- Oxime esters of anthraquinone as photo-induced DNA-cleaving agents for single- and double-strand scissions
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Anthraquinone-O-9-(4-cyanobenzoyl)oxime (13) with binding constant of 4.49×104 M-1 exhibited single-strand scission of DNA at the concentration of 10 μM and double-strand scission at 50 μM upon UV irradiation.
- Hwu, Jih Ru,Tsay, Shwu-Chen,Hong, Shih Chin,Leu, Yi-Jing,Liu, Chih-Fen,Chou, Shang-Shing P.
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Read Online
- Nickel-Catalyzed NO Group Transfer Coupled with NOxConversion
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Nitrogen oxide (NOx) conversion is an important process for balancing the global nitrogen cycle. Distinct from the biological NOx transformation, we have devised a synthetic approach to this issue by utilizing a bifunctional metal catalyst for producing value-added products from NOx. Here, we present a novel catalysis based on a Ni pincer system, effectively converting Ni-NOx to Ni-NO via deoxygenation with CO(g). This is followed by transfer of the in situ generated nitroso group to organic substrates, which favorably occurs at the flattened Ni(I)-NO site via its nucleophilic reaction. Successful catalytic production of oximes from benzyl halides using NaNO2 is presented with a turnover number of >200 under mild conditions. In a key step of the catalysis, a nickel(I)-?NO species effectively activates alkyl halides, which is carefully evaluated by both experimental and theoretical methods. Our nickel catalyst effectively fulfills a dual purpose, namely, deoxygenating NOx anions and catalyzing C-N coupling.
- Padmanaban, Sudakar,Choi, Jonghoon,Vazquez-Lima, Hugo,Ko, Donghwi,Yoo, Dagyum,Gwak, Jinseong,Cho, Kyung-Bin,Lee, Yunho
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supporting information
p. 4585 - 4593
(2022/03/02)
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- Novel phenanthridine amide analogs as potential anti-leishmanial agents: In vitro and in silico insights
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In the current work, sixteen novel amide derivatives of phenanthridine were designed and synthesized using 9-fluorenone, 4-Methoxy benzyl amine, and alkyl/aryl acids. The characterization of the title compounds was performed using LCMS, elemental analysis, 1HNMR, 13CNMR and single crystal XRD pattern was also developed for compounds A8. All the final analogs were screened in vitro for anti-leishmanial activity against promastigote form of L. infantum strain. Among the tested analogs, four compounds (A-06, A-11, A-12, and A-15) exhibited significant anti-leishmanial activity with EC50 value ranges from 8.9 to 21.96 μM against amastigote forms of tested L. infantum strain with SI ranges of 1.0 to 4.3. From the activity results it was found that A-11 was the most active compound in both promastigote and amastigotes forms with EC50 values 8.53 and 8.90 μM respectively. In-silico ADME prediction studies depicted that the titled compounds obeyed Lipinski's rule of five as that of the approved marketed drugs. The predicted in-silico toxicity profile also confirmed that the tested compounds were non-toxic. Finally, molecular docking and molecular dynamics study was also performed for significantly active compound (A-11) in order to study it's putative binding pattern at the active site of the selected leishmanial trypanothione reductase target as well as to understand the stability pattern of target-ligand complex for 100 ns. Single crystal XRD of compound A-08 revealed that the compound crystallizes in monoclinic C2/c space group and showed interesting packing arrangements.
- Aggarwal, Himanshu,Bala?a-Fouce, Rafael,Chandra Sekhar, Kondapalli Venkata Gowri,Karan Kumar, Banoth,Melcón-Fernandez, Estela,Murugesan, Sankaranarayanan,Nandikolla, Adinarayana,Pérez-Pertejo, Yolanda,Srinivasarao, Singireddi
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supporting information
(2021/11/01)
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- Synthesis of hydroxyethyl methyl morpholinium azide (HEM Morph)N3: A highly efficient new task specific azide-based ionic liquid and its dual application as an azide source and media for synthesis of some novel aromatic O-oxime ethers-1,2,3-triazole conjugates as a potential antihistaminic agents
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The synthesis, characterization and application of hydroxyethyl methyl morpholinium azide (HEM Morph)N3 as a new azide-based ionic liquid (ABIL) has been described. (HEM Morph)N3 is used as a source of azide and reaction media for three components ‘Click’ Huisgen cycloaddition reaction between O-propargyl oxime ether and alkyl bromide to acquire novel aromatic O-oxime ethers-1,2,3-triazole conjugates as potential antihistaminic agents in good yields. The influence of parameters like temperature, amount of IL, type of azide-based ionic liquids and its reusability is investigated. The (HEM Morph)N3 is proved to be an efficient, thermally stable, inexpensive and recyclable azide-based ionic liquid which can be easily synthesized and used as both azide's source and reaction media for ‘Click’ Huisgen cycloaddition reaction.
- Rad, Mohammad Navid Soltani,Behrouz, Somayeh,Saremi, Hossein,Mohammadtaghi-Nezhad, Javad
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- Arylboronic Acid-Catalyzed C-Allylation of Unprotected Oximes: Total Synthesis of N-Me-Euphococcine
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O-Unprotected keto-and aldoximes are readily C-allylated with allyl diisopropyl boronate in the presence of arylboronic acid catalysts to yield highly substituted N-α-secondary and tertiary homoallylic hydroxylamines. The method was used in the total synthesis of the trace alkaloid N-Me-Euphococcine.
- Kürti, László,Kattamuri, Padmanabha V.,Siitonen, Juha H.,Yousufuddin, Muhammed
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supporting information
(2020/03/24)
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- Access to Cyanoimines Enabled by Dual Photoredox/Copper-Catalyzed Cyanation of O-Acyl Oximes
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An efficient strategy for the synthesis of pharmaceutically important and synthetically useful cyanoimines, as well as cyanamides, has been described. This strategy is enabled by dual photoredox/copper-catalyzed cyanation of O-acyl oximes or O-acyl hydroxamides. This state of the art protocol for cyanoimines and cyanamides features readily available starting materials, mild reaction conditions, good functional group tolerance, and operational simplicity. The resultant cyanoimines can be transformed into structurally diverse and functionally important N-containing heterocycles.
- Wei, Ziyan,Yu, Shouyun,Zhang, Ai Hua,Zhang, Hao
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supporting information
p. 7315 - 7320
(2020/10/02)
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- The impact of cation structure upon the acidity of triazolium salts in dimethyl sulfoxide
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A series of triazolium salts, selected for their varying electronic and steric properties, were prepared and their pKa values were determined in DMSO at 25 °C using the bracketing indicator method. The effect of each systematic structural variation upon the acidity of the triazolium cation has been considered, in particular examining the effects of systematically altering electronic properties, quantified through the use of Hammett σ parameters. The first pKa value for an azolium salt that generates a mesionic carbene is also reported. These new data allow for the selection of appropriate bases for the deprotonation of such triazolium salts and the potential to correlate the pKa values determined herein with the nucleophilicity of the corresponding carbenes.
- Konstandaras, Nicholas,Dunn, Michelle H.,Guerry, Max S.,Barnett, Christopher D.,Cole, Marcus L.,Harper, Jason B.
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supporting information
p. 66 - 75
(2019/12/26)
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- Application of phenanthridine compounds to pesticides
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The invention relates to an application of phenanthridine compounds shown in general formula (1) to pesticides. Part of the compounds is used as a plant virus agent and can well inhibit the tobacco mosaic virus; when used as a bactericide, the compounds have good inhibitory activity on tomato early blight, wheat scab, potato late blight, phytophthora capsici, rape sclerotinia rot, cucumber gray mould, rice sheath blight disease, cucumber fusarium wilt, cercospora brown spot of peanut, apple ring rot, wheat sharp eyespot, corn southern leaf blight, watermelon anthracnose and rice bakanae disease; when used as an insecticide, the compounds have poisonous activity on armyworms, mosquito larvae, cotton bollworms, ostrinia nubilalis, aphids, adult mites and plutella xylostella. In the formula,when molecular nitrogen is not imine, R can represent hydrogen atoms, methyl, acetyl and benzoyl; R and R represent a hydrogen atom or an oxygen atom simultaneously; R and R can represent hydroxyl, acetoxyl, methoxyl, methyleneoxy, a fluorine atom and the hydrogen atom; R is a bromine atom or the fluorine atom; R is the hydrogen atom or vinyl. When nitrogen is imine, R doesnot represent any group; one of R and R does not represent any group, and the other can represent the hydrogen atom, methoxyl, ethyoxyl, benzyloxy and a chlorine atom; R, R, R and Rrepresent the hydrogen atom.
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Paragraph 0020; 0029; 0030
(2019/10/01)
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- Copper(ii)-promoted direct conversion of methylarenes into aromatic oximes
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A simple and efficient catalytic system for direct conversion of methylarenes into aromatic oximes has been developed, with Cu(OAc)2 as catalyst, NHPI (N-Hydroxyphthalimide) as additive, TBN (tert-butyl nitrite) as both the nitrogen source and the oxidant. This process proceeds under mild conditions, tolerates a wide range of substrates, affording the targeted aromatic oximes in 63-86% yields.
- Yu, Jiatao,Lu, Ming
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supporting information
p. 7397 - 7401
(2015/07/15)
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- Copper(II)-promoted direct conversion of methylarenes into aromatic oximes
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A simple and efficient catalytic system for direct conversion of methylarenes into aromatic oximes has been developed, with Cu(OAc)2 as catalyst, NHPI (N-Hydroxyphthalimide) as additive, TBN (tert-butyl nitrite) as both the nitrogen source and the oxidant. This process proceeds under mild conditions, tolerates a wide range of substrates, affording the targeted aromatic oximes in 63-86% yields.
- Yu, Jiatao,Lu, Ming
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supporting information
p. 7397 - 7401
(2015/11/27)
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- Synthesis of oximes from the corresponding of organic carbonyl compounds with NH2 OH.HCl and oxalic acid
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The oximation of a variety of aldehydes and ketones was carried out with NH2 OH?HCl in the presence of oxalic acid as catalyst under reflux conditions. The reactions were performed in CH3 CN with excellent yields(90-95%) of products in appropriate times (55-90 min).
- Ghozlojeh, Negin Piri,Setamdideh, Davood
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p. 1823 - 1825
(2016/01/25)
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- Identification, synthesis and pharmacological evaluation of novel anti-EV71 agents via cyclophilin A inhibition
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In this work, the relationship between cyclophilin A (CypA) and EV71 prompted us to screen a series of small molecular CypA inhibitors which were previously reported by our group. Among them, compounds 1 and 2 were discovered as non-immunosuppressive anti-EV71 agents with an EC50 values of 1.07 ± 0.17 μM and 3.36 ± 0.45 μM in virus assay, respectively, which were desirably for the further study. The subsequent chemical modifications derived a novel class of molecules, among which compound 11 demonstrated the most potent anti-EV71 activity in virus assay (EC50 = 0.37 ± 0.17 μM), and low cytotoxicity (CC50 > 25 μM). The following CypA enzyme inhibition studies indicated that there was not only the enzyme inhibition activity, undoubtedly important, functioning in the antiviral process, but also some unknown mechanisms worked in combination, and the further study is underway in our laboratory. Nevertheless, to the best of our knowledge, compound 11 was probably the most potent small molecular anti-EV71 agent via CypA inhibitory mechanism to date. Consequently, our study provided a new potential small molecule for curing EV71 infection.
- Yan, Wenzhong,Qing, Jie,Mei, Hanbing,Nong, Junxiu,Huang, Jin,Zhu, Jin,Jiang, Hualiang,Liu, Lei,Zhang, Linqi,Li, Jian
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supporting information
p. 5682 - 5686
(2015/11/24)
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- Novel amide and sulphonamide derivatives of 6-(piperazin-1-yl)phenanthridine as potent Mycobacterium tuberculosis H37Rv inhibitors
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A series of thirty three novel 6-(piperazin-1-yl)phenanthridine amide and sulphonamide analogues were synthesized, characterized and screened for their in vitro antimycobacterial activity against Mycobacterium tuberculosis (MTB) H37Rv strain. These compounds exhibited minimum inhibitory concentration (MIC) between >56 and 50 μg/mL. Out of these derivatives, few compounds 6l, 6r, 7b, 7f, 7g and 7k exhibited moderate activity (MIC = 6.25 μg/mL) and compounds 6b, 6e, 6k, 6n, 7h, 7i and 7n displayed good activity (MIC = 3.13 μg/mL), whereas compounds 6m, 6s and 7d exhibited excellent anti-tubercular activity (MIC = 1.56 μg/mL). In addition, MTT assay was accomplished on the active analogues of the series against mouse macrophage (RAW 264.7) cells to evaluate the toxicity profile of the newly synthesized compounds and selectivity index of the compounds was determined. Additionally, compounds 6b and 7d were docked to the ATPase domain of M. tuberculosis GyrB protein to know the interaction profile and structures of compounds 6b and 7d were further substantiated through single crystal XRD.
- Naidu, Kalaga Mahalakshmi,Nagesh, Hunsur Nagendra,Singh, Manjeet,Sriram, Dharmarajan,Yogeeswari, Perumal,Sekhar, Kondapalli Venkata Gowri Chandra
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p. 415 - 426
(2015/03/05)
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- An eco-friendly system for oximation of organic carbonyl compounds under microwave irradiation
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The oximation of a variety of organic carbonyl compounds was efficiently carried out with NH2OH?HCl under microwave irradiation. The reactions were performed in water or water-ethanol as green solvents to give Z-aldoxime isomers from the corresponding aldehydes and E-ketoxime isomers from the corresponding ketones in a perfect selectively with excellent yields.
- Batmani, Hana,Setamdideh, Davood
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p. 699 - 703
(2015/01/16)
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- Synthesis and evaluation of anti-tubercular activity of 6-(4-substitutedpiperazin-1-yl) phenanthridine analogues
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A series of seventeen new 6-(4-substitutedpiperazin-1-yl)phenanthridine derivatives were designed, synthesized, and evaluated for their anti-tubercular activity against Mycobacterium tuberculosis H37Rv by Microplate Alamar Blue Assay and most active compounds were tested for cytotoxicity studies against mouse macrophage cell lines (RAW264.7). Among the tested compounds, ten compounds exhibited significant activity against the growth of M.tuberculosis (MIC ranging from 1.56 to 6.25 μg/mL). In particular, compounds 5e, 5j and 5k displayed excellent activity against the growth of M.tuberculosis (MIC 1.56 μg/mL). The selectivity index values were found to be >25, indicating compounds likeliness in drug development for tuberculosis. The structure of 5k is substantiated by X-ray crystallographic study. Structure-activity correlation indicates the importance of substituent at 4th position of piperazinyl phenanthridine ring.
- Nagesh, Hunsur Nagendra,Suresh, Narva,Mahalakshmi Naidu, Kalaga,Arun, Boyineni,Padma Sridevi, Jonnalagadda,Sriram, Dharmarajan,Yogeeswari, Perumal,Sekhar, Kondapalli Venkata Gowri Chandra
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p. 333 - 339
(2014/02/14)
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- Synthesis of fluorene and/or benzophenone O-oxime ethers containing amino acid residues and study of their cardiovascular and antibacterial effects
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The syntheses and biological studies of O -oxime ethers having α-amino acid residues as new analogs of IPS-339 have been described. In this synthesis, the reaction of fluorene and/or benzophenone O-oxime with epichlorohydrin or epibromohydrin afforded the corresponding O-oxime ether adducts. The N-alkylation of amino acid with O-oxime ether adducts led to synthesis of new analogs of IPS-339. The products were examined for their cardiovascular property. It was demonstrated that 2-(3-(9H-fluoren-9- ylideneaminooxy)-2-hydroxypropylamino)-3-methyl-butanoic acid as the most potent compound substantially reduces the heart rate of dogs. Compounds were also evaluated for their in vitro antibacterial activity against some Gram-negative and Gram-positive bacteria. The antibacterial screening proved the considerable antibacterial activity against both groups of bacteria. The docking analysis demonstrated the appropriate fitting of 2-(3-(9H-fluoren-9-ylideneaminooxy)-2- hydroxy-propylamino)-3-methyl-butanoic acid in human β2- adrenergic receptor active site. Potential drug toxicity for some active compounds has also been predicted. Springer Science+Business Media 2014.
- Soltani Rad, Mohammad Navid,Behrouz, Somayeh,Zarenezhad, Elham,Moslemin, Mohammad Hossein,Zarenezhad, Ali,Mardkhoshnood, Mehdi,Behrouz, Marzieh,Rostami, Saeid
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p. 3810 - 3822
(2014/08/05)
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- CATALYST FOR OLEFIN POLYMERIZATION, METHOD FOR ITS PREPARATION AND USE THEREOF
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The invention relates to a catalyst for olefin polymerization represented by the general formula (1): wherein; M is a transition metal; X1 and X2 are independently selected from the group consisting of halide, alkyl group, aryl group, alkyl amine group, or alkyl aryl group, and are directly bond to M, R1 and R2 are independently selected from the group consisting of hydrogen, alkyl group or aryl group; and Cp is a cyclopentadienyl group.
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Paragraph 0037; 0038
(2015/01/07)
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- Catalyst for olefin polymerization, method for its preparation and use thereof
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The invention relates to a catalyst for olefin polymerization represented by the general formula (I): ???????? R1R2C=N-OMCPX1X2 wherein; M is a transition metal; X1 and X2 are independently selected from the group consisting of halide, alkyl group, aryl group, alkyl amine group, or alkyl aryl group, and are directly bond to M, R1 and R2 are independently selected from the group consisting of hydrogen, alkyl group or aryl group; and Cp is a cyclopentadienyl group.
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Paragraph 0037; 0038
(2015/01/18)
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- Design, synthesis and evaluation of 6-(4-((substituted-1H-1,2,3-triazol-4- yl)methyl)piperazin-1-yl)phenanthridine analogues as antimycobacterial agents
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Focus in this Letter is made to design and synthesize a series of nineteen new 6-(4-((substituted-1H-1,2,3-triazol-4-yl)methyl)piperazin-1-yl) phenanthridine analogues employing click chemistry and evaluated for their anti-tubercular activity against Mycobacterium tuberculosis H37Rv. Among the tested compounds, 7f and 7j exhibited good activity (MIC = 3.125 μg/mL), while 8a displayed excellent activity (MIC = 1.56 μg/mL) against the growth of M. tuberculosis H37Rv. In addition, 7f, 7j and 8a compounds were subjected to cytotoxic studies against mouse macrophage (RAW264.7) cell lines and the selectivity index values are >15 indicating suitability of compounds for further drug development.
- Nagesh, Hunsur Nagendra,Naidu, Kalaga Mahalakshmi,Rao, Damarla Harika,Sridevi, Jonnalagadda Padma,Sriram, Dharmarajan,Yogeeswari, Perumal,Chandra Sekhar, Kondapalli Venkata Gowri
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p. 6805 - 6810
(2014/01/06)
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- Relationship between structure of conjugated oxime esters and their ability to cleave DNA
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The size and geometry of polycycles are critical to intercalation into DNA. This work involves the establishment of a new compound library that includes 35 O-benzoyl oxime esters with intercalators of five types. These conjugated compounds were synthesized by the condensation of substituted benzoyl chlorides (XC6H4COCl; X = H, Me, CN, F, and NO2) or naphthoyl chlorides with oximes of fluoren-9-one, 9,10-anthraquinone, xanthen-9-one, thioxanthen-9-one, and 9H-thioxanthen-9-one 10,10-dioxide to give the corresponding esters in 80-99% yields. All of these compounds could cleave DNA when photolyzed by UV light. Of these conjugates, 9,10-anthraquinone-O-9-(4- fluorobenzoyl)oxime with a binding constant of 4.49 × 104 M-1 cleaved DNA most efficiently. Examination of the structure-activity relationship supports a conclusion that two factors affect DNA-cleaving potency. These are (1) the planarity of the intercalating moiety, and (2) the size and substituents of the benzoyl ring. The DNA-cleaving ability followed the order 9,10-anthraquinone > fluoren-9-one ≥ xanthen-9-one ~ thioxanthen-9-one > 9H-thioxanthen-9-one 10,10-dioxide. The benzoyl-containing oxime ester conjugates were more active than the corresponding naphthoyl-containing conjugates. The potency that was associated with the different substituents on the benzoyl ring followed the order F > CN ≥ NO2 > Me ~ H.
- Hwu, Jih Ru,Tsay, Shwu-Chen,Hong, Shih Chin,Hsu, Ming-Hua,Liu, Chih-Fen,Chou, Shang-Shing P.
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p. 1778 - 1783
(2014/01/06)
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- Synthesis of oximes with NH2OH.HCl/DOWEX(R)50WX4 system
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The oximation of a variety of carbonyl compounds was efficiently carried out with DOWEX(R)50WX4/NH2OH·HCl system. The reactions were performed in ethanol to give Z-aldoximation isomers of aldehydes and E-oximaton of acetophenone derivatives in a perfect selectively. The oximation of compounds with two carbonyl groups was carried out selectively on one carbonyl moiety. Also, the oximation of aldehydes over ketones has been accomplished successfully by this system.
- Setamdideh, Davood,Khezri, Behrooz,Esmaeilzadeh, Seyran
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p. 1119 - 1124
(2012/10/30)
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- 'Click synthesis' of some novel o-substituted oximes containing 1,2,3-triazole-1,4-diyl residues as new analogs of β-adrenoceptor antagonists
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The 'click synthesis' of some novel O-substituted oximes, 7a-7t, which contain 1,2,3-triazolediyl residues, as new analogs of β-adrenoceptor antagonists is described (Schemes 1-4). The synthesis of these compounds was achieved in four to five steps. The formation of oximes of 9H-fluoren-9-one and benzophenone, i.e., 9a and 9b, respectively, followed by their reaction with propargyl bromide, afforded O-propargyl oximes 10a and 10b, respectively, which by a subsequent CuI-catalyzed Huisgen cycloaddition with prepared β-azido alcohols 11a-11j (Schemes 2 and 3), led to the target compounds 7a-7t in good yields. Copyright
- Rad, Mohammad Navid Soltani,Behrouz, Somayeh,Karimitabar, Fatemeh,Khalafi-Nezhad, Ali
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experimental part
p. 491 - 501
(2012/05/04)
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- Synthesis OF 5,6-dihydrophenanthridine (DHPA) sulfonamides and subsequent acid-catalyzed rearrangement to diaryl sulfones
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As part of an ongoing investigation into the rearrangement of cyclic aryl aminesulfonanilides to diarylsulfones, a series of novel 5,6- dihydrophenanthridine (DHPA) sulfonamides were synthesized. Acid catalysts were used to rearrange them to DHPA arylsulfones. Taylor & Francis Group, LLC.
- Marie, Lisa,Meseroll, Neuls,McKee, James R.,Zanger, Murray
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experimental part
p. 2557 - 2568
(2011/08/07)
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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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experimental part
p. 627 - 636
(2010/04/29)
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- An efficient one-pot synthesis of oxime ethers from alcohols using triphenylphosphine/carbon tetrachloride
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A convenient and efficient one-pot O-alkylation of oximes from alcohols using triphenylphosphine in carbon tetrachloride is described. In this method, treatment of alcohols with a mixture of triphenylphosphine, carbon tetrachloride, oxime, and DBU in the presence of catalytic amounts of tetrabutylammonium iodide in refluxing acetonitrile regioselectively furnishes the corresponding O-alkyl ethers in good yields. This methodology is highly efficient O-alkylation of oximes with various structurally diverse alcohols. Semiempirical quantum-mechanic calculations (AM1) for unsymmetrical oxime ethers, indicated a lower heat of formation for Z-isomers. Georg Thieme Verlag Stuttgart - New York.
- Soltani Rad, Mohammad Navid,Khalafi-Nezhad, Ali,Karimitabar, Fatemeh,Behrouz, Somayeh
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experimental part
p. 1724 - 1730
(2010/07/08)
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- Regiospecific synthesis of unsubstituted basic skeletons of heterocycles containing nitrogen neighboring an aromatic ring by the reductive ring expansion reaction using diisobutylaluminum hydride
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A systematic investigation of reductive ring expansion reaction of oximes with diisobutylaluminum hydride (DIBAH) was performed. The reaction regiospecifically provided a variety of unsubstituted bicyclic heterocycles 3a-3g or tricyclic heterocycles 3h, 3j-3l that contained nitrogen attached to an aromatic ring.
- Cho, Hidetsura,Iwama, Yusuke,Sugimoto, Kenji,Kwon, Eunsang,Tokuyama, Hidetoshi
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experimental part
p. 1183 - 1190
(2009/11/30)
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- Discovering potent small molecule inhibitors of cyclophilin A using de novo drug design approach
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This work describes an integrated approach of de novo drug design, chemical synthesis, and bioassay for quick identification of a series of novel small molecule cyclophilin A (CypA) inhibitors (1-3). The activities of the two most potent CypA inhibitors (3h and 3i) are 2.59 and 1.52 nM, respectively, which are about 16 and 27 times more potent than that of cyclosporin A. This study clearly demonstrates the power of our de novo drug design strategy and the related program LigBuilder 2.0 in drug discovery.
- Ni, Shuaishuai,Yuan, Yaxia,Huang, Jin,Mao, Xiaona,Lv, Maosheng,Zhu, Jin,Shen, Xu,Pei, Jianfeng,Lai, Luhua,Jiang, Hualiang,Li, Jian
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supporting information; experimental part
p. 5295 - 5298
(2010/02/28)
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- Generation and characterization of the selenocysteinyl radical: Direct evidence from time-resolved UV/Vis, electron paramagnetic resonance, and fourier transform infrared spectroscopy
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The selenocysteinyl radical 1 has been generated for the first time by laser flash photolysis (λexc = 266 nm) of dimethyl bis(N-tert-butoxycarbonyl)-L-selenocystine 2 and of [(9-fluorenylideneamino)- oxycarbonyl]methyl(N-tert-butoxycarbonyl)-L-selenocysteine 3 in acetonitrile and characterized by time-resolved (TR) UV/Vis, Fourier transform infrared (FTIR), and electron paramagnetic spectroscopy in combination with theoretical methods. A detailed product study was conducted using gas chromatography and one- and two-dimensional NMR spectroscopy. In the case of [(9-fluorenylideneamino) oxycarbonyl]methyl(N-tert-butoxycarbonyl)-L-selenocysteine 3, the (9-fluorenylideneamino)oxycarbonyl moiety serves as a photolabile protection group providing a caged selenocysteinyl radical suitable for biophysical applications. Cleavage of the diselenide bridge or the selenium-carbonyl bond by irradiation is possible in high quantum yields. Because of the lack of a good IR chromophore in the mid-IR region, the selenocysteinyl radical 1 cannot be monitored directly by TR FTIR spectroscopy. TR UV/Vis spectroscopy revealed the formation of the selenocysteinyl radical 1 from both precursors. The selenocysteinyl radical 1 has a lifetime τ ≈ 63 μs and exhibits a strong band located at λmax = 335 nm. Calculated UV absorptions of the selenocysteinyl radical (UB3LYP/6-311G(d,p)) are in good agreement with the experimental results. The use of TR UV/Vis spectroscopy permitted the determination of the decay rates of the selenocysteinyl radical in the presence of two quenchers. The product studies demonstrated the reversible photoreaction of dimethyl bis(N-tert-butoxycarbonyl) -L-selenocystine 2. Products of the photolysis of the caged selenocysteinyl radical precursor 3 are dimethyl bis(N-tert- butoxycarbonyl)-L-selenocystine 2, carbon dioxide, and some further smaller fragments. In addition, the photo-decomposition of the (9-fluorenylideneamino) oxycarbonyl moiety produced 9-fluorenone-oxime 4, 9-fluoren-imine 5, and 6 and 7 as products of the dimerization of two 9-fluorenoneiminoxy radicals 8.
- Kolano, Christoph,Bucher, Goetz,Schade, Olaf,Grote, Dirk,Sander, Wolfram
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p. 6609 - 6615
(2007/10/03)
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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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- Thermal decomposition of O-benzyl ketoximes; role of reverse radical disproportionation
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Thermolyses of seven dialkyl, two alkyl-aryl and two diaryl O-benzyl ketoxime ethers, R1R2C=NOCH2Ph, have been examined in three hydrogen donor solvents: tetralin, 9,10-dihydrophenanthrene, and 9,10-dihydroanthracene. All the oxime ethers gave the products expected from homolytic scission of both the O-C bond (viz., R1R2C=NOH and PhCH3) and N-O bond (viz., R1R2C=NH and PhCH2OH). The yields of these products depended on which solvent was used and the rates of decomposition of the O-benzyl oxime ethers were greater in 9,10-dihydrophenanthrene and 9,10-dihydroanthracene than in tetralin. These results indicated that a reverse radical disproportionation reaction in which a hydrogen atom was transferred from the solvent to the oxime ether, followed by β-scission of the resultant aminoalkyl radical, must be important in the latter two solvents. Benzaldehyde was found to be an additional product from thermolyses conducted in tetralin. This, and other evidence, indicated that another induced decomposition mode involving abstraction of a benzylic hydrogen atom, followed by β-scission of the resulting benzyl radical, became important for some substrates. Participation by minor amounts of enamine tautomers of the oxime ethers was shown to be negligible by comparison of thermolysis data for the O-benzyloxime of bicyclo[3.3.1]nonan-9-one, which cannot give an enamine tautomer, with that of the O-benzyloxime of cyclohexanone.
- Blake, Jessie A.,Ingold, Keith U.,Lin, Shuqiong,Mulder, Peter,Pratt, Derek A.,Sheeller, Brad,Walton, John C.
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p. 415 - 420
(2007/10/03)
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- Non-vertical energy transfer to oximes: Role of structural changes
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Energy transfer to aromatic ketone oximes can exhibit non-vertical behaviour depending on the planarity of ground state equilibrium geometry, a fact discussed in terms of structural changes of ground and triplet states.
- Lalevee,Allonas,Louerat,Fouassier,Tachi,Izumitani,Shirai,Tsunooka
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p. 2721 - 2722
(2007/10/03)
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- The Photochemistry of α,β-Unsaturated Nitro Compounds and Nitronic Acids. Concerning Deconjugation and α,β-Unsaturated Ketone Formation
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The photochemistry of cyclohexylidenenitromethane (6), 3-ethyl-2-nitropent-2-ene (7), (Z)-α-methyl-α'-nitrostilbene (12), (E)-3-methyl-1-nitro-1-phenylbut-1-ene (15) and 4,4-dimethyl-3-nitro-5α-cholest-2-ene (27) has been examined to determine the structural features required for deconjugation to the β,γ-unsaturated isomer.The mechanism of the light-induced formation of the corresponding α,β-unsaturated ketone, which may accompany deconjugation, has also been examined.Support for a scheme involving γ-hydrogen abstraction to give an unsaturated nitronic acid, followed by N-hydroxyoxaziridine formation and collapse to the ketone, is provided in the photochemistry of the stable nitronic acids, 4-t-butyl-aci-nitrocyclohexane (17) and 9-aci-nitrofluorene (18).Syntheses of the nitro olefins (6), (7), (12), (15) and (27), and the nitronic acid (17) are also reported.
- Grant, Richard D.,Pinhey, John T.,Rizzardo, Ezio,Smith, Geoffrey C.
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p. 1505 - 1519
(2007/10/02)
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- Ketene. Part 21. Reactions of Heterocumulenes with Nitrones
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Degradative and mass spectrometric evidence confirms the formation of the isoxazolidinones (2) from the reaction of cyano-t-butylketene with the N-alkyl nitrones (1), whilst the reaction with the N-phenyl nitrone (1d) gives the expected oxazolidinone (3b).Cyano-t-butylketene reacts with diphenyl nitrone to give the indolones (10a) and (10b).The reaction of phenyl isocyanate with diphenyl nitrone, and the N-alkyl nitrones (1a) and (1d) gives the normal 1,3-dipolar cycloadducts without rearrangement.Ethoxycarbonyl-t-butylketene reacts with the N-phenyl nitrone (1d) to give an oxazolidinone , but reaction with the N-alkyl nitrones (1) gives only fluorenone azine.This ketene reacts with diphenyl nitrone to give the anil (15) and the dihydroindole (16).
- Evans, Andrew R.,Hafiz, Mushtaq,Taylor, Giles A.
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p. 1241 - 1246
(2007/10/02)
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- Synthesis of β-blocking oximes. Influence of terminal amine on β-selectivity
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Three series of oximinopropanolamine derivatives in which the terminal nitrogen has been substituted by various arylalkyl groups were synthesized. The beta-adrenergic blocking activity of the 21 compounds was determined in vitro on the guinea-pig. The structure-activity relationship is discussed.
- Amlaiky,Leclerc,Decker,Schwartz
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p. 437 - 439
(2007/10/02)
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- Keten. Part 17. Addition Reactions of Ketens with N-Phenyl Nitrones
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The N-phenyl nitrones (1a), (4b), and (15) react with ketens in two totally different ways.Triphenylnitrone (4b) forms oxidolones (6) whereas (1a) and (15) form oxazolidinones (2) and (17).The differences appear to be caused by steric interactions in (1a) and (15) which distort the nitrone function and prevent the N-phenyl group adopting the conformation necessary for the oxindole-forming pathway.
- Hafiz, Mushtag,Taylor, Giles A.
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p. 1700 - 1705
(2007/10/02)
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