- Tris-(2-pyridylmethyl)amine-ligated Cu(II) 1,3-diketonate complexes: Anaerobic retro-Claisen and dehalogenation reactivity of 2-chloro-1,3-diketonate derivatives
-
We report synthetic, structural and reactivity investigations of tris-(2-pyridylmethyl)amine (TPA)-ligated Cu(ii) 1,3-diketonate complexes. These complexes exhibit anaerobic retro-Claisen type C-C bond cleavage reactivity which exceeds that found in analo
- Elsberg, Josiah G. D.,Anderson, Stephen N.,Tierney, David L.,Reinheimer, Eric W.,Berreau, Lisa M.
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p. 1712 - 1720
(2021/02/22)
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- A practical synthesis of α-bromo/iodo/chloroketones from olefins under visible-light irradiation conditions
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A practical synthesis of α-bromo/iodo/chloroketones from olefins under visible-light irradiation conditions has been developed. In the presence of PhI(OAc)2 as promoter and under ambient conditions, the reactions of styrenes and triiodomethane undergo the transformation smoothly to deliver the corresponding α-iodoketones without additional photocatalyst in good yields under sunlight irradiation. Meanwhile, the reactions of styrenes with tribromomethane and trichloromethane generate the desired α-bromoketones and α-chloroketones in high yields by using Ru(bpy)3Cl2 as a photocatalyst under blue LED (450–455 nm) irradiation.
- Wang, Zhihui,Wang, Lei,Wang, Zhiming,Li, Pinhua,Zhang, Yicheng
-
supporting information
p. 429 - 432
(2020/02/29)
-
- Facile Synthesis of α-Haloketones by Aerobic Oxidation of Olefins Using KX as Nonhazardous Halogen Source
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An operationally simple and safe synthesis of α-haloketones using KBr and KCl as nonhazardous halogen sources is reported. It involves an iron-catalysed reaction of alkenes with KBr/KCl using O2 as terminal oxidant under the irradiation of visible-light. This strategy avoids the risks associated with handling halo-contained electrophiles (Cl2, Br2, NCS, NBS). The process is tolerant to several functional groups, and extended to a range of substituted styrenes in up to 89% yield. A radical reaction pathway is proposed based on control experiments and spectroscopy studies.
- Luo, Zhibin,Meng, Yunge,Gong, Xinchi,Wu, Jie,Zhang, Yulan,Ye, Long-Wu,Zhu, Chunyin
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supporting information
p. 173 - 177
(2020/01/02)
-
- A new exploration towards aminothiazolquinolone oximes as potentially multi-targeting antibacterial agents: Design, synthesis and evaluation acting on microbes, DNA, HSA and topoisomerase IV
-
This work did a new exploration towards aminothiazolquinolone oximes as potentially multi-targeting antimicrobial agents. A class of novel hybrids of quinolone, aminothiazole, piperazine and oxime fragments were designed for the first time, conveniently synthesized as well as characterized by 1H NMR, 13C NMR and HRMS spectra. Biological activity showed that some of the synthesized compounds exhibited good antimicrobial activities in comparison with the reference drugs. Especially, O-methyl oxime derivative 10b displayed excellent inhibitory efficacy against MRSA and S. aureus 25923 with MIC values of 0.009 and 0.017 mM, respectively. Further studies indicated that the highly active compound 10b showed low toxicity toward BEAS-2B and A549 cell lines and no obvious propensity to trigger the development of bacterial resistance. Quantum chemical studies have also been conducted and rationally explained the structural features essential for activity. The preliminarily mechanism exploration revealed that compound 10b could not only exert efficient membrane permeability by interfering with the integrity of cells, bind with topoisomerase IV–DNA complex through hydrogen bonds and π-π stacking, but also form a steady biosupramolecular complex by intercalating into DNA to exert the efficient antibacterial activity. The supramolecular interaction between compound 10b and human serum albumin (HSA) was a static quenching, and the binding process was spontaneous, where hydrogen bonds and van der Waals force played vital roles in the supramolecular transportation of the active compound 10b by HSA.
- Wang, Liang-Liang,Battini, Narsaiah,Bheemanaboina, Rammohan R. Yadav,Ansari, Mohammad Fawad,Chen, Jin-Ping,Xie, Yun-Peng,Cai, Gui-Xin,Zhang, Shao-Lin,Zhou, Cheng-He
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p. 166 - 181
(2019/07/02)
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- The Mn-catalyzed paired electrochemical facile oxychlorination of styrenes: Via the oxygen reduction reaction
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Reported herein is the electrochemical engendering of chlorine radicals by a manganese catalyst with a controllable pattern, and inexpensive MgCl2 as the chlorine source. In combination with the oxygen reduction reaction, chloroacetophenones were synthesized with abundant styrene as the feedstock in good to excellent yields.
- Tian, Siyu,Jia, Xiaofei,Wang, Ling,Li, Baoying,Liu, Siyuan,Ma, Li,Gao, Wei,Wei, Yingqin,Chen, Jianbin
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supporting information
p. 12104 - 12107
(2019/10/14)
-
- CV-driven Optimization: Cobalt-Catalyzed Electrochemical Expedient Oxychlorination of Alkenes via ORR
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Instead of screening reaction conditions by yield-based chemical trial-and-error, potential-based cyclic voltammetry was alternatively employed for optimization of electrochemical oxychlorination of alkenes. With this unconventional screening method, the catalyst system including catalysts, molar ratio of chloride sources and solvents were identified in a rational, time- and energy-efficient manner. The optimal catalytic system in combination with oxygen reduction reaction enabled broad substrate scopes for the desired transformation by taking advantages of persistent radical effect. UV-vis and CV titration experiments confirmed the in-situ formed catalytic species [CoCl5]. Moreover, cyclic voltammetry was applied to obtain mechanistic insights in our reaction system. (Figure presented.).
- Tian, Siyu,Lv, Shide,Jia, Xiaofei,Ma, Li,Li, Baoying,Zhang, Guofeng,Gao, Wei,Wei, Yingqin,Chen, Jianbin
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supporting information
p. 5626 - 5633
(2019/11/22)
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- Iodine-DMSO-promoted divergent reactivities of arylacetylenes
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An unprecedented set of efficient, economical, atom-economic and exceedingly selective I2-DMSO-promoted methods is described for the generation of different structures. The reaction represents the first of its kind, involving the use of different iodine concentrations, temperatures, acids and salt to adjust the selectivity for the synthesis of different alkenes, α-functionalized ketones and α-ketomethylthioesters.
- Rather, Suhail A.,Kumar, Atul,Ahmed, Qazi Naveed
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supporting information
p. 4511 - 4514
(2019/04/26)
-
- An efficient heterogeneous gold(I)-catalyzed hydration of haloalkynes leading to α-halomethyl ketones
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A highly efficient heterogeneous gold(I)-catalyzed hydration of haloalkynes has been developed that proceeds smoothly under mild and neutral conditions and provides a general and practical route for the synthesis of a variety of α-halomethyl ketones with high atom-economy, excellent yield, and recyclability of the gold(I) catalyst. The presented method delivers an attractive alternative to classical α-halogenation of ketones.
- Hu, Sifan,Liu, Dayi,Yan, Chenyu,Cai, Mingzhong
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supporting information
p. 2983 - 2991
(2018/12/04)
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- Novel carbazole-triazole conjugates as DNA-targeting membrane active potentiators against clinical isolated fungi
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A series of carbazole-triazole conjugates were designed, synthesized and characterized by IR, NMR, and HRMS spectra. Biological assay showed that most of the synthesized compounds exhibited moderate and even strong antifungal activities, especially 3,6-dibromocarbazolyl triazole 5d displayed excellent inhibitory efficacy against most of the tested fungal strains (MIC = 2–32 μg/mL) and effectively fungicidal ability towards C. albicans, C. tropicals and C. parapsilosis ATCC 22019 (MFC = 4–8 μg/mL). Its combination use with fluconazole could enhance the antifungal efficacy, and compound 5d also did not obviously trigger the development of resistance in C. albicans even after 10 passages. Preliminary mechanism study revealed that the active molecule 5d could depolarize fungal membrane potential and intercalate into DNA to possibly block DNA replication, thus possibly exhibiting its powerful antifungal abilities. Conjugate 5d could interact with HSA, which was constructive for the further design, modification and screening of drug molecules. Docking investigation demonstrated a non-covalent binding of 5d with CYP51 through hydrogen bond and hydrophobicity. These results strongly suggested that compound 5d could act as a potential template for the development of promising antifungal drugs.
- Zhang, Yuan,Tangadanchu, Vijai Kumar Reddy,Bheemanaboina, Rammohan R. Yadav,Cheng, Yu,Zhou, Cheng-He
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p. 579 - 589
(2018/06/20)
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- Iridium-Catalyzed Asymmetric Hydrogenation of Halogenated Ketones for the Efficient Construction of Chiral Halohydrins
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Iridium-catalyzed asymmetric hydrogenation of prochiral halogenated ketones was successfully developed to prepare various chiral halohydrins with high reactivities and excellent enantioselectivities under basic reaction condition (up to >99% conversion, 99% yield, >99% ee). Moreover, gram-scale experiment was performed well in the presence of just 0.005 mol% (S/C=20 000) Ir/f-amphox catalyst with 99% yield and >99% ee. (Figure presented.).
- Yin, Congcong,Wu, Weilong,Hu, Yang,Tan, Xuefeng,You, Cai,Liu, Yuanhua,Chen, Ziyi,Dong, Xiu-Qin,Zhang, Xumu
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supporting information
p. 2119 - 2124
(2018/04/30)
-
- Cascade Trisulfur Radical Anion (S3?-) Addition/Electron Detosylation Process for the Synthesis of 1,2,3-Thiadiazoles and Isothiazoles
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Trisulfur radical anion (S3?-) mediated reactions with in situ formed azoalkenes and α,β-usaturated N-sulfonylimines for the construction of 1,2,3-thiadiazoles and isothiazoles has been developed. S3?- is in situ generated from potassium sulfide in DMF. These two approaches provide a new, safe, and simple way to construct 4-subsituted 1,2,3-thiadiazoles, 5-subsituted 1,2,3-thiadiazoles, and isothiazole in good yields. The reactions include the formation of the new C-S and N-S bonds via S3?- addition and electron detosylation under mild conditions.
- Liu, Bei-Bei,Bai, Hui-Wen,Liu, Huan,Wang, Shun-Yi,Ji, Shun-Jun
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p. 10281 - 10288
(2018/07/25)
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- Facile and efficient preparation of α-halomethyl ketones from α-diazo ketones catalyzed by iron(III) halides and silica gel
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An efficient and mild method for the synthesis of α-halomethyl ketones from α-diazo ketones was developed using ferric chloride or bromide as the halogen source and silica gel as the hydrogen source, with good to excellent yields.
- Shi, Xinxia,Zhang, Lingqiong,Yang, Pengfei,Sun, Han,Zhang, Yilan,Xie, Chunsong,Ou-yang, Zhen,Wang, Min
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supporting information
p. 1200 - 1203
(2018/03/08)
-
- Simple synthesis of 3-hydroxyquinolines via Na2S2O4-mediated reductive cyclization of (2-(2-nitrophenyl)oxiran-1-yl)(aryl)methanones (o-nitrobenzalacetophenone oxides)
-
An efficient sodium dithionite (Na2S2O4)-mediated method for construction of 3-hydroxyquinolines via in situ Meinwald rearrangement/intramolecular reductive cyclization of o-nitrobenzalacetophenone oxides has been developed. The practical approach is of excellent functional group compatibility with as high as 98% yield under mild reaction conditions. Moreover, further manipulation successfully furnished 4-bromo substituted derivatives which may provide a promising potential application in exploring biologically active analogs of 3-hydroxyquinolines.
- Mamedov, Vakhid A.,Mamedova, Vera L.,Syakaev, Victor V.,Korshin, Dmitry E.,Khikmatova, Gul'naz Z.,Mironova, Ekaterina V.,Bazanova, Olga B.,Rizvanov, Il'dar Kh.,Latypov, Shamil K.
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p. 5082 - 5090
(2017/07/28)
-
- Design, synthesis, & biological activity of new triazole & nitro-triazole derivatives as antifungal agents
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In this study two series of fluconazole derivatives bearing nitrotriazole (series A) or piperazine ethanol (series B) side chain were designed and synthesized and then docked in the active site of lanosterol 14α-demethylase enzyme (1EA1) using the Autodock 4.2 program (The scripps research institute, La Jolla, CA, USA). The structures of synthesized compound were confirmed by various methods including elemental and spectral (NMR, CHN, and Mass) analyses. Then antifungal activities of the synthesized compound were tested against several natural and clinical strains of fungi using a broth microdilution assay against several standard and clinical fungi. Nitrotriazole derivatives showed excellent and desirable antifungal activity against most of the tested fungi. Among the synthesized compounds, 5a-d and 5g, possessing nitrotriazole moiety, showed maximum antifungal activity, in particular against several fluconazole-resistant fungi.
- Sadeghpour, Hossein,Khabnadideh, Soghra,Zomorodian, Kamiar,Pakshir, Keyvan,Hoseinpour, Khadijeh,Javid, Nabiollah,Faghih-Mirzaei, Ehsan,Rezaei, Zahra
-
-
- AuIII-Catalyzed Formation of α-Halomethyl Ketones from Terminal Alkynes
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A AuIII-catalyzed synthesis of α-halomethyl ketones from terminal alkynes was developed. This approach features excellent functional group compatibility and good yields for both aromatic and aliphatic terminal alkynes. The resulting α-halomethyl ketones were used to prepare heterocyclic indolizine structures. The plausible mechanism of the one-pot reaction is proposed.
- Xing, Yalan,Zhang, Ming,Ciccarelli, Sarah,Lee, John,Catano, Bryant
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supporting information
p. 781 - 785
(2017/02/15)
-
- Systematic Synthesis of Diphenyl-Substituted Carotenoids as Molecular Wires
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A general method for the construction of diphenyl-substituted carotenoids has been developed through the stereoselective synthesis of dienyl sulfones with a phenyl substituent. Systematic synthetic pathways to the dienyl sulfones were delineated starting from readily available acetophenones with para-substituent X of various electronic natures, which provided the carotenoids with diverse physicochemical characteristics. The sulfone olefination method together with the Ramberg–B?cklund reaction produced a 9,9′-cis-10,10′-diphenylcarotene and all-trans-9,9′-diphenylcarotenes. Conductance measurements of the all-trans carotenoids by the scanning tunnelling microscopy break-junction method revealed a positional effect of the phenyl groups as well as a polar effect of the phenyl substituent X according to the electronic nature.
- Lim, Boram,Oh, Eun-Taek,Im, JongOne,Lee, Kyu Sang,Jung, Hyunuk,Kim, Minsoo,Kim, Dahye,Oh, Jung Taek,Bae, Sung-Hee,Chung, Wook-Jin,Ahn, Kwang-Hyun,Koo, Sangho
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p. 6390 - 6400
(2017/12/01)
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- Metal-free hydration of aromatic haloalkynes to α-halomethyl ketones
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A highly regioselective and efficient metal-free hydration of aromatic haloalkynes to α-halomethyl ketones using cheap tetrafluoroboric acid as catalyst is described. The protocol is conducted under convenient conditions and affords products in good to excellent yields, with broad substrate scope, including a variety of aromatic alkynyl chlorides, alkynyl bromides, and alkynyl iodides.
- Ye, Min,Wen, Yuelu,Li, Huifang,Fu, Yejuan,Wang, Qinghao
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supporting information
p. 4983 - 4986
(2016/10/21)
-
- In(OTf)3/acid co-catalyzed hydration of 1-haloalkynes to α-halomethyl ketones
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A novel and efficient In(OTf)3and HOAc cooperatively catalyzed hydration of 1-haloalkynes is described. This method provides ready access to α-chloromethyl ketones, α-bromomethyl ketones and α-iodomethyl ketones in moderate to high yields from simple, inexpensive starting materials. A broad substrate scope is achieved, and the reaction is compatible with various functional groups, including alkoxy, trifluoromethyl, halide, hydroxyl, cyclohexyl, and heterocyclic groups.
- Zeng, Ming,Huang, Rui-Xue,Li, Wen-Yi,Liu, Xiao-Wen,He, Fu-Ling,Zhang, Yi-Yuan,Xiao, Fang
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p. 3818 - 3822
(2016/07/06)
-
- Synthetic method of 2-bromo-4-(2-chloro-ethyl)-aniline
-
The invention relates to a synthetic method of 2-bromo-4-(2-chloro-ethyl)-aniline and belongs to the field of chemical synthesis. The method comprises the following steps: using chlorobenzene and anhydrous AlCl2 as raw materials, dropwise adding chloroacetyl chloride, using ice water and hydrochloric acid, stirring and reacting, carrying out suction filtration, washing with sodium hydroxide and deionized water, carrying out vacuum suction filtration and collecting chlorobenzene, carrying out rotary evaporation until collecting 4-chloro-benzeneacetyl chloride, heating a 4-chloro-benzeneacetyl chloride solution, hydrazine hydrate and diglycol and carrying out reflux reaction, collecting 1-chloro-4-(2-chloroethyl)benzene and drying under reduced pressure to prepare light yellow powder, carrying out a bromination reaction and dropwise adding a sodium hypochlorite solution and an ammonium sulfite solution, washing and collecting saffron yellow particles so as to prepare 2-bromo-4-(2-chloro-ethyl)-aniline.
- -
-
Paragraph 0007
(2016/11/28)
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- High-yielding aqueous synthesis of chloroacetophenones and aroyl chlorohydrins
-
The use of large amounts of volatile organic solvents in industrial chemical processes contributes to widespread environmental pollution. To help solve this problem, water and a phase transfer catalyst were used to replace organic solvents in the transformations of bromoacetophenones into chloroacetophenones and aroyl epoxides into aroyl chlorohydrins. The reactions were promoted by sulfonyl chlorides and gave quantitative or close to quantitative yields. Notably, chromatographic purification, which is laborious and consumes large amounts of organic solvents, was not needed. These two processes have opened a green and cost-effective channel to prepare the chemical intermediates chloroacetophenones and aroyl chlorohydrins. The reaction mechanisms are discussed based on control experiments.
- Zhang, Xixi,Liu, Lei,Li, Chunbao
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p. 25339 - 25345
(2016/03/22)
-
- Vanadium-catalyzed chlorination under molecular oxygen
-
A catalytic chlorination of ketones was performed by using a vanadium catalyst in the presence of Bu4NI and AlCl3 under atmospheric molecular oxygen. This catalytic chlorination could be applied to the chlorination of alkenes to give the corresponding vic-dichlorides. AlCl3 was found to serve as both a Lewis acid and a chloride source to induce the facile chlorination. A combination of Bu4NI and AlI3 in the presence of a vanadium catalyst under atmospheric molecular oxygen induced the iodination of ketones.
- Moriuchi, Toshiyuki,Fukui, Yasuhiro,Kato, Satoshi,Kajikawa, Tomomi,Hirao, Toshikazu
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p. 177 - 180
(2015/03/04)
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- AgF/TFA-promoted highly efficient synthesis of α-haloketones from haloalkynes
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A AgF/TFA-promoted highly efficient synthesis of a wide range of α-haloketones from haloalkynes is described. The reactions are conducted under convenient conditions and provide products in moderate to excellent yields, with broad substrate scope, including a variety of aromatic chloroalkynes and bromoalkynes.
- Chen, Zheng-Wang,Ye, Dong-Nai,Ye, Min,Zhou, Zhong-Gao,Li, Shen-Huan,Liu, Liang-Xian
-
supporting information
p. 1373 - 1375
(2014/03/21)
-
- Direct conversion of alcohols to α-chloro aldehydes and α-chloro ketones
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Direct conversion of primary and secondary alcohols into the corresponding α-chloro aldehydes and α-chloro ketones using trichloroisocyanuric acid, serving both as stoichiometric oxidant and α-halogenating reagent, is reported. For primary alcohols, TEMPO has to be added as an oxidation catalyst, and for the transformation of secondary alcohols (TEMPO-free protocol), MeOH as an additive is essential to promote chlorination of the intermediary ketones.
- Jing, Yuanyuan,Daniliuc, Constantin G.,Studer, Armido
-
supporting information
p. 4932 - 4935
(2015/04/27)
-
- Synthesis and biological evaluation of α-triazolyl chalcones as a new type of potential antimicrobial agents and their interaction with calf thymus DNA and human serum albumin
-
A series of α-triazolyl chalcones were efficiently synthesized. Most of the prepared compounds showed effective antibacterial and antifungal activities. Noticeably, α-triazolyl derivative 9a exhibited low MIC value of 4 μg/mL against MRSA and Micrococcus luteus, which was comparable or even superior to reference drugs. The further research revealed that compound 9a could effectively intercalate into Calf Thymus DNA to form 9a-DNA complex which might block DNA replication to exert their powerful antimicrobial activities. Competitive interactions between 9a and metal ions to Human Serum Albumin (HSA) suggested the participation of Fe3+, K+ and Mg 2+ ions in 9a-HSA system could increase the concentration of free 9a, shorten its storage time and half-life in the blood, thus improving its antimicrobial efficacy.
- Yin, Ben-Tao,Yan, Cong-Yan,Peng, Xin-Mei,Zhang, Shao-Lin,Rasheed, Syed,Geng, Rong-Xia,Zhou, Cheng-He
-
p. 148 - 159
(2014/01/06)
-
- Experimental study on the reaction pathway of α-haloacetophenones with NaOMe: Examination of bifurcation mechanism
-
The reaction of PhCOCH2Br and NaOMe in MeOH gave PhCOCH 2OH as the major product and PhCOCH2OMe as the minor product. Substituent effects on the reactivity and product selectivity revealed that an electron-withdrawing substituent on the phenyl ring enhanced the overall reactivity and gave more alcohol than ether. It was indicated that the alcohol was formed via carbonyl addition-epoxidation, whereas the ether was formed by direct substitution. Substituent effects on the reaction rates, as well as the effects of NaOMe concentration on the rate and product ratio for both reactions of PhCOCH2Br and PhCOCH2CI are in line with the mechanism that the alcohol and ether products were formed via two independent and concurrent routes, carbonyl addition and a-carbon attack, respectively, and thus the reaction mechanism could be different from the bifurcation mechanism previously predicted for the reaction of PhCOCH2Br by a simulation study in the gas phase.
- Tagawa, Kohei,Sasagawa, Keita,Wakisaka, Ken,Monjiyama, Shunsuke,Katayama, Mika,Yamataka, Hiroshi
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p. 119 - 126
(2014/02/14)
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- The α-chlorination of aryl methyl ketones under aerobic oxidative conditions
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The novel reaction system air/ammonium nitrate/iodine/hydrochloric acid [air/NH4NO3(cat.)/I2(cat.)/HCl] is introduced as a simple, safe, cheap, efficient and regioselective mediator for the α-chlorination of aryl, heteroaryl and alkyl methyl ketones under aerobic oxidative conditions. The inventive use of a catalytic amount of iodine enabled the moderate to quantitative, regioselective chlorination of a comprehensive scope of different methyl ketone derivatives including those bearing oxidizable heteroatom (S, N) substituents, some of which possess declared potential biological and pharmaceutical activity. Air oxygen under a slight overpressure plays the role of the terminal oxidant catalytically activated by redox cycles of nitrogen oxides released from the catalytic amount of ammonium nitrate (NH4NO3) under acidic conditions of hydrochloric acid (HCl) and co-catalyzed by elemental iodine (I2), which was found to be essential for the high efficiency of the reaction system.
- Prebil, Rok,Stavber, Stojan
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supporting information
p. 1266 - 1274
(2014/05/06)
-
- Continuous flow generation and reactions of anhydrous diazomethane using a teflon AF-2400 tube-in-tube reactor
-
A continuous process for generation, separation, and reactions of anhydrous diazomethane in a tube-in-tube reactor was developed. The inner tube of the reactor is made of hydrophobic, gas-permeable Teflon AF-2400. The diazomethane is formed in the inner tube and then diffuses through the permeable membrane into the outer chamber and subsequently reacts in the solution carried within. This technique allows safe and scalable reactions with dry diazomethane to be performed on a laboratory scale.
- Mastronardi, Federica,Gutmann, Bernhard,Oliver Kappe
-
supporting information
p. 5590 - 5593
(2013/11/19)
-
- Target-oriented synthesis: Miscellaneous synthetic routes to access 1,4-enediones through the coupling of 1,3-dicarbonyl compounds with multiform substrates
-
Target-oriented synthetic protocol was presented for the synthesis of 1,4-enediones. The approach can efficiently construct 1,4-enediones through different reaction pathways from multiform substrates α-halo aromatic ketones, 2-hydroxy-aromatic ketones and methyl carbinols. In this reaction, CuI was found to be the most efficient catalyst. Multiform substrates were also found to perform well to afford the products in a one-pot fashion.
- Zhu, Yan-Ping,Cai, Qun,Gao, Qing-He,Jia, Feng-Cheng,Liu, Mei-Cai,Gao, Meng,Wu, An-Xin
-
supporting information
p. 6392 - 6398
(2013/07/25)
-
- Design, synthesis and evaluation of clinafloxacin triazole hybrids as a new type of antibacterial and antifungal agents
-
A series of clinafloxacin triazole hybrids as a new type of antibacterial and antifungal agents were synthesized for the first time and screened for their antimicrobial efficacy against four Gram-positive bacteria, four Gram-negative bacteria and two fungi by two fold serial dilution technique. The bioactive assay indicated that most of the target compounds displayed broad antimicrobial spectrum and good antibacterial and antifungal activities with low MIC values ranging from 0.25 to 2 μg/mL against all the tested strains which exhibited comparable or even better efficiency in comparison with the reference drugs Chloramphenicol, Clinafloxacin and Fluconazole, respectively. Notably, some synthesized clinafloxacin triazoles showed stronger efficacy against methicillin-resistant Staphylococcus aureus than their parent Clinafloxacin.
- Wang, Yan,Damu, Guri L.V.,Lv, Jing-Song,Geng, Rong-Xia,Yang, Da-Cheng,Zhou, Cheng-He
-
scheme or table
p. 5363 - 5366
(2012/09/22)
-
- α-Halogenation of carbonyl compounds: Halotrimethylsilane-nitrate salt couple as an efficient halogenating reagent system
-
A mixture of chloro/bromotrimethylsilane and nitrate salt is found to be an effective reagent system for the α-chlorination/bromination of carbonyl compounds. The reaction occurs under mild conditions yielding the products in moderate to good yields.
- Prakash, G.K. Sxurya,Ismail, Rehana,Garcia, Jessica,Panja, Chiradeep,Rasul, Golam,Mathew, Thomas,Olah, George A.
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experimental part
p. 1217 - 1221
(2011/03/22)
-
- New, efficient synthesis of α-chloroketones using SiCl 4/urea-hydrogen peroxide or SiCl4/iodosylbenzene reagent systems
-
Alkyl aryl ketones on treatment with SiCl4/urea-hydrogen peroxide (UHP) or SiCl4/iodosylbenzne reagent systems afforded -chloroketones in excllent yields, while ketones with higher enol content provide exclusively,-dichloroketones under exceedingly mild conditions. The reaction proceeds via the initial formation of silyl enol ethers. A polarized chlorine intermediate that resulted from the coordination of SiCl4 with the in situ formed trichlorosilyl hypochlorite Cl3SiOCl is thought to be the active chlorinating agent.
- El-Ahl, Abdel Aziz S.,Elbeheery, Akram H.,Amer, Fathy A.
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experimental part
p. 1508 - 1513
(2011/06/17)
-
- N-Halosuccinimide/SiCl4 as general, mild and efficient systems for the α-monohalogenation of carbonyl compounds and for benzylic halogenation
-
Combinations of N-halosuccinimide and tetrachlorosilane in acetonitrile were found to be efficient systems for the selective α-monohalogenation of carbonyl compounds as well as for benzylic halogenation under mild conditions.
- Salama, Tarek A.,Novák, Zoltán
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experimental part
p. 4026 - 4029
(2011/08/09)
-
- Synthesis and molecular structure of 1-(Pyrimidin-2-yl)-2-(4-aryl-1,3- thiazol-2-yl)hydrazines
-
Reactions of some 2-hydrazinopyrimidine hydrochlorides with potassium thiocyanate gave 1-(pyrimidin- 2-yl)thiosemicarbazides which underwent Hantzsch condensation with aryl chloromethyl ketones to produce 1-(pyrimidin-2-yl)-2-(4- aryl-1,3-thiazol-2-yl)hydrazine hydrochlorides. The protonation was accompanied by mutually dependent tautomeric rearrangements of heterocyclic fragments. Pleiades Publishing, Ltd., 2011.
- Erkin,Krutikov
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experimental part
p. 1699 - 1704
(2011/12/03)
-
- Simple and efficient methods for selective preparation of α-mono or α,α-dichloro ketones and β-ketoesters by using DCDMH
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New processes that can selectively prepare α-mono or α,α-dichloro ketones and β-ketoesters using 1,3-dichloro-5,5-dimethylhydantoin (DCDMH) are reported. Using silica gel as the catalyst and methanol as the solvent and heating for 1 h under reflux, α-monochlorinated products were selectively obtained in 86-98% yield. However using a deep eutectic solvent (choline chloride: p-TsOH = 1:1) as the solvent and stirring for 45 min at room temperature, α,α- dichlorinated products were selectively obtained in 86-95% yield.
- Chen, Zizhan,Zhou, Bin,Cai, Huihua,Zhu, Wei,Zou, Xinzhuo
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experimental part
p. 275 - 278
(2010/04/22)
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- 1,2-H shift in copper-chlorocarbenoid intermediate during CuCl/bpy-promoted stereoselective dechlorination of 2,2,2-trichloroethyl alkyl ethers to (Z)-1-alkoxy-2-chloroethenes
-
(Chemical Equation Presented) Reaction of 2,2,2-trichloroethyl alkyl ethers with 2 molar equiv of CuCl/bpy in refluxing DCE yielded (Z)-1-alkoxy-2- chloroethenes stereoselectively as the major product via 1,2-H shift in copper-chlorocarbenoid intermediate. 2,2,2-Trichloroethyl carboxylates undergo a radical 1,2-acyloxy shift under similar conditions.
- Ram, Ram N.,Manoj
-
supporting information; experimental part
p. 2243 - 2246
(2009/05/11)
-
- Copper(I)-promoted synthesis of chloromethyl ketones from trichloromethyl carbinols
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(Chemical Equation Presented) Reaction of several trichloromethyl carbinols with 2 equiv of CuCl/bpy in refluxing DCE for 3 h afforded chloromethyl ketones in excellent yield by 1,2-H shift in the copper-chlorocarbenoid intermediate.
- Ram, Ram N.,Manoj
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p. 5633 - 5635
(2008/12/21)
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- Efficient α-chlorination and α-bromination of carbonyl compounds using N-halosuccinimides/UHP in ionic liquid
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A facile and efficient method for the α-halogenation of carbonyl compounds utilizing N-halosuccinimides (NXS) in the presence of urea-hydrogen peroxide (UHP) in [bmim]BF4 has been newly developed. Copyright Taylor & Francis Group, LLC.
- Lee, Jong Chan,Park, Hyun Jung
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- α-chlorination of acetophenones using 1,3-dichloro-5,5- dimethylhydantoin
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A novel method for the synthesis of α-chloroacetophenones using 1,3-dichloro-5,5-dimethylhydantoin (DCDMH) and p-toluenesulfonic acid in methanol at 30-35°C is described. Substituted acetophenones at the para position or meta position of aromatic ring give α-chloroacetophenones in high yield. However, reaction of o-nitroacetophenone does not take place under the same condition. Copyright Taylor & Francis LLC.
- Xu, Zijin,Zhang, Deyan,Zou, Xinzhuo
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p. 255 - 258
(2007/10/03)
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- Efficient α-chlorination of aryl ketones using aluminum chloride/urea-hydrogen peroxide in ionic liquid
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Effective α-chlorination reactions of aryl ketones into the corresponding α-chloroketones have been accomplished with aluminum chloride hexahydrate and urea-hydrogen peroxide in [bmim]BF4 ionic liquid. Copyright Taylor & Francis Group, LLC.
- Jong, Chan Lee,Hyun, Jung Park
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p. 777 - 780
(2007/10/03)
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- PROCESS FOR THE PREPARATION OF ALPHA-CHLOROKETONES FROM ALKYL ESTERS
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The present invention relates to a process for the preparation of α-chloroketones from readily available alkyl esters by the reaction of a sulfoxonium ylide on said alkyl esters to generate a keto sulfoxonium ylide that is in turn treated with anhydrous HCl.
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Page/Page column 5
(2010/02/11)
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- One-Carbon Chain Extension of Esters to α-Chloroketones: A Safer Route without Diazomethane
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The reaction of a variety of methyl esters with dimethylsulfoxonium methylide at 0-25 °C affords the chain-extended β-keto dimethylsulfoxonium ylides. Subsequent treatment with hydrogen chloride in THF proceeds with loss of DMSO to afford the corresponding α-chloroketones. This sequence has been utilized to convert the methyl esters of CBZ-protected alanine and valine to the anti N-protected α-amino epoxides, which are important pharmaceutical intermediates. When the same protocol is applied to BOC-protected phenylalanine methyl ester, epimerization occurs so that the use of a more reactive aryl ester is required. This chemistry provides a practical route to α-chloroketones that avoids the use of toxic and explosive diazomethane.
- Wang, Dengjin,Schwinden, Mark D.,Radesca, Lilian,Patel, Bharat,Kronenthal, David,Huang, Ming-Hsing,Nugent, William A.
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p. 1629 - 1633
(2007/10/03)
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- Catalytic process for regiospecific chlorination of alkanes, alkenes and arenes
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The present invention provides a process for regiospecific chlorination of an aromatic or aliphatic compound with a chlorine source comprising a metal chloride and other than Cl2and SO2Cl2in presence of hypervalent iodine catalyst and in acidic medium.
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Page column 6
(2008/06/13)
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- Chemoenzymatic synthesis of enantiomerically pure terminal 1,2-diols
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A new practical method for the enzymatic synthesis of 1,2-diols has been developed by employing a lipase catalyzed one-pot transesterification protocol. A series of substituted α-acetoxyphenylethanones 3a-g have been reduced to the corresponding alcohols under mild conditions employing sodium borohydride and moist neutral alumina, and further subjected for lipase catalyzed irreversible transesterification in the same pot to give mono- and diacetate diols (R)-4 and (S)-5, which on hydrolysis afforded terminal 1,2-diols, (R)- and (S)-6 in high enantiomeric excess.
- Kamal, Ahmed,Sandbhor, Mahendra,Ahmed, Kaleem,Adil,Shaik, Ahmad Ali
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p. 3861 - 3866
(2007/10/03)
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- α-(4-Nitro Phenoxy) chalcones as synthons for cis-(±)-1,5- benzothiazepines
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α-(4-Nitro Phenoxy) chalcones, V have been utilized as intermediate for the synthesis of some new cis- (±)-2-aryl-3-(4-nitro phenoxy)-4-phenyl-1,5- benzothiazepine VI by cycloconden-sation of 2-amino thiophenol in the presence of mild base.
- Rao,Arun Kumar Gupta,Gupta
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p. 2763 - 2768
(2007/10/03)
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- Synthesis and fungicidal activity of 2-imino-3-(4-arylthiazol-2-yl)- thiazolidin-4-ones and their 5-arylidene derivatives
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Five derivatives of 2-imino-3-(4-arylthiazol-2-yl)-thiazolidin-4-ones and a series of their 5-arylidene derivatives have been synthesized and tested for antifungal activity against seven agricultural fungi. 2-Imino-3-(2,4-dichloro-5- fluorophenylthiazol-2-yl)-4-thiazolidi-none and 2-imino-3-(2,4- dichlorophenylthiazol-2-yl)-4-thiazolidione, both of them new compounds, exhibited higher fungicidal effects than the other compounds prepared.
- Liu, Hui-Ling,Li, Zongcheng,Anthonsen, Thorleif
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p. 1055 - 1061
(2007/10/03)
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- Reactions of alkynylselenonium salts with tetrabutylammonium halides: Apparent umpolung of alkynyl moiety
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The reactions of alkynylselenonium salts with n-Bu4NX (X = I, Br, Cl) in CH2Cl2 gave 1-halo-1-alkynes or phenacyl halide derivatives and selenide, while the reaction with F afforded a terminal alkyne and a selenoxide. Seemingly, the selenonium salts acted as alkynyl cations in the former case and as alkynyl anions in the latter case.
- Kataoka, Tadashi,Watanabe, Shin-ichi,Yamamoto, Keiichirou
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p. 931 - 934
(2007/10/03)
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- Reactions of trichloromethanesulfonyl chloride and carbon tetrachloride with silyl enol ethers catalyzed by a ruthenium(II) phosphine complex
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The reactions of trichloromethanesulfonyl chloride with trimethylsilyl enol ethers of acetophenones in the presence of a ruthenium(II) phosphine complex gave 1-aryl-3,3-dichloropropen-1-one together with α-chloroacetophenones. The product ratio depended on the substituent on the aromatic ring of the silyl enol ether. The reactions of carbon tetrachloride with the silyl enol ethers under similar conditions afforded 1-aryl-3,3-dichloropropen-1-one in good yield.
- Kamigata, Nobumasa,Udodaira, Kumiko,Yoshikawa, Manabu,Shimizu, Toshio
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- Reactions of perfluoroalkanesulfonyl chlorides with silyl enol ethers catalyzed by a ruthenium(II) phosphine complex
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Reactions of trifluoromethane- and tridecafluorohexanesulfonyl chlorides with silyl enol ethers have been investigated in the presence of a ruthenium(II) phosphine complex. Perfluoroalkylation and chlorination occurred depending on the substituent of silyl enol ether; i.e. perfluoroalkylated compound was selectively obtained in the reactions with silyl enol ether possessing an electron-withdrawing group, on the other hand, chlorinated compounds selectively formed in the reaction with a silyl enol ether possessing electron-donating group.
- Kamigata, Nobumasa,Udodaira, Kumiko,Shimizu, Toshio
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p. 155 - 168
(2007/10/03)
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- S4N4SbCl5 complex: a useful reagent for conversion of sterically less hindred α-bromo ketones to α-chloro ketones
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The reactions of sterically less hindered α-bromo alkyl and aryl ketones with tetrasulfur tetranitride antimony pentachloride (S4N4SbCl5) complex in toluene at reflux gave the corresponding α-chloro kerones in good to excellent yields.
- Kim, Kil-Joong,Kim, Kyongtae
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p. 4227 - 4230
(2007/10/03)
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- The Acidity of Weak Carbon Acids. Part 6. Acidity of p-Substituted Acetophenones in the Absence and Presence of Cyclodextrins as Determined by Rates of Chlorination by Hypochlorite
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Rate coefficients have been measured for the chlorination of a series of p-substituted acetophenones in water at several temperatures in both the absence and presence of α- and β-cyclodextrins, as well as in aqueous dioxane.The rate determining ionisation of the acetophenones is subject to catalysis by inclusion in the cyclodextrins.The effects of substitution have been assessed by means of the Hammett equation.The catalysis appears to arise from an anionic secondary hydroxy group on the cyclodextrin and a microsolvent effect on the transmission of the polar effects.
- Bowden, Keith,Nair, T. D. Radhakrishnan
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p. 1201 - 1215
(2007/10/02)
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