- Oxidation of Ni(II) to Ni(IV) with Aryl Electrophiles Enables Ni-Mediated Aryl-CF3 Coupling
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This communication describes the synthesis and reactivity of NiIV(aryl)(CF3)2 complexes supported by trispyrazolylborate and 4,4′-di-tert-butylbipyridine ligands. We demonstrate that isolable NiIV complexes can be accessed under mild conditions via the oxidation of NiII precursors with S-(trifluoromethyl)dibenzothiophenium triflate as well as with diaryliodonium and aryl diazonium reagents. The NiIV intermediates undergo high yielding aryl-CF3 bond-forming reductive elimination. These studies support the potential viability of NiIV intermediates in nickel-catalyzed coupling reactions involving diaryliodonium and aryldiazonium electrophiles.
- Bour, James R.,Camasso, Nicole M.,Sanford, Melanie S.
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Read Online
- 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU)-promoted decomposition of difluorocarbene and the subsequent trifluoromethylation
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Difluorocarbene derived from various carbene precursors could be effectively decomposed by 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). This decomposition process was successfully applied in the subsequent trifluoromethylation of a variety of (hetero)aryl iodides without the addition of an external fluoride ion. Mechanistic investigation revealed the detailed difluorocarbene conversion process in which the decomposed difluorocarbene is finally transformed into a fluoride ion and carbon monoxide.
- Zheng, Jian,Lin, Jin-Hong,Deng, Xiao-Yun,Xiao, Ji-Chang
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Read Online
- Cross-Coupling through Ag(I)/Ag(III) Redox Manifold
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In ample variety of transformations, the presence of silver as an additive or co-catalyst is believed to be innocuous for the efficiency of the operating metal catalyst. Even though Ag additives are required often as coupling partners, oxidants or halide scavengers, its role as a catalytically competent species is widely neglected in cross-coupling reactions. Most likely, this is due to the erroneously assumed incapacity of Ag to undergo 2e? redox steps. Definite proof is herein provided for the required elementary steps to accomplish the oxidative trifluoromethylation of arenes through AgI/AgIII redox catalysis (i. e. CEL coupling), namely: i) easy AgI/AgIII 2e? oxidation mediated by air; ii) bpy/phen ligation to AgIII; iii) boron-to-AgIII aryl transfer; and iv) ulterior reductive elimination of benzotrifluorides from an [aryl-AgIII-CF3] fragment. More precisely, an ultimate entry and full characterization of organosilver(III) compounds [K]+[AgIII(CF3)4]? (K-1), [(bpy)AgIII(CF3)3] (2) and [(phen)AgIII(CF3)3] (3), is described. The utility of 3 in cross-coupling has been showcased unambiguously, and a large variety of arylboron compounds was trifluoromethylated via [AgIII(aryl)(CF3)3]? intermediates. This work breaks with old stereotypes and misconceptions regarding the inability of Ag to undergo cross-coupling by itself.
- Demonti, Luca,Mézailles, Nicolas,Nebra, Noel,Saffon-Merceron, Nathalie
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supporting information
p. 15396 - 15405
(2021/10/12)
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- Cobalt Nanoparticles-Catalyzed Widely Applicable Successive C?C Bond Cleavage in Alcohols to Access Esters
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Selective cleavage and functionalization of C?C bonds have important applications in organic synthesis and biomass utilization. However, functionalization of C?C bonds by controlled cleavage remains difficult and challenging because they are inert. Herein, we describe an unprecedented efficient protocol for the breaking of successive C?C bonds in alcohols to form esters with one or multiple carbon atoms less using heterogeneous cobalt nanoparticles as catalyst with dioxygen as the oxidant. A wide range of alcohols including inactive long-chain alkyl aryl alcohols undergo smoothly successive cleavage of adjacent ?(C?C)n? bonds to afford the corresponding esters. The catalyst was used for seven times without any decrease in activity. Characterization and control experiments disclose that cobalt nanoparticles are responsible for the successive cleavage of C?C bonds to achieve excellent catalytic activity, while the presence of Co-Nx has just the opposite effect. Preliminary mechanistic studies reveal that a tandem sequence reaction is involved in this process.
- Dai, Wen,Gao, Shuang,Li, Guosong,Luo, Huihui,Lv, Ying,Shang, Sensen,Wang, Lianyue
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supporting information
p. 19268 - 19274
(2020/08/26)
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- Discovery of [1,2,4]triazole derivatives as new metallo-β-lactamase inhibitors
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The emergence and spread of metallo-β-lactamase (MBL)-mediated resistance to β-lactam antibacterials has already threatened the global public health. A clinically useful MBL inhibitor that can reverse β-lactam resistance has not been established yet. We here report a series of [1,2,4]triazole derivatives and analogs, which displayed inhibition to the clinically relevant subclass B1 (Verona integron-encoded MBL-2) VIM-2. 3-(4-Bromophenyl)-6,7-dihydro-5H-[1,2,4]triazolo [3,4-b][1,3]thiazine (5l) manifested the most potent inhibition with an IC50 (half-maximal inhibitory concentration) value of 38.36 μM. Investigations of 5l against other B1 MBLs and the serine β-lactamases (SBLs) revealed the selectivity to VIM-2. Molecular docking analyses suggested that 5l bound to the VIM-2 active site via the triazole involving zinc coordination and made hydrophobic interactions with the residues Phe61 and Tyr67 on the flexible L1 loop. This work provided new triazole-based MBL inhibitors and may aid efforts to develop new types of inhibitors combating MBL-mediated resistance.
- Yuan, Chen,Yan, Jie,Song, Chen,Yang, Fan,Li, Chao,Wang, Cheng,Su, Huiling,Chen, Wei,Wang, Lijiao,Wang, Zhouyu,Qian, Shan,Yang, Lingling
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- Ruthenium-catalyzed hydrogenation of CO2as a route to methyl esters for use as biofuels or fine chemicals
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A novel robust diphosphine-ruthenium(ii) complex has been developed that can efficiently catalyze both the hydrogenation of CO2 to methanol and its in situ condensation with carboxylic acids to form methyl esters; a TON of up to 3260 is achievable for the CO2 to methanol step. Both aromatic and aliphatic carboxylic acids can be transformed to their corresponding methyl esters with high conversion and selectivity (17 aliphatic and 18 aromatic examples). On the basis of a series of experiments, a mechanism has been proposed to account for the various steps involved in the catalytic pathway. More importantly, this approach provides a promising route for using CO2 as a C1 source for the production of biofuels, fine chemicals and methanol.
- Li, Yong,Liu, Qingbin,Ma, Yanping,Solan, Gregory A.,Sun, Wen-Hua,Wang, Zheng,Zhang, Qiuyue,Zhao, Ziwei,Zhong, Yanxia
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p. 6766 - 6774
(2020/08/25)
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- Palladium-Catalyzed, Copper(I)-Promoted Methoxycarbonylation of Arylboronic Acids with O-Methyl S-Aryl Thiocarbonates
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Here, we report O-methyl S-aryl thiocarbonates as a versatile esterification reagent for palladium-catalyzed methoxycarbonylation of arylboronic acid in the presence of copper(I) thiophene-2-carboxylate (CuTC). The reaction condition is mild, and a variety of substituents including sensitive-Cl,-Br, and free-NH2 could be tolerated. Further applications in the late-stage esterification of some pharmaceutical drugs demonstrate the broad utility of this method.
- Cao, Ya-Fang,Li, Ling-Jun,Liu, Min,Xu, Hui,Dai, Hui-Xiong
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p. 4475 - 4481
(2020/04/10)
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- Synthesis method of m-trifluoromethyl methyl benzoate
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The invention belongs to the technical field of synthesis of pesticide intermediates, and particularly relates to a synthesis method of m-trifluoromethyl methyl benzoate, and the compound is an important intermediate for synthesizing insecticide metaflumi
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Paragraph 0019-0034
(2019/05/15)
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- Cathodic C-H Trifluoromethylation of Arenes and Heteroarenes Enabled by an in Situ-Generated Triflyltriethylammonium Complex
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While several trifluoromethylation reactions involving the electrochemical generation of CF3 radicals via anodic oxidation have been reported, the alternative cathodic, reductive radical generation has remained elusive. Herein, the first cathodic trifluoromethylation of arenes and heteroarenes is reported. The method is based on the electrochemical reduction of an unstable triflyltriethylammonium complex generated in situ from inexpensive triflyl chloride and triethylamine, which produces CF3 radicals that are trapped by the arenes on the cathode surface.
- Cantillo, David,Jud, Wolfgang,Kappe, C. Oliver,Maljuric, Snjezana
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supporting information
(2019/10/08)
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- Selective conversion of primary amides to esters promoted by KHSO4
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Primary amides, either aliphatic or aromatic, are easily converted to the corresponding esters via reflux in lower primary alcohols in the presence of KHSO4. Secondary amides lead to complicated mixtures under analogous conditions, whereastertiary amides were inert. Use of isopropyl alcohol resulted inthe formation of product atslower rate and lower yieldalong withside products, whereas, use of tertiary alcoholsdid not give successful conversion andallyl and benzyl alcohol provided complex mixtures.
- Sattenapally, Narsimha,Sharma, Jhanvi,Hou, Yuqing
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p. 174 - 183
(2018/09/10)
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- Visible-Light photoredox decarboxylation of perfluoroarene iodine(III) Trifluoroacetates for C-H trifluoromethylation of (Hetero)arenes
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A scalable and operationally simple decarboxylative trifluoromethylation of (hetero)arenes with easily accessible C6F5I(OCOCF3)2 under photoredox catalysis has been developed. This method is tolerant of various (hetero)arenes and functional groups. Notably, C6F5I is recycled from the decarboxylation reaction and further used for the preparation of C6F5I(OCOCF3)2. The combination of photoredox catalysis and hypervalent iodine reagent provides a practical approach for the application of trifluoroacetic acid in trifluoromethylation reactions.
- Yang, Bin,Yu, Donghai,Xu, Xiu-Hua,Qing, Feng-Ling
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p. 2839 - 2843
(2018/04/14)
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- Oxalic acid as the: In situ carbon monoxide generator in palladium-catalyzed hydroxycarbonylation of arylhalides
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An efficient palladium-catalyzed hydroxycarbonylation reaction of arylhalides using oxalic acid as a CO source has been developed. The reaction features high safety, low catalyst loading, and a broad substrate scope, and provides a safe and tractable approach to access a variety of aromatic carboxylic acid compounds. Mechanistic studies revealed the decomposition pattern of oxalic acid.
- Shao, Changdong,Lu, Ailan,Wang, Xiaoling,Zhou, Bo,Guan, Xiaohong,Zhang, Yanghui
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supporting information
p. 5033 - 5040
(2017/07/10)
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- Synthesis method of o-trifluoromethyl methyl benzoate, m-trifluoromethyl methyl benzoate and p-trifluoromethyl methyl benzoate
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The invention provides a synthesis method of o-trifluoromethyl methyl benzoate, m-trifluoromethyl methyl benzoate and p-trifluoromethyl methyl benzoate. The synthesis method comprises the following steps: taking methyl benzoic acid as a raw material, carrying out acylating chlorination to obtain methylbenzoyl chloride, carrying out side-chain chlorination to obtain trichloromethyl benzoyl chloride, carrying out fluorination substitution to obtain trifluoromethyl benzoyl fluoride, and carrying out esterification to obtain a final product which is trifluoromethyl methyl benzoate. The synthesis method can be used for producing the o-trifluoromethyl methyl benzoate, the m-trifluoromethyl methyl benzoate and the p-trifluoromethyl methyl benzoate, is easily available in raw material, mild in reaction mechanism, high in reaction yield, few in reaction by-products, low in yield of three wastes and easy in treatment of three wastes, and is suitable for industrial production.
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Paragraph 0016
(2018/03/01)
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- Synthesis and biological evaluation of novel resveratrol-oxadiazole hybrid heterocycles as potential antiproliferative agents
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A novel class of resveratrol-oxadiazole hybrid compounds was synthesized to screen for their in vitro antiproliferative activity against three human cancer cell lines. All the compounds showed superior antiproliferative activity than the reference compound resveratrol. The most promising active compounds in this series were 1g, 2g, 1c, 2c, 2i and 1a (GI50 0.1 μM), endowed with excellent antiproliferative activity. Thus, we believe that resveratrol-oxadiazole hybrid compounds may possibly be used as a good leads for the development of new antiproliferative agents. Structures of newly synthesized compounds were confirmed by NMR and IR spectral data.
- Murty,Penthala, Raju,Polepalli, Sowjanya,Jain
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p. 627 - 643
(2016/03/08)
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- METHOD FOR PRODUCING 2-TRIFLUOROMETHYL BENZOIC ACID ESTER
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PROBLEM TO BE SOLVED: To provide a method for obtaining a 2-trifluoromethyl benzoic acid ester by a simple, efficient, and industrially excellent method using a starting substrate and a reagent which are inexpensive and industrially available without passing through an expensive synthetic intermediate. SOLUTION: The method for producing 2-trifluoromethyl benzoic acid ester represented by the following formula where n is an integer of 1-4 comprises: converting 2-halogen-substituted benzotrifluoride to a Grignard reagent; reacting the Grignard reagent with dialkyl carbonate; and subsequently subjecting to hydrolysis treatment. SELECTED DRAWING: None COPYRIGHT: (C)2016,JPOandINPIT
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Paragraph 0045-0049; 0052
(2017/03/24)
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- TCDA: Practical Synthesis and Application in the Trifluoromethylation of Arenes and Heteroarenes
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A practical synthesis of the reagent trimethylsilyl chlorodifluoroacetate (TCDA) is reported on 50 g scale. The trifluoromethylation with TCDA was optimized, and the reaction shows very broad scope with respect to electron-deficient, -neutral, -rich aryl/heteroaryl iodides, as well as excellent functional group tolerability, such as ester, amide, aldehyde, hydroxyl, and carboxylic acid. The reagent was also applied to the late-stage trifluoromethylation of three medicinally relevant compounds. Additionally, the building block trifluoromethylpyridine and one drug related molecule Boc-Fluoxetin were synthesized in 10 g scale by this method, demonstrating its practical applications in process chemistry.
- Wang, Jian,Zhang, Xiaomin,Wan, Zehong,Ren, Feng
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p. 836 - 839
(2016/05/19)
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- New Reagent for Highly Efficient Synthesis of Trifluoromethyl-Substituted Arenes and Heteroarenes
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A new reagent trimethylsilyl chlorodifluoroacetate (TCDA) is reported for the introduction of a -CF3 group to arenes and heteroarenes. Compared with current known reagents, TCDA shows very broad scope with respect to electron-deficient, -neutral, and -rich aryl/heteroaryl iodides as well as excellent functional group tolerance, including ester, amide, aldehyde, hydroxyl, and carboxylic acid. (Chemical Equation Presented).
- Zhang, Xiaomin,Wang, Jian,Wan, Zehong
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supporting information
p. 2086 - 2089
(2015/05/13)
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- Selenium-catalyzed C(sp3)-H acyloxylation: Application in the expedient synthesis of isobenzofuranones
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Oxidative Se-catalyzed C(sp3)-H bond acyloxylation has been used to construct a diverse array of isobenzofuranones from simple ortho-allyl benzoic acid derivatives. The synthetic procedure employs mild reaction conditions and gives high chemoselectivity enabled by an inexpensive organodiselane catalyst. The presented approach offers a new synthetic pathway toward the core structures of phthalide natural products.
- Kr?tzschmar, Felix,Kassel, Martin,Delony, Daniel,Breder, Alexander
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p. 7030 - 7034
(2015/05/05)
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- Direct oxidative esterification of alcohols and hydration of nitriles catalyzed by a reusable silver nanoparticle grafted onto mesoporous polymelamine formaldehyde (AgNPs@mPMF)
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A nitrogen-rich mesoporous organic polymer was synthesized as a novel support. A silver nanoparticle was synthesized and grafted onto it. The prepared catalyst (AgNPs@mPMF) was characterized by powder X-ray diffraction (XRD), scanning electron microscopy(SEM) and energy dispersive X-ray spectrometry (EDS), thermogravimetric analysis (TGA), high-resolution transmission electron microscopy (HRTEM), UV-vis diffuse reflectance spectroscopy (DRS), N2 adsorption, Raman spectroscopy and EPR study. The catalytic activity was evaluated for the oxidative esterification reaction of alcohols and hydration of nitriles. The oxidative esterification reaction was carried out for various activated alcohols giving excellent yields of the corresponding ester products. The catalyst was also efficient in the hydration of nitriles. Both reactions were optimized by varying the bases, temperatures and solvents. The catalyst can be facilely recovered and reused six times without a significant decrease in its activity and selectivity.
- Ghosh, Kajari,Iqubal, Md. Asif,Molla, Rostam Ali,Mishra, Ashutosh,Kamaluddin,Islam, Sk Manirul
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p. 1606 - 1622
(2015/04/27)
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- Selenium catalyzed oxidation of aldehydes: Green synthesis of carboxylic acids and esters
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The stoichiometric use of hydrogen peroxide in the presence of a selenium-containing catalyst in water is here reported as a new ecofriendly protocol for the synthesis of variously functionalized carboxylic acids and esters. The method affords the desired products in good to excellent yields under very mild conditions starting directly from commercially available aldehydes. Using benzaldehyde as a prototype the gram scale synthesis of benzoic acid is described, in which the aqueous medium and the catalyst could be recycled at last five times while achieving an 87% overall yield.
- Sancineto, Luca,Tidei, Caterina,Bagnoli, Luana,Marini, Francesca,Lenardo, Eder J.,Santi, Claudio
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p. 10496 - 10510
(2015/08/06)
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- Copper-catalyzed decarboxylative methylation of aromatic carboxylic acids with PhI(OAc)2
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The copper-catalyzed decarboxylative methylation of aromatic carboxylic acids was developed by using PhI(OAc)2 to provide a new strategy for the methylation of aryl acids through the decarboxylation of alkyl acids. The mechanism and the roles of each reactant in the reaction were investigated extensively. Copyright
- Jiang, Yuyu,Pan, Shulei,Zhang, Yanghui,Yu, Jingxun,Liu, Hongqiang
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supporting information
p. 2027 - 2031
(2014/04/17)
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- COMPOUNDS AND METHODS FOR INHIBITING PHOSPHATE TRANSPORT
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Compounds having activity as phosphate transport inhibitors, more specifically, inhibitors of intestinal apical membrane Na/phosphate co-transport, are disclosed. The compounds have the following structure (I): including stereoisomers, pharmaceutically ac
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Page/Page column 47-48
(2012/02/01)
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- Room-temperature base-free copper-catalyzed trifluoromethylation of organotrifluoroborates to trifluoromethylarenes
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An efficient room temperature copper-catalyzed trifluoromethylation of organotrifluoroborates under the base free condition using an electrophilic trifluoromethylating reagent is demonstrated. The corresponding trifluoromethylarenes were obtained in good to excellent yields and the reaction tolerates a wide range of functional groups.
- Huang, Yuanyuan,Fang, Xin,Lin, Xiaoxi,He, Weiming,Yuan, Yaofeng,Weng, Zhiqiang,Li, Huaifeng,Huang, Kuo-Wei
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p. 9949 - 9953,5
(2012/12/12)
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- Oxidative trifluoromethylation of arylboronates with shelf-stable potassium (trifluoromethyl)trimethoxyborate
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Introducing CF3: Arylboronic acid pinacol esters are converted into the corresponding benzotrifluorides with the easy-to-use one-component trifluoromethylating reagent potassium (trifluoromethyl)trimethoxyborate, mediated by copper acetate under an oxygen atmosphere (see scheme). Copyright
- Khan, Bilal A.,Buba, Annette E.,Goossen, Lukas J.
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supporting information; experimental part
p. 1577 - 1581
(2012/03/10)
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- Palladium-catalyzed aerobic oxidative direct esterification of alcohols
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One step from alcohol to ester: A palladium-catalyzed oxidative esterification of various benzylic alcohols with methanol and long-chain aliphatic alcohols was carried out in the presence of molecular oxygen as the oxidant (see scheme). By considering the effects of substitution and potential mechanistic pathways, the applicability of this method to a range of different substrates was shown. Copyright
- Liu, Chao,Wang, Jing,Meng, Lingkui,Deng, Yi,Li, Yao,Lei, Aiwen
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supporting information; experimental part
p. 5144 - 5148
(2011/06/26)
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- Copper-catalyzed trifluoromethylation of aryl boronic acids using a CF 3+ reagent
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A copper-catalyzed process for trifluoromethylation of aryl, heteroaryl, and vinyl boronic acids has been developed. The reaction is conducted under mild conditions and shows tolerance to moisture and a variety of functional groups.
- Xu, Jun,Luo, Dong-Fen,Xiao, Bin,Liu, Zhao-Jing,Gong, Tian-Jun,Fu, Yao,Liu, Lei
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supporting information; experimental part
p. 4300 - 4302
(2011/06/21)
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- Antileishmanial activity screening of 5-nitro-2-heterocyclic benzylidene hydrazides
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A series of 53 nitro derivatives rationally designed were obtained by parallel synthesis and screened against Leishmania donovani. Six compounds exhibited IC50 values lower than standard drugs. Brief SAR analysis revealed that substitution is important to the activity. Nitrothiophene analogues were more potent than the nitrofuran ones. This was attributed to the ability of sulfur atoms in accommodating electrons from nitro group, which facilitate its reduction and therefore the formation of free radicals lethal to parasites.
- Rando, Daniela G.,Avery, Mitchell A.,Tekwani, Babu L.,Khan, Shabana I.,Ferreira, Elizabeth I.
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p. 6724 - 6731
(2008/12/22)
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- Method of preparing an ester of an aromatic carboxylic acid bearing at least one perfluoroalkyl group
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The invention relates to a method of preparing an ester of an aromatic carboxylic acid bearing at least one perfluoroalkyl group on the aromatic ring and, more specifically, alkyl esters with low carbon condensation. The inventive method is characterised
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Page/Page column 4
(2008/06/13)
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- A facile direct conversion of aldehydes to esters and amides using acetone cyanohydrin
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Aromatic aldehydes with electron-withdrawing groups undergo rapid reactions with a variety of alcohols and secondary amines to afford the corresponding esters and amides, respectively, in high yields, when treated with NaCN or acetone cyanohydrin and base under ambient reaction conditions. In case of α,β-unsaturated aldehydes, simultaneous reduction of the CC bond along with esterification occurred to produce the saturated esters in high yields.
- Raj, I. Victor Paul,Sudalai
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p. 8303 - 8306
(2007/10/03)
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- Mechanism of the oxidation of benzylic ethers photosensitized by a 2,4,6-triphenylpyrylium salt
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The photooxidation of various benzyl methyl ether derivatives (XPhCH2OMe, with X = H, 4-MeO, 4-Me, 3-Cl, 4-CF3 and 3-CF3) sensitized by 2,4,6-triphenylpyrylium tetrafluoroborate in MeCN, in the presence of oxygen, was investigated by product analysis, fluorescence quenching and quantum yield determinations. The reaction is suggested to proceed through a benzylic radical cation intermediate, formed by electron transfer from the ether to the sensitizer. Besides the back electron transfer reaction, which gives the reactant again, the primarily formed radical cation is deprotonated and the resultant α-methoxybenzyl radical reacts through two different paths to yield benzaldehydes and methyl benzoates in a ratio that depends on the ring substituent. Fluorescence quenching and quantum yield studies have pointed out that (i) the singlet-excited state of the acceptor is mainly involved and (ii) the competition between deprotonation and back electron transfer reaction is regulated by the nature of the substituent. Hydrogen peroxide, detected together with the organic products, has been suggested to be formed in the TPP+ regeneration process through the involvement of oxygen and the acidity of the medium.
- Giacco, Tiziana Del,Lipparoni, Luca,Ranchella, Michele,Rol, Cesare,Sebastiani, Giovanni Vittorio
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p. 1802 - 1807
(2007/10/03)
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- Nucleophilic substitution at a trigonal carbon. Part 6.1 Substituent and bromide/chloride leaving group effects in the reactions of aromatic acyl chlorides with methanol in acetonitrile
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For the methanolyses in acetonitrile at 25.0°C of benzoyl chloride and eleven para- or meta-substituted derivatives, the kinetics of methyl ester formation have contributions both first-order and second-order in methanol. The Hammett plots for the overall second- and third-order processes are curved and both plots can be analyzed in terms of the simultaneous operation of two reaction channels. An addition-elimination process is favored by electron-withdrawing substituents and a loose SN2 process by electron-supplying substituents. Comparisons of widely varying halogen leaving-group effects suggest that the addition-elimination processes for solvolyses of haloformate esters and acyl halides have an identical addition step but they then differ in the sequence of the two elimination steps.
- Kevill, Dennis N.,Wang, William F. K.
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p. 2631 - 2637
(2007/10/03)
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- A New Indirect Application of Aggregative Activation: Synthesis of Esters by Cobalt-Catalyzed Carbonylation of Aryl, Heterocyclic, and Vinyl Halides under Atmospheric Pressure
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Sun lamp illuminated alkoxycarbonylation of aryl, heteroaryl, and vinyl halides was performed under atmospheric pressure of CO in the presence of a cobalt catalyst in situ generated from Co(OAc)2.Illunination through a Pyrex flask was sufficient to catalyze the reaction.This process avoids the use of Co2(CO)8 and excess CH3I, which were required in the earlier procedure.A SRN1 mechanism is proposed.
- Marchal, Joel,Bodiguel, Jacques,Fort, Yves,Caubere, Paul
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p. 8336 - 8340
(2007/10/02)
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- Electrosynthesis of (trifluoromethyl)copper complexes from bromotrifluoromethane: reactivities with various organic halides
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The synthesis of (trifluoromethyl)copper complexes is achieved easily by electroreduction of bromotrifluoromethane in N,N-dimethylformamide, in the presence of a sacrificial copper anode and various potential ligands.Three (trifluoromethyl)copper species are considered; two copper(II) and one copper(I).The mechanism of formation of the (trifluoromethyl)copper species is discussed and a study of their reactivities towards various organic halides is reported. Keywords: Copper; Trifluoromethyl derivatives; Electroreduction; Mechanism; Bromotrifluoromethane; (Trifluoromethyl)copper complexes
- Paratian, J. M.,Labbe, E.,Sibille, S.,Perichon, J.
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p. 137 - 144
(2007/10/02)
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- An efficient cobalt catalyzed alkoxycarbonylation of aryl and heteroaryl halides
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Cobalt carbonyl catalyzed carbonylation (1 atm) of aryl and heteroaryl halides may be easily achieved with CoCRACO in alcohol under photostimulation to afford the corresponding esters in high yield. Irradiation may be achieved very easily with a commercial sun lamp. Easy to prepare and handle on a preparative scale, CoCRACO must be regarded as very promising tool in the preparation of various esters.
- Vanderesse,Marchal,Caubere
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p. 1361 - 1370
(2007/10/02)
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- Correlation of Carbon-13 Substituent-Induced Chemical Shifts: meta- and para-Substituted Methyl Benzoates
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Carbon-13 NMR spectra are reported for 69 substituted methyl benzoates in deuteriochloroform or in its mixture with dimethyl sulphoxide-d6.The substituent-induced chemical shifts (SCS) of the CO carbon correlate poorly with dual substituent parameters (DSP) in all possible modifications, and for meta derivatives in particular this correlation is both overparameterized and imprecise.A much better correlation was obtained with parameters (designated Bm, Bp and Cp) derived previously by principal component analysis (PCA) from a larger set.The SCS of the CH3 carbon correlate very well with the original simple Hammett equation, and no DSP treatment is needed.The clustering of substituents is not consequential in such a large set.KEY WORDS Methyl benzoates 13C NMR Substituent effects
- Budesinsky, Milos,Exner, Otto
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p. 585 - 591
(2007/10/02)
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- Selective Dimerizations of Substituted N-Aminopyridinium Salts and Their Benzologues
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N-Aminopyridinium salts bearing ester, aroyl, and cyano functions in position 2 as well as their differently annelated benzologues were reacted with hydroxide ion and alkoxides.In the case of ester compounds 1, 3, and 5, transesterification and dimerization reactions were found.Keto salts 7, 13, and 15 showed dimerization reactions coupled with methanolysis.Monocyclic cyano salt 17 gave amino-as-triazinium double salt 20 while the benzologues (21 and 27) showed three different reactions depending on the conditions used: (a) removal of the cyano group (formation of 22 and 28), (b) formation of new fused 1,2,4-triazole derivatives (26 and 29), and (c) formation of tetrazine-fused dimers (24 and 30).All N-amino-3-substituted-isoquinolinium salts (32) resulted in dimerizations retaining the 3-substituent.Comparison of these results showed that reactivity of the N-amino compound is mainly influenced by the nature of the substituents and by the relative position of the fused benzene ring with respect to the N-amino function.
- Batori, S.,Hajos, G.,Sandor P.,Messmer, A.
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p. 3062 - 3068
(2007/10/02)
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- 2,5,6,7-tetranor-4,8-inter-m-phenylene PGI2 derivatives
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Disclosed herein are novel prostaglandin I2 (PGI2) derivatives exhibiting excellent in vivo duration and activities, said derivatives being represented by the general formula: STR1 wherein R1, X, R2 and R3 are as defined herein.
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- A NEW ELECTROPHILIC 2-PYRONE BEARING A CF3-GROUP ITS PREPARATON AND ITS CYCLOADDITION REACTIONS.
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An efficient method for the synthesis of 4-methoxycarbonyl-6-trifluoromethyl-2H-pyran-2-one (4) starting from the 1:1-adduct of the CuCl-catalysed addition of 1,1,1-trichloro-2,2,2-trifluoroethane to dimethyl itaconate is presented.The new electrophilic 2
- Martin, Pierre,Streith, Jacques,Rihs, Grety,Winkler, Tammo,Bellus, Daniel
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p. 3947 - 3950
(2007/10/02)
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- CONVENIENT APPROACHES TO HETEROCYCLES VIA COPPER-CATALYSED ADDITIONS OF ORGANIC POLYHALIDES TO ACTIVATED OLEFINS
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An efficient method for the synthesis of 2,3-dichloro-5-substituted (Cl, CF3, alkyl) pyridines 29 starting from the 1:1 adducts of the copper-catalysed addition of chloral or the corresponding 2,2-dichloroaldehydes to acrylonitrile is presented.Proper choice of experimental conditions allows the preparation of 29 in one-pot process.Similarly, the CuCl-catalysed reaction of methyl itaconate with several trichloromethyl compounds R-CCl3 gives 6-R-substituted 2-pyrone derivatives 40 via dehalogenation and subsequent thermal ring closure of the primary 1:1-adducts. The new electrophilic 2-pyrone 40b undergoes-cycloaddition reactions with inverse electron demand with a number of olefins and acetylenes, allowing thereby regioselective transfer of a trifluoromethyl group from a simple Freon derivative (1,1,1-trichloro-2,2,2-trifluoroethane) into more complex organic molecules.Finally, the 1:1-adduct of trichloroacetylchloride with methyl acrylate allows a very covenient synthesis of novel N-substituted derivatives 66 of pyroglutamic acid as well as of proline.
- Martin, Pierre,Steiner, Eginhard,Streith, Jacques,Winkler, Tammo,Bellus, Daniel
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p. 4057 - 4078
(2007/10/02)
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- Antidepressant activity of 5-aryl-2,3,5,6-tetrahydroimidazo[2,1-a]isoquinolin-5-ols
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A series of 5-aryl-2,3,5,6-tetrahydroimidazo[2,1-a]isoquinolin-5-ols was prepared and evaluated for potential antidepressant activity in the reserpine-induced hypothermia model and selected central nervous system and autonomic activity tests. Several members of the series, notably the 4-chloro- and 4-fluorophenyl analogues, demonstrated pharmacological activity in the range of imipramine. Both compounds provided a marked potentiation of the 5-hydroxytryptophan-facilitated monosynaptic spike in the spinal cat preparation.
- Houlihan,Gogerty,Parrino,Ryan
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p. 765 - 768
(2007/10/02)
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