- Enantioselective Morita-Baylis-Hillman reaction catalyzed by a chiral phosphine oxide
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An application of a hypervalent silicon complex, generated from a chiral phosphine oxide catalyst and silicon tetrachloride, to the enantioselective organocatalytic Morita-Baylis-Hillman reaction is described. A chloride anion liberated from the hypervalent silicon complex smoothly generated a γ-chloro silyl enol ether that subsequently reacted with an aldehyde to afford the Baylis-Hillman adducts in good yields and with good enantioselectivities.
- Kotani, Shunsuke,Ito, Masaya,Nozaki, Hirono,Sugiura, Masaharu,Ogasawara, Masamichi,Nakajima, Makoto
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Read Online
- I2-Promoted Intramolecular Oxidative Cyclization of Butenyl Anilines: A Facile Route to Benzo[b]azepines
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A metal-free approach for the synthesis of seven-membered N-heterocycles has been developed by the I2-promoted intramolecular cross-coupling/annulation of butenyl anilines. This cyclization reaction involves C?H activation and C?C bond formation and exhibits good functional group tolerance. A series of benzo[b]azepine derivatives are obtained in moderate to good yields.
- An, Zhenyu,Ren, Yi,Liu, Yafeng,Yan, Rulong
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supporting information
p. 2614 - 2617
(2021/08/06)
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- V2O5@TiO2 Catalyzed Green and Selective Oxidation of Alcohols, Alkylbenzenes and Styrenes to Carbonyls
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The versatile application of different functional groups such as alcohols (1° and 2°), alkyl arenes, and (aryl)olefins to construct carbon-oxygen bond via oxidation is an area of intense research. Here, we report a reusable heterogeneous V2O5@TiO2 catalyzed selective oxidation of various functionalities utilizing different mild and eco-compatible oxidants under greener reaction conditions. The method was successfully applied for the alcohol oxidation, oxidative scission of styrenes, and benzylic C?H oxidation to their corresponding aldehydes and ketones. The utilization of mild and eco-friendly oxidizing reagents such as K2S2O8, H2O2 (30 % aq.), TBHP (70 % aq.), broad substrate scope, gram-scale synthesis, and catalyst recyclability are notable features of the developed protocol.
- Upadhyay, Rahul,Kumar, Shashi,Maurya, Sushil K.
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p. 3594 - 3600
(2021/07/02)
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- Iron-Catalyzed Wacker-type Oxidation of Olefins at Room Temperature with 1,3-Diketones or Neocuproine as Ligands**
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Herein, we describe a convenient and general method for the oxidation of olefins to ketones using either tris(dibenzoylmethanato)iron(III) [Fe(dbm)3] or a combination of iron(II) chloride and neocuproine (2,9-dimethyl-1,10-phenanthroline) as catalysts and phenylsilane (PhSiH3) as additive. All reactions proceed efficiently at room temperature using air as sole oxidant. This transformation has been applied to a variety of substrates, is operationally simple, proceeds under mild reaction conditions, and shows a high functional-group tolerance. The ketones are formed smoothly in up to 97 % yield and with 100 % regioselectivity, while the corresponding alcohols were observed as by-products. Labeling experiments showed that an incorporated hydrogen atom originates from the phenylsilane. The oxygen atom of the ketone as well as of the alcohol derives from the ambient atmosphere.
- Kataeva, Olga,Kn?lker, Hans-Joachim,Linke, Philipp,Puls, Florian
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supporting information
p. 14083 - 14090
(2021/05/24)
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- Catalytic Aerobic Oxidation of Alkenes with Ferric Boroperoxo Porphyrin Complex; Reduction of Oxygen by Iron Porphyrin
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We herein describe the development of a mild and selective catalytic aerobic oxidation process of olefins. This catalytic aerobic oxidation reaction was designed based on experimental and spectroscopic evidence assessing the reduction of atmospheric oxygen using a ferric porphyrin complex and pinacolborane to form a ferric boroperoxo porphyrin complex as an oxidizing species. The ferric boroperoxo porphyrin complex can be utilized as an in-situ generated intermediate in the catalytic aerobic oxidation of alkenes under ambient conditions to form oxidation products that differ from those obtained using previously reported ferric porphyrin catalysis. Moreover, the mild reaction conditions allow chemoselective oxidation to be achieved.
- Kimura, Kento,Kurahashi, Takuya,Matsubara, Seijiro,Murano, Shunpei
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supporting information
p. 2493 - 2497
(2021/12/29)
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- Synthesis and Evaluation of 2-Azetidinone and 1H-Pyrrole-2,5-dione Derivatives as Cholesterol Absorption Inhibitors for Reducing Inflammation Response and Oxidative Stress
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Excess lipid accumulation can initiate the development and progression of atherosclerotic lesions, thus eventually leading to cardiovascular disease. Lipid-lowering medication therapy is one of the cornerstones of cardiovascular disease therapy. On the basis of the cholesterol absorption inhibitor ezetimibe, we successfully synthesized seven 2-azetidinone derivatives and eighteen 1H-pyrrole-2,5-dione derivatives. Most of the new compounds significantly inhibited cholesterol uptake in vitro. In addition, one of the most active inhibitors, 3-(4-fluorophenyl)-1-[(3S)-3-hydroxy-3-(4-hydroxyphenyl)propyl]-4-(4-hydroxyphenyl)-1H-pyrrole-2,5-dione (14q), showed no cytotoxicity in L02 and HEK293T cell lines. Further evaluation indicated that 14q inhibited considerably the amount of TNF-α, ROS, MDA, and LDH in vitro. Therefore, 14q might be a novel cholesterol absorption inhibitor.
- Xia, Yineng,Zhu, Lijuan,Yuan, Xinrui,Wang, Yubin
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- Manganese-Catalyzed Electrochemical Deconstructive Chlorination of Cycloalkanols via Alkoxy Radicals
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A manganese-catalyzed electrochemical deconstructive chlorination of cycloalkanols has been developed. This electrochemical method provides access to alkoxy radicals from alcohols and exhibits a broad substrate scope, with various cyclopropanols and cyclobutanols converted into synthetically useful β- and γ-chlorinated ketones (40 examples). Furthermore, the combination of recirculating flow electrochemistry and continuous inline purification was employed to access products on a gram scale.
- Allen, Benjamin D. W.,Hareram, Mishra Deepak,Seastram, Alex C.,McBride, Tom,Wirth, Thomas,Browne, Duncan L.,Morrill, Louis C.
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supporting information
p. 9241 - 9246
(2019/11/19)
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- Oxidation of secondary alcohols using solid-supported hypervalent iodine catalysts
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It is shown how secondary alcohols are oxidized to provide the corresponding ketones by use of Oxone and solid-supported hypervalent iodine catalysts. Under experimentally simple conditions with acetonitrile at elevated temperatures, excellent conversions were achieved with low catalyst loadings (0.2-5 mol%) when employing the conjugates 5 and 6 derived from IBX and IBS. The catalysts are broadly applicable to a range of alcohol substrates. Of primary importance with respect to sustainability issues, the metal-free catalysts are easily removed from the reaction mixture through filtration, and they can be re-used in oxidation processes for multiple times, without loss of catalytic activity.
- Ballaschk, Frederic,Kirsch, Stefan F.
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supporting information
p. 5896 - 5903
(2019/11/11)
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- A Novel Phenylchromane Derivative Increases the Rate of Glucose Uptake in L6 Myotubes and Augments Insulin Secretion from Pancreatic Beta-Cells by Activating AMPK
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Purpose: A series of novel polycyclic aromatic compounds that augment the rate of glucose uptake in L6 myotubes and increase glucose-stimulated insulin secretion from beta-cells were synthesized. Designing these molecules, we have aimed at the two main pathogenic mechanisms of T2D, deficient insulin secretion and diminished glucose clearance. The ultimate purpose of this work was to create a novel antidiabetic drug candidate with bi-functional mode of action. Methods: All presented compounds were synthesized, and characterized in house. INS-1E cells and L6 myoblasts were used for the experiments. The rate of glucose uptake, mechanism of action, level of insulin secretion and the druggability of the lead compound were studied. Results: The lead compound (6-(1,3-dithiepan-2-yl)-2-phenylchromane), dose- and time-dependently at the low μM range increased the rate of glucose uptake in L6 myotubes and insulin secretion in INS-1E cells. The compound exerted its effects through the activation of the LKB1 (Liver Kinase B1)-AMPK pathway. In vitro metabolic parameters of this lead compound exhibited good druggability. Conclusions: We anticipate that bi-functionality (increased rate of glucose uptake and augmented insulin secretion) will allow the lead compound to be a starting point for the development of a novel class of antidiabetic drugs.
- Rozentul, Naomi,Avrahami, Yosef,Shubely, Moran,Levy, Laura,Munder, Anna,Cohen, Guy,Cerasi, Erol,Sasson, Shlomo,Gruzman, Arie
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p. 2873 - 2890
(2017/10/13)
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- Wacker-Type Oxidation Using an Iron Catalyst and Ambient Air: Application to Late-Stage Oxidation of Complex Molecules
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A practical and general iron-catalyzed Wacker-type oxidation of olefins to ketones is presented, and it uses ambient air as the sole oxidant. The mild oxidation conditions enable exceptional functional-group tolerance, which has not been demonstrated for any other Wacker-type reaction to date. The inexpensive and nontoxic reagents [iron(II) chloride, polymethylhydrosiloxane, and air] can, therefore, also be employed to oxidize complex natural-product-derived and polyfunctionalized molecules.
- Liu, Binbin,Jin, Fengli,Wang, Tianjiao,Yuan, Xiaorong,Han, Wei
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supporting information
p. 12712 - 12717
(2017/09/11)
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- Method forsynthesizing ketone by oxidation of alkene under catalysis of iron
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The invention discloses a method for synthesizing ketoneby oxidation of alkene under catalysis of iron, and belongs to the field of catalyzed synthesis technologies and fine chemical synthesis. According to the specific method, air or oxygen is taken as an oxidizing agent under the acceleration action ofhydrosilaneand a ketone compound is synthesized byoxidation of alkene under catalysis of iron. The method has the advantages that the catalyst is wide in source, cheap and environment-friendly; the oxidant is wide in source and cheap and does not generate a waste; the reaction conditions are mild, the selectivity is high and the yield is high;a substrate is wide and stable; a functional group of the substrate is good in compatibility and the application range of the substrate is wide; and alkene molecules can be well converted into the ketone. The separation yield of a target product reaches 98% under the optimized reaction conditions.
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Paragraph 0124; 0125; 0126
(2017/07/23)
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- A combined computational and experimental investigation of the oxidative ring-opening of cyclic ethers by oxoammonium cations
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The propensity of oxoammonium cations to facilitate the oxidative ring-opening of cyclic ethers to their corresponding distal hydroxy ketones is investigated. The reaction has been evaluated using experimental and computational methods to gain deeper insight into trends in reactivity.
- Loman, Jacob. J.,Carnaghan, Emma R.,Hamlin, Trevor A.,Ovian, John M.,Kelly, Christopher B.,Mercadante, Michael A.,Leadbeater, Nicholas E.
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p. 3883 - 3888
(2016/05/24)
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- Sodium Bromide-Catalyzed Oxidation of Secondary Benzylic Alcohols Using Aqueous Hydrogen Peroxide as Terminal Oxidant
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A halide salt, hydroperoxide and AcOH catalyst system was applied to the oxidation of secondary benzylic alcohols. This simple system can be applied to a variety of secondary benzylic alcohols and scaled up for gram-scale preparation. High secondary benzylic alcohol selectivity of the present method is demonstrated in hydroxyketone synthesis. Based on several experimental results, a catalytic cycle for our oxidation is proposed.
- Komagawa, Hiromi,Maejima, Yukako,Nagano, Takashi
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supporting information
p. 789 - 793
(2016/03/09)
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- Asymmetric Hydrogenation of β-Secondary Amino Ketones Catalyzed by a Ruthenocenyl Phosphino-oxazoline-ruthenium Complex (RuPHOX-Ru): The Synthesis of γ-Secondary Amino Alcohols
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A ruthenocenyl phosphino-oxazoline-ruthenium complex (RuPHOX-Ru) was applied successfully to the asymmetric hydrogenation of β-secondary amino ketones, directly affording the corresponding chiral γ-secondary amino alcohols in up to 99% yield and with 99% ee. Reaction with β-(benzylamino)-1-phenylpropan-1-one could be performed on a gram-scale with a relatively low catalyst loading (up to 2000 S/C). The resulting hydrogenated product could be used for the synthesis of synthetically useful compounds.
- Wang, Jianxia,Wang, Yanzhao,Liu, Delong,Zhang, Wanbin
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supporting information
p. 3262 - 3272
(2015/11/03)
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- The synthesis of ω-(2-aryl-1,3-dioxolan-2-yl)alkyl purine derivatives and their activity towards HIV reverse transcriptase
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Novel derivatives of 6-substituted purines were synthesized by alkylation of 6-substituted purines with various 2-(chloroalkyl)-2-aryl-1,3-dioxolanes and related compounds. Their inhibitory properties toward HIV reverse transcriptase were studied. The structure-activity relationship within the synthesized compounds was found.
- Komissarov,Valuev-Elliston,Ivanova,Kochetkov,Kritzyn
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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)
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- PERMANENTLY POSITIVELY CHARGED ANTIDEPRESSANTS
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The present invention provides compounds comprising a substructure of below formula 3: or a salt or prodrug thereof and the use of such compounds in treatment of e.g. CNS disorders.
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Page/Page column 74
(2013/03/26)
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- Candida tenuis xylose reductase catalyzed reduction of aryl ketones for enantioselective synthesis of active oxetine derivatives
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Candida tenuis xylose reductase shows high catalytic efficiencies in carbonyl reduction of acetophenone and 1-phenyl-1-propanone derivatives. The quite low substrate solubility in aqueous buffer systems is circumvented by addition of methanol or by two-phase solvent systems. In the latter, methanol improves the substrate phase transfer as solvent mediator and leads to reasonable space/time yields. Resulting enantiomerically pure chiral alcohols are key intermediates for synthesis of active pharmaceutical ingredients. (R)-Atomoxetine is exemplarily synthesized in four steps, and the further use for generation of other oxetine derivatives and a polo-like kinase 1 inhibitor are discussed. Copyright
- Vogl, Michael,Brecker, Lothar,Kratzer, Regina,Nidetzky, Bernd
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p. 847 - 853,7
(2020/07/31)
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- Direct and selective benzylic oxidation of alkylarenes via C-H abstraction using alkali metal bromides
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A direct benzylic oxidation of alkylarenes via C-H bond abstraction was developed using alkali metal bromides and oxidants under mild conditions. This reaction proceeded with excellent selectivity by thermal oxidation or photooxidation to provide a broad range of carbonyl compounds containing electron-deficient aryl carbonyl compounds in high yields.
- Moriyama, Katsuhiko,Takemura, Misato,Togo, Hideo
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supporting information; experimental part
p. 2414 - 2417
(2012/06/18)
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- Design and synthesis of 3-(azol-1-yl)phenylpropanes as microbicidal spermicides for prophylactic contraception
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We designed a series of 25 3-(azol-1-yl)phenylpropanes which yielded 10 compounds (3, 4, 7, 8, 13, 14, 19, 21, 23, 26) that irreversibly immobilized 100% human sperm at 1% (w/v) concentration in 60 s; 12 compounds (8, 9, 15, 16, 19-21, 23-25, 27, 28) that showed potent microbicidal activity at 12.5-50 μg/mL against Trichomonas vaginalis; and 17 compounds (3-11, 13, 15, 19, 21, 23, 26, 28, 30) that exhibited potent anticandida activity with minimum inhibitory concentration (MIC) of 12.5-50 μg/mL. Almost all the compounds exhibited high level of safety towards normal vaginal flora (Lactobacillus) and human cervical (HeLa) cells in comparison to the marketed spermicide nonoxynol-9 (N-9). All the biological activities were evaluated in vitro. Two compounds (4, 8) with good safety profile exhibited multiple (spermicidal, antitrichomonas and anticandida) activities, warranting further lead optimization for furnishing a prophylactic vaginal contraceptive.
- Kumar, Lalit,Sarswat, Amit,Lal, Nand,Jain, Ashish,Kumar, Sumit,Kiran Kumar,Maikhuri, Jagdamba P.,Pandey, Atindra K.,Shukla, Praveen K.,Gupta, Gopal,Sharma, Vishnu L.
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supporting information; experimental part
p. 176 - 181
(2011/02/27)
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- Synthesis of enantiomerically pure γ-azidoalcohols by lipase-catalyzed transesterification
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An enantioselective synthesis of chiral γ-azidoalcohols via lipase-catalyzed resolution is described. The efficiency of various lipases and the effect of different solvents have been studied. Pseudomonas cepacia immobilized on diatomaceous earth (PS-D) in n-hexane catalyzed the transesterification process in an efficient manner providing γ-azidoalcohols in high enantiomeric excess.
- Kamal, Ahmed,Malik, M. Shaheer,Shaik, Ahmad Ali,Azeeza, Shaik
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p. 1078 - 1083
(2008/09/19)
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- 1-[(3-Aryloxy-3-aryl)propyl]-1H-imidazoles, new imidazoles with potent activity against Candida albicans and dermatophytes. Synthesis, structure-activity relationship, and molecular modeling studies
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New 1-[(3-aryloxy-3-aryl)propyl]-1H-imidazoles were synthesized and evaluated against Candida albicans and dermatophytes in order to develop structure-activity relationships (SARs). Against C. albicans the new imidazoles showed minimal inhibitory concentrations (MICs) comparable to those of ketoconazole, miconazole, and econazole, and were more potent than fluconazole. Several derivatives (10, 12, 14, 18-20, 24, 28, 29, 30, and 34) turned out to be potent inhibitors of C. albicans strains resistant to fluconazole, with MIC values less than 10 μg/mL. Against dermatophytes strains, compounds 20, 25, and 33 (MIC ≤ 5 μg/mL) were equipotent to ketoconazole, econazole, and miconazole. SARs of imidazoles 10-44 were rationalized with reasonable accuracy by a previously developed quantitative pharmacophore for antifungal agents.
- La Regina, Giuseppe,D'Auria, Felicia Diodata,Tafi, Andrea,Piscitelli, Francesco,Olla, Stefania,Caporuscio, Fabiana,Nencioni, Lucia,Cirilli, Roberto,La Torre, Francesco,De Melo, Nadja Rodrigues,Kelly, Steven L.,Lamb, David C.,Artico, Marino,Botta, Maurizio,Palamara, Anna Teresa,Silvestri, Romano
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scheme or table
p. 3841 - 3855
(2009/04/11)
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- PROCESS FOR PREPARING DAPOXETINE
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This invention relates to a new process for preparation of enantiomerically pure dapoxetine or an acid addition salt thereof i.e. S(+)-N,N-dimethyl-2-[2-(naphthalenyl oxy)ethyl]benzenemethanamine hydrochoride, a potent serotonin re-uptake inhibitor (SSRI), which comprises resolving racemic (±)-dapoxetine i.e. (±)- N,N-dimethyl-2-[2- (naphthalenyloxy)ethyl] benzene methanamine with a chiral acid so as to obtain salt of the chiral acid and (+)-dapoxetine, substantially free from (-)-dapoxetine.
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Page/Page column 8; 9-10
(2010/11/30)
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- Identification of alkylarene chloromethylation products using gas-chromatographic retention indices
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Gas-chromatographic retention indices on standard nonpolar polydimethylsiloxane stationary phases allow identification of products formed by known organic reactions even without using mass-spectrometric data. The efficiency of this approach was demonstrated by the example of identification of previously uncharacterized chloromethyl derivatives of alkylarenes, including structural isomers of compounds containing several chloromethyl groups, directly in reaction mixtures. Chromatographic analysis of such reaction mixtures allows identification of positional isomers of the starting alkylarenes even when they are present simultaneously. The retention indices were determined for the first time for more than 50 alkyl-(chloromethyl)arenes, by-products of chloromethylation, and chloromethyl derivatives of the simplest alkyl phenyl ketones. Nauka/Interperiodica 2007.
- Zenkevich,Makarov
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p. 611 - 619
(2008/03/18)
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- Imidazole analogues of fluoxetine, a novel class of anti-Candida agents
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Imidazole analogues of fluoxetine have been obtained by replacing the methylamino terminus of aminopropane chain with the imidazole ring. The newly designed imidazoles showed potent anti-Candida activity, superior to those of miconazole and other antifungal agents of clinical interest. 1-(4-Chlorophenyl)-l-(2,4-dichlorophenoxy)-3-(1H-imidazol-1-yl)propane (16), the most active among test imidazoles, Was about 2-fold more active and as much less cytotoxic than miconazole. High increase of activity was observed with methyl, nitro, fluorine, and chlorine (Cl > F > CH3 > NO2 > CF3).
- Silvestri, Romano,Artico, Marino,La Regina, Giuseppe,Di Pasquali, Alessandra,De Martino, Gabriella,D'Auria, Felicia Diodata,Nencioni, Lucia,Palamara, Anna Teresa
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p. 3924 - 3926
(2007/10/03)
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- FUSED PYRIMIDINONE MATRIX METALLOPROTEINASE INHIBITORS
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Selective MMP-13 inhibitors are fused pyrimidinones of the formula or a pharmaceutically acceptable salt thereof, wherein: W, together with the carbon atoms to which it is attached, form a 5-membered ring diradical X is O, S, SO, SO2, NR5, or CH 2; B is O or NR5; or A and B are taken together to form--C≡C--; R1, R4, and R 5 are hydrogen, alkyl, alkenyl, alkynyl, (CH2)n aryl, (CH2)n cycloalkyl, C1-C6 alkanoyl, or (CH2)n heteroaryl; R2 and R3 are hydrogen, alkyl, alkenyl, alkynyl CN, NO2, NR 4R5, (CH2)n cycloalkyl, (CH2) n aryl, or (CH2)n heteroaryl; R2 may further be halo; n is an integer of from 0 to 5; and R4 and R5 when taken together with a nitrogen to which they are both attached complete a 3-to 8-membered ring containing carbon atoms and optionally containing O, S, or N, and substituted or unsubstituted; with the proviso that R1 and R3 are not both selected from hydrogen and C1-C6 alkyl.
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- Synthesis, X-ray structure, thermal stability and reactions of triaryl(3-oxoalkyl)bismuthonium salts
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Treatment of triarylbismuth difluorides 2 with siloxycyclopropanes 3 in the presence of trimethylsilyl trifluoromethanesulfonate (triflate) or boron trifluoride-diethyl ether gave the corresponding triaryl(3-oxoalkyl)bismuthonium salts 4 as crystals.X-ray crystallographic analysis of the triflate 4a showed that the central bismuth atom has a distorted tetrahedral geometry with weak intramolecular coordination by the oxygen atoms of the carbonyl group and triflate anion.Whilst all onium salts 4 are thermally stable in a solid state, the triflate 4a slowly decomposed in chloroform to give triphenylbismuthane 6 and an ester 7 quantitatively.In nucleophilic solvents such as MeOH, DMSO and DMF, both triflate 4a and tetrafluoroborate 4d underwent decomposition in a complicated way to afford the bismuthane 6, 3-methoxypropanoyl compounds 8a,b, α,β-unsaturated carbonyl compounds 9a,b, diphenylbismuth triflate 10a or tetrafluoroborate 10b and alkoxysulfonium salts 11a,b.The formate 12 was an additional product from 4d in DMF.The bismuthonium salt 4d reacted with dimethyl sulfide 13 and sodium benzenesulfinate 15 to afford the sulfonium salt 14 and the sulfonyl ketone 16, respectively.Reaction of the salt 4d with potassium halides 17 in DMF gave the enone 9b, formate 12 and halogeno ketone 18 in varying yields depending on the nucleophilic nature of the halogen anions employed.When treated with KOBut, the salt 4d underwent facile β-elimination to yield the enone 9b.In all of these reactions, the triphenylbismuthane moiety behaved as a good leaving group.
- Matano, Yoshihiro,Azuma, Nagao,Suzuki, Hitomi
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p. 2543 - 2550
(2007/10/02)
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- Modern Friedel-Crafts chemistry XIII. Intra- and intermolecular cyclization of some carbonyl derivatives under Friedel-Crafts conditions
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Carbonyl group deactivation in the cycloalkylation of aryl haloalkyl ketones was studied.Ketones 1-5 were prepared and subjected to treatment with AlCl3, AlCl3/H2SO4 and H2SO4 catalysts.Whereas AlCl3 catalyst gave no cyclization products, the use of AlCl3/H2SO4 and H2SO4 catalysts afforded the corresponding indanones and/or tetralones (6-11).The intermediate p-methylacrylophenone (12) was also obtained in the case of ketone 2.Furthermore intermolecular cyclizations of benzene, toluene and p-xylene with 3-chloropropionyl chloride (13) and 4-chlorobutyryl chloride (14) were investigated.In the presence of AlCl3/CH3NO2 catalyst, only the corresponding aryl haloalkyl ketones (1-5) were formed whereas the use of AlCl3 catalyst gave, in addition, some cyclic ketones.However, the use of AlCl3/H2SO4 catalyst gave only the corresponding cyclic ketones (6-11).Results are discussed and mechanisms are suggested.In conclusion, carbonyl group deactivation for ring closure is demonstrated in the investigated ketones and cyclization can only effected under strenuous conditions.
- Khalaf, Ali A.,Abdel-Wahab, Aboel-Magd A.,El-Khawaga, Ahmed M.,El-Zohry, Maher F.
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p. 285 - 291
(2007/10/02)
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