonium salt.
- Ovian, John M.,Kelly, Christopher B.,Pistritto, Vincent A.,Leadbeater, Nicholas E.
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p. 1286 - 1289
(2017/03/22)
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- Room Temperature Carbonylation of (Hetero) Aryl Pentafluorobenzenesulfonates and Triflates using Palladium-Cobalt Bimetallic Catalyst: Dual Role of Cobalt Carbonyl
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An efficient method for the carbonylation of (hetero) aryl pentafluorobenzenesulfonates and triflates under exceptionally mild conditions using palladium/dicobalt octacarbonyl [Pd/Co2(CO)8] has been developed. Besides acting as carbon monoxide (CO) source, Co2(CO)8enhances the reaction rate by accelerating the CO insertion through an in situ generated bimetallic palladium cobalt tetracarbonyl [Pd-Co(CO)4] complex. Under the optimized reaction condition, carbonylation of a wide range of activated and deactivated, as well as sterically hindered and heteroaromatic, substrates proceeded efficiently at room temperature. The high chemoselectivity and improved synthesis of biologically relevant Isoguvacine and Lazabemide intermediates highlights its scope as a valuable synthetic method. The generality of this protocol was further extended to other electrophiles (bromides, chlorides and tosylates). (Figure presented.).
- Joseph, Jayan T.,Sajith, Ayyiliath M.,Ningegowda, Revanna C.,Shashikanth, Sheena
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p. 419 - 425
(2017/02/10)
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- Cu(ii)-catalyzed esterification reaction via aerobic oxidative cleavage of C(CO)-C(alkyl) bonds
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A novel Cu(ii)-catalyzed aerobic oxidative esterification of simple ketones for the synthesis of esters has been developed with wide functional group tolerance. This process is assumed to go through a tandem sequence consisting of α-oxygenation/esterification/nucleophilic addition/C-C bond cleavage and carbon dioxide is released as the only byproduct.
- Ma, Ran,He, Liang-Nian,Liu, An-Hua,Song, Qing-Wen
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supporting information
p. 2145 - 2148
(2016/02/09)
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- Synthesis, characterization and urease inhibiting derivatives of 5-(3,4-Methylenedioxyphenyl)-1,3,4-Oxadiazol-2-thiol
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In the present work, the urease inhibition activity of 1,3,4-oxadiazole bearing molecules was evaluated and were found to be potential inhibitors. 3,4-(Methylenedioxy)benzoic acid (1) was employed to synthesize 5-(3,4-methylenedioxyphenyl)-1,3,4-oxadiazol-2-thiol (4) via a series of steps. It was further stepped to yield S-substituted-5-(3,4-methylenedioxyphenyl)-1,3,4-oxadiazole derivatives (6a-h) on reaction with alkyl/aralkyl halides (5a-h) in DMF using LiH as an activator. All the synthesized compounds were well supported by IR, 1H NMR and EIMS spectral analysis. The enzyme inhibition activity against urease enzyme showed these molecules as potent inhibitors of this enzyme.
- Aziz-Ur-Rehman,Siddiqa, Asia,Abbasi, M. Athar,Rasool, Shahid,Akhtar, M. Nadeem,Lodhi, M. Arif,Nafeesa, Khadija,Khan, Ajmal
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p. 4605 - 4609
(2014/12/10)
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- Correlation of the rates of solvolysis of electron-rich benzoyl chloride using the extended Grunwald-Wistein equation
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The solvolysis rate constants of piperonyloyl chloride (1) in 27 different solvents are well correlated with the extended Grunwald-Winstein equation, using the NT solvent nucleophilicity scale, YCl solvent ionizing scale, and I aromatic ring parameter with sensitivity values of 0.30 ± 0.05, 0.71 ± 0.02, and 0.60 ± 0.04 for l, m, and h, respectively. The solvent kinetic isotope effect values (SKIE, kMeOH/kMeOD and k 50%MeOD-50%D2O) of 1.16 and 1.12 were also in accord with the values for the SN1 mechanism and/or the dissociative SN2 mechanism. The product selectivity values (S) for solvolysis of 1 in alcohol/water mixtures were in the range of 0.5 to 1.9, which is also consistent with the proposed unimolecular ionization mechanism.
- Oh, Hyunjung,Choi, Hojune,Park, Jong Keun,Yang, Kiyull,Koo, In Sun
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p. 2697 - 2701
(2013/10/22)
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- An unusual 1,2-aryl shift in palladium-catalyzed cross-coupling ethoxycarbonylation of arylboronic acids with α-iminoesters
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The Pd-catalyzed cross-coupling ethoxycarbonylation of aryl boronic acids with N-aryl-α-iminoesters affords aryl carboxylic esters via carbonyl-imino σ bond cleavage. This unprecedented mode of reaction allows regioselective installation of the ethoxycarbonyl group into target molecules. Mechanism studies have revealed that an unusual 1,2-aryl shift process is involved in the transformation. The Royal Society of Chemistry.
- Qian, Cheng,Chen, Jiayan,Fu, Meiqin,Zhu, Shiya,Chen, Wen-Hua,Jiang, Huanfeng,Zeng, Wei
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p. 6013 - 6022
(2013/09/12)
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- Oxidative esterification of aldehydes with alcohols and phenols in air
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Nucleophilic carbene-catalysed oxidative esterification of aldehydes with alcohols and phenols without additional oxidant under an air atmosphere has been achieved, which provides a metal-free new methodology for the oxidative esterification of aldehydes.
- Cheng, Shuanghua,Chen, Jiuxi,Gao, Wenxia,Jin, Huile,Ding, Jinchang,Wu, Huayue
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experimental part
p. 130 - 132
(2010/06/19)
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- Novel 4H-1,3,4-oxadiazin-5(6H)-ones with hydrophobic and long alkyl chains: Design, synthesis, and bioactive diversity on inhibition of monoamine oxidase, chitin biosynthesis and tumor cell
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A new series of nitrogen-containing heterocycles 4H-1,3,4-oxadiazin-5(6H)-ones derivatives with hydrophobic and long chains were designed and synthesized by direct cyclization reaction of N′-alkylation substituted aroylhydrazines with chloroacetyl chloride. The preliminary assays showed that some of the compounds displayed moderate to good inhibitory activities toward monoamine oxidase (MAO) at the concentration of 10-5-10-3 M, and antitumor activities against human lung cancer A-549 and human prostate cancer PC-3 cell lines at μM level, which might provide new scaffold for anticancer agents. Furthermore, compounds 5i and 5m exhibited significant inhibitory activity on chitin biosynthesis, which might represent a novel class of highly potential inhibitors of chitin synthesis. Crown Copyright
- Ke, Shao-Yong,Qian, Xu-Hong,Liu, Feng-Yi,Wang, Ni,Yang, Qing,Li, Zhong
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scheme or table
p. 2113 - 2121
(2009/10/02)
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- 1,3,4-Oxadiazoline derivatives as novel potential inhibitors targeting chitin biosynthesis: Design, synthesis and biological evaluation
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Two series of 1,3,4-oxadiazoline heterocycle derivatives were designed, synthesized and identified. Bioactivity assays showed that all synthesized compounds inhibited chitin synthesis in yeast, suggesting they might be a novel class of potential inhibitors against chitin biosynthesis. The structure-activity relationships (SAR) of these compounds are discussed.
- Ke, Shaoyong,Liu, Fengyi,Wang, Ni,Yang, Qing,Qian, Xuhong
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scheme or table
p. 332 - 335
(2011/02/26)
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- 1,3,4-Oxadiazole-3(2H)-carboxamide derivatives as potential novel class of monoamine oxidase (MAO) inhibitors: Synthesis, evaluation, and role of urea moiety
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A new series of 1,3,4-oxadiazole-3(2H)-carboxamide derivatives have been synthesized by direct heterocyclization reaction of substituted benzoylisocyanate with various aroylhydrazones as novel monoamine oxidase inhibitors (MAOIs). The target molecules have been identified on the basis of satisfactory analytical and spectra (IR, 1H NMR, 13C NMR, and HR-MS) data. The newly synthesized compounds were evaluated for their MAO inhibitory activity by kynuramine fluorimetric assay method. The preliminary results showed that most of the compounds have moderate inhibitory activities toward MAO at the concentration of 10-5-10-3 M. This work may provide a novel class of lead compounds with potential MAO inhibitions for further optimization.
- Ke, Shaoyong,Li, Zhong,Qian, Xuhong
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p. 7565 - 7572
(2008/12/23)
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- A simple and facile carboxylation method and its application for synthesis of liquid crystals
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Sonication of a mixture of magnesium powder, 1,2-dibromoethane, aryl bromide and diethyl dicarbonate in THF followed by treatment with BF 3·OEt2 at room temperature afforded aryl ester with reasonable yield. A series of aryl bromides were investigated and transformed to their corresponding aryl esters under the reaction conditions.
- Lee, Adam Shih-Yuan,Wu, Chih-Chiang,Lin, Li-Shin,Hsu, Hsiu-Fu
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p. 568 - 572
(2007/10/03)
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- Novel imidazole derivatives with anti-inflammatory activity
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Novel imidazole derivatives of formula I and their salts, solvates and prodrugs, wherein the meanings of the different radicals are as shown in the description. Said compounds are useful as anti-inflammatory agents.
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- Thermal and photochemical decomposition pathways of trinitromethylarenes. part II. The effects of ethanol on the photolysis reactions of some alkoxy- and dialkoxyarenes in the presence of tetranitromethane. enhancement of adduct and trinitromethyl substitution product formation
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The photolysis of the charge transfer (CT) complex of tetranitromethane with 1-methoxynaphthalene, 1,4-dimethoxybenzene, 1,2-dimethoxybenzene, 1,2-methylenedioxybenzene or 2-methylanisole is reported for dichloromethane, acetonitrile, dichloromethane-ethanol and acetonitrile-ethanol solvent systems. The effects of adding ethanol (8% v/v ? 1.4 mol dm-3) to dichloromethane or acetonitrile as reaction solvents include: (i) the stabilization of alkoxytrinitro-methylarenes, thus reducing their normal tendency for decomposition according to ArC (NO2)3→ArCOOH→ArNO2, (ii) a reduction in the nucleophilicity of trinitromethanide ion, and (iii) changes in the regioselectivity of trinitromethanide ion attack on the radical cations of alkoxyaromatic compounds away from attack ipso to the alkoxy substituent. Adducts are also stabilized, as shown by the photolysis of the CT complex of 1,4-dimethoxybenzene-tetranitromethane in dichloromethane-ethanol (8% v/v) which gives the epimeric 1,4-dimethoxy-3-nitro-6-trinitromethylcyclohexa-1,4-dienes and 1,4-dimethoxy-2-trinitromethylbenzene, in addition to 1,4-dimethoxy-2-nitrobenzene. The adducts are detected also among the products of photolysis reactions in neat dichloromethane or acetonitrile. Acta Chemica Scandinavica 1997.
- Butts, Craig P.,Eberson, Lennart,Hartshorn, Michael P.,Persson, Ola
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p. 718 - 732
(2007/10/03)
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- Substituted naphtho pyrazoles
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Substituted naphtho [1,2-c] pyrazoles, e.g., 3-(4-pyridyl)-2H-naphtho[1,2-c]-pyrazole, are useful as non-estrogenic anti-fertility agents.
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