- Continuous Synthesis and Separation ofp-Bromobenzyl Bromide Using Atom-Efficient Bromination ofp-Bromotoluene without Any Organic Effluent: Potential for Green Industrial Practice
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This work focuses on the bromination ofp-bromotoluene (PBT) using different brominating agents such as liquid Br2, NaBr-NaBrO3, NaBr-NaBrO3-NaCl, NaBr-H2O2, and HBr-H2O2. NaBr-NaBrO3-NaCl is an eco-friendly brominating agent obtained from a bromine recovery plant. Both NaBr-NaBrO3and NaBr-NaBrO3-NaCl were found to be nonhazardous and efficient brominating agents. Pure NaBr-NaBrO3resulted in the best PBT conversion with 79.7% Br atom efficiency in water and 98.2% average Br atom efficiency using dichloroethane as a solvent. Dichloroethane is de facto no longer used in the US and Europe and is not eco-friendly; the process with water as a solvent is the best. The substrate to active bromine molar ratio of 3:1 was found to be sufficient to get the maximum selectivity ofp-bromobenzyl bromide (PBBB). The low-temperature crystallization method was used for separation cum purification of the product. Unreacted PBT was recycled along with the dibromo byproduct obtained. The dibromo product, which was built up gradually in the reaction mixture over 10 successive batches, was converted back into PBBB/PBT through NaBH4treatment of the mother liquor. This continuous process is highly sustainable and produces zero organic waste, making it potentially attractive toward green industrial implementation.
- Sancheti, Sonam V.,Yadav, Ganapati D.
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p. 2071 - 2080
(2021/09/13)
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- PYRROLIDINE GLYCOSIDASE INHIBITORS
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Compounds of formula (I) wherein A, W, R3b, Z and p have the meaning according to the claims can be employed, inter alia, for the treatment of tauopathies and Alzheimer's disease.
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Page/Page column 130
(2020/03/15)
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- N -Hydroxyphthalimide/benzoquinone-catalyzed chlorination of hydrocarbon C-H bond using N -chlorosuccinimide
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The direct chlorination of C-H bonds has received considerable attention in recent years. In this work, a metal-free protocol for hydrocarbon C-H bond chlorination with commercially available N-chlorosuccinimide (NCS) catalyzed by N-hydroxyphthalimide (NHPI) with 2,3-dicyano-5,6-dichlorobenzoquinone (DDQ) functioning as an external radical initiator is presented. Aliphatic and benzylic substituents and also heteroaromatic ones were found to be well tolerated. Both the experiments and theoretical analysis indicate that the reaction goes through a process wherein NHPI functions as a catalyst rather than as an initiator. On the other hand, the hydrogen abstraction of the C-H bond conducted by a PINO species rather than the highly reactive N-centered radicals rationalizes the high chemoselectivity of the monochlorination obtained by this protocol as the latter is reactive towards the C(sp3)-H bonds of the monochlorides. The present results could hold promise for further development of a nitroxy-radical system for the highly selective functionalization of the aliphatic and benzylic hydrocarbon C-H.
- Li, Zi-Hao,Fiser, Béla,Jiang, Biao-Lin,Li, Jian-Wei,Xu, Bao-Hua,Zhang, Suo-Jiang
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supporting information
p. 3403 - 3408
(2019/04/01)
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- NMP-mediated chlorination of aliphatic alcohols with aryl sulfonyl chloride for the synthesis of alkyl chlorides
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NMP-mediated chlorination of aliphatic alcohols has been developed for the synthesis of alkyl chlorides. This facile, efficient and practical approach used simple and readily available aryl sulfonyl chlorides as the chlorination reagent for the construction of C–Cl bond in good to excellent yields with mild conditions and broad substrate scope.
- Zheng, Dagui,Mao, Liu-Liang,Zhu, Xian-Hong,Zhou, An-Xi
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supporting information
p. 2793 - 2800
(2018/11/06)
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- Halogenation through Deoxygenation of Alcohols and Aldehydes
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An efficient reagent system, Ph3P/XCH2CH2X (X = Cl, Br, or I), was very effective for the deoxygenative halogenation (including fluorination) of alcohols (including tertiary alcohols) and aldehydes. The easily available 1,2-dihaloethanes were used as key reagents and halogen sources. The use of (EtO)3P instead of Ph3P could also realize deoxy-halogenation, allowing for a convenient purification process, as the byproduct (EtO)3Pa?O could be removed by aqueous washing. The mild reaction conditions, wide substrate scope, and wide availability of 1,2-dihaloethanes make this protocol attractive for the synthesis of halogenated compounds.
- Chen, Jia,Lin, Jin-Hong,Xiao, Ji-Chang
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supporting information
p. 3061 - 3064
(2018/05/28)
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- NOVEL DIHYDROPYRIDINONE AND DIHYDROPYRIMIDINONE COMPOUNDS AND THEIR USE
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The present invention is directed to novel compounds of Formula I; pharmaceutically acceptable salts or solvates thereof, and their use.
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Page/Page column 61
(2017/12/27)
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- SNAr catalysis enhanced by an aromatic donor-acceptor interaction; Facile access to chlorinated polyfluoroarenes
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Selective catalytic SNAr reaction of polyfluoroaryl C-F bonds with chloride is shown. Stoichiometric TMSCl makes the reaction exergonic and allows catalysis, which involves ground state elevation of chloride, aromatic donor-acceptor interactions, and stabilization of the Meisenheimer complex. Traditional cross-coupling of the products is now possible and demonstrates the utility.
- Senaweera, Sameera,Weaver, Jimmie D.
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supporting information
p. 7545 - 7548
(2017/07/12)
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- EPIDITHIODIKETOPIPERAZINE COMPOUNDS, COMPOSITIONS, AND METHODS
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Epidithiodiketopiperazine compounds, pharmaceutical compositions based thereon and methods of their synthesis, as part of treating, inhibiting and reducing transcription and translation of hypoxia inducible genes are described. In another aspect, the present disclosure describes a method for interfering with hypoxia-induced transcriptional pathway in a cell comprising: contacting the cell with at least one compound disclosed herein. In another aspect, the present disclosure describes a method for treating breast cancer, a solid cancer, a blood cancer, a subject suffering from carcinoma in need of said treatment, and renal cell carcinoma (RCC), comprising: administering to the subject an effective amount of at least one compound disclosed herein. In some embodiments of the methods described herein, the method further comprises administering an additional anti-cancer and/or cytotoxic agent.
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Paragraph 0193
(2015/07/07)
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- Rasta resin-triphenylphosphine oxides and their use as recyclable heterogeneous reagent precursors in halogenation reactions
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Heterogeneous polymer-supported triphenylphosphine oxides based on the rasta resin architecture have been synthesized, and applied as reagent precursors in a wide range of halogenation reactions. The rasta resin-triphenylphosphine oxides were reacted with either oxalyl chloride or oxalyl bromide to form the corresponding halophosphonium salts, and these in turn were reacted with alcohols, aldehydes, aziridines and epoxides to form halogenated products in high yields after simple purification. The polymersupported triphenylphosphine oxides formed as a byproduct during these reactions could be recovered and reused numerous times with no appreciable decrease in reactivity.
- Xia, Xuanshu,Toy, Patrick H.
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supporting information
p. 1397 - 1405
(2014/07/22)
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- Sulfite formation versus chlorination of benzyl alcohols with thionyl chloride
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Recently, we have reported the photolytic decay of a library of para-substituted dibenzylic sulfites in a Srinivasan-Griffin-Rayonet photochemical reactor. In an attempt to synthesize the complete library for that study we discovered that bis(p-methoxybenzyl) sulfite and bis(p-phenoxybenzyl) sulfite could not be formed and only their corresponding benzyl chlorides were synthesized. Thus, sulfite formation versus chlorination of a range of para-substituted benzyl alcohols with thionyl chloride was investigated. Sulfite formation was observed to be parabolically related to Swain and Lupton's Field ?-values while chloride formation was found to be linearly related to Swain and Lupton's Field ?-values.
- Rodriguez, Deana A.,Priefer, Ronny
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p. 3045 - 3048
(2014/05/20)
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- Palladium-catalyzed carboxylative coupling of benzyl chlorides with allyltributylstannane: Remarkable effect of palladium nanoparticles
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Palladium-catalyzed carboxylative coupling of benzyl chlorides with allyltributylstannane was successfully conducted to produce benzyl but-3-enoates in satisfactory to good yields. The carboxylative coupling reaction occurred smoothly under mild conditions in the presence of palladium nanoparticles in tetrahydrofuran.
- Feng, Xiujuan,Sun, Anle,Zhang, Sheng,Yu, Xiaoqiang,Bao, Ming
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supporting information
p. 108 - 111
(2013/04/10)
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- Regio- and chemoselective palladium-catalyzed benzylallylation of activated olefins: The remarkable effect of palladium nanoparticles
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The palladium-catalyzed three-component reactions of benzyl halides, activated olefins, and allyltributylstannane were successfully conducted to produce the corresponding benzylallylation products in satisfactory to high yields. The benzylallylation reaction proceeded smoothly under mild conditions in the presence of palladium nanoparticles in tetrahydrofuran. The Royal Society of Chemistry 2013.
- Zhang, Xuan,Feng, Xiujuan,Yu, Xiaoqiang,He, Ren,Bao, Ming
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p. 4016 - 4024
(2013/07/05)
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- Treatment of alcohols with tosyl chloride does not always lead to the formation of tosylates
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Treatment of substituted benzyl alcohols with tosyl chloride resulted in the formation of the corresponding chlorides, not the usual tosylates. A series of experiments demonstrated that it was possible to predict whether chlorination or tosylation would occur for substituted benzyl alcohols and pyridine methanols. Treatment of electron withdrawing group-substituted benzyl alcohols with tosyl chloride gave the corresponding chlorides in moderate yields under mild conditions, which provided a simple way to directly prepare chlorides from alcohols.
- Ding, Rui,He, Yong,Wang, Xiao,Xu, Jingli,Chen, Yurong,Feng, Man,Qi, Chuanmin
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experimental part
p. 5665 - 5673
(2011/09/20)
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- N-Halosuccinimide/SiCl4 as general, mild and efficient systems for the α-monohalogenation of carbonyl compounds and for benzylic halogenation
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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)
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- Chlorination of various substrates in subcritical carbon tetrachloride
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Various aliphatic hydrocarbons and the side chains of aromatic hydrocarbons were chlorinated in subcritical carbon tetrachloride. Chlorination of aromatic compounds including 1,4-disubstituted benzenes was investigated. Ketones and sulfones were stable under the employed conditions. Sulfoxides were converted into sulfides in a low to modest yields. The coupling adducts between olefins and carbon tetrachloride were obtained from the reactions of olefins.
- Tanemura, Kiyoshi,Suzuki, Tsuneo,Nishida, Yoko,Horaguchi, Takaaki
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experimental part
p. 2881 - 2888
(2010/06/16)
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- Environmentally benign nucleophilic substitution reactions
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Herein, the development of environmentally benign conditions for heterogeneous nucleophilic addition reactions under novel high speed ball milling conditions is described.
- Vogel, Philip,Figueira, Sarah,Muthukrishnan, Sivaramakrishnan,Mack, James
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scheme or table
p. 55 - 56
(2009/04/11)
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- Chlorination of aromatic compounds with chlorous acid under non-aqueous conditions
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The non-aqueous solution of chlorous acid is a versatile chlorinating agent for aromatic compounds, e.g. alkylbenzenes, anisoles, and acetanililides. It is also an effective chlorine-substitute for the conversion of aryl bromides into aryl chlorides under mild conditions. The stoichiometry of the chlorination reaction is ArH+3HOClO→ArCl+2ClO2+2H2O, and the mode of dissociation of chlorous acid in dichloromethanc is 3HOClO→HOCl+2ClO2+H2O.
- Muathen, Hussni A.
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p. 1493 - 1497
(2007/10/03)
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- Nickel-catalyzed benzylic oxidation with NaOCl
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Ni(bpy)2Cl2 has been found to be an efficient catalyst for the oxidation of various alkylbenzenes with hypochlorite. Substituted toluenes having electron withdrawing group at 4-position were oxidized to the corresponding substituted benzoic acids in excellent yields.
- Yamazaki, Shigekazu
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p. 2211 - 2216
(2007/10/03)
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- Halogenative Allylation and Reduction of Aromatic Acetals by Double Substitution of Alkoxyl Groups in Acetal
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In the presence of excessive amount of acetyl halide along with a catalytic amount of tin(II) halide, aromatic acetals react with allyltrimethylsilane or triethylsilane to give α-allylbenzyl halides or benzyl halides, respectively, in good to excellent yields.
- Oriyama, Takeshi,Iwanami, Katsuyuki,Tsukamoto, Kazuhisa,Ichimura, Yuichi,Koga, Gen
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p. 1410 - 1412
(2007/10/02)
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- Regiochemistry and reactivity in the chlorination of sulfides
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Huheey's original method for the calculation of substituent electronegativities is modified so that isomeric groups have different electronegativities.The modified form of Huheey's method is then employed to show that our previously published method for anticipating regiochemistry in asymmetric sulfide chlorination, i.e., ΔXP calculations for the α and α' substituents in the sulfide substrates, is successful in all fifty known cases.A new reactivity function (RP) is defined, for the sulfenium ion intermediates, which permits one to anticipate when substrates become inert to chlorine in exhaustive chlorinations conducted in aprotic media.
- Hancock, James Reid,Hardstaff, William Rayne,Johns, Paul Alan,Langler, Richard Francis,Mantle, William Stanley
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p. 1472 - 1480
(2007/10/02)
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- 1-[2-(1-Adamantyl)-2-(R-thio)ethyl]imidazoles and 1-[2-(1-adamantyl)-2-(R-oxy)ethyl]imidazoles
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Compounds of the formula STR1 wherein R is alkyl, cycloalkyl, cycloalkyl lower alkyl, phenyl or phenyl lower alkyl, said phenyl and phenyl lower alkyl optionally substituted on the phenyl ring with one or more substituents independently selected from the group consisting of halo, lower alkyl and trifluoromethyl; and X is oxygen or sulfur with the proviso that X is not oxygen when R is phenyl or substituted phenyl; and the antimicrobial acid addition salts thereof are useful as antifungal, antibacterial and antiprotozoal agents.
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