- Hydrothermal synthesis and catalysis of Nb2O5-WO x nanofiber crystal
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Nb2O5-WOx synthesized by a hydrothermal method having a long nano-crystalline structure with ca. 10 nm diameter exhibited a high catalytic activity in the Friedel-Crafts alkylations and acylations when it was calcined in N2. The Royal Society of Chemistry.
- Okumura, Kazu,Tomiyama, Takuya,Shirakawa, Shuhei,Ishida, Soichiro,Sanada, Takashi,Arao, Masazumi,Niwa, Miki
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Read Online
- Rh-Catalyzed Coupling of Aldehydes with Allylboronates Enables Facile Access to Ketones
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We present herein a novel strategy for the preparation of ketones from aldehydes and allylic boronic esters. This reaction involves the allylation of aldehydes with allylic boronic esters and the Rh-catalyzed chain-walking of homoallylic alcohols. The key to this successful development is the protodeboronation of alkenyl borylether intermediate via a tetravalent borate anion species in the presence of KHF2 and MeOH. This approach features mild reaction conditions, broad substrate scope, and excellent functional group tolerance. Mechanistic studies also supported that the tandem allylation and chain-walking process were involved.
- Zhang, Kezhuo,Huang, Jiaxin,Zhao, Wanxiang
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supporting information
(2022/02/21)
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- Discovery of Novel 3-Amino-4-alkoxyphenylketones as PDE4 Inhibitors with Improved Oral Bioavailability and Safety against Spatial Memory Impairments
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To realize PDE4 inhibitors with good developmental potentiality for the treatment of dementia, structure-based optimizations of lead compound FCPR03 resulted in novel aminophenylketones 9c and 9H with low nanomolar potency, which displayed comparable acti
- Feng, Kai-Wen,He, Jia-Peng,Liu, Lu,Wang, Hai-Tao,Xia, Chuang,Xu, Jiang-Ping,Zheng, Lei,Zhou, Zhong-Zhen
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p. 390 - 405
(2022/02/07)
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- Aminophenone compounds as well as preparation method and application thereof
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The invention belongs to the technical field of medicinal chemistry, and particularly relates to aminophenone compounds as well as a preparation method and application thereof. The aminophenone compounds provided by the invention have a good inhibition effect on PDE4, also have good bioavailability, can be applied to preparation of drugs for treating PDE4-related diseases, and increase the optionsof drugs for treating PDE4-related diseases; and the effect of a part of the aminophenone compounds is equivalent to the effect of positive drugs, and the aminophenone compounds have good developmentpotential.
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Paragraph 0047; 0051-0053; 0208-0209; 0213-0215
(2021/02/06)
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- Iron-Catalyzed C-C Single-Bond Cleavage of Alcohols
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An iron-catalyzed deconstruction/hydrogenation reaction of alcohols through C-C bond cleavage is developed through photocatalysis, to produce ketones or aldehydes as the products. Tertiary, secondary, and primary alcohols bearing a wide range of substituents are suitable substrates. Complex natural alcohols can also perform the transformation selectively. A investigation of the mechanism reveals a procedure that involves chlorine radical improved O-H homolysis, with the assistance of 2,4,6-collidine.
- Liu, Wei,Wu, Qiang,Wang, Miao,Huang, Yahao,Hu, Peng
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supporting information
p. 8413 - 8418
(2021/11/01)
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- AN IMPROVED AND COMMERCIALLY VIABLE PROCESS FOR PREPARATION OF ARYL KETONES
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The present disclosure provides a process for preparing an aryl ketone of Formula I, comprising reacting a substituted benzene of Formula II with a carboxylic acid of formula IIIa and/or a carboxylic anhydride of formula IIIb in presence of an alkyl sulfonic acid acting as catalyst cum solvent/contacting medium. I, II, IIIa, IIIb, wherein, R1, R2, R3 and R4 are as defined in the description.
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Paragraph 0076; 0087
(2020/09/12)
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- Facile preparation of 5-alkyl-1-aryltetrazoles with arenes, acyl chlorides, hydroxylamine, and diphenylphosphoryl azide
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Successive treatment of arenes with acyl chlorides and AlCl3, the addition of water and removal of solvent, the reaction with NH2OH?HCl and K2CO3, and the reaction with diphenylphosphoryl azide and DBU under warming conditions gave the corresponding 5-alkyl-1-aryltetrazoles efficiently in good to moderate yields. The present method is one-pot transformation of arenes into 5-alkyl-1-aryltetrazoles using the Friedel-Crafts acylation and the Beckmann rearrangement under transition-metal-free conditions.
- Shibasaki, Kaho,Togo, Hideo
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p. 1816 - 1830
(2020/11/19)
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- Iridium-Catalyzed Asymmetric Hydrogenation of α-Fluoro Ketones via a Dynamic Kinetic Resolution Strategy
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The discrimination of a fluorine atom from a hydrogen atom has been challenging in asymmetric catalysis. We herein report iridium-catalyzed hydrogenation of α-fluoro ketones using a strategy of dynamic kinetic resolution. Both enantiomeric and diastereomeric selectivities were satisfactory in the preparation of β-fluoro alcohols. The DFT calculation revealed a C-F···Na charge-dipole interaction in the transition state of hydride transfer. This noncovalent interaction would be responsible for the diastereomeric control.
- Tan, Xuefeng,Wen, Jialin,Zeng, Weijun,Zhang, Xumu
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supporting information
p. 7230 - 7233
(2020/10/02)
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- Acylation of aryl halides and α-bromo acetates with aldehydes enabled by nickel/tbadt cocatalysis
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In this protocol aryl halides and α-bromo acetates are efficiently cross-coupled with an array of (hetero)aromatic and aliphatic aldehydes under the cooperative catalysis of nickel and tetrabutylammonium decatungstate as a hydrogen-atom-transfer photocatalyst. This method provides a concise approach to a variety of ketones with high compatibility of various functional groups.
- Fan, Pei,Zhang, Chang,Zhang, Linchuan,Wang, Chuan
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supporting information
p. 3875 - 3878
(2020/05/14)
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- Electrochemical [4+2] Annulation-Rearrangement-Aromatization of Styrenes: Synthesis of Naphthalene Derivatives
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We report the first electrochemical strategy to synthesize functionalized naphthalene derivatives through [4+2] annulation—rearrangement–aromatization from styrenes under mild conditions. The electrolysis does not require metals, oxidants and high valence substrates, indicating the atom and step-economy ideals. The dehydrodimer produced through [4+2] cycloaddition of 4-methoxy α-methyl styrene is isolated and proved to be the key intermediate for the following oxydehydrogenation to form carbon cation, which undergoes rearrangement–aromatization to afford the final products. This reaction represents a powerful access to construct multi-substituted naphthalene blocks in a single step.
- Ma, Yueyue,Lv, Jufeng,Liu, Chengyu,Yao, Xiantong,Yan, Guoming,Yu, Wei,Ye, Jinxing
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supporting information
p. 6756 - 6760
(2019/04/17)
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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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- Palladium-Catalyzed Carbonylative Coupling of Aryl Iodides with Alkyl Bromides: Efficient Synthesis of Alkyl Aryl Ketones
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Alkyl aryl ketones are important structures with applications in many areas of chemistry. Hence, efficient procedures for their production are particularly attractive. In this communication, a general and efficient carbonylative cross-coupling of aryl iodides and unactivated alkyl bromides is presented. By using a simple palladium catalyst, a series of alkyl aryl ketones were synthesized in moderate to excellent yields from readily available alkyl and aryl halides in an In-Ex tube with formic acid as the CO source. In this study both primary and secondary alkyl bromides/iodides were suitable coupling partners. Additionally, this method can also be employed for the late-stage functionalization of complex natural products and polyfunctionalized molecules. (Figure presented.).
- Peng, Jin-Bao,Chen, Bo,Qi, Xinxin,Ying, Jun,Wu, Xiao-Feng
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supporting information
p. 4153 - 4160
(2018/09/21)
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- Dirhodium(ii)/P(t-Bu)3 catalyzed tandem reaction of α,β-unsaturated aldehydes with arylboronic acids
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Phosphine ligated dirhodium(ii) acetate is advocated as a catalyst for the synthesis of aryl alkyl ketones by the tandem reaction of α,β-unsaturated aromatic or aliphatic aldehydes with arylboronic acids. This tandem procedure included arylation followed by the isomerization reaction. This method exhibits good functional group tolerance and has a broad substrate scope. With the conjugated aldehydes, the one-step synthesis of γ,δ-unsaturated ketones was realized through this reaction. It is noteworthy that the length of the Rh-P bond is an important factor affecting catalytic reactions. The comparative analysis of the crystal structures of axially alkylphosphane and arylphosphane ligated dirhodium(ii) acetate revealed that the shorter Rh-P bond length favors the isomerization process as compared to the longer one. In addition, the dirhodium(ii) compound can be recovered after the completion of the reaction.
- Ma, Ziling,Wang, Yuanhua
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supporting information
p. 7470 - 7476
(2018/10/24)
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- Intermolecular Oxidative Radical Addition to Aromatic Aldehydes: Direct Access to 1,4- and 1,5-Diketones via Silver-Catalyzed Ring-Opening Acylation of Cyclopropanols and Cyclobutanols
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A novel silver-catalyzed ring-opening acylation of cyclopropanols and cyclobutanols is described. The reaction proceeds under mild and neutral conditions and provides a facile access to nonsymmetric 1,4- and 1,5-diketones in promising yields with broad substrate scope. Mechanistic studies including DFT calculations suggest the involvement of an uncommon water-assisted 1,2-HAT process, which is strongly exothermic and thus promotes addition of carbon radicals to aldehydes. In contrast to traditional reductive radical addition protocols, this work represents the first example of the intermolecular oxidative radical addition to aldehydes, thus offering a novel strategy for the direct synthesis of acyclic ketones from readily accessible aldehydes.
- Che, Chao,Qian, Zhaosheng,Wu, Mingchang,Zhao, Ying,Zhu, Gangguo
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p. 5665 - 5673
(2018/05/14)
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- Isolation and Characterization of Regioisomers of Pyrazole-Based Palladacycles and Their Use in α-Alkylation of Ketones Using Alcohols
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Regioisomers of 3,5-diphenyl-1-(4-(trifluoromethyl)phenyl)-1H-pyrazole-based palladacycles (1 and 2) were synthesized by the aromatic C-H bond activation of N/3-aryl ring. The application of these regioisomers as catalysts to enable the formation of α-alkylated ketones or quinolines with alcohols using a hydrogen borrowing process is evaluated. Experimental results reveal that palladacycle 2 is superior over palladacycle 1 to catalyze the reaction under similar reaction conditions. The reaction mechanisms for the palladacycles 1 and 2 catalyzed α-alkylation of acetophenone were studied using density functional theoretical (DFT) methods. The DFT studies indicate that palladacycle 2 has an energy barrier lower than that of palladacycle 1 for the alkylation reaction, consistent with the better catalytic activity of palladacycle 2 seen in the experiments. The palladacycle-phosphine system was found to tolerate a wide range of functional groups and serves as an efficient protocol for the synthesis of α-alkylated products under solvent-free conditions. In addition, the synthetic protocol was successfully applied to prepare donepezil, a drug for Alzheimer's disease, from simple starting materials.
- Mamidala, Ramesh,Samser, Shaikh,Sharma, Nishant,Lourderaj, Upakarasamy,Venkatasubbaiah, Krishnan
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supporting information
p. 3343 - 3351
(2017/09/18)
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- Catalytic Ring-Opening of Cyclic Alcohols Enabled by PCET Activation of Strong O-H Bonds
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We report a new photocatalytic protocol for the redox-neutral isomerization of cyclic alcohols to linear ketones via C-C bond scission. Mechanistic studies demonstrate that key alkoxy radical intermediates in this reaction are generated via the direct homolytic activation of alcohol O-H bonds in an unusual intramolecular PCET process, wherein the electron travels to a proximal radical cation in concert with proton transfer to a weak Br?nsted base. Effective bond strength considerations are shown to accurately forecast the feasibility of alkoxy radical generation with a given oxidant/base pair.
- Yayla, Hatice G.,Wang, Huaiju,Tarantino, Kyle T.,Orbe, Hudson S.,Knowles, Robert R.
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p. 10794 - 10797
(2016/09/09)
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- Synthesis and characterization of AlCl3 impregnated molybdenum oxide as heterogeneous nano-catalyst for the Friedel-Crafts acylation reaction in ambient condition
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Aluminum trichloride (AlCl3) impregnated molybdenum oxide heterogeneous nano-catalyst was prepared by using simple impregnation method. The prepared heterogeneous catalyst was characterized by powder X-ray diffraction, FT-IR spectroscopy, solid-state NMR spectroscopy, SEM imaging, and EDX mapping. The catalytic activity of this protocol was evaluated as heterogeneous catalyst for the Friedel-Crafts acylation reaction at room temperature. The impregnated MoO4(AlCl2)2 catalyst showed tremendous catalytic activity in Friedel-Crafts acylation reaction under solvent-free and mild reaction condition. As a result, 84.0% yield of acyl product with 100% consumption of reactants in 18 h reaction time at room temperature was achieved. The effects of different solvents system with MoO4(AlCl2)2 catalyst in acylation reaction was also investigated. By using optimized reaction condition various acylated derivatives were prepared. In addition, the catalyst was separated by simple filtration process after the reaction and reused several times. Therefore, heterogeneous MoO4(AlCl2)2 catalyst was found environmentally benign catalyst, very convenient, high yielding, and clean method for the Friedel-Crafts acylation reaction under solvent-free and ambient reaction condition.
- Jadhav, Arvind H.,Chinnappan, Amutha,Hiremath, Vishwanath,Seo, Jeong Gil
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p. 8243 - 8250
(2015/11/27)
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- Vanadium-catalyzed green oxidation of benzylic alcohols in water under air atmosphere
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The oxidation of alcohols using catalytic amounts of metal complexes is highly attractive from the viewpoint of green chemistry principles. However, examples of metal complex-catalyzed oxidations of alcohols with O2 using water as the solvent are still rare, and precious metals, high-pressure O2 or air, and a stoichiometric amount of base are often required. In this study, it was found that an oxovanadium-4,4′-t-Bubpy (4,4′-di-tert-butyl-2,2′-bipyridyl) complex exhibited high catalytic activity in the oxidation of benzhydrols under an atmosphere of O2 in water as the sole solvent. Interestingly, this catalytic oxidation method could be applied to the gram-scale aerobic oxidation of alcohols in water under the atmosphere.
- Marui, Kuniaki,Higashiura, Yuuki,Kodama, Shintaro,Hashidate, Suguru,Nomoto, Akihiro,Yano, Shigenobu,Ueshima, Michio,Ogawa, Akiya
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p. 2431 - 2438
(2014/04/03)
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- New approach to oximes through reduction of nitro compounds enabled by visible light photoredox catalysis
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A range of nitro compounds are smoothly reduced to their corresponding oximes under the synergistic effects of visible light irradiation, the Ru(bpy)3Cl2 photocatalyst, Hünig's base, Mg(ClO 4)2 activation, and MeCN solvent. This remarkably mild and environmentally benign protocol, when orchestrated with classical Beckmann rearrangement, enables such high-value industrial feedstock as caprolactam to be readily accessed from simple precursor nitrocyclohexane.
- Cai, Shunyou,Zhang, Shaolong,Zhao, Yaohong,Wang, David Zhigang
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supporting information
p. 2660 - 2663
(2013/07/11)
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- A base-promoted deprotection of 1,3-dioxolanes to ketones
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An effective deprotection methodology of dioxolanes was developed, affording moderate to excellent yield via a LTMP-promoted reaction in THF, which displays admirable chemoselectivity in the presence of dimethylketal, 1,3-dioxane, 1,3-dithiane, or other acid-sensitive protective groups.
- Yuan, Changchun,Yang, Li,Yue, Guizhou,Yu, Tianzi,Zhong, Weiming,Liu, Bo
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supporting information
p. 6972 - 6976
(2013/01/15)
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- Friedel-crafts acylation of arenes with carboxylic acids using polystyrene-supported aluminum triflate
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Cross-linked polystyrene-supported aluminum triflate (Ps-Al(OTf) 3) has been shown to be a mild, efficient, and chemoselective heterogeneous Lewis acid catalyst for the acylation of aromatic compounds. The catalyst can be easily prepared from cheap starting materials, is stable (as a bench top catalyst) and is reusable.
- Boroujeni, Kaveh Parvanak,Parvanak, Kamran
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experimental part
p. 155 - 163
(2012/01/02)
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- Synthesis and investigations on the oxidative degradation of C3/C5-Alkyl-1,2,4-triarylpyrroles as ligands for the estrogen receptor
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In this study, we synthesized 1,2,4-triarylpyrroles as ligands for the estrogen receptor (ER). Two pyrrole series were prepared with either C3-alkyl or C3/C5-dialkyl residues. Compounds from both series were susceptible to oxidative degradation-dialkylated compounds (t1/2=33-66h) to a higher extent than their monoalkylated congeners (t1/2=140-211h). Nevertheless, stability was sufficient for determination of in vitro ER binding affinity. The most active agonist in hormone-dependent, ERα-positive MCF-7/2a and U2-OS/α cells was 1,2,4-tris(4-hydroxyphenyl)-3-propyl-1H-pyrrole (6d) (MCF-7/2a: EC50=70nM; U2-OS/α: EC50=1.6nM). A corresponding inactivity in U2-OS/β cells demonstrated the high ERα selectivity. This trend was confirmed in a competition experiment using estradiol (E2) and purified hERα and hERβ proteins (relative binding affinity (RBA) calculated for 6d: RBA(ERα)=1.85%; RBA(ERβ) 0.01%). Generally, C3/C5-dialkyl substitution led to reduction of activity, possibly due to lower stability. Triarylpyrroles with C3-alkyl or C3/C5-dialkyl residues were synthesized as ligands for the estrogen receptor (ER). The compounds exhibited transcription activation selectively for ERα but only marginally displaced estradiol from its binding site. The compounds were susceptible to oxidative degradation-dialkylated compounds to a higher extent than their monoalkylated congeners. The reasons for instability were elucidated; thus, by changing the substitution pattern, it will be possible to generate stable triarylpyrroles.
- Schaefer, Anja,Wellner, Anja,Gust, Ronald
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scheme or table
p. 794 - 803
(2012/01/06)
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- Acylation of aromatic ethers using different carboxylic acid anhydrides as acylating agents in the presence of nontoxic, noncorrosive resin amberlyst 15 as a solid acid catalyst
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Friedel-Crafts acylation of aromatic ethers, anisole, 2-methoxynaphthalene, and dimethoxybenzenes with different acid anhydrides is carried out in the presence of an inexpensive and nonhazardous solid acid, Amberlyst 15. The catalyst is reusable, thus making the process environmentally friendly.
- Pande, Manoj A.,Samant, Shriniwas D.
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experimental part
p. 754 - 761
(2011/04/12)
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- Ru- and Pd-catalysed synthesis of 2-arylfurans by one-flask heck arylation/oxidation
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2,5-Disubstituted furans were synthesized by one-flask Heck arylation/oxidation sequences. The starting materials are 2-substituted 2,3-dihydrofurans, conveniently available by RCM/isomerization sequences, and arenediazonium salts. These react in ligand-free Heck reactions to afford 2,5-disubstituted 2,5-dihydrofurans, which are oxidized to the corresponding furans without isolation or intermediate workup. The oxidation is conveniently achieved with chloranil or DDQ, depending on the substrate.
- Schmidt, Bernd,Geissler, Diana
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p. 4814 - 4822
(2011/10/09)
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- Palladium-catalyzed oxidative coupling of trialkylamines with aryl iodides leading to alkyl aryl ketones
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Chemical equations presented. A new, simple method for selectively synthesizing alkyl aryl ketones has been developed by palladium-catalyzed oxidative coupling of trialkylamines with aryl iodides. In the presence of PdCl2(MeCN)2, TBAB, and ZnO, a variety of aryl iodides underwent an oxidative coupling reaction with tertiary amines and water to afford the corresponding alkyl aryl ketones in moderate to excellent yields. It is noteworthy that this method is the first example of using trialkylamines as the carbonyl sources for constructing alkyl aryl ketone skeletons.
- Liu, Yan,Yao, Bo,Deng, Chen-Liang,Tang, Ri-Yuan,Zhang, Xing-Guo,Li, Jin-Heng
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supporting information; scheme or table
p. 2184 - 2187
(2011/06/20)
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- Pd-NHC catalyzed conjugate addition versus the mizoroki-heck reaction
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Ace of base: A catalytic system is presented that, solely by choice of the base, selectively switches between conjugate addition and the Mizoroki-Heck reaction of aryl halides with Michael acceptors (see scheme; R, R′=alkyl, aryl). For conjugate addition reactions, this avoids the preparation and use of organometallics.
- Gottumukkala, Aditya L.,Devries, Johannes G.,Minnaard, Adriaan J.
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scheme or table
p. 3091 - 3095
(2011/04/22)
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- Hydrogen-bonding-promoted oxidative addition and regioselective arylation of olefins with aryl chlorides
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The first, general, and highly efficient catalytic system that allows a wide range of activated and unactivated aryl chlorides to couple regioselectively with olefins has been developed. The Heck arylation reaction is likely to be controlled by the oxidative addition of ArCl to Pd(0). Hence, an electron-rich diphosphine, 4-MeO-dppp, was introduced to facilitate the catalysis. Solvent choice is critical, however; only sluggish arylation is observed in DMF or DMSO, whereas the reaction proceeds well in ethylene glycol at 0.1-1 mol % catalyst loadings, displaying excellent regioselectivity. Mechanistic evidence supports that the arylation is turnover-limited by the oxidative addition step and, most importantly, that the oxidative addition is accelerated by ethylene glycol, most likely via hydrogen bonding to the chloride at the transition state as shown by DFT calculations. Ethylene glycol thus plays a double role in the arylation, facilitating oxidative addition and promoting the subsequent dissociation of chloride from Pd(II) to give a cationic Pd(II)-olefin species, which is key to the regioselectivity observed.
- Ruan, Jiwu,Iggo, Jonathan A.,Berry, Neil G.,Xiao, Jianliang
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supporting information; experimental part
p. 16689 - 16699
(2011/02/23)
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- Friedel-Crafts acylation of arenes with carboxylic acids using silica gel supported AlCl3
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Aromatic compounds react smoothly with carboxylic acids in the presence of silica gel supported aluminium trichloride to afford the corresponding ketones with high regioselectivity in high to excellent yields. The catalyst is stable (as a bench top catalyst) and can be easily recovered and reused without appreciable change in its efficiency. tuebitak.
- Parvanak Boroujeni, Kaveh
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experimental part
p. 621 - 630
(2010/11/04)
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- Microwave-assisted acylation of aromatic compounds using carboxylic acids and zeolite catalysts
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Acylation of aromatic compounds with carboxylic acids smoothly proceeded at 190-230 °C in the presence of zeolite catalysts under microwave irradiation to give aromatic ketones efficiently. H-Y (SiO2/Al2O 3 = 30-80) and H-beta (25) zeolites were active for the acylation reaction, giving the aromatic ketones in good yields. Carboxylic acids such as hexanoic and butyric acid smoothly underwent the acylation, while propionic acid showed somewhat lower reactivity. Anisole gave the para-acylation products nearly selectively. Anisole, 2,3-dihydrobenzofuran, and thiophene were reactive aromatic compounds. 2,3-Dihydrobenzofuran also reacted at the para position to the oxygen atom predominantly to give the corresponding ketones as the major products. The microwave reactions were generally faster than the conventional oil bath reactions and gave higher yields of the acylation products. Activation energies for the reaction of anisole with butyric acid by microwave and by oil bath heating were also estimated on the basis of the Arrhenius plots.
- Yamashita, Hiroshi,Mitsukura, Yumi,Kobashi, Hiroko
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experimental part
p. 80 - 86
(2010/11/17)
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- Synthesis of a series of novel 2,4,5-trisubstituted selenazole compounds as potential PLTP inhibitors
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Based on a homology-modeled structure of PLTP and characteristic structural features of reported cholesteryl ester transfer protein (CETP) inhibitors, we designed and synthesized a novel series of 2,4,5-trisubstituted selenazole compounds. Biological evaluation reveals that compounds 12 and 17 exhibit favorable PLTP activity, and their IC50s are 8 μM and 10 μM, respectively.
- Ling, Cui,Zheng, Zhibing,Jiang, Xian Cheng,Zhong, Wu,Li, Song
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scheme or table
p. 5123 - 5125
(2010/10/19)
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- Thermal retro-aldol reaction using fluorous ether F-626 as a reaction medium
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A high-boiling, fluorous-organic hybrid ether, F-626, was tested for use in thermal retro-aldol reactions and found to be an excellent reaction medium in view of the ease of separation from the product by fluorous/organic biphasic treatment. The recovered F-626 can be readily reused for subsequent runs.
- Fukuyama, Takahide,Kawamoto, Takuji,Okamura, Takahiro,Denichoux, Aurelien,Ryu, Ilhyong
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experimental part
p. 2193 - 2196
(2010/10/21)
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- Direct acylation of aryl chlorides with aldehydes by palladium-pyrrolidine Co-catalysis
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A palladium catalyst system has been developed that allows for the direct acylation of aryl chlorides with aldehydes. The choice of ligand, as well as the presence of pyrrolidine and molecular sieves is shown to be critical to the catalysis, which appears to proceed via an enamine intermediate. The reaction was successful for a wide range of aryl chlorides and tolerant of functionality on the aldehyde component, giving easy access to alkyl aryl ketones in modest to good yields.
- Colbon, Paul,Ruan, Jiwu,Purdie, Mark,Xiao, Jianliang
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supporting information; experimental part
p. 3670 - 3673
(2010/10/20)
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- Unified oxidation protocol for the synthesis of carbonyl compounds using a manganese catalyst
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We have developed a unified protocol for the oxidation of ethers, benzylic compounds, and alcohols to carbonyl compounds. The protocol uses catalytic amounts of manganese(II) chloride tetrahydrate and tri(t-butyl)-2,2':6',2Prime;- terpyridine in combination with a stoichiometric amount of either m-chloroperbenzoic acid (MCPBA) or potassium hydrogen peroxysulfate (KHSO 5). A reagent system consisting of the Mn catalyst and MCPBA permitted the chemoselective sp3 C-H oxidation of alkyl ethers and benzylic compounds to generate the corresponding ketones. Alternatively, the water-soluble inorganic salt KHSO5 in combination with the Mn catalyst was used to oxidize alcohols to ketones or carboxylic acids. Importantly, the Mn catalyst/KHSO5 system eliminates technical difficulties associated with the isolation of carboxylic acid products. All the oxidations presented in this feature article proceed at sup-ambient temperature in an aerobic atmosphere, and can therefore be used in practical syntheses of complex organic molecules. Georg Thieme Verlag Stuttgart · New York.
- Kamijo, Shin,Amaoka, Yuuki,Inoue, Masayuki
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experimental part
p. 2475 - 2489
(2010/09/06)
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- Biocatalytic promiscuity of lipase in chemoselective oxidation of aryl alcohols/acetates: a unique synergism of cal-b and [hmim]br for the metal-free h2o2 activation
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A unique synergistic combination of lipase and Ionic liquid [hmlm]Br Is reported for metal-free H2O2 activation, which is the first example of blocatalytlc promiscuity of CAL-B for chemoselectlve oxidation of aryl alcohols/acetates. The catalytic system exhibits excellent functional group compatibility under neutral conditions besides reusability up to ten cycles thereby making the process economically and environmentally viable.
- Sharma, Upendra K.,Sharma, Nandini,Kumar, Rakesh,Kumar, Rajesh,Sinha, Arun K.
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supporting information; experimental part
p. 4846 - 4848
(2010/01/16)
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- Oxygen and base-free oxidative heck reactions of arylboronic acids with olefins
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A mild and efficient protocol for palladium-catalyzed oxidative Heck reactions of arylboronic acids with both electron-rich and -deficient olefins is described. In contrast to the normal oxidative Heck coupling, this new method works in the absence of a base, oxygen, or other external oxidants. With a wide variety of substrates tolerated, the method broadens the scope of palladium-catalyzed coupling reactions. Copyright
- Ruan, Jiwu,Li, Xinming,Saidi, Ourida,Xiao, Jianliang
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p. 2424 - 2425
(2008/09/18)
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- Friedel-Crafts Acylation Process in Ionic Liquids
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A preparation process of aromatic ketones by a Friedel-Crafts acylation reaction in an ionic liquid of formula (I), in the absence of any other catalyst and/or solvent. In formula (I), [Q]+ is selected from substituted-imidazolium cations, substituted-pyridinium cations, ammonium cations, and phosponium cations. It allows to carry out Friedel-Crafts acylations with good yields and high selectivity in para position of the Friedel-Crafts aromatic substrate without using chlorine-containing solvents and conventional Friedel-Crafts catalysts. It is industrially useful because provides a “Green Chemistry” technology for carrying out Friedel-Crafts acylations of general aplicability. [in-line-formulae][Q]+[CF3SO3]???(I)[/in-line-formulae]
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Page/Page column 2-3
(2009/01/20)
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- Direct acylation of aryl bromides with aldehydes by palladium catalysis
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A new protocol for the direct acylation of aryl bromides with aldehydes is established. It appears to involve palladium-amine cooperative catalysis, affording synthetically important alkyl aryl ketones in moderate to excellent yields in a straightforward manner, and broadening the scope of metal-catalyzed coupling reactions. Copyright
- Ruan, Jiwu,Saidi, Ourida,Iggo, Jonathan A.,Xiao, Jianliang
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supporting information; experimental part
p. 10510 - 10511
(2009/02/05)
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- One-step preparation of α-chlorostyrenes
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α-Chlorostyrenes were prepared via a one-step method involving Friedel-Crafts reaction of various aromatic substrates with acid chlorides in the presence of a heterogeneous Si-Fe catalyst.
- Borate, Hanumant B.,Gaikwad, Abaji G.,Maujan, Suleman R.,Sawargave, Sangmeshwer P.,Kalal, Kamalakar M.
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p. 4869 - 4872
(2008/02/05)
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- Synthesis of novel nitro-substituted triaryl pyrazole derivatives as potential estrogen receptor ligands
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Novel tetrasubstituted pyrazole derivatives bearing a nitro substituent on their A-phenol ring were synthesized and their binding affinity towards the estrogen receptor (ER) subtypes ERα and ERβ was determined. Among compounds tested, the 2-nitrophenol derivative 5c was found to bind satisfactorily to both estrogen receptor subtypes (RBAα=5.17 and RBAβ=3.27). In general, the introduction of a nitro group into the A ring of these compounds was found to benefit their ERβ binding abilities.
- Naoum, Fotini,Kasiotis, Konstantinos M.,Magiatis, Prokopios,Haroutounian, Serkos A.
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p. 1259 - 1273
(2008/02/08)
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- Recyclable hafnium(IV) bis(perfluorooctanesulfonyl)amide complex for catalytic Friedel-Crafts acylation and Prins reaction in fluorous biphase system
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In fluorous biphase system, hafnium(IV) bis(perfluorooctanesulfonyl)amide complex (Hf[N(SO2C8F17)2]4) was found to be a highly reactive and recyclable Lewis acid catalyst for Friedel-Crafts acylation and Prins reaction at significantly low catalyst loadings (≤1 mol%). In these reactions, Hf[N(SO2C8F17)2]4 is selectively soluble in the lower fluorous phase and can be recovered simply by phase separation. Furthermore, the catalyst can be reused without decrease of activity.
- Hao, Xiuhua,Yoshida, Akihiro,Hoshi, Nobuto
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p. 1396 - 1401
(2008/09/18)
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- Atom-efficient cross-coupling reactions of triarylbismuths with acyl chlorides under Pd(0) catalysis
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The atom-efficient cross-coupling reaction of triarylbismuths with a variety of aliphatic, aromatic, and hetero-aromatic acyl chlorides was demonstrated to afford high yields of cross-coupled ketones under palladium catalysis. The corresponding cross-coupling reaction with diacid chlorides also furnished bis-coupled ketones in good yields.
- Rao, Maddali L.N.,Venkatesh, Varadhachari,Banerjee, Debasis
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p. 12917 - 12926
(2008/03/28)
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- METHOD FOR FRIEDEL-CRAFTS ACYLATION IN IONIC LIQUIDS
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A preparation process of aromatic ketones by a Friedel-Crafts acylation reaction in an ionic liquid of formula (I), in the absence of any other catalyst and/or solvent. In formula (I), [Q]+ is selected from substituted-imidazolium cations, substituted-pyridinium cations, ammonium cations, and phosponium cations. It allows to carry out Friedel-Crafts acylations with good yields and high selectivity in para position of the Friedel-Crafts aromatic substrate without using chlorine-containing solvents and conventional Friedel-Crafts catalysts. It is industrially useful because provides a "Green Chemistry" technology for carrying out Friedel-Crafts acylations of general aplicability. ????????[Q]+ [CF3SO3]-?????(I)
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Page/Page column 4
(2008/06/13)
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- Palladium-catalyzed synthesis of aryl ketones by coupling of aryl bromides with an acyl anion equivalent
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Palladium-catalyzed couplings of aryl bromides with N-tert-butylhydrazones as acyl anion equivalents to form aryl ketones are reported. The coupling process occurs at the C-position of hydrazones to form N-tert-butyl azo compounds. Isomerization of these azo compounds to the corresponding hydrazones, followed by hydrolysis, gave the desired mixed alkyl aryl ketones. The selectivity of C- versus N-arylation was strongly influenced by the substituent on nitrogen. Arylation at carbon occurred with N-tert-butylhydrazones, whereas N-arylation occurred with N-arylhydrazones. The arylation of hydrazones containing primary and secondary alkyl groups, as well as aryl groups, gave the desired ketones in good yields after hydrolysis. Functional groups on the aromatic ring, such as alkoxy, cyano, trifluoromethyl, carboalkoxy, carbamoyl, and keto groups, were tolerated. This reaction likely occurs by C-C bond-forming reductive elimination from an intermediate containing an η1-diazaallyl ligand. Copyright
- Takemiya, Akihiro,Hartwig, John F.
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p. 14800 - 14801
(2008/02/05)
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- Metal bis(perfluorooctanesulfonyl)amides as highly efficient Lewis acid catalysts for fluorous biphase organic reactions
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In fluorous biphase system, metal bis(perfluorooctanesulfonyl)amides are better Lewis acid catalysts than the analogous triflates toward either transesterifications, or direct esterifications, or Friedel-Crafts acylations or Baeyer-Villiger oxidations. These catalysts are selectively soluble in lower fluorous phase and can be recovered simply by phase separation. Furthermore, these catalysts can be reused without decrease of activity in most cases.
- Hao, Xiuhua,Yoshida, Akihiro,Nishikido, Joji
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p. 193 - 199
(2007/10/03)
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- Hf[N(SO2C8F17)2] 4-catalyzed Friedel-Crafts acylation in a fluorous biphase system
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In a fluorous biphase system, Hf[N(SO2C8F 17)2]4 complex (1 mol %) catalyzes Friedel-Crafts acylation of aromatic compounds such as anisole, toluene and chlorobenzene, and the corresponding aromatic ketones are obtained in satisfactory to high yields. The catalyst is selectively soluble in lower fluorous phase and can be easily recovered by simple phase separation. Furthermore, the catalyst can be reused without decrease of activity in most cases.
- Hao, Xiuhua,Yoshida, Akihiro,Nishikido, Joji
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p. 2697 - 2700
(2007/10/03)
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- Aluminum dodecatungstophosphate (AlPW12O40) as a non-hygroscopic Lewis acid catalyst for the efficient Friedel-Crafts acylation of aromatic compounds under solvent-less conditions
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Stable and non-hygroscopic aluminum dodecatungstophosphate (AlPW 12O40), which is prepared easily from cheap and commercially available compounds was found to be an effective catalyst for Friedel-Crafts acylation reactions using carboxylic acids, acetic anhydride and benzoyl chloride in the absence of solvent under mild reaction conditions.
- Firouzabadi, Habib,Iranpoor, Nasser,Nowrouzi, Farhad
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p. 10843 - 10850
(2007/10/03)
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- Acylation of aromatic compounds using moisture insensitive mesoporous Si-MCM-41 supported Ga2O3 catalyst
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Mesoporous Si-MCM-41 supported Ga2O3 is a highly active catalyst for the acylation of aromatic compounds with different acyl chlorides. Moreover, this catalyst is not deactivated by water and hence does not require moisture-free reaction conditions.
- Choudhary, Vasant R.,Jana, Suman K.
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p. 2843 - 2848
(2007/10/03)
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- Efficient acylation of toluene and anisole with aliphatic carboxylic acids catalysed by heteropoly salt Cs2.5H0.5PW12O40
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Heteropoly salt Cs2.5H0.5PW12O40 is a highly efficient and reusable solid acid catalyst for the liquid-phase acylation of toluene or anisole with C2 - C12 aliphatic carboxylic acids.
- Kaur, Jaspal,Kozhevnikov, Ivan V.
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p. 2508 - 2509
(2007/10/03)
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- Acylation of aromatic compounds using moisture insensitive InCl3 impregnated mesoporous Si-MCM-41 catalyst
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Acylation of aromatic compounds (benzene, toluene, p-xylene, mesitylene, anisole, naphthalene, methylnaphthalene and methoxynaphthalene) by an acyl chloride (benzoyl chloride, phenylacetyl chloride, propionyl chloride or butyryl chloride) in high yield, in a short reaction period (3 h), even in the presence of moisture in the aromatic substrate or solvent (dichloroethane), can be accomplished at low temperature (80±1°C) using an InCl3 impregnated Si-MCM-41 catalyst in low catalyst concentration.
- Choudhary, Vasant R.,Jana, Suman K.,Patil, Nilesh S.
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p. 1105 - 1107
(2007/10/03)
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- Pyrazole ligands: Structure - Affinity/activity relationships and estrogen receptor-α-selective agonists
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We have found that certain tetrasubstituted pyrazoles are high-affinity ligands for the estrogen receptor (ER) (Fink et al. Chem. Biol. 1999, 6, 205-219) and that one pyrazole is considerably more potent as an agonist on the ERα than on the ERβ subtype (Sun et al. Endocrinology 1999, 140, 800-804). To investigate what substituent pattern provides optimal ER binding affinity and the greatest enhancement of potency as an ERα-selective agonist, we prepared a number of tetrasubstituted pyrazole analogues with defined variations at certain substituent positions. Analysis of their binding affinity pattern shows that a C(4)-propyl substituent is optimal and that a p-hydroxyl group on the N(1)-phenyl group also enhances affinity and selectivity for ERα. The best compound in this series, a propylpyrazole triol (PPT, compound 4g), binds to ERα with high affinity (ca. 50% that of estradiol), and it has a 410-fold binding affinity preference for ERα. It also activates gene transcription only through ERα. Thus, this compound represents the first ERα-specific agonist. We investigated the molecular basis for the exceptional ERα binding affinity and potency selectivity of pyrazole 4g by a further study of structure-affinity relationships in this series and by molecular modeling. These investigations suggest that the pyrazole triols prefer to bind to ERα with their C(3)-phenol in the estradiol A-ring binding pocket and that binding selectivity results from differences in the interaction of the pyrazole core and C(4)-propyl group with portions of the receptor where ERα has a smaller residue than ERβ. These ER subtype-specific interactions and the ER subtype-selective ligands that can be derived from them should prove useful in defining those biological activities in estrogen target cells that can be selectively activated through ERα.
- Stauffer,Coletta,Tedesco,Nishiguchi,Carlson,Sun,Katzenellenbogen,Katzenellenbogen
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p. 4934 - 4947
(2007/10/03)
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