- Synthesis of fluorine-containing prenylated benzophenones
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In this study, an effective route to synthesize fluorine-containing prenylated benzophenones was developed. Friedel–Crafts acylation and electrophilic aromatic substitution reactions were the key reactions of this synthesis to achieve these fluorinated prenylated benzophenones. The use of DBU in the prenylation step achieved only the C-prenylated benzophenones, whereas K2CO3 produced the C- and O-prenylated benzophenones.
- Mzozoyana, Vuyisa,van Heerden, Fanie R.
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supporting information
p. 2226 - 2235
(2020/07/09)
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- The Natural Product Elegaphenone Potentiates Antibiotic Effects against Pseudomonas aeruginosa
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Natural products represent a rich source of antibiotics that address versatile cellular targets. The deconvolution of their targets via chemical proteomics is often challenged by the introduction of large photocrosslinkers. Here we applied elegaphenone, a largely uncharacterized natural product antibiotic bearing a native benzophenone core scaffold, for affinity-based protein profiling (AfBPP) in Gram-positive and Gram-negative bacteria. This study utilizes the alkynylated natural product scaffold as a probe to uncover intriguing biological interactions with the transcriptional regulator AlgP. Furthermore, proteome profiling of a Pseudomonas aeruginosa AlgP transposon mutant provided unique insights into the mode of action. Elegaphenone enhanced the elimination of intracellular P. aeruginosa in macrophages exposed to sub-inhibitory concentrations of the fluoroquinolone antibiotic norfloxacin.
- Zhao, Weining,Cross, Ashley R.,Crowe-McAuliffe, Caillan,Weigert-Munoz, Angela,Csatary, Erika E.,Solinski, Amy E.,Krysiak, Joanna,Goldberg, Joanna B.,Wilson, Daniel N.,Medina, Eva,Wuest, William M.,Sieber, Stephan A.
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supporting information
p. 8581 - 8584
(2019/05/28)
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- Hydrogen bond donor solvents enabled metal and halogen-free Friedel–Crafts acylations with virtually no waste stream
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We have developed a metal and halogen-free Friedel–Crafts acylation protocol with virtually no waste stream generation. We propose a hydrogen bonding donor solvent will form a hydrogen bonding network and may provide significant rate enhancement for Friedel–Crafts reactions. Trifluoroacetic acid is one of the strongest H-bond donor solvents, which is also volatile and can be easily recovered by distillation without need for reaction workup. Our protocol is a ‘green’ Friedel–Crafts acylation process: 1) the catalyst can be recovered and reused; 2) using halogen free starting material (carboxylic acids anhydride or carboxylic acids); 3) no need for aqueous reaction work-up; 4) minimum or no waste steam generation.
- Liu, Guangchang,Xu, Bo
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supporting information
p. 869 - 872
(2018/02/09)
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- Synthesis of 3-geranyl- and 3-prenyl-2,4,6-trihydroxybenzophenone
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Biologically active phenyl[3-(3,7-dimethyl-2,6-octadienyl)-2,4,6-trihydroxyphenyl]methanone (2) and phenyl[2,4,6-trihydroxy-3-(3-methyl-2-butenyl)phenyl]methanone (3) were synthesized by an efficient and convenient synthetic sequence. The reaction steps of this synthesis included methylation, Friedel-Crafts acylation, demethylation and geranylation steps.
- Mzozoyana, Vuyisa,van Heerden, Fanie R.
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supporting information
p. 599 - 603
(2017/03/15)
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- P -Selective (sp2)-C-H functionalization for an acylation/alkylation reaction using organic photoredox catalysis
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p-Selective (sp2)-C-H functionalization of electron rich arenes has been achieved for acylation and alkylation reactions, respectively, with acyl/alkylselenides by organic photoredox catalysis involving an interesting mechanistic pathway.
- Pandey, Ganesh,Tiwari, Sandip Kumar,Singh, Bhawana,Vanka, Kumar,Jain, Shailja
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p. 12337 - 12340
(2017/11/20)
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- Hexafluoro-2-propanol-Promoted Intermolecular Friedel-Crafts Acylation Reaction
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The intermolecular Friedel-Crafts acylation was carried out in hexafluoro-2-propanol to yield aryl and heteroaryl ketones at room temperature without any additional reagents.
- Vekariya, Rakesh H.,Aubé, Jeffrey
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supporting information
p. 3534 - 3537
(2016/08/16)
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- Facile formation of methylenebis(chalcone)s through unprecedented methylenation reaction. Application to antiparasitic and natural product synthesis
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The formation of methylenebis(chalcone)s has been discovered during deprotection with methoxymethyl groups from trihydroxychalcones. Studies on this methylenation reaction led to a mechanism hypothesis that was extended to other chalcones and to dihydrochalcone, acetophenone, benzophenone and flavone derivatives. This new method was applied to the rapid synthesis of natural product piperanduncin C. These original methylenebis compounds were also evaluated for their antiparasitic activity. Copyright
- Thevenin, Marion,Mouray, Elisabeth,Grellier, Philippe,Dubois, Joelle
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supporting information
p. 2986 - 2992
(2014/05/20)
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- Phenyltellanyl triflate (PhTeOTf) as a powerful tellurophilic activator in the friedel-crafts reaction
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A powerful electrophilic activator for organotellurium compounds was developed. Phenyltellanyl triflate (PhTeOTf) prepared in situ from dibromophenyl(phenyltellanyl)telluride and AgOTf selectively activated various organotellurium compounds in the presence of aromatic compounds yielding the corresponding Friedel-Crafts reaction products. Polymer-end organotellurium compounds were also activated by PhTeOTf providing the corresponding end-functionalized polymers. Copyright
- Yamada, Takeshi,Mishima, Eri,Ueki, Kazuya,Yamago, Shigeru
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p. 650 - 651
(2008/12/20)
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- A facile phenol-driven intramolecular diastereoselective thermal/base-catalyzed dipolar [2 + 2] annulation reactions: An easy access to complex bioactive natural and unnatural benzopyran congeners
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The complex bioactive natural and unnatural benzopyran congeners have been synthesized using one-/two-step approaches in very good yields from the reactions of two different dihydroxyphthalides, natural resorcyclic acid derivative, and trihydroxybenzophenone with citral and/or farnesal, via the phenol-driven intramolecular diastereoselective thermal/base-catalyzed dipolar [2 + 2] cycloaddition reactions and three different thermal intramolecular cyclization reactions. The effects of the nature and the position of phenolic groups in the starting materials on the course of these cycloaddition reactions have also been described. Depending upon the absence or presence of intramolecular hydrogen bonding of the phenolic group with the carbonyl moiety in the starting materials, these phenol-driven intramolecular thermal/base-catalyzed dipolar [2 + 2] cycloaddition reactions either furnished the kinetically controlled products or directly formed the thermodynamically controlled rearranged products, respectively.
- Mondal, Mukulesh,Puranik, Vedavati G.,Argade, Narshinha P.
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p. 2068 - 2076
(2007/10/03)
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- Highly selective catalytic Friedel-Crafts acylation and sulfonylation of activated aromatic compounds using indium metal
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The Friedel-Crafts acylation of activated benzenes with various aromatic and aliphatic acid chlorides was studied in the presence of indium metal. The reaction was accomplished in high isolated yields under solvent or solvent-less conditions. The method is also applicable for preparing diaryl sulfones from aromatic compounds and aryl sulfonyl chlorides.
- Jang, Doo Ok,Moon, Kyung Soo,Cho, Dae Hyan,Kim, Joong-Gon
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p. 6063 - 6066
(2007/10/03)
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- Synthesis of aryl ketones or ketimines by palladium-catalyzed arene C-H addition to nitriles
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The unprecedented palladium-catalyzed C-H addition of arenes to nitriles provides moderate to excellent yields of aryl ketones or the corresponding hindered imines. The addition of a small amount of DMSO increases the yields dramatically. Both intermolecular and intramolecular reactions are successful, although the intramolecular reactions tend to be more sluggish. This novel chemistry is believed to involve palladium-catalyzed C-H activation of the arene by electrophilic aromatic substitution, followed by the unusual carbopalladation of a nitrile. Similar reactions have been successfully developed employing arylboronic acids and nitriles. A concise route to xanthones starting from cheap starting materials has been developed employing this synthetic protocol.
- Zhou, Chengxiang,Larock, Richard C.
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p. 3551 - 3558
(2007/10/03)
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- Synthesis of Aryl Ketones by the Pd-Catalyzed C-H Activation of Arenes and Intermolecular Carbopalladation of Nitriles
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The palladium-catalyzed reaction of simple arenes and nitriles provides good to excellent yields of aryl ketones or the corresponding hindered imines. The addition of a small amount of DMSO increases the yields dramatically. Both intermolecular and intramolecular examples of this process are successful. This novel chemistry is believed to involve palladium-catalyzed C?H activation, followed by carbopalladation of the nitrile. Copyright
- Zhou, Chengxiang,Larock, Richard C.
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p. 2302 - 2303
(2007/10/03)
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- Preparative and Structural Chemistry of Diastereomeric Derivatives of 3-PhosphanylpyrroIidine and Their Palladium(II) Complexes -Asymmetric Grignard Cross-Coupling Reaction
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The preparation of both diastereomeric derivatives of 3-(diphenylphosphanyljpyrrolidine with chiral (tetrahydrofuran2-yl}methyl and [(/V-neopentyl)pyrrolidin-2-yl]methyl groups as substituents on the pyrrolidine nitrogen atom and of (2S,4S)-l-benzyl-4-(diphenylphosphanyl)-2-(methoxymethyljpyrrolidine is reported. [3S,P(fiS)]-3-(phenylphosphanyljpyrrolidine, bearing an additional chiral center on phosphorus, is the starting material for the preparation of phosphanes, in which one phenyl group of the PPh2 moiety is substituted by an 2-methoxyphenyl (= An) or 2,4,6-trimethoxyphenyl (= TMP) group. PdI2 complexes of these ligands were separated into diastereomers by chromatography on silica gel columns. The structural chemistry of these novel phosphane diastereomers and their PdI2 complexes is investigated by X-ray crystallography and NMR. At the P,N-coordinated palladium center displacement of an iodide anion is found for P,N,N' ligands only. In the nickel complex catalysed cross-coupling reaction, yielding 3-phenyl-l-butene, we obtain the highest enantioselectivities in the case of simple l-alkyl-3-(diphenylphosphanyl)pyrrolidine ligands. The enantioselectivity obtained with diastereomeric derivatives, bearing additional ether or amine ligating sites is mainly determined by the chiral center in 3-position of the 3-(phosphanyl)pyrrolidine part of these ligands. Optimisation of enantioselectivity with these ligands can be carried out by a variation of the ligand to nickel ratio and by the choice of the vinyl halide used as starting compound. The catalytic cycle must contain at least one catalytically active species, bearing more than one ss-aminoalkylphosphane ligand. VCH Verlagsgesellschaft mbH,.
- Nagel, Ulrich,Nedden, Hans Guenter
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p. 989 - 1006
(2007/10/03)
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- 2-Substituted 1,3-Benzoxathiolium Tetrafluoroborates as Useful Acylating Agents of Electron-Rich Aromatic and Heteroaromatic Compounds
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2-Substituted 1,3-benzoxathiolium tetrafluoroborates were used for the two-step acylation of electron-rich aromatic and heteroaromatic compounds: 1,3-dimethoxybenzene, 1,3,5-trimethoxybenzene, pyrrole and indoles.In most of the cases intermediate 2,2-disubstituted 1,3-benzoxathioles were obtained in good to high yields (55-100percent) and subsequent hydrolysis of these with mercury(II) oxide and aqueous tetrafluoroboric acid (35percent) in tetrahydrofuran afforded the corresponding ketones in almost quantitative yields.
- Cadamuro, Silvano,Degani, Iacopo,Fochi, Rita,Gatti, Antonella,Regondi, Valeria
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p. 311 - 314
(2007/10/02)
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- Triflic acid catalyzed aroylation of arenes with aromatic nitriles
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In the presence of triflic acid, the reaction of different aromatic nitriles with arenes under a variety of conditions was examined.In addition to the normal reaction products (the s-triazines), aroylation of the arene to produce diaryl ketones in 20 to 50 percent yield was observed.Possible mechanism for the reaction was proposed.
- El-Khagawa, Ahmed M.
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p. 372 - 374
(2007/10/02)
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- Synthesis of Vismiaphenone-B: A Naturally Occurring Prenylated Benzophenone
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Vismiaphenone-B, 5-C-prenyl-2,6-dihydroxy-6'',6''-dimethylchromenobenzophenone (II), has been synthesised starting from 2,4,6-trihydroxybenzophenone (V).V on prenylation with prenyl bromide in the presence of methanolic sodium methoxide yields three products, viz. 3,5-di-C-prenyl-2,4,6-trihydroxybenzophenone (VI), 2,6-dihydroxy-4-O-prenylbenzophenone (VII) and a brown oil, which could not be characterised.VI on cyclodehydrogenation with DDQ affords II, identical in all respects (UV, IR and PMR) with a natural sample.
- Pathak, V. P.,Khanna, R. N.
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p. 253 - 254
(2007/10/02)
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