- Photocatalytic Carbinol Cation/Anion Umpolung: Direct Addition of Aromatic Aldehydes and Ketones to Carbon Dioxide
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We have developed a new photocatalytic umpolung reaction of carbonyl compounds to generate anionic carbinol synthons. Aromatic aldehydes or ketones reacted with carbon dioxide in the presence of an iridium photocatalyst and 1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzimidazole (DMBI) as a reductant under visible-light irradiation to furnish the corresponding α-hydroxycarboxylic acids through nucleophilic addition of the resulting carbinol anions to electrophilic carbon dioxide.
- Okumura, Shintaro,Uozumi, Yasuhiro
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supporting information
p. 7194 - 7198
(2021/09/22)
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- Synthesis of α-hydroxycarboxylic acids from various aldehydes and ketones by direct electrocarboxylation: A facile, efficient and atom economy protocol
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In present work, the formation of α-hydroxycarboxylic acids have been described from various aromatic aldehydes and ketones via direct electrocarboxylation method with 80-92% of yield without any side product and can be purified by simple recrystallization using sacrificial Mg anode and Pt cathode in an undivided cell, CO2at (1 atm) was continuously bubbled in the cell throughout the reaction using tetrapropylammonium chloride as a supporting electrolyte in acetonitrile. The synthesized compounds obtained in fair to excellent yield with a high level of purity. The characterization of electrocarboxylated compounds was done with spectroscopic techniques like IR, NMR (1H & 13C), mass and elemental analysis.
- Singh, Kishanpal,Sohal, Harvinder Singh,Singh, Baljit
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p. 839 - 845
(2021/04/09)
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- Visible light-induced aerobic oxidation of diarylalkynes to α-diketones catalyzed by copper-superoxo at room temperature
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We have developed the visible light induced simple copper(ii) chloride catalyzed oxidation of diarylacetylenes to α-diketones by molecular oxygen at room temperature. The in situ generated copper(ii)-superoxo complex is a light-absorbing species that oxidizes inert diarylacetylenes to α-diketones. In contrast to reported photochemical processes, the current oxidation protocol does not require any exogenous photocatalyst or radical initiator. The green chemistry metrics evaluation signifies that the E-factor for the current oxidation process is ～2.3 times better than that of reported photochemical processes. The current reaction scores 63 on the EcoScale of 0-100, indicating an adequate synthesis process. Thus, the overall oxidation process is simple, environmentally benign, and economically feasible. This journal is
- Charpe, Vaibhav Pramod,Hwang, Kuo Chu,Sagadevan, Arunachalam
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supporting information
p. 4426 - 4432
(2020/08/10)
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- Hydrodebromination of Aromatic Bromides Catalyzed by Unsupported Nanoporous Gold: Heterolytic Cleavage of Hydrogen Molecule
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Unsupported nanoporous gold (AuNPore) is a highly efficient, practically applicable, and recyclable catalyst for hydrodebromination of aromatic bromides. The AuNPore-catalyzed hydrodebromination of aromatic bromides proceeded smoothly at relatively low hydrogen pressure and temperature to achieve good to excellent yields of the corresponding non-bromine variants. The selective hydrodebromination reaction occurred exclusively in the coexistence of chlorine atom. For the first time, a mechanistic study revealed that the H?H bond splits in a heterolysis manner on the surface of AuNPore to generate Au?H hydride species.
- Bao, Ming,Feng, Xiujuan,Yamamoto, Yoshinori,Zhang, Sheng,Zhao, Yuhui
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p. 4951 - 4957
(2020/09/09)
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- A Bifunctional Iron Nanocomposite Catalyst for Efficient Oxidation of Alkenes to Ketones and 1,2-Diketones
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We herein report the fabrication of a bifunctional iron nanocomposite catalyst, in which two catalytically active sites of Fe-Nx and Fe phosphate, as oxidation and Lewis acid sites, were simultaneously integrated into a hierarchical N,P-dual doped porous carbon. As a bifunctional catalyst, it exhibited high efficiency for direct oxidative cleavage of alkenes into ketones or their oxidation into 1,2-diketones with a broad substrate scope and high functional group tolerance using TBHP as the oxidant in water under mild reaction conditions. Furthermore, it could be easily recovered for successive recycling without appreciable loss of activity. Mechanistic studies disclose that the direct oxidation of alkenes proceeds via the formation of an epoxide as intermediate followed by either acid-catalyzed Meinwald rearrangement to give ketones with one carbon shorter or nucleophilic ring-opening to generate 1,2-diketones in a cascade manner. This study not only opens up a fancy pathway in the rational design of Fe-N-C catalysts but also offers a simple and efficient method for accessing industrially important ketones and 1,2-diketones from alkenes in a cost-effective and environmentally benign fashion.
- Ma, Zhiming,Ren, Peng,Song, Tao,Xiao, Jianliang,Yang, Yong,Yuan, Youzhu
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p. 4617 - 4629
(2020/05/19)
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- Room Temperature Coupling of Aryldiazoacetates with Boronic Acids Enhanced by Blue Light Irradiation
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A visible-light-promoted photochemical protocol is reported for the coupling of aryldiazoacetates with boronic acids. This photochemical reaction shows great enhancement compared to the same protocol performed in the absence of light. Except for a few cases, the room temperature coupling in the dark (thermal process) generally does not work. When it does, it is likely to also involve free carbenes as key intermediates. Alternatively, photochemical reactions show a broad scope, can be performed under air and tolerate a wide variety of functional groups. Reaction-evolution monitoring, DFT calculations and control experiments have been used to evaluate the main aspects of this intricate mechanistic scenario. Biologically active molecules Adiphenine, Benactyzine and Aprophen have been prepared as examples of synthetic applications.
- da Silva, Amanda F.,Afonso, Marco A. S.,Cormanich, Rodrigo A.,Jurberg, Igor D.
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p. 5648 - 5653
(2020/04/22)
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- Magnetic magnetite nanoparticals catalyzed selective oxidation of Α-hydroxy ketones with air and one-pot synthesis of benzilic acid and phenytoin derivatives
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A clean and efficient protocol for selective oxidation of α-hydroxy ketones using magnetic magnetite nanoparticals (Fe3O4·MNPs) as catalyst with air as green oxidant has been developed. Application of Fe3O4·MNPs was also proved to be successful in one-pot synthesis of benzilic acid and phenytoin derivatives. The facile one-pot procedure enhanced the production efficiency, shortened the reaction time and minimized the chemical waste. Notably, the catalyst can be reused at least for five times without any appreciable loss of its activity.
- Li, Xiaona,Xia, Dandan,Wen, Zhiyong,Gong, Bowen,Sun, Maolin,Wu, Yue,Zhang, Jie,Sun, Jun,Wu, Yang,Bao, Kai,Zhang, Weige
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-
- Synthesis of diphenyl glycolic acid
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The invention relates to synthesis of diphenyl glycolic acid. The synthesis comprises the following process steps: adding 2.5-3.6 g of diphenylethylenedione and 15mL of ethanol with the concentrationof 95% to a round bottom flask with the volume of 50mL, dissolving by heating, dropwise adding a solution obtained by dissolving 2.7g of potassium hydroxide in 5-10mL of water, and performing a reaction while stirring magnetically, refluxing for 30-60min, then transferring a reaction mixture to a small beaker, placing in an ice water bath to separate out crystals of potassium diphenylglycolate, performing suction filtration, washing the crystals by using a small amount of cold ethanol, dissolving the filtered potassium salt in 70-90mL of water, dropwise adding 2-5 drops of concentrated hydrochloric acid, keeping a small amount of unreacted diphenylethylenedione to be in a state of a colloidal suspension, decolorizing by adding about two flat spoons of activated carbon, filtering in a hot state, cooling a filtrate to a room temperature, acidifying by using hydrochloric acid with the concentration of 5% until Congo red test paper turns blue, keeping stirring to guarantee that a product is loose, cooling in an ice water bath to achieve complete crystallization, performing suction filtration, washing for several times by using cold water to remove inorganic salt and the hydrochloric acid in the crystals, and drying the product in a drying oven with the temperature of 85 DEG C till the constant weight.
- -
-
Paragraph 0007; 0008
(2018/10/11)
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- Enhanced solvent-free selective oxidation of cyclohexene to 1,2-cyclohexanediol by polyaniline@halloysite nanotubes
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One-dimensional polyaniline@halloysite (PANI@HA) nanotubes with enhanced selective oxidation activity of cyclohexene are fabricated by employing aniline (ANI) chemical polymerization on halloysite nanotubes in situ. By facilely controlling the doping acid, acidity, and ANI/HA weight ratio during the fabrication, PANI with a controllable doping degree, redox state, and content is grown on halloysite nanotubes. The cyclohexene selective oxidation result shows that PANI@HA nanotubes are effective catalysts in a solvent-free reaction system with H2O2 as the oxidant, and their catalytic activity relies on the doping acid, acidity, and ANI/HA weight ratio in the fabrication. PANI@HA synthesized with HCl as a doping acid to condition the acidity at 1 M and 2.04 ANI/HA weight ratio (PANI@HA/1 M/2.04-HCl) demonstrates highest catalytic activity (98.17% conversion and 99.50% selectivity to 1,2-cyclohexanediol). The cyclohexene selective catalytic activity matches well with the PANI doping degree in PANI@HA. In addition, the optimal reaction condition is 20 mg catalyst, 2.5 mL H2O2, 70 °C, and 24 h. Furthermore, PANI@HA/1 M/2.04-HCl exhibits superior dihydroxylation activity toward 2,3-dimethyl-2-butene and cycling performance with 99.11% conversion and 96.92% selectivity to 1,2-cyclohexanediol after five cycles. The CV of PANI@HA indicates that the cyclohexene selective oxidation is attributed to a reversible redox reaction of PANI in PANI@HA for catalytic decomposition of H2O2.
- Zhou, Tianzhu,Zhao, Yue,Han, Wenmei,Xie, Huazhong,Li, Cuiping,Yuan, Mingquan
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supporting information
p. 18230 - 18241
(2017/09/08)
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- A Facile and Solvent-Free Silica-Supported Route for the Preparation of Pyrazolium Salts and Its Catalytic Responses
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Synthesis of di/trimeric substituted pyrazolium salts was carried out under a conventional/solvent-free silica-supported muffle furnace method. The solid phase method observed remarkable response compared with the conventional method for the preparation of pyrazolium salts. Di/trimeric substituted pyrazolium salts acted as a very good catalyst for benzilic acid preparation while compared with existing literatures.
- Ramalingam, Tamilarasan,Kilivelu, Ganesan
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supporting information
p. 2817 - 2821
(2017/09/26)
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- A 2 the hydroxy [...] ― 2,2 the the ― 3 α [...] diphenylgermanium acetic acid [...] (8 the [...] azabicyclo [3, 2, 1]) ― 3 the method for the preparation of octyl [...]
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The invention discloses a method for preparing 2-hydroxy-2,2-diphenylacetic acid-3alpha-(8-aza-bicyclo(3,2,1))-3-trioctyl. The method comprises the following steps of: by taking dibenzoyl as a raw material, carrying out rearrangement on the raw material so as to obtain dihydroxy-phenylacetic acid; reacting dihydroxy-phenylacetic acid with dimethyl carbonate under the DBU catalysis and microwave actions so as to obtain methyl benzilate; reacting the methyl benzilate with tropine so as to obtain tropine benzilate; and carrying out N formylation and alcoholysis on the obtained tropine benzilate so as to obtain nor-tropine benzilate. Compared with the prior art, the total reaction time of the method disclosed by the invention is greatly reduced, the total yield is increased greatly, and the reaction condition is more simple, and therefore, the method is suitable for industrial production.
- -
-
Paragraph 0033; 0035; 0036
(2016/12/12)
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- Electrochemical reduction of aromatic ketones in 1-butyl-3-methylimidazolium-based ionic liquids in the presence of carbon dioxide: the influence of the ketone substituent and the ionic liquid anion on bulk electrolysis product distribution
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Electrochemical reduction of aromatic ketones, including acetophenone, benzophenone and 4-phenylbenzophenone, has been undertaken in 1-butyl-3-methylimidazolium-based ionic liquids containing tetrafluoroborate ([BF4]-), trifluoromethanesulfonate ([TfO]-) and tris(pentafluoroethyl)trifluorophosphate ([FAP]-) anions in the presence of carbon dioxide in order to investigate the ketone substituent effect and the influence of the acidic proton on the imidazolium cation (C2-H) on bulk electrolysis product distribution. For acetophenone, the minor products were dimers (50%) derived from proton coupled electron transfer reactions involving the electrogenerated radical anions and C2-H. In the cases of both acetophenone and benzophenone, the product distribution is essentially independent of the ionic liquid anion. By contrast, 4-phenylbenzophenone shows a product distribution that is dependent on the ionic liquid anion. Higher yields of carboxylic acids (～40%) are obtained with [TfO]- and [FAP]- anions because in these ionic liquids the C2-H is less acidic, making the formation of alcohol less favourable. In comparison with benzophenone, a higher yield of carboxylic acid (>30% versus ～15%) was obtained with 4-phenylbenzophenone in all ionic liquids due to the weaker basicity of 4-phenylbenzophenone radical anion.
- Zhao, Shu-Feng,Horne, Mike,Bond, Alan M.,Zhang, Jie
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p. 19247 - 19254
(2015/07/27)
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- NOVEL COMPOUNDS AS ANTI-TUBERCULAR AGENTS
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The present invention relates to novel compounds of formula (1): The present invention also discloses compounds of formula (1) along with other pharmaceutical acceptable excipients and use of the compounds as anti-tubercular agents.
- -
-
Page/Page column 37-38
(2015/12/17)
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- Transition-metal-free and chemoselective NaOtBu-O 2-mediated oxidative cleavage reactions of vic-1,2-diols to carboxylic acids and mechanistic insight into the reaction pathways
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A method for efficient oxidative cleavage of vic-1,2-diols using a NaO tBu-O2 system resulted in the formation of carboxylic acids in high yields. The present protocol is an eco-friendly alternative to a conventional transition-metal-based method. This new strategy allows large-scale production with nonchromatographic purification while also suppressing competitive reaction pathway such as benzilic acid rearrangement.
- Kim, Sun Min,Kim, Dong Wan,Yang, Jung Woon
-
supporting information
p. 2876 - 2879
(2014/06/23)
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- Silicon nanowires as photoelectrodes for carbon dioxide fixation
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Lights on: When illuminated, p-type Si nanowires donate photogenerated electrons to aromatic ketones, producing reactive radicals that can harvest CO2 to yield α-hydroxy acids (see scheme). The reaction scheme closely resembles that of natural photosynthesis and gives up to 98 % yield and selectivity. Products obtained by this reaction include important precursors for nonsteroidal anti-inflammatory drugs, such as ibuprofen and naproxen. Copyright
- Liu, Rui,Yuan, Guangbi,Joe, Candice L.,Lightburn, Thomas E.,Tan, Kian L.,Wang, Dunwei
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supporting information; experimental part
p. 6709 - 6712
(2012/09/22)
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- Ionic liquid/potassium hydroxide catalyzed solvent-free, one-pot synthesis of diarylglycolic acids from aromatic aldehydes under microwave
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Ionic liquid in conjugation with KOH brings about an efficient, one-pot, green synthesis of α,α-diarylglycolic acids in reasonably high yields from aromatic aldehydes under solvent-free condition using conventional heating as well as microwave irradiation.
- Singh, Neetu,Singh, Satish Kumar,Khanna,Singh, Krishna Nand
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experimental part
p. 2419 - 2422
(2011/05/09)
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- PROCESS FOR THE PREPARATION OF SUBSTITUTED BENZILIC ACID FROM SUBSTITUTED BENZILS
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The classical process for the rearrangement of substituted benzil to benzilic acid is performed in the presence of sodium or potassium hydroxide as a base using ethanol-ether as a medium. The reaction requires reflux temperature for complete conversion. However, these bases containing metallic ions and generate metallic containing effluent waste which may require additional expenditure for treatment. Moreover, because of corrosive nature of base, and use of flammable solvent, the safety measures are needed during large scale production. Another method also reported for benzilic acid rearrangement at 380° C. which is practically not feasible. The present invention describes the use of quaternary ammonium hydroxides as a base for the rearrangement of the substituted benzils to benzilc acids. It also avoids the use of solvent and reaction can be carried out at relatively lower temperatures. Because of the solvent free reaction condition it reduces the mass/volume of reaction mixture.
- -
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Page/Page column 3
(2010/10/19)
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- The epimetallation and carbonation of carbonyl and imino derivatives: Epivanadation route to 2-amino and 2-hydroxy acids
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The feasibility of hydrocarboxylating carbonyl and imino derivatives by the two-step process of epimetallation and carbonation has been demonstrated with the model substrates of 9-fluorenone and 9-fluorenone anil. With lithium vanadium dihydride as the epimetallating agent, such hydrocarboxylation has led to a 75% yield of 9-hydroxy-9-fluorenecarboxylic acid and a 65% yield of 9-(N-phenylamino)-9-fluorenecarboxylic acid, respectively. Some initial success in extending the scope of this reaction to other substrates, such as benzophenone, has been achieved by using other epimetallating agents, like the presumed LiV(CH3)2 and Ti(OPri)2. A brief review of the processes and organic synthetic applications of epimetallation and transfer epimetallation of C-C π-bonds is offered as background.
- Eisch, John J.,Fregene, Paul O.,Gitua, John N.
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p. 4647 - 4653
(2008/03/12)
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- Decomposition of sodium trichloroacetate in the presence of quaternary ammonium under microwave irradiation: A convenient one-pot synthesis of α-hydroxy acids in water
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A good yielding phase-transfer-catalyzed procedure for one-pot preparation of α-hydroxy acids from carbonyl compounds and sodium trichloroacetate by in situ addition and hydrolysis under microwave irradiation is described. Decomposition of sodium trichloroacetate is strongly accelerated by the presence of quaternary ammonium. The reaction can be conducted in water. Copyright Taylor & Francis Group, LLC.
- Yu, Haitao,Fang, Yun,Xia, Yongmei,Wu, Jing
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p. 2421 - 2426
(2007/10/03)
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- 3,6-DISUBSTITUTED AZABICYCLO [3.1.0]HEXANE DERIVATIVES USEFUL AS MUSCARINIC RECEPTOR ANTAGONISTS
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This invention generally relates to the derivatives of 3,6 disubstituted azabicyclo[3.1.0]hexanes. The compounds of this invention are muscarinic receptor antagonists which are useful, inter-alia, for the treatment of various diseases of the respiratory, urinary and gastrointestinal systems mediated through muscarinic receptors. The invention also relates to a process for the preparation of compounds of the present invention, pharmaceutical compositions containing the compounds of the present invention and the methods for treating the diseases mediated through muscarinic receptors.
- -
-
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- Microwave-assisted heterogeneous benzil-benzilic acid rearrangement
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A new procedure for carrying out the benzil-benzilic acid rearrangement in the solid state has been developed which provides a new route to synthesize the pharmacologically interesting anticonvulsant dilantin.
- Yu, Hui-Ming,Chen, Same-Ting,Tseng, Min-Jen,Chen, Shui-Tein,Wang, Kung-Tsung
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- Visible light-induced photofixation of CO2 into benzophenone: Roles of poly(p-phenylene) as photocatalyst and two-electron mediator in the presence of quaternary onium salts
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Visible light-induced photocatalytic fixation of CO2 into benzophenone (1) has been carried out in CO2-saturated DMF (N,N-dimethylformamide) using poly(p-phenylene) (PPP) as a heterogeneous photocatalyst and triethylamine as an electron donor. Diphenylglycolic acid (2) is produced as a CO2-fixed product together with benzhydrol (3), benzopinacol (4) and 1,1-diphenylpropane-1,2-diol (5). The presence of quaternary onium salts such as tetraethylammonium chloride (Et4NCl) increases the yield of 2 in the presence of CO2 and those of 3 and 5 in the absence of CO2. The soft onium cations from quaternary onium salts are proposed to stabilize diphenylcarbinol anion (9) as a common precursor of 2, 3 and 5 on the basis of the HSAB concept. Further, the enhanced formation of PPP dianions (7) through PPP radical anions (6) has been examined in the reduction of PPP with sodium metal in the presence of Et4NCl. Photocatalysis of PPP in the CO2 fixation is discussed in terms of onium salt effects and favorable photoformation of 6 and 7 as an electron pool in the presence of quaternary onium cations.
- Wada, Yuji,Ogata, Tomoyuki,Hiranaga, Kunizo,Yasuda, Hiroyuki,Kitamura, Takayuki,Murakoshi, Kei,Yanagida, Shozo
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p. 1999 - 2004
(2007/10/03)
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- Azido acids in a novel method of solid-phase peptide synthesis
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Azido acids were produced from α-branched acids by α-bromination with NBS followed by substitution with sodium azide and the products were used in a novel method of solid-phase synthesis. The azido acids were transformed into the highly activated acid chlorides and used synthesis of extremely hindered peptides containing up to four successive diphenyl glycine or Aib residues. By reaction of the genetically encoded amino acids with TfN3 and then SOCl2 they were transformed into α-azido acid chlorides used in solid-phase peptide synthesis without racemization.
- Meldal, Morten,Juliano, Maria A.,Jansson, Anita M.
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p. 2531 - 2534
(2007/10/03)
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- Visible-light induced photofixation of carbon dioxide into aromatic ketones and benzyl halides catalysed by CdS nanocrystallites
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Photocatalytic fixation of CO2 into organic substrates was carried out in a CO2-saturated DMF (N,N-dimethylformamide) solution using CdS nanocrystallites prepared in DMF (CdS-DMF, mean diameter = 4 nm, hexagonal) as a photocatalyst under visible light irradiation (λ > 400 nm). Benzilic acid (BpCO2H), atrolactic acid [methyl(phenyl)glycolic; ApCO2H] and phenylacetic acid (BnCO2H) were produced from benzophenone, acetophenone and benzyl halides such as benzyl bromide (BnBr) and benzyl chloride (BnCl), respectively. The formation of CO2 anion radical (CO2.-) was confirmed by EPR spectroscopic measurements by using 5,5-dimethyl-3,4-dihydropyrrole N-oxide (DMPO) as a spin trapping agent. Both the formation of CO2.- and the concurrent one-electron reduction of the organic substrates were indispensable in the photofixation process, which suggests that the photofixation proceeds via their bimolecular coupling on the surface of CdS nanocrystallites.
- Fujiwara, Hiroaki,Kanemoto, Masashi,Ankyu, Hirofumi,Murakoshi, Kei,Wada, Yuji,Yanagida, Shozo
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p. 317 - 321
(2007/10/03)
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- Biomimetic investigations of propiverinhydrochloride and 1-methyl-4-piperidyl benzilate
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The reaction of propiverinhydrochloride (1) and 1-methyl-4-piperidyl benzilate (2) with the biomimetic system manganese(III)-5,10,15,20-tetrakis(pentafluorophenyl)-β-tetrasulfonat oporphyrin chloride (MnTPFPS4PCl)/imidazole/hydrogen peroxide in aqueous solution at pH 7-8 affords unchanged 1 and 2 and numerous metabolites, which are products of fission of the ester bond, of O-dealkylation, decarboxylation, N-demethylation, and oxidation of the tertiary amine function. In contrast to the nonaqueous system with the catalyst manganese(III)-5,10,15,20-tetrakis(pentafluorophenyl)porphyrin chloride (MnTPFPPCl) aromatic hydroxylation is not observed. This result shows conformity with the studies of metabolism in men.
- Froehlich,Pietzyk,Smolinka,Goeber
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p. 745 - 747
(2007/10/03)
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- Biomimetic oxidation of propiverinhydrochloride and 1-methyl-4-piperidyl benzilate
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The reaction of propiverinhydrochloride (1) and 1-methyl-4-piperidyl benzilate (2) with the biomimetic system manganese(III)-5,10,15,20-tetrakis(pentafluorophenyl)porphyrin chloride (MnTPFPPCl)/pyridine/hydrogen peroxide affords unchanged 1 and 2 and 15 potential metabolites, which were isolated and identified. These compounds are products of cleavage of the ester bond, of O-dealkylation, aromatic oxidation, respectively of decarboxylation, demethylation, and N-oxidation. Products were identified by TLC, UV, and MS in comparison with authentic samples. Thereby we found a nearly conformity with rat metabolism.
- Frohlich,Pietzyk,Gober
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p. 736 - 740
(2007/10/03)
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- Visible-light Induced Photocatalytic Fixation of CO2 into Benzophenone Using Poly(p-phenylene) as a Photocatalyst
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Photoreductive fixation of CO2 into benzophenone can be achieved in a CO2-saturated DMF solution by using poly(p-phenylene) as a heterogeneous photocatalyst and triethylamine as an electron donor.The presence of quaternary ammonium salts increases the yield of benzylic acid as a CO2-photofixed product from benzophenone.
- Ogata, Tomoyuki,Hiranaga, Kunizo,Matsuoka, Shinjiro,Wada, Yuji,Yanagida, Shozo
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p. 983 - 984
(2007/10/02)
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- Visible-Light Induced Photofixation of CO2 into Benzophenone Catalyzed by Colloidal CdS Microcrystallites
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Photocatalytic fixation of CO2 into benzophenone has been achieved under λ > 400-nm light irradiation of a CO2-saturated DMF solution of colloidal CdS microcrystallites as photocatalysts, triethylamine as a sacrificial electron donor, and benzophenone yielding benzilic acid with benzhydrol and benzopinacol.
- Kanemoto, Masashi,Ankyu, Hirofumi,Wada, Yuji,Yanagida, Shozo
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p. 2113 - 2114
(2007/10/02)
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- Nucleophilic substitution in diphenylmethyl derivatives. I. Formolysis of diarylmethyl derivatives: an α-substituent effect
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The reactions of formic acid with and without addition of sodium formate with diphenylmethanol (4) and chlorodiphenylmethane (3) were compared to those with hydroxydiphenylacetic (benzilic) acid (12a) and chlorodiphenylacetic acid (14a).Formic acid did not favour any SN1-type reaction on 4, but a strong catalysis by iodide ion was observed.Sodium formate rapidly performed the substitution of the chlorine in 3.A similar outcome was obtained with chloro acid 14a, but the rationalization of the results is different.Chloro acid 14a and its methyl ester 14b were prompt to react, but the equilibria were shiftet to α-formyloxy products 13 only by the addition of HCOONa.HCOOH was unable to perform any reduction on either 3 or 4 or 12a and 14a, a fact which was taken as evidence for concerted substitution mechanism on ion pairs or betaine 15.Mechanistic implications are drawn.
- Strazzolini, Paolo,Giumanini, Angelo G.,Verardo, Giancarlo
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-
- One-flask preparation of symmetrical ketones and 1,2-diketones from esters
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A convenient one-flask preparation of a series of symmetrical 1,2-diketones from esters is reported using sodium metal induced acyloin condensation followed by reaction with thionyl chloride. Symmetrical monoketones were obtained when after initial acyloin condensation, the reaction mixture is oxidized with aqueous sodium bromate and then reacted with thionyl chloride. Preparative aspects, the scope of the reaction, and the suggested mechanism are discussed.
- Olah,Wu
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p. 1177 - 1179
(2007/10/02)
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- Benzylic Acid Rearrangement in the Solid State
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Benzylic acid rearrangements in the solid state were studied and some of them were found to proceed faster than in solution.Although the rearrangement which is initiated by an attack of OH- and then proceeds via radical intermediate was clarified to be similar to that in solution, the effect of alkali metal hydroxide on the rearrangement in the solid state was different from that in solution.
- Toda, Fumio,Tanaka, Koichi,Kagawa, Yukiko,Sakaino, Yoshiko
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p. 373 - 376
(2007/10/02)
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- Investigations on Photolysis of Diaryliodonium Salts
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The photolysis of diaryliodonium salts in solution leads to various competitive and consecutive reactions.Upon irradiation, the excited state desactivates mainly through homolytic cleavage of the C-I-bond, but to a minor extent also through heterolytic cleavage of the same bond.Thus, several photolysis products have been obtained: aromatics, new iodonium salts, iodoaromatics, substitution products of the solvent, protonic acid in aqueous solutions, iodide and iodate ions and iodine.In the case of diphenyliodonium iodide the yields of iodine are higher compared to those of other salts because of electron transfer processes.The quantum yields of the disappearance of the iodonium salt (ΦI) and of the formation of protonic acids (ΦP) are equal within the experimental error.These values do not depend on the nature of the solvent, with the exception of H-donor solvents, on the initial salt concentration and on oxygen.But, they depend strongly on the light intensity and on the substituent at the aromatic ring.The ΦP-data also depend on the oxidation potential of the anion used.For diphenyliodonium chloride, the quantum yield of iodobenzene formation reaches only the half of the values for ΦI and ΦP.A kinetic scheme is given for the explanation of the light intensity dependence, which is based on 1. and 2. order reactions of intermediates formed by the homolytic pathway.It is assumed, that the electron transfer reaction by iodide salts proceeds only between the iodide ion and the intermediate products.
- Timpe, H.-J.,Schikowsky, V.
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p. 447 - 460
(2007/10/02)
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- Electrocarboxylation de composes carbonyles aliphatiques, aromatiques et vinyliques: interet de l'utilisation d'une anode consommable en magnesium
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In the presence of carbon dioxide in DMF, the electroreduction of carbonyl compounds or α,β-ketoalkenes at high concentration yields respectively α-hydroxyacids and β-ketoacids.The use of a sacrificial magnesium anode allows constant current electrolyses in a diaphragmless cell.
- Mcharek, Slah,Heintz, Monique,Troupel, Michel,Perichon, Jacques
-
-
- Biotransformation of denaverine hydrochloride (Spasmalgan) in the rat
-
After oral application of denaverine hydrochloride to rats (200-250 mg/kg) 12 metabolites have been detected in urine.Besides the unchanged drug, 8 metabolites were identified by MS as 2,2-diphenyl-(2-dimethylaminoethyl)acetate (3), diphenylacetic (5) and benzilic acid (6), methyl- and ethyl acetate (7,11), methylbenzilate (10),N-demethyl-1 (12) and 3,3-diphenylmorpholin-2-one (13). 6 and metabonate 13 represent the main metabolic products.Compounds 7 and 11 indicate the metabolic pathway about an alkoxybenzilic acid (4).Phenols resp. conjugates were not detected.
- Goeber, B.,Lisowski, Hannelore,Friese, Dagmar,Franke, P.
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p. 493 - 495
(2007/10/02)
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- Ytterbium Metal-promoted Novel Cross-coupling Reaction between Diaryl Ketones and Electrophiles
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In the presence of Yb metal, diaryl ketones react nucleophilically with octan-2-one, acetonitrile, epoxides, and CO2 to give the corresponding unsymmetrical pinacols, α-hydroxy ketones, 1,3-diols, and α-hydroxy carboxylic acids, respectively.
- Hou, Zhaomin,Takamine, Kan,Aoki, Osamu,Shiraishi, Hiroyuki,Fujiwara, Yuzo,Taniguchi, Hiroshi
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p. 668 - 670
(2007/10/02)
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- Nucleophilic Addition of Lanthanoid Metal Umpoled Diaryl Ketones to Electrophiles
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Ytterbium metal promoted cross-coupling reactions of diaryl ketones with a variety of electrophiles are described.Diaryl ketones treated with 1-2 equiv of Yb metal react smoothly with other ketones, nitriles, epoxides, CO2, etc., to give the corresponding unsymmetrical pinacols, α-hydroxy ketones, 1,3-diols, α-hydroxy carboxylic acids, etc., in good yields respectively.These reactions occur via nucleophilic addition of the intermediates 4a-c to electrophiles.Reaction of benzophenone (1a) with Yb metal is discussed in detail and some information on the composition of the intermediates of the reaction of diaryl ketones with Yb metal are also given.
- Hou, Zhaomin,Takamine, Kan,Aoki, Osamu,Shiraishi, Hiroyuki,Fujiwara, Yuzo,Taniguchi, Hiroshi
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p. 6077 - 6084
(2007/10/02)
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- A SIMPLE SYNTHESIS AND SOME CHEMICAL PROPERTIES OF BENZO-1,4-DITHIAFULVENES
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The synthesis of benzo-1,4-dithiafulvenes by a simple treatment of 2-substituted 1,3-benzodithiolium tetrafluoroborates - obtained starting from carboxylic acids or acyl chlorides and tetrafluoroboric acid/ ether complex - with acetonitrile water is reported.The reaction is very fast and affords the products in high over-all yields and under mild conditions.The reactions of benzo-1,4-dithiafulvenes with reducing agents (zinc/trifluoroacetic acid and acetonitrile, zinc/deuterated trifluoroacetic acid and acetonitrile, Raney nickel) and with oxidizing agents (hydrogen peroxide/ acetic acid, sodium hypochlorite, chlorine gas/water) are also reported.These reactions show the interesting synthetic potential of benzo-1,4-dithiafulvenes.
- Barbero, Margherita,Cadamuro, Silvano,Ceruti, Maurizio,Degani, Iacapo,Fochi, Rita,Regondi, Valeria
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p. 227 - 236
(2007/10/02)
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- The synthesis of anilines or azoxybenzenes from the reduction of nitrobenzenes in basic alcoholic media
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Reduction of substituted nitrobenzenes in alkaline alcoholic solutions affords, depending on the experimental conditions used, either anilines or azoxybenzenes in good yields.In the presence of a methylketone, such as acetophenone, the reaction of nitroarenes with aqueous KOH in 2-propanol provides the corresponding anilines in high yields (80-90 percent).On the other hand, when the reaction is carried out in the CH3OH/toluene/KOH system, in the absence of methylketones, the azoxyderivatives are isolated in 70-90 percent yield.
- Prato, Maurizio,Quintily, Ugo,Scapol, Lucia,Scorrano, Gianfranco
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- ELECTROCHEMICAL CARBOXYLATION OF ALDEHYDES AND KETONES WITH SACRIFICIAL ALUMINUM ANODES.
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The electrocarboxylation of aldehydes to the corresponding α-hydroxyacids was described as impossible with conventional electrochemical systems.It is reported here that it is possible to realize it in diaphragmless cells making use of sacrificial aluminum anodes.The method can be used also for the electrocarboxylation of ketones with good yields.
- Silvestri, G.,Sambino, S.,Filardo, G.
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p. 3429 - 3430
(2007/10/02)
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- Syntheses of Benzilic Acids through Electrochemical Reductive Carboxylation of Benzophenones in the Presence of Carbon Dioxide
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Reaction conditions for the electrochemical synthesis of benzilic acid (2a) under the atmosphere of carbon dioxide was investigated from the preparative points of view.The highest yield of 2a (86percent) was obtained under the following conditions; cathode: mercury, electricity passed: 2.3 F/mol, constant current density: 2.5 mA/cm2, benzophenone (1a) (8.2*10-3 mol), electrolyte(KI, 1.7*10-2 mol) in DNF (50 ml).This method and conditions were applied to the syntheses of twelve benzilic acids (2b-2m) and yielded acids in the range of 10-92percent.The yields were strongly depended on the electronic effect of substituents and benzilic acids were not obtained when the ring substituent was NO2, OH, or Br group.
- Ikeda, Yoshikazu,Manda, Eiichiro
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p. 1723 - 1726
(2007/10/02)
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- ACTIVATED Ba(OH)2 AS CATALYST IN ORGANIC SYNTHESIS
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Several barium hydroxide catalysts have been prepared.Of these, the one called C-200 has been shown to be the most active.It has been used in several organic reactions: aldol and Claisen-Schmidt condensations, ester hydrolysis, esterification of acid chlorides, Williamson's ether synthesis, benzil-benzilic acid rearrangement and the synthesis of Δ2-pyrazolines.
- Garcia-Raso, Angel,Sinisterra, Jose V.,Marinas, Jose M.
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p. 1435 - 1445
(2007/10/02)
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- Reactions of 5,6-Dilithioacenaphthene-N,N,N',N'-Tetramethyl-1,2-ethanediamine Complex with α-Diketones. II. Competitive Oxophilic and Carbophilic Additions and Redox Reactions
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The reaction of the title complex (3) with benzil did not give the 1:1 cyclic addition product expected, but gave 5,6-dibenzoylacenaphthene, 5-(1-hydroxy-2-oxo-1,2-diphenylethyl)-6-(2-oxo-1,2-diphenylethoxy)acenaphthene (5), 5-benzoyl-6-(1-hydroxy-2-oxo-1,2-diphenylethyl)acenaphthene, benzoin, and benzilic acid.Compound 5 suggests a new type of oxophilic addition accompanied by a carbophilic addition.The reaction of 3 with 9,10-phenanthrequinone in a 1:1 molar ratio gave both the oxidative homo-coupling product of 3, 1,2,7,8-tetrahydrodicyclopentaperylene,and the hydroquinone dianion, which was converted into 9,10-diacetoxyphenanthrene on acetolysis.The differences in the reaction modes between 3 and α-diketones can basically be understood in terms of the redox potentials and the steric factors of the α-diketones.
- Tanaka, Norio,Kasai, Toshiyasu
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p. 3026 - 3032
(2007/10/02)
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- COORDINATIVE ROLE OF ALKALI CATIONS IN ORGANIC REACTIONS. VI. MOLECULAR TRANSFORMATION OF BENZIL TO BENZILIC ACID
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Studies on the rearrangement of benzil (1) to benzilic acid (2) in the presence of caustic alkalis (M+OH-) reveal that the transformation is triggered by 1-M+ coordination and is propagated by a nucleophilic attack of OH- on the M+-complexed 1.Solid 1-M+OH- complexes can be isolated from CHCl3-EtOH (1:1) medium which can be transformed to M+-benzilate on refluxing.Conductometric studies reveal 1-M+ coordination in EtOH-water (transformation medium) while UV spectrophotometric studies reveal that the presence of a Lewis acid is a prerequisite for the 1 to 2 transformation to take place.A modified mechanism for the transformation is proposed.
- Poonia, Narinder S.,Porwal, Prafulla K.,Sen, Swagata
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p. 247 - 254
(2007/10/02)
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- Acid catalysed Hydrolysis of some α-Hydroxy Esters
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Kinetics of the acid catalysed hydrolysis of some α-hydroxy esters viz: Ethyl glycolate, ethyl lactate, ethyl mandelate, and ethyl benzilate have been investigated in aqueous solutions of hydrochloric acid at 50, 37, 50 and 80 degC respectively.Pseudo first order hydrolysis has been observed in each case.Variation in acid (HCl) concentration in the range 0.01-4.0 M indicated slight rise in rates, which gradually lower down after attaining optimum values.Positive salt effect has been ascertained in all cases.The observed dual nature of rates is shown to involve functions: exp (b'H+μ) and (aH2O)n alternatively depending on the bulk acidity.Following linear free energy, relationship of BUNNETT and OLSEN, Es. the polar and steric contribution of various substituents in neutral rate have been evaluated.Various activation parameters are computed.
- Mishra, J. P.,Bansal, N. L.
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p. 683 - 690
(2007/10/02)
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