- Design and synthesis of sinomenine isoxazole derivatives via 1,3-dipolar cycloaddition reaction
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A novel structure of sinomenine isoxazole derivatives is synthesised from sinomenine hydrochloride and aromatic aldehydes and requires six steps. 19 target compounds have been obtained in good yields. The sinomenine hydrochloride transforms to 4-alkynyl sinomenine, which is a key intermediate product to synthesise the target sinomenine isoxazole compounds, after a neutralisation reaction with ammonia and substitution reaction with 3-chloropropyne. Another key intermediate product is 1,3-dipole, which can be obtained from aromatic aldehyde. After treatment with hydroxylamine hydrochloride and then sodium carbonate solution, aromatic aldehyde is converted to aldehyde oxime, which reacts with N-chlorosuccinimide (NCS) to afford aryl hydroximino chloride. 1,3-Dipole is eventually formed in situ while triethylamine (TEA) in DMF is added dropwise. Then 4-alkynyl sinomenine is added to provide the sinomenine isoxazole derivative via 1,3-dipolar cycloaddition reaction as the key step. All the target compounds are characterised by melting point, 1H NMR, 13C NMR, HRMS and FT-IR spectroscopy.
- Pan, Hongmei,Lu, Tong,Wu, Xuedan,Gu, Chengwen,Tao, Naili,Zhang, Biao,Wang, Ao,Chen, Guangmei,Zhang, Kehua,Cheng, Jie,Jin, Jie
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supporting information
p. 2360 - 2364
(2019/11/11)
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- HCl-mediated cascade cyclocondensation of oxygenated arylacetic acids with arylaldehydes: one-pot synthesis of 1-arylisoquinolines
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In this paper, a concise, open-vessel synthesis of 1-arylisoquinolines is describedviaHCl-mediated intermolecular cyclocondensation of oxygenated arylacetic acids with arylaldehydes in the presence of NH2OH and alcoholic solvents under mild and one-pot reaction conditions. A plausible mechanism is proposed and discussed herein. In the overall reaction process, only water was generated as the byproduct. Various environmentally friendly reaction conditions are investigated for convenient transformationviathe (4C + 1C + 1N) annulation. This protocol provides a highly effective ring closureviathe formations of one carbon-carbon (C-C) bond, two carbon-nitrogen (C-N) bonds and one carbon-oxygen (C-O) bond.
- Hsueh, Nai-Chen,Chen, Shin-Mei,Lin, Chun-Yi,Chang, Meng-Yang
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p. 1047 - 1059
(2021/02/16)
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- Dibenzazepine-linked isoxazoles: New and potent class of α-glucosidase inhibitors
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α-Glucosidase inhibition is a valid approach for controlling hyperglycemia in diabetes. In the current study, new molecules as a hybrid of isoxazole and dibenzazepine scaffolds were designed, based on their literature as antidiabetic agents. For this, a series of dibenzazepine-linked isoxazoles (33–54) was prepared using Nitrile oxide-Alkyne cycloaddition (NOAC) reaction, and evaluated for their α-glucosidase inhibitory activities to explore new hits for treatment of diabetes. Most of the compounds showed potent inhibitory potency against α-glucosidase (EC 3.2.1.20) enzyme (IC50 = 35.62 ± 1.48 to 333.30 ± 1.67 μM) using acarbose as a reference drug (IC50 = 875.75 ± 2.08 μM). Structure-activity relationship, kinetics and molecular docking studies of active isoxazoles were also determined to study enzyme-inhibitor interactions. Compounds 33, 40, 41, 46, 48–50, and 54 showed binding interactions with critical amino acid residues of α-glucosidase enzyme, such as Lys156, Ser157, Asp242, and Gln353.
- Umm-E-Farwa,Ullah, Saeed,Khan, Maria Aqeel,Zafar, Humaira,Atia-tul-Wahab,Younus, Munisaa,Choudhary, M. Iqbal,Basha, Fatima Z.
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supporting information
(2021/05/10)
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- Electrochemical synthesis of 1,2,4-oxadiazoles from amidoximes through dehydrogenative cyclization
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A convenient and efficient method for the generation of the iminoxy radical through anodic oxidation was developed for the synthesis of 3,5-disubstituted 1,2,4-oxadiazoles fromN-benzyl amidoximes. The transformation proceeds through 1.5-Hydrogen Atom Transfer (1,5-HAT) and intramolecular cyclization. The process features simple operation, mild conditions, broad substrate scope and high functional group compatibility, and provides a facile and practical way for the preparation of 1,2,4-oxadiazoles.
- Hu, Aixi,Jiang, chan,Li, mingfang,Xu, Leitao,Ye, Jiao,Yi, Yangjie
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supporting information
p. 10611 - 10616
(2021/12/27)
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- Microwave synthesis method of benzaldoxime compounds
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The invention discloses a microwave synthesis method of benzaldoxime compounds. The method comprises the following steps: dissolving a substituted benzaldehyde, hydroxylamine hydrochloride and an alkaline compound in an organic solvent, placing the formed solution in a microwave reaction kettle for a reaction, spin-drying the solvent after the reaction is finished, conducting mixed extraction withethyl acetate and water, separating an organic phase, carrying out drying with anhydrous sodium sulfate, and successively performing filtering and desolventizing to obtain a benzaldoxime compound. Based on the structure of the substituted benzaldehyde, the substituted benzaldoxime compound is obtained by reacting the aldehyde with hydroxylamine hydrochloride in the microwave reaction kettle. Themethod is simple in process, convenient to operate, short in reaction time and high in yield, meets the requirement for environment friendliness and improves economic benefits.
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Paragraph 0056-0059
(2020/12/08)
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- Synthesis and SAR study of simple aryl oximes and nitrofuranyl derivatives with potent activity against Mycobacterium tuberculosis
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Background: Oximes and nitrofuranyl derivatives are particularly important compounds in medicinal chemistry. Thus, many researchers have been reported to possess antibacterial, antiparasitic, insecticidal and fungicidal activities. Methods: In this work, we report the synthesis and the biological activity against Mycobacterium tuberculosis H37RV of a series of fifty aryl oximes, ArCH=N-OH, I, and eight nitrofuranyl compounds, 2-nitrofuranyl-X, II. Results: Among the oximes, I: Ar = 2-OH-4-OH, 42, and I: Ar = 5-nitrofuranyl, 46, possessed the best activity at 3.74 and 32.0 μM, respectively. Also, 46, the nitrofuran compounds, II; X = MeO, 55, and II: X = NHCH2Ph, 58, (14.6 and 12.6 μM, respectively), exhibited excellent biological activities and were non-cytotoxic. Conclusion: The compound 55 showed a selectivity index of 9.85. Further antibacterial tests were performed with compound 55 which was inactive against Enterococcus faecalis, Klebisiella pneumonae, Pseudomonas aeruginosa, Staphylococcus aureus, Salmonella typhymurium and Shigel-la flexneri. This study adds important information to the rational design of new lead anti-TB drugs. Structure-activity Relationship (SAR) is reported.
- Calixto, Stephane Lima,Carvalho, Guilherme da Silva Louren?o,Coimbra, Elaine Soares,Granato, Juliana da Trindade,Louren?o, Maria Cristina da Silva,Wardell, James,da Costa, Cristiane Fran?a,de Souza, Marcus Vinicius Nora
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- Chlorotropylium Promoted Conversions of Oximes to Amides and Nitriles
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Chlorotropylium chloride as a catalyst for the transformations of oximes, ketones, and aldehydes to their corresponding amides and nitriles in excellent yields (up to 99 %) and in short reaction times (mostly 10–15 min). Oximes were electrophilically attacked on the hydroxyl oxygen by chlorotropylium. The produced tropylium oxime ethers were the key intermediates, of which the ketoxime ether led to amide through Beckmann rearrangement, and the aldoxime ether led to nitrile by nitrogen base DBU assisted formal dehydration. This chlorotropylium activation protocol offered general, mild, and efficient avenues bifurcately from oximes to both amides and nitriles by one organocatalyst.
- Xu, Jiaxi,Gao, Yu,Li, Zhenjiang,Liu, Jingjing,Guo, Tianfo,Zhang, Lei,Wang, Haixin,Zhang, Zhihao,Guo, Kai
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p. 311 - 315
(2020/01/25)
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- SO2F2-Mediated one-pot cascade process for transformation of aldehydes (RCHO) to cyanamides (RNHCN)
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A simple, mild and practical cascade process for the direct conversion of aldehydes to cyanamides was developed featuring a wide substrate scope and great functional group tolerability. This method allows for transformations of readily available, inexpensive, and abundant aldehydes to highly valuable cyanamides in a pot, atom, and step-economical manner with a green nitrogen source. This protocol will serve as a robust tool for the installation of the cyanamide moiety in various complicated molecules.
- Ding, Chengrong,Ge, Shuting,Wei, Junjie,Zhang, Guofu,Zhao, Yiyong
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p. 17288 - 17292
(2020/05/18)
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- Synthesis and in vitro evaluation of neutral aryloximes as reactivators of Electrophorus eel acetylcholinesterase inhibited by NEMP, a VX surrogate
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Casualties caused by nerve agents, potent acetylcholinesterase inhibitors, have attracted attention from media recently. Poisoning with these chemicals may be fatal if not correctly addressed. Therefore, research on novel antidotes is clearly warranted. Pyridinium oximes are the only clinically available compounds, but poor penetration into the blood-brain barrier hampers efficient enzyme reactivation at the central nervous system. In searching for structural factors that may be explored in SAR studies, we synthesized and evaluated neutral aryloximes as reactivators for acetylcholinesterase inhibited by NEMP, a VX surrogate. Although few tested compounds reached comparable reactivation results with clinical standards, they may be considered as leads for further optimization.
- Cavalcante, Samir F. de A.,Kitagawa, Daniel A.S.,Rodrigues, Rafael B.,Bernardo, Leandro B.,da Silva, Thiago N.,dos Santos, Wellington V.,Correa, Ana Beatriz de A.,de Almeida, Joyce S.F.D.,Fran?a, Tanos C.C.,Ku?a, Kamil,Simas, Alessandro B.C.
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- Catalyst control in positional-selective C-H alkenylation of isoxazoles and a ruthenium-mediated assembly of trisubstituted pyrroles
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High levels of catalyst control are demonstrated in determining the positional selectivity in C-H alkenylation of isoxazoles. A cationic rhodium-mediated, strong-directing group promotes C(sp2)-H activation at the proximal aryl ring whereas, the palladium-mediated electrophilic metallation leads to the C(sp2)-H activation at the distal position of the directing group. Synthetic elaboration of this C-H alkenylation product via ruthenium and copper co-catalysis leads to an efficient method for the assembly of densely substituted pyrroles.
- Kumar, Pravin,Kapur, Manmohan
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supporting information
p. 2134 - 2138
(2019/03/26)
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- Cascade Process for Direct Transformation of Aldehydes (RCHO) to Nitriles (RCN) Using Inorganic Reagents NH2OH/Na2CO3/SO2F2 in DMSO
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A simple, mild, and practical process for direct conversion of aldehydes to nitriles was developed feathering a wide substrate scope and great functional group tolerability (52 examples, over 90% yield in most cases) using inorganic reagents (NH2OH/Na2CO3/SO2F2) in DMSO. This method allows for transformations of readily available, inexpensive, and abundant aldehydes to highly valuable nitriles in a pot, atom, and step-economical manner without transition metals. This protocol will serve as a robust tool for the installation of cyano-moieties to complicated molecules.
- Fang, Wan-Yin,Qin, Hua-Li
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p. 5803 - 5812
(2019/05/14)
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- A Transition-Metal-Free One-Pot Cascade Process for Transformation of Primary Alcohols (RCH2OH) to Nitriles (RCN) Mediated by SO2F2
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A new transition-metal-free one-pot cascade process for the direct conversion of alcohols to nitriles was developed without introducing an “additional carbon atom”. This protocol allows transformations of readily available, inexpensive, and abundant alcohols to highly valuable nitriles.
- Jiang, Ying,Sun, Bing,Fang, Wan-Yin,Qin, Hua-Li
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supporting information
p. 3190 - 3194
(2019/05/21)
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- Betulinic acid derivatives: a new class of α-glucosidase inhibitors and LPS-stimulated nitric oxide production inhibition on mouse macrophage RAW 264.7 cells
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Chemical manipulation studies were conducted on betulinic acid (1), twenty-one new rationally designed analogues of 1 with modifications at C-28 were synthesized for their evaluation of inhibitory effects on α-glucosidase and LPS-stimulated nitric oxide production in mouse macrophage RAW 264.7 cells. Compound 2 (IC50 = 5.4 μM) exhibited an almost 1.4-fold increase in α-glucosidase inhibitory activity on yeast α-glucosidase while analogues 5 (IC50 16.4 μM) and 11 (IC50 16.6 μM) exhibited a 2-fold enhanced inhibitory activity on NO-production than betulinic acid.
- Gundoju, Narayanarao,Bokam, Ramesh,Yalavarthi, Nageswara Rao,Azad, Rajaram,Ponnapalli, Mangala Gowri
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supporting information
p. 2618 - 2622
(2018/04/30)
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- Iodine Promoted One-Pot Synthesis of 2-Aryl Benzoxazoles from Amidoximes via Oxidative Cyclization and Ring Contraction
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A molecular I2-promoted one-pot synthesis of 2-aryl benzoxazoles has been developed by using amidoximes rather than the limited 2-aminophenols or 2-haloamides as substrates. The amidoxime substrates provided unique and efficient strategies for converting readily available aniline and benzaldehyde precursors into valuable chemicals. This transformation proceeded smoothly under transition-metal-free conditions through a sequential oxidative cyclization and ring contraction, and provided a potential route for introducing certain groups at any site of the scaffold.
- Zhang, Yong,Ji, Min
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supporting information
p. 7506 - 7510
(2019/11/28)
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- Palladium-Catalyzed α-Arylation of Silylenol Ethers in the Synthesis of Isoquinolines and Phenanthridines
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A diverse array of isoquinolines and phenanthridines have been accessed by developing a two-step, one-pot method constituting regioselective palladium-catalyzed Kuwajima-Urabe α-arylation of silylenol ethers and acid-mediated deprotection, annulation, and aromatization. Structural diversity in the silylenol ethers leads to three different classes of isoquinolines and phenanthridines from which related natural products can be derived. The synthetic utility of this method by the quick assembly of the natural product trispheridine is also demonstrated.
- Saini, Gaurav,Kumar, Pravin,Kumar, Gangam Srikanth,Mangadan, Arun Raj Kizhakkayil,Kapur, Manmohan
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supporting information
p. 441 - 444
(2018/01/28)
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- A radical cyclization cascade of 2-alkynylbenzonitriles with sodium arylsulfinates
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A convenient radical cyclization cascade procedure for the construction of sulfonated indenones from 2-alkynylbenzonitriles and sodium arylsulfinates has been explored under mild reaction conditions. The present methodology offers a low-cost and operationally straightforward approach to synthesizing various sulfonated indenones in moderate to good yields by simple use of cheap sodium persulfate as an oxidant and environmentally benign water as a co-solvent.
- Zhou, Bang,Chen, Wenqi,Yang, Yuzhong,Yang, Yuan,Deng, Guobo,Liang, Yun
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supporting information
p. 7959 - 7963
(2018/11/21)
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- Synthesis of Nitriles from Primary Amides or Aldoximes under Conditions of a Catalytic Swern Oxidation
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The preparation of nitriles from primary amides or aldoximes was achieved by using oxalyl chloride with a catalytic amount of dimethyl sulfoxide in the presence of Et3N. The reactions were complete within 1 h after addition at room temperature. A diverse range of cyano compounds were obtained in good to excellent yields, including aromatic, heteroaromatic, cyclic, and acyclic aliphatic species.
- Ding, Rui,Liu, Yongguo,Han, Mengru,Jiao, Wenyi,Li, Jiaqi,Tian, Hongyu,Sun, Baoguo
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p. 12939 - 12944
(2018/10/20)
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- Preparation technology for 3-aryl-4-nitro isoxazole compound
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The invention discloses a preparation technology for a 3-aryl-4-nitro isoxazole compound. The preparation technology comprises the following steps: synthesizing a compound shown as formula II through the nucleophilic addition of hydroxylamine hydrochloride and the compound shown as formula I used as the raw material; acquiring the compound shown as formula III through the substitution reaction of the compound shown as formula II and N-chlorosuccinimide; preparing 1-dimethyl amino-2-nitro ethylene through the reaction of N,N-dimethylformamide dimethyl acetal and nitromethane used as the raw material; and acquiring a target product 3-aryl-4-nitro isoxazole compound through the cyclization reaction of the compound shown as formula III and 1-dimethyl amino-2-nitro ethylene. The raw materials in the synthesis route are low in cost and easily acquired, the operation condition is mild and is easily controlled, the product is easily purified and the preparation technology is a new method for synthesizing the 3-aryl-4-nitro isoxazole compound.
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Paragraph 0036; 0037
(2018/03/01)
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- Dimeric isoxazolyl-1,4-dihydropyridines have enhanced binding at the multi-drug resistance transporter
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A series of dimeric isoxazolyl-1,4-dihydropyridines (IDHPs) were prepared by click chemistry and examined for their ability to bind the multi-drug resistance transporter (MDR-1), a member of the ATP-binding cassette superfamily (ABC). Eight compounds in t
- Steiger, Scott A.,Li, Chun,Backos, Donald S.,Reigan, Philip,Natale
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supporting information
p. 3223 - 3234
(2017/05/29)
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- Catalytic Enantioselective [3 + 2] Cycloaddition of α-Keto Ester Enolates and Nitrile Oxides
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An enantioselective [3 + 2] cycloaddition reaction between nitrile oxides and transiently generated enolates of α-keto esters has been developed. The catalyst system was found to be compatible with in situ nitrile oxide-generation conditions. A versatile array of nitrile oxides and α-keto esters could participate in the cycloaddition, providing novel 5-hydroxy-2-isoxazolines in high chemical yield with high levels of diastereo- and enantioselectivity. Notably, the optimal reaction conditions circumvented concurrent reactions via O-imidoylation and hetero-[3 + 2] pathways.
- Bartlett, Samuel L.,Sohtome, Yoshihiro,Hashizume, Daisuke,White, Peter S.,Sawamura, Miki,Johnson, Jeffrey S.,Sodeoka, Mikiko
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supporting information
p. 8661 - 8666
(2017/07/06)
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- Alkyl Nitrites: Novel Reagents for One-Pot Synthesis of 3,5-Disubstituted Isoxazoles from Aldoximes and Alkynes
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An efficient, one-pot approach has been described for the synthesis of 3,5-disubstituted isoxazoles from substituted aldoximes (mixture of E and Z) and alkynes, using alkyl nitrites under conventional heating conditions. The key nitrile oxide intermediates that are required for the synthesis of isoxazoles are formed by treatment of substituted aldoxime with either tert-butyl nitrite or isoamyl nitrite. The generated nitrile oxides underwent in situ [3+2] dipolar cycloaddition to the substituted alkynes to give 3,5-disubstituted isoxazoles regioselectively in high to excellent yields. The developed synthetic methodology was applied for the synthesis of a previously reported potent hDGAT1 inhibitor.
- Kadam, Kishorkumar S.,Gandhi, Thirumanavelan,Gupte, Amol,Gangopadhyay,Sharma, Rajiv
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p. 3996 - 4008
(2016/11/11)
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- Cu(I) catalyzed microwave assisted telescopic synthesis of 3,5-disubstituted isoxazoles in green media
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A facile and efficient microwave assisted telescopic synthesis of diverse isoxazoles was reported in green reaction medium. Initially, N-hydroxyl imidoyl chlorides were reacted with substituted alkynes in aqueous medium using 2 mol% of [Cu(phen)(PPh3
- Meena,Maiti, Barnali,Chanda, Kaushik
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p. 5514 - 5517
(2016/11/19)
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- Synthesis of Novel 3-aryl-1-oxa-2,8-diazaspiro[4.5]dec-2-ene Derivatives and Their Biological Evaluation Against Protein Tyrosine Phosphatase 1B
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A series of novel 3-aryl-1-oxa-2,8-diazaspiro[4.5]dec-2-ene derivatives were designed, synthesized, and evaluated as a new class of inhibitors against protein tyrosine phosphatase 1B. Among them, compound 6f displayed moderate inhibitory activity with IC50 of 2.87 ± 0.24 μm and can be used as a novel lead compound for the design of inhibitors of protein tyrosine phosphatase 1B. A series of novel 3-aryl-1-oxa-2,8-diazaspiro[4.5]dec-2-ene derivatives were designed, synthesized, and evaluated as a new class of inhibitors against PTP1B. Among them, compound 6f displayed moderate inhibitory activity with IC50 of 2.87 ± 0.24 μm and can be used as a novel lead compound for the design of inhibitors of PTP1B.
- Wang, Wen-Long,Chen, Xia,Gao, Li-Xin,Sheng, Li,Li, Jing-Ya,Li, Jia,Feng, Bainian
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p. 1161 - 1167
(2015/10/28)
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- Enantioselective synthesis of diaryl aziridines using tetrahydrothiophene- based chiral sulfides as organocatalysts
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This work describes catalytic and asymmetric aziridinations (15 examples, 95-98% ee) of benzyl bromide and imines via the imino Corey-Chaykovsky reaction using (thiolan-2-yl)diarylmethanol benzyl ether as an organocatalyst. The catalyst and analogues thereof were prepared through an expeditious and efficient synthetic route featuring a double nucleophilic substitution and Shi epoxidation as key steps.
- Huang, Meng-Ting,Wu, Hsin-Yi,Chein, Rong-Jie
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supporting information
p. 1101 - 1103
(2014/01/17)
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- One-pot synthesis of isoxazolines from aldehydes catalyzed by iodobenzene
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A convenient one-pot, three-step procedure for the synthesis of isoxazolines starting from aldehydes has been developed involving catalytic cycloaddition between nitrile oxides and alkenes, in which iodobenzene is used as the catalyst for the in situ generation of a hypervalent iodine intermediate. In this approach, the aldehydes are first transformed with hydroxylamine sulfate into aldoximes, which are then oxidized to nitrile oxides by the in situ generated hypervalent iodine intermediate; finally, a 1,3-dipolar cycloaddition between the nitrile oxides and alkenes occurs to provide the isoxazolines in moderate to good yields.
- Han, Liuquan,Zhang, Bijun,Xiang, Changbin,Yan, Jie
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p. 503 - 509
(2014/03/21)
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- Formation of C-O bond via cross-dehydrogenative coupling between isochroman and oxime under metal-free oxidation conditions
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DDQ-mediated C-O bond formation through cross-dehydrogenative coupling (CDC) reaction without any metal catalyst under mild conditions was developed. Series of isochromans and oximes could be employed as substrates, and the products were obtained in good yields. Georg Thieme Verlag Stuttgart New York.
- He, Hua-Feng,Wang, Kai,Xing, Bo,Sheng, Guorong,Ma, Tingxuan,Bao, Weiliang
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supporting information
p. 211 - 214
(2013/03/13)
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- Highly selective and efficient lewis acid-base catalysts based on lanthanide-containing polyoxometalates for oximation of aldehydes and ketones
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Two lanthanide-containing polyoxometalates (POMs) have been developed as Lewis acid-base catalysts for highly selective and efficient oximation of various aldehydes and ketones under mild conditions. Copyright
- Zhao, Shen,Huang, Lujiang,Song, Yu-Fei
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p. 1659 - 1663
(2013/05/09)
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- Orthogonal aerobic conversion of N-benzyl amidoximes to 1,2,4-oxadiazoles or quinazolinones
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Concise synthesis of 1,2,4-oxadiazoles was achieved by heating N-benzyl amidoximes with K3PO4 in DMF at 60°C under an O 2 atmosphere via benzylic C-H oxygenation. On the other hand, aerobic treatment of N-benzyl amidoximes
- Zhang, Feng-Lian,Wang, Yi-Feng,Chiba, Shunsuke
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supporting information
p. 6003 - 6007
(2013/09/12)
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- Synthesis of benzisoxazoles by the [3 + 2] cycloaddition of in situ generated nitrile oxides and arynes
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"Chemical Equation Presented" A variety of substituted benzisoxazoles has been prepared by the [3 + 2] cycloaddition of nitrile oxides and arynes. Both components, being highly reactive intermediates, have been generated in situ by fluoride anion from readily prepared aryne precursors and chlorooximes, The reaction scope is quite general, affording a novel, direct route to functionalized benzisoxazoles under mild reaction conditions
- Dubrovskiy, Anton V.,Larock, Richard C.
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supporting information; experimental part
p. 1180 - 1183
(2010/05/02)
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- Significant self-acceleration effects of nitrile additives in the rhodium-catalyzed conversion of aldoximes to amides: A New mechanistic aspect
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It was found that the catalytic activity of rhodium complexes was highly sensitive to the type of N-heterocyclic carbene (NHC) ligands in the conversion of aldoximes to amides. Among those species examined, the (cyclooctadiene) rhodium chloride-carbene complex Rh(cod)(IMes)Cl exhibited the highest reactivity when it was employed in combination with a Bronsted acid, thus allowing mild reaction conditions. A significant rate acceleration effect resulting from the addition of nitrile additives was also observed. With the new protocol, the substrate scope of aldoximes has been widely expanded to include sterically congested and electronically varied derivatives. On the basis of detailed mechanistic studies, it is proposed that the reaction proceeds mainly via intramolecular electrophilic addition of aldoxime to rhodium-bound nitrile, which is different from the generally postulated two-step route: dehydration of aldoxime to nitrile followed by hydration of the latter intermediate.
- Kim, Min,Lee, Jinwoo,Lee, Hee-Yoon,Chang, Sukbok
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supporting information; experimental part
p. 1807 - 1812
(2011/02/25)
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- Concise synthesis and antimicrobial activities of new substituted 5-isoxazolpenicillins
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The synthesis of a series of new 5-isoxazolpenicillins is described, which were obtained by coupling substituted isoxazoles with 6-APA. Concise large-scale synthesis of 3,5-disubstituted isoxazoles by 1,3-dipolar cycloaddition using copper(I) as catalyst was also investigated. Representative compounds were assayed for antimicrobial activities, showing satisfactory antimicrobial activities against Gram-negative bacteria.
- Wang, Xi-Zhao,Jia, Jiong,Zhang, Yan,Xu, Wei-Ren,Liu, Wei,Shi, Fang-Niu,Wang, Jian-Wu
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p. 643 - 652
(2008/03/11)
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- One-pot copper(I)-catalyzed synthesis of 3,5-disubstituted isoxazoles
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3,5-Disubstituted isoxazoles are obtained in good yields by a convenient one-pot, three-step procedure utilizing a regioselective copper(I)-catalyzed cycloaddition reaction between in situ generated nitrile oxides and terminal acetylenes. Most functional
- Hansen, Trond V.,Wu, Peng,Fokin, Valery V.
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p. 7761 - 7764
(2007/10/03)
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- Solid-phase synthesis of oximes
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In an extremely fast, high efficient and novel method, the reaction of hydroxylamine hydrochloride with a number of aldehydes and ketones under solventless 'dry' condition gave oximes in quantitative yield.
- Hajipour,Mohammadpoor-Baltork,Nikbaghat,Imanzadeh
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p. 1697 - 1701
(2007/10/03)
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- Herbicidal 3-isoxazolidinones and hydroxamic acids
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Novel 3-isoxazolidinone compounds and novel hydroxamic acid intermediates from which they are prepared exhibit herbicidal activity to grassy and broad-leaf plant species while leaving legumes, especially soybeans, unaffected. The preparation and herbicidal activity of the compounds is exemplified.
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