- MOF-Zn-NHC as an efficient N-heterocyclic carbene catalyst for aerobic oxidation of aldehydes to their corresponding carboxylic acids: Via a cooperative geminal anomeric based oxidation
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As an efficient heterogenous N-heterocyclic carbene (NHC) catalyst, MOF-Zn-NHC was used in the aerobic oxidation of aryl aldehydes to their corresponding carbocyclic acids via an anomeric based oxidation. Features such as mild reaction conditions and no need for a co-catalyst or oxidative reagent can be considered as the major advantages of the presented method in this study. This journal is
- Babaee, Saeed,Zarei, Mahmoud,Zolfigol, Mohammad Ali
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p. 36230 - 36236
(2021/12/02)
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- An attempt to synthesize a terthienyl-based analog of indacenedithiophene (IDT): unexpected synthesis of a naphtho[2,3-b]thiophene derivative
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We report herein our attempt to synthesize an analog of indacenedithiophene (IDT) based on a tetraphenylhexyl substituted, covalently bridgedsyn-terthienyl unit. Instead of the expected compound the adopted synthetic route led to the formation of an unexpected, new naphtho[2,3-b]thiophene derivative. The structure of this compound was fully characterized by NMR and HRMS as well as single crystal X-ray diffraction and its electronic properties have been analyzed by UV-vis absorption spectroscopy and cyclic voltammetry. A possible mechanism for the formation of this compound is also proposed on the basis of detailed theoretical investigations.
- Anghel, C?t?lin C.,Stroia, Ioan,Pop, Alexandra,Bende, Atilla,Grosu, Ion,H?dade, Niculina D.,Roncali, Jean
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p. 9894 - 9900
(2021/03/23)
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- Disproportionation of aliphatic and aromatic aldehydes through Cannizzaro, Tishchenko, and Meerwein–Ponndorf–Verley reactions
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Disproportionation of aldehydes through Cannizzaro, Tishchenko, and Meerwein–Ponndorf–Verley reactions often requires the application of high temperatures, equimolar or excess quantities of strong bases, and is mostly limited to the aldehydes with no CH2 or CH3 adjacent to the carbonyl group. Herein, we developed an efficient, mild, and multifunctional catalytic system consisting AlCl3/Et3N in CH2Cl2, that can selectively convert a wide range of not only aliphatic, but also aromatic aldehydes to the corresponding alcohols, acids, and dimerized esters at room temperature, and in high yields, without formation of the side products that are generally observed. We have also shown that higher AlCl3 content favors the reaction towards Cannizzaro reaction, yet lower content favors Tishchenko reaction. Moreover, the presence of hydride donor alcohols in the reaction mixture completely directs the reaction towards the Meerwein–Ponndorf–Verley reaction. Graphic abstract: [Figure not available: see fulltext.].
- Sharifi, Sina,Sharifi, Hannah,Koza, Darrell,Aminkhani, Ali
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p. 803 - 808
(2021/07/20)
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- Sequential Connection of Mutually Exclusive Catalytic Reactions by a Method Controlling the Presence of an MOF Catalyst: One-Pot Oxidation of Alcohols to Carboxylic Acids
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A functionalized metal-organic framework (MOF) catalyst applied to the sequential one-pot oxidation of alcohols to carboxylic acids controls the presence of a heterogeneous catalyst. The conversion of alcohols to aldehydes was acquired through aerobic oxidation using a well-known amino-oxy radical-functionalized MOF. In the same flask, a simple filtration of the radical MOF with mild heating of the solution completely altered the reaction media, providing radical scavenger-free conditions suitable for the autoxidation of the aldehydes formed in the first step to carboxylic acids. The mutually exclusive radical-catalyzed aerobic oxidation (the first step with MOF) and radical-inhibited autoxidation (the second step without MOF) are sequentially achieved in a one-pot manner. Overall, we demonstrate a powerful and efficient method for the sequential oxidation of alcohols to carboxylic acids by employing a readily functionalizable heterogeneous MOF. In addition, our MOF in-and-out method can be utilized in an environmentally friendly way for the oxidation of alcohols to carboxylic acids of industrial and economic value with broad functional group tolerance, including 2,5-furandicarboxylic acid and 1,4-benzenedicarboxylic acid, with good yield and reusability. Furthermore, MOF-TEMPO, as an antioxidative stabilizer, prevents the undesired oxidation of aldehydes, and the perfect "recoverability"of such a reactive MOF requires a re-evaluation of the advantages of MOFs from heterogeneity in catalytic and related applications.
- Kim, Seongwoo,Lee, Ha-Eun,Suh, Jong-Min,Lim, Mi Hee,Kim, Min
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supporting information
p. 17573 - 17582
(2020/12/22)
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- Cobalt-catalyzed carboxylation of aryl and vinyl chlorides with CO2
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The transition-metal-catalyzed carboxylation of aryl and vinyl chlorides with CO2 is rarely studied, and has been achieved only with a Ni catalyst or combination of palladium and photoredox. In this work, the cobalt-catalyzed carboxylation of aryl and vinyl chlorides and bromides with CO2 has been developed. These transformations proceed under mild conditions and exhibit a broad substrate scope, affording the corresponding carboxylic acids in good to high yields.
- Wang, Yanwei,Jiang, Xiaomei,Wang, Baiquan
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supporting information
p. 14416 - 14419
(2020/12/01)
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- Method for preparing aromatic carboxylic acid compound
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The invention discloses a method for preparing an aromatic carboxylic acid compound. The method comprises the following steps: 1) heating carbon dioxide and hydrosilane in the presence of a copper catalyst in a reaction medium A; and 2) adding a reaction medium B, aryl halide, a palladium catalyst and a base to the reaction mixture in the step 1), sealing the reaction system, and performing a heating reaction. The method has the advantages that raw materials are simple and easy to obtain, the raw materials are cheap and stable, the catalyst is common, easy to obtain and stable, the reaction conditionsaremild, the aftertreatment is simple, the yield is high, and the like.
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-
Paragraph 0085-0086; 0097-0099; 0175
(2020/02/14)
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- Cobalt-Catalyzed Reductive Carboxylation of Aryl Bromides with Carbon Dioxide
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Cobalt-catalyzed reductive carboxylation of aryl bromides with carbon dioxide has been developed. The reaction proceeded under one atm pressure of CO2 at 40 °C in the presence of cobalt iodide/2,2′-bipyridine catalysts and zinc dust as a reducing reagent. Various aryl bromides could be converted to the corresponding carboxylic acids in good to high yields. Preliminary mechanistic experiments ruled out intervention of intermediate organozinc species for carboxylation with CO2, thus suggesting a direct CO2 insertion into the corresponding ArCoBr species. (Figure presented.).
- Hang, Wei,Yi, Yaping,Xi, Chanjuan
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supporting information
p. 2337 - 2341
(2020/04/30)
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- CO2 activation by electrogenerated divalent samarium for aryl halide carboxylation
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The reductive carboxylation of aryl halides has been investigated using a samarium electrode as a sacrificial anode to yield the corresponding benzoic acids, providing a smooth strategy for CO2 activation. Carboxylation occurred after an efficient reduction of carbon dioxide mediated by an electrogenerated Sm(ii)-complex acting as a strong monoelectronic reductive reagent.
- Bazzi, Sakna,Le Duc, Ga?tan,Schulz, Emmanuelle,Gosmini, Corinne,Mellah, Mohamed
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supporting information
p. 8546 - 8550
(2019/10/02)
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- Dehydrogenation of Alcohols to Carboxylic Acid Catalyzed by in Situ-Generated Facial Ruthenium- CPP Complex
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A selective catalytic system for the dehydrogenation of primary alcohols to carboxylic acids using a facial ruthenium complex generated in situ from the [Ru(COD)Cl2]n and a hybrid N-heterocyclic carbene (NHC)-phosphine-phosphine ligand (CPP) has been first reported. The facial coordination model was unveiled by NMR analysis of the reaction mixture. Such a fac-ruthenium catalyst system exhibited high catalytic activity and stability, and a high turnover number of 20 000 could be achieved with catalyst loading as low as 0.002 mol %. The exceedingly high catalyst stability was tentatively attributed to both the anchoring role of NHC and the hemi-lability of phosphines. The catalytic system also features a wide substrate scope. In particular, the facial coordination of CPP ligands was found to be beneficial for sterically hindered alcohols, and ortho-substituted benzylic alcohols and bulky adamantanyl methanol as well as cholesterol were all found to be viable dehydrogenation substrates.
- Liu, Hui-Min,Jian, Lei,Li, Chao,Zhang, Chun-Chun,Fu, Hai-Yan,Zheng, Xue-Li,Chen, Hua,Li, Rui-Xiang
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p. 9151 - 9160
(2019/08/12)
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- Tandem one-pot CO2 reduction by PMHS and silyloxycarbonylation of aryl/vinyl halides to access carboxylic acids
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The present study discloses the synthesis of aryl/vinyl carboxylic acids from Csp2-bound halides (Cl, Br, I) in a carbonylative path by using silyl formate (from CO2 and hydrosilane) as an instant CO-surrogate. Hydrosilane provides hydride for reduction and its oxidation product silanol serves as a coupling partner. Mono-, di-, and tri-carboxylic acids were obtained from the corresponding aryl/vinyl halides.
- Paridala, Kumaraswamy,Lu, Sheng-Mei,Wang, Meng-Meng,Li, Can
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supporting information
p. 11574 - 11577
(2018/10/31)
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- Studies on Iron-Catalyzed Aerobic Oxidation of Benzylic Alcohols to Carboxylic Acids
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A comprehensive study on aerobic oxidation of benzylic alcohols to carboxylic acids with a catalytic amount each of Fe(NO 3) 3 ·9H 2 O, TEMPO, and KCl is conducted. Various synthetically useful functional groups are well tolerated in the reaction. Distinct electronic and steric effects are observed in the reaction: electron-withdrawing groups accelerate the reaction while electron-donating groups make the reaction slower, and ortho -substituted substrates react slower than meta -substituted substrates. Several large-scale reactions (100 mmol) are conducted using a slow air flow of 30 mL/min to demonstrate the practicality of this method in an academic laboratory.
- Jiang, Xingguo,Ma, Shengming
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p. 1629 - 1639
(2018/02/26)
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- A 2 - bromo - 3 - thiophene carboxylic acid intermediates of the synthesis method (by machine translation)
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The invention relates to 2 - bromo - 3 - thiophenecarboxylic acid synthesis method, comprises the following synthetic steps: 1): by 3 - methyl thiophene as raw materials, adding N - bromosuccinimide synthesis of 2 - bromo - 3 methyl thiophene; 2): by the 2 - bromo - 3 methyl thiophene to carbon tetrachloride as solvent, azobisisobutyronitrile as initiator with the N - bromosuccinimide synthesis of 2 - bromo - 3 - (bromomethyl) thiophene; 3): by the 2 - bromo - 3 - (bromomethyl) thiophene is 2 - iodo acyl benzoic acid oxidation to obtain 2 - bromo - 3 - thiophene formaldehyde; 4): by the 2 - bromo - 3 - thiophene formaldehyde sodium hydroxide aqueous solution as the solvent, is potassium permanganate oxidation to obtain 2 - bromo - 3 - thiophenecarboxylic acid. The invention has the advantages of: this invention uses the first to 2 of bit bromine substituted, then 3 of the oxidation of the synthetic route, mild reaction conditions, reactants are cheap and easily obtained, the yield is high. 2nd, greatly inhibit the double-bromo product, increasing the yield. (by machine translation)
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Paragraph 0025-0029; 0043; 0050-0052
(2017/08/28)
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- Palladium-Catalyzed Ligand-Controlled Selective Synthesis of Aldehydes and Acids from Aryl Halides and Formic Acid
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Selective synthesis is in the core of modern organic chemistry. In this communication, a novel ligand-dependent palladium-catalyzed carbonylation procedure for the divergent synthesis of aldehydes and carboxylic acids from easily available aryl halides was established. Under the same reaction conditions, the reaction pathway could be controlled by the ligands applied to give formylated and carboxylated products selectively. Sterically hindered monodentate ligands facilitated the reductive carbonylation and provided aldehydes, whereas bidentate ligands preferred the carboxylation reaction and produced carboxylic acids. A wide range of functional groups were tolerated, and the products were, in general, obtained in moderate to excellent yields.
- Wu, Fu-Peng,Peng, Jin-Bao,Meng, Ling-Shen,Qi, Xinxin,Wu, Xiao-Feng
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p. 3121 - 3124
(2017/08/29)
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- Palladium-Catalyzed Carbonylative Transformation of Organic Halides with Formic Acid as the Coupling Partner and CO Source: Synthesis of Carboxylic Acids
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A palladium-catalyzed carbonylative transformation of organic halides with formic acid as the coupling partner to produce carboxylic acids has been developed. With a catalytic amount of DCC as the activator of formic acid, the process can be realized successfully through benzoic formic anhydride as the intermediate. Both vinyl and aryl (pseudo)halides were conveniently transformed into the corresponding acids in good yields.
- Wu, Fu-Peng,Peng, Jin-Bao,Qi, Xinxin,Wu, Xiao-Feng
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p. 9710 - 9714
(2017/09/23)
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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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- Metal-Free Dehomologative Oxidation of Arylacetic Acids for the Synthesis of Aryl Carboxylic Acids
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A novel I2-promoted direct conversion of arylacetic acids into aryl carboxylic acids under metal-free conditions has been described. This remarkable transformation involves decarboxylation followed by an oxidation reaction enabled just by using DMSO as the solvent as well as an oxidant. Notably, aryl carboxylic acids are isolated by simple filtration technique and obtained in good to excellent yields. This protocol is free from chromatographic purification, which makes it applicable for large-scale synthesis.
- Kalmode, Hanuman P.,Vadagaonkar, Kamlesh S.,Shinde, Suresh L.,Chaskar, Atul C.
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p. 3781 - 3786
(2017/04/11)
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- Visible-Light-Driven Carboxylation of Aryl Halides by the Combined Use of Palladium and Photoredox Catalysts
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A highly useful, visible-light-driven carboxylation of aryl bromides and chlorides with CO2 was realized using a combination of Pd(OAc)2 as a carboxylation catalyst and Ir(ppy)2(dtbpy)(PF6) as a photoredox catalyst. This carboxylation reaction proceeded in high yields under 1 atm of CO2 with a variety of functionalized aryl bromides and chlorides without the necessity of using stoichiometric metallic reductants.
- Shimomaki, Katsuya,Murata, Kei,Martin, Ruben,Iwasawa, Nobuharu
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supporting information
p. 9467 - 9470
(2017/07/24)
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- Aerobic Oxidation of Diverse Primary Alcohols to Carboxylic Acids with a Heterogeneous Pd-Bi-Te/C (PBT/C) Catalyst
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Heterogeneous catalytic aerobic oxidation methods represent a near-ideal approach for the conversion of primary alcohols to carboxylic acids. Here, we report that a heterogeneous catalyst composed of Pd, Bi, and Te supported on activated carbon is highly effective for the oxidation of diverse benzylic and aliphatic primary alcohols, including 5-(hydroxymethyl)furfural (HMF) and substrates bearing heterocycles and other important functional groups. In many cases, the desired carboxylic acid product is obtained in >90% yield. Additionally, the catalyst has been demonstrated in a continuous-flow packed-bed reactor for the oxidation of benzyl alcohol, achieving near-quantitative yield while undergoing over 30 000 turnovers.
- Ahmed, Maaz S.,Mannel, David S.,Root, Thatcher W.,Stahl, Shannon S.
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supporting information
p. 1388 - 1393
(2017/09/22)
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- A Strained Disilane-Promoted Carboxylation of Organic Halides with CO2 under Transition-Metal-Free Conditions
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By using a strained four-membered ring disilane (3,4-benzo-1,1,2,2-tetraethyldisilacyclobutene) and CsF, a wide range of aryl, alkenyl, alkynyl, benzyl, allyl, and alkyl halides was successfully carboxylated under an ambient CO2 atmosphere (CO2 balloon) at room temperature within 2 h. In this carboxylation, a highly reactive silyl anion, which is generated from the disilane and CsF, is a key to facilitating the formation of a carbanion equivalent. The resulting anionic species can be trapped with CO2 to produce carboxylic acids with high efficiency.
- Mita, Tsuyoshi,Suga, Kenta,Sato, Kaori,Sato, Yoshihiro
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supporting information
p. 5276 - 5279
(2015/11/18)
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- Ligand-Free Palladium-Catalyzed Hydroxycarbonylation of Aryl Halides under Ambient Conditions: Synthesis of Aromatic Carboxylic Acids and Aromatic Esters
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Aryl halides were readily converted into their corresponding aromatic carboxylic acids in high yields with high selectivity by ligand-free palladium-catalyzed hydroxycarbonylation at room temperature and atmospheric pressure. The new method is operationally simple and scalable. In addition, aromatic esters were easily synthesized through one-pot hydroxycarbonylation/alkylation with alkyl halides.
- Han, Wei,Jin, Fengli,Zhou, Qing
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p. 1861 - 1868
(2015/06/30)
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- Electrophilicity and nucleophilicity of commonly used aldehydes
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The present approach for determining the electrophilicity (E) and nucleophilicity (N) of aldehydes includes a kinetic study of KMNO4 oxidation and NaBH4 reduction of aldehydes. A transition state analysis of the KMNO4 promoted aldehyde oxidation reaction has been performed, which shows a very good correlation with experimental results. The validity of the experimental method has been tested using the experimental activation parameters of the two reactions. The utility of the present approach is further demonstrated by the theoretical versus experimental relationship, which provides easy access to E and N values for various aldehydes and offers an at-a-glance assessment of the chemical reactivity of aldehydes in various reactions. the Partner Organisations 2014.
- Pratihar, Sanjay
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p. 5781 - 5788
(2014/07/22)
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- Copper-catalyzed synthesis of aromatic carboxylic acids from arylboronic acids and acetyl acetate
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A simple and efficient copper-catalyzed method for the synthesis of aromatic carboxylic acids in moderate to high yields with great functional-group compatibility in the substrates has been developed. The new method uses readily available arylboronic acids and acetyl acetate as the starting materials and inexpensive CuI as the catalyst.
- Zheng, Rui,Zhou, Qizhong,Gu, Haining,Jiang, Huajiang,Wu, Jiashou,Jin, Zhengneng,Han, Deman,Dai, Guoliang,Chen, Rener
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supporting information
p. 5671 - 5675
(2014/12/11)
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- Nickel-catalysed carboxylation of organoboronates
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A nickel/N-heterocyclic carbene (NHC) catalysed carboxylation of aryl-, heteroaryl- and alkenylboronates, affording the corresponding carboxylic acids, has been developed. This transformation proceeds under one atmosphere of CO 2 with a broad range of substrates and exhibits good functional group compatibility. the Partner Organisations 2014.
- Makida, Yusuke,Marelli, Enrico,Slawin, Alexandra M. Z.,Nolan, Steven P.
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supporting information
p. 8010 - 8013
(2014/07/08)
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- Catalytic aerobic photooxidative cleavage of carbon-carbon triple bonds using carbon tetrabromide
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We developed the aerobic photooxidative cleavage of carbon-carbon triple bonds to carboxylic acids in the presence of catalytic amounts of carbon tetrabromide under photoirradiation with a high-pressure mercury lamp. Georg Thieme Verlag Stuttgart · New York..
- Yamaguchi, Tomoaki,Nobuta, Tomoya,Kudo, Yasuhisa,Hirashima, Shin-Ichi,Tada, Norihiro,Miura, Tsuyoshi,Itoh, Akichika
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p. 607 - 610
(2013/04/23)
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- Aerobic photooxidative cleavage of 1,3-diketones to carboxylic acids using 2-chloroanthraquinone
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We developed direct aerobic photooxidation of 1,3-diketones to corresponding carboxylic acids in the presence of a catalytic amount of 2-chloroanthraquinone under visible light irradiation from fluorescent lamps.
- Tachikawa, Yuma,Cui, Lei,Matsusaki, Yoko,Tada, Norihiro,Miura, Tsuyoshi,Itoh, Akichika
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p. 6218 - 6221
(2013/10/22)
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- Silver(i)-catalyzed carboxylation of arylboronic esters with CO2
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A variety of arylboronic esters were efficiently carboxylated with CO 2 using a simple AgOAc/PPh3 catalyst, affording the corresponding carboxylic acids in good yield. This simple and efficient silver(i) catalytic system showed wide functional group compatibility. The Royal Society of Chemistry 2012.
- Zhang, Xiao,Zhang, Wen-Zhen,Shi, Ling-Long,Guo, Chun-Xiao,Zhang, Ling-Ling,Lu, Xiao-Bing
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supporting information; experimental part
p. 6292 - 6294
(2012/07/16)
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- Process for the carboxylation of aryl halides with palladium catalysts
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A process for the carboxylation of an aryl halide to yield an aryl carboxylic acid, in which the aryl halide and CO2 are contacted in an organic solvent under inert atmosphere and in the presence of a reducing agent and an adequate catalyst system.
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Page/Page column 10
(2011/05/04)
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- Catalytic oxidative cleavage of 1,3-diketones to carboxylic acids by aerobic photooxidation with iodine
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We report the catalytic oxidative cleavage of 1,3-diketones to the corresponding carboxylic acids by aerobic photooxidation with iodine under irradiation with a high-pressure mercury lamp. Georg Thieme Verlag Stuttgart. New York.
- Tada, Norihiro,Shomura, Motoki,Cui, Lei,Nobuta, Tomoya,Miura, Tsuyoshi,Itoh, Akichika
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experimental part
p. 2896 - 2900
(2012/01/03)
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- Copper-catalyzed aerobic oxidative synthesis of aromatic carboxylic acids
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A simple, practical and efficient copper-catalyzed method for synthesis of aromatic carboxylic acids has been developed. The protocol uses inexpensive CuI/l-proline as the catalyst/ligand, and readily available aryl halides and malononitrile as the starting materials, and the corresponding aromatic carboxylic acids were obtained in moderate to good yields. The method is of tolerance towards functional groups in the substrates.
- Yang, Daoshan,Yang, Haijun,Fu, Hua
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supporting information; experimental part
p. 2348 - 2350
(2011/03/21)
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- Synthesis of novel furo-, thieno-, and pyrroloazepines
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The synthesis of novel furo-, thieno-, and pyrroloazepine compounds, using the oxidative radical alkylation of three five-membered heterocyclic 3-acetic acid derivatives, is described. The bicyclic systems were obtained, via a small number of steps, directly from commercially available materials. Georg Thieme Verlag Stuttgart New York.
- Villarreal, Carlos,Martinez, Roberto
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experimental part
p. 3346 - 3352
(2010/11/17)
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- An improved protocol for the oxidative cleavage of alkynes, alkenes, and diols with recyclable Ru/C
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Efficient synthesis of carboxylic acids from alkynes; aldehydes from alkenes and diols employing Ru/C-based recyclable catalytic system is reported with good to excellent yields. Georg Thieme Verlag Stuttgart.
- Vijay Kumar,Prakash Reddy,Sridhar,Srinivas,Rama Rao
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experimental part
p. 739 - 742
(2009/07/18)
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- Palladium-catalyzed direct carboxylation of aryl bromides with carbon dioxide
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(Chemical Equation Presented) A novel protocol for the direct carbon dioxide insertion (CO2) into aryl halides in a catalytic manner is presented herein. Unlike other carboxylation methods using CO2, there is no need for the synthesis of the corresponding organometallic intermediates. Additionally, and in contrast to the well-established carbonylation processes, our protocol does not use highly toxic CO for the preparation of benzoic acids. Furthermore, this method is distinguished by its mild conditions, allowing the tolerance of a wide range of functional groups and substitution patterns. The crucial step of the process involves a challenging catalytic CO2 insertion into Pd-C bonds. Copyright
- Correa, Arkaitz,Martin, Ruben
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supporting information; experimental part
p. 15974 - 15975
(2010/02/15)
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- Aerobic oxidation under visible light irradiation of a fluorescent lamp with a combination of carbon tetrabromide and triphenyl phosphine
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A combination of CBr4-Ph3P, a non-metal method, enables us to carry out aerobic photo-oxidation of alcohols and aromatic methyl groups to the corresponding carboxylic acids under irradiation of vis from a general-purpose fluorescent lamp. Aliphatic primary- and secondary alcohols, benzyl alcohols, and methyl groups at the aromatic nucleus generally afforded the carboxylic acids directly in good to high yield.
- Sugai, Taichi,Itoh, Akichika
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p. 9096 - 9099
(2008/09/16)
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- Novel thienopyrrole glycogen phosphorylase inhibitors: Synthesis, in vitro SAR and crystallographic studies
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Two series of novel thienopyrrole inhibitors of recombinant human liver glycogen phosphorylase a (GPa) which are effective in reducing glucose output from rat hepatocytes are described. Representative compounds have been shown to bind at the dimer interface site of the rabbit muscle enzyme by X-ray crystallography.
- Whittamore, Paul R.O.,Addie, Matthew S.,Bennett, Stuart N.L.,Birch, Alan M.,Butters, Michael,Godfrey, Linda,Kenny, Peter W.,Morley, Andrew D.,Murray, Paul M.,Oikonomakos, Nikos G.,Otterbein, Ludovic R.,Pannifer, Andrew D.,Parker, Jeremy S.,Readman, Kristy,Siedlecki, Pawel S.,Schofield, Paul,Stocker, Andy,Taylor, Melvyn J.,Townsend, Linda A.,Whalley, David P.,Whitehouse, Jennifer
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p. 5567 - 5571
(2007/10/03)
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- Rhodium(I)-catalyzed carboxylation of aryl- and alkenylboronic esters with CO2
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When the esters of arylboronic acids with 2,2-dimethylpropan-1,3-diol were treated with a catalytic amount of [Rh(OH)(cod)]2 in the presence of 1,3-bis(diphenylphosphino)propane and CsF in dioxane at 60 °C under carbon dioxide atmosphere, the benzoic acid derivatives were obtained in good yields. Reactions of alkenylboronic esters also proceeded under similar conditions to give α,β-unsaturated carboxylic acids. As these boronic esters are now easily available through coupling or direct borylation reactions, this method would be a useful method for the preparation of various functionalized aryl- and alkenyl-carboxylic acids. Copyright
- Ukai, Kazutoshi,Aoki, Masao,Takaya, Jun,Iwasawa, Nobuharu
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p. 8706 - 8707
(2007/10/03)
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- Aerobic photo-oxidation of alcohols in the presence of a catalytic inorganic bromo source
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Alcohols were found to be oxidized to the corresponding carboxylic acid in the presence of a catalytic inorganic bromo source, for example, lithium bromide, bromine, and hydrobromic acid, under photo-irradiation.
- Hirashima, Shin-ichi,Hashimoto, Shouei,Masaki, Yukio,Itoh, Akichika
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p. 7887 - 7891
(2007/10/03)
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- Facile aerobic photooxidation of alcohols in the presence of catalytic N-bromosuccinimide
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Alcohols were found to be oxidized to the corresponding carboxylic acid in the presence of catalytic N-bromosuccinimide in an oxygen atmosphere. Georg Thieme Verlag Stuttgart.
- Kuwabara, Kiyoto,Itoh, Akichika
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p. 1949 - 1952
(2007/10/03)
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- Process for producing heterocyclic aldehyde
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The present invention provides a process for preparing a heterocyclic aldehyde by oxidizing a heterocyclic alcohol with high selectivity and high yield. Specifically, the heterocyclic aldehyde is prepared by reacting a heterocyclic compound having at least one hydroxymethyl group bonded to a carbon atom of a heterocyclic ring with a hypohalogenous acid salt in the presence of a base to oxidize the hydroxymethyl group, wherein reaction is conducted in the co-presence of a 2,2,6,6-tetramethylpiperidine-1-oxyl derivative having at least two 2,2,6,6-tetramethylpiperidine-1-oxyl-4-yl groups.
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Page/Page column 11
(2008/06/13)
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- Benzothiadiazine compounds
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Compound of formula (I): wherein: R1 represents hydroxy, RCO—O— or RCO—NRa—, R2 represents hydrogen, halogen, or hydroxy, R′CO—O or R′CO—NR′a—, R and R′, which may be identical or different, represent linear or branched (C1-C6)alkyl optionally substituted by aryl, linear or branched (C2-C6)alkenyl optionally substituted by aryl, linear or branched (C1-C6)perhaloalkyl, (C3-C7)cycloalkyl, adamantyl, aryl or heteroaryl, Ra and R′a, which may be identical or different, represent hydrogen or linear or branched (C1-C6)alkyl, linear or branched (C1-C6)perhaloalkyl, linear or branched (C1-C6)acyl, aryl or heteroaryl, its isomer and addition salts thereof with a pharmaceutically acceptable acid or base and medicinal products containing the same are useful as AMPA modulators.
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- Regioselective Preparation of 2,4-, 3,4-, and 2,3,4-Substituted Furan Rings. 1. [1,4] O → C and [1,4] C → O Silyl Migrations of Silyl Ethers and Esters Attached to Furan and Thiophene Rings
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[1,4] O → C and [1,4] C → O rearrangements are described for a variety of furans and thiophenes. Treatment of 3-((silyloxy)methyl)furans and -thiophenes with n-BuLi in HMPA provided 2-silylated-3-(hydroxymethyl)furans and -thiophenes in good to excellent yields. The reaction was shown by crossover studies to proceed via an intramolecular [1,4] O → C silyl migration. Silyl esters of 3-furoic acids also underwent an intramolecular [1,4] O → C silyl migration to provide 2-silylated-3-furoic acids in moderate to good yield when treated with a mixture of LDA and HMPA. Finally, the above silyl migrations were shown to be reversible. Treatment of 2-silylated-3-(hydroxymethyl)-furans and -thiophenes with NaH in DMF provided 3-((silyloxy)methyl)furans and -thiophenes in excellent yields via a [1,4] C → O silyl migration. The [1,4] C → O silyl migration was also shown to be an intramolecular process by a crossover study.
- Bures, Edward,Spinazze, Patrick G.,Beese, Giovanna,Hunt, Ian R.,Rogers, Christine,Keay, Brian A.
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p. 8741 - 8749
(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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- 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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- Antiparasitic agents
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The invention provides novel compounds having the formula: STR1 wherein R when taken individually is H; R1 when taken individually is H or OH; R and R1 when taken together represent a double bond; R2 is an alpha-branched C3 -C8 alkyl, alkenyl, alkynyl, alkoxyalkyl or alkylthioalkyl group; a C3 -C8 cycloalkyl, C5 -C8 cycloalkenyl or C5 -C8 cycloalkylalkyl group, any of which may be substituted by methylene or one or more C1 -C4 alkyl groups or halo atoms; or a 3 to 6 membered oxygen or sulphur containing heterocyclic ring which may be substituted by one or more C1 -C4 alkyl groups or halo atoms; R3 is hydrogen or methyl; R4 is H or 4'-(alpha-L-oleandrosyl)-alpha-L-oleandrosyloxy with the proviso that when R2 is alkyl it is not isopropyl or sec-butyl; when R4 is H, each of R and R1 is H, and R2 is not methyl or ethyl; and when R4 is H, R is H, R1 is OH, and R2 is not 2-buten-2-yl, 2-penten-2-yl or 4-methyl-2-penten-2-yl. The compounds are broad spectrum antiparasitic agents having utility as anthelmintics, ectoparasiticides, insecticides and acaricides. The invention also provides a process for producing the novel avermectin and milbemycin derivatives by adding a carboxylic acid or derivative thereof to a fermentation of an avermectin or milbemycin producing organism.
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- GAS-PHASE PYROLYTIC REACTIONS. PART 4. ARRHENIUS PARAMETERS AND HAMMETT ρ CONSTANTS IN GAS-PHASE ELIMINATIONS OF ALKYL PYRIDYL-, FURYL-, AND THIENYLCARBOXYLATE ESTERS
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The first-order rate coefficients ( 105k/s-1) of the gas-phase pyrolytic reactions of seven isopropyl (hetero)arylcarboxylate esters were calculated for 600 K to be: 75.34 for benzoate, and 100.0, 70.46, 94.03, 65.58, 100.9 and 120.2 for 2-thienyl-, 3-thienyl-, 2-furyl-, 3-furyl-, 3-pyridyl- and 4-pyridylcarboxylate, respectively.The corresponding Hammett replacement ρ0 substituent constants of the heterocyclic groups are: 0.53, -0.13, 0.42, -0.26, 0.55 and 0.88, respectively.The reported ρ0 constants are in agreement with other gas-phase and solution data, and are amenable to rationalization in terms of normal electronic and structural effects.Further, the physical constants of four new isopropyl heteroarylcarboxylate esters are described.
- Al-Awadi, Nouria A.,Al-Bashir, Rasha F.,ElDusouqui, Osman M. E.
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p. 2911 - 2916
(2007/10/02)
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- GAS-PHASE PYROLYTIC REACTIONS. PART 3. HAMMETT ρ CONSTANTS OF GAS-PHASE ELIMINATIONS OF ALKYLARYLCARBOXYLATE AND ETHANOATE ESTERS AND THEIR CORRELATION WITH SUBSTRATE MOLECULAR FRAMEWORK
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The kinetics of the gas-phase thermal elimination of seven tert-butyl (hetero)arylcarboxylate esters (GCO2But) were measured over a temperature range 50 K; the groups were the phenyl, 3- and 4-pyridyl, 2- and 3-furyl, and 2- and 3-thienyl moieties.The reactions were homogeneous and unimolecular with log A/s-1 scaling 12.45 +/- 0.44, and with an entropy of activation uniformly negative and small.The kinetics obeyed a first-order rate equation, and at 600 K the rate coefficients (103k/s-1) of the esters, in the order given above, were: 54.1, 85.3, 120.5, 76.9, 43.2, 86.3 and 46.1, respectively.Hammett correlation of the present kinetic data with the literature ρ0 - values of the given substituents gave a reaction ρ constant compatible with the ethanoate molecular frame rather than with the carboxylate structure.The physical constants of five new t-butyl heteroarylcarboxylate esters are also described.
- Al-Awadi, Nouria A.,Al-Bashir, Rasha F.,ElDusouqui, Osman M. E.
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p. 2903 - 2910
(2007/10/02)
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- GAS-PHASE REPLACEMENT ?0 SUBSTITUENT CONSTANTS OF HETEROARYL GROUPS
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Hammett replacement ?0 substituent constants of pyridyl, thienyl, and furyl groups are reported for the first time from gas-phase eliminations of their t-butyl and isopropyl heteroarylcarboxylate esters.
- Al-Awadi, Nouria A.,Al-Bashir, Rasha F.,ElDusouqui, Osman M. E.
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p. 1699 - 1702
(2007/10/02)
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- A CONVENIENT ROUTE TO POLYTHIOPHENES
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The Michael addition of aldehydes to α,β-unsaturated ketones (or their Mannich base precursors) developed by Stetter1 has been applied to the synthesis of 1,4-diketones containing one or more thiophene rings.These diketones could be cyclized in high yields to terthienyls.
- Wynberg, Hans,Metselaar, Jan
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- 9,10-Bis(aminoalkoxy)anthracenes
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This disclosure describes certain substituted 9,10-bis(2-aminoethoxy)anthracenes which are useful as modulators of the immune response system in warm-blooded animals and for inducing the regression of tumors in such animals.
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- PHOTOLYSES OF BIS(2-THIOPHENECARBONYL) AND BIS(3-THIOPHENECARBONYL) PEROXIDES IN BENZENE. PRODUCTION OF BIPHENYL FROM THE SOLVENT BENZENE CONTROLLED BY THE PHOTOLYSIS RATE
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Direct and sensitized photolyses of bis(2-thiophenecarbonyl) (2-TPO) and bis(3-thiophenecarbonyl) peroxide (3-TPO) in benzene afforded biphenyl derived solely from the solvent among the products.The yield of biphenyl depended upon the rate with which the radical intermediates were generated from the peroxides in sufficiently high concentrations to dimerize.
- Urano, Toshiyuki,Kitamura, Akihide,Sakuragi, Hirochika,Tokumaru, Katsumi
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p. 867 - 870
(2007/10/02)
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