- Copper on charcoal: Cu0nanoparticle catalysed aerobic oxidation of α-diazo esters
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By using a charcoal supported nano Cu0catalyst (Cu/C), a highly efficient oxidation of α-diazo esters to α-ketoesters with molecular oxygen as the sole oxidant has been developed. In the presence of the Cu/C catalyst, 2-aryl-α-diazo esters with both electron-donating and electron-withdrawing groups can be oxidized to the corresponding α-ketoesters efficiently. Furthermore, this Cu/C catalyst can catalyse the reaction of aryl α-diazo ester with water to form aryl ketoester, 2-aryl-2-hydroxyl acetate ester and 2-aryl acetate ester. In this case, water is split by α-diazo ester, and the diazo group is displaced by the oxygen or hydrogen atom in water. Mechanistic investigation showed that the reaction of α-diazo ester with oxygen proceeds through a radical pathway. In the presence of 2,2,6,6-tetramethyl piperidine nitrogen oxide, the reaction of α-diazo ester with oxygen is dramatically inhibited. Furthermore, the reaction of α-diazo ester with water is investigated by an isotopic tracer method, and GCMS detection showed that a disproportionation reaction occurred between α-diazo ester and water.
- Chu, Changhu,Dong, Wenwen,Lin, Jia,Teng, Jiangge,Wang, Zhiwei,Zhao, Rong
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p. 6120 - 6126
(2021/07/21)
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- Metal-Free Oxidative Esterification of Ketones and Potassium Xanthates: Selective Synthesis of α-Ketoesters and Esters
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A novel and efficient oxidative esterification for the selective synthesis of α-ketoesters and esters has been developed under metal-free conditions. In the protocol, various α-ketoesters and esters are available in high yields from commercially available ketones and potassium xanthates. Mechanistic studies have proven that potassium xanthate not only promotes oxidative esterification but also provides an alkoxy moiety for the reaction, which involves the cleavage and reconstruction of C-O bonds.
- Luo, Xianglin,He, Runfa,Liu, Qiang,Gao, Yanping,Li, Jingqing,Chen, Xiuwen,Zhu, Zhongzhi,Huang, Yubing,Li, Yibiao
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p. 5220 - 5230
(2020/05/18)
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- Electrochemistry-Enabled Ir-Catalyzed Vinylic C-H Functionalization
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Synergistic use of electrochemistry and organometallic catalysis has emerged as a powerful tool for site-selective C-H functionalization, yet this type of transformation has thus far mainly been limited to arene C-H functionalization. Herein, we report the development of electrochemical vinylic C-H functionalization of acrylic acids with alkynes. In this reaction an iridium catalyst enables C-H/O-H functionalization for alkyne annulation, affording α-pyrones with good to excellent yields in an undivided cell. Preliminary mechanistic studies show that anodic oxidation is crucial for releasing the product and regeneration of an Ir(III) intermediate from a diene-Ir(I) complex, which is a coordinatively saturated, 18-electron complex. Importantly, common chemical oxidants such as Ag(I) or Cu(II) did not give significant amounts of the desired product in the absence of electrical current under otherwise identical conditions.
- Yang, Qi-Liang,Xing, Yi-Kang,Wang, Xiang-Yang,Ma, Hong-Xing,Weng, Xin-Jun,Yang, Xiang,Guo, Hai-Ming,Mei, Tian-Sheng
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supporting information
p. 18970 - 18976
(2019/12/04)
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- Simple preparation method of felbinac
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The invention provides a simple preparation method of felbinac. The method comprises the following steps: taking biphenyl and ethyl oxalyl monochloride as initial raw materials; carrying out Friedel-Crafts reaction under the action of aluminum trichloride to generate biphenylethyl glyoxylate under the condition of low temperature; then carrying out alkaline hydrolysis to obtain felbinac salt; carrying out Huang-Minlon reaction reduction and acidification to obtain the felbinac. The method has the advantages of no need of intermediate separation, simplicity and convenience in operation, environment friendliness, high yield and industrial production value.
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Paragraph 0032; 0034; 0035; 0039-0041; 0042; 0046-0049
(2017/08/29)
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- Switchable C-H Functionalization of N-Tosyl Acrylamides with Acryloylsilanes
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A controllable Rh-catalyzed protocol to access alkylation and alkenylation-annulation of N-tosyl acrylamide with acryloyl silane is reported. In contrast to the directing group or catalyst-dependent divergent sp2 C-H alkylation/alkenylation, the intrinsic property of acryloylsilane allows the switchable reaction manifold, thereby affording either alkylation or annulation products with slight modification of the reaction conditions.
- Song, Shengjin,Lu, Ping,Liu, Huan,Cai, Sai-Hu,Feng, Chao,Loh, Teck-Peng
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supporting information
p. 2869 - 2872
(2017/06/13)
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- Copper(II)-Catalyzed Benzylic C(sp3)-H Aerobic Oxidation of (Hetero)Aryl Acetimidates: Synthesis of Aryl-α-ketoesters
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A straightforward method is developed in this paper for the synthesis of α-ketoesters through copper-catalyzed aerobic oxidation of (hetero)aryl acetimidates using molecular oxygen as a sustainable oxidant. The reaction represents the first example of the direct synthesis of aryl-α-ketoesters from arylacetimidates through the aerobic oxidation of a benzylic C(sp3)-H (CO) bond in moderate to good yield. This transformation occurs under mild reaction conditions with a wide range of substrates and utilizes a readily available oxidant and catalyst. The synthetic utility of this transformation is demonstrated through scaled-up synthesis. A plausible reaction mechanism is also proposed.
- Kumar, Yogesh,Jaiswal, Yogesh,Kumar, Amit
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p. 12247 - 12257
(2016/12/23)
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- In Situ Generated AgII-Catalyzed Selective Oxo-Esterification of Alkyne with Alcohol to α-Ketoester: Photophysical Study
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An expert and easy one-step catalytic method for the multi O-C coupling of alkyne is developed for the synthesis of valuable α-ketoesters and their chiral analogues, in contrast to the generation of esters by a noncatalytic method. The in situ generated powerful AgII catalyst from AgOTf is the workhorse in the oxidative grafting of alkyne with PhIO and alcohol. The radical mechanism is confirmed in our controlled experiments and UV-vis study.
- Laha, Radha M.,Khamarui, Saikat,Manna, Saikat K.,Maiti, Dilip K.
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supporting information
p. 144 - 147
(2016/01/12)
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- Asymmetric Hydrogenation of α-Substituted Acrylic Acids Catalyzed by a Ruthenocenyl Phosphino-oxazoline-Ruthenium Complex
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Asymmetric hydrogenation of various α-substituted acrylic acids was carried out using RuPHOX-Ru as a chiral catalyst under 5 bar H2, affording the corresponding chiral α-substituted propanic acids in up to 99% yield and 99.9% ee. The reaction could be performed on a gram-scale with a relatively low catalyst loading (up to 5000 S/C), and the resulting product (97%, 99.3% ee) can be used as a key intermediate to construct bioactive chiral molecules. The asymmetric protocol was successfully applied to an asymmetric synthesis of dihydroartemisinic acid, a key intermediate required for the industrial synthesis of the antimalarial drug artemisinin.
- Li, Jing,Shen, Jiefeng,Xia, Chao,Wang, Yanzhao,Liu, Delong,Zhang, Wanbin
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supporting information
p. 2122 - 2125
(2016/06/01)
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- Destruction and Construction: Application of Dearomatization Strategy in Aromatic Carbon-Nitrogen Bond Functionalization
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The formation of carbon-carbon bonds through the functionalization of aromatic carbon-nitrogen bonds is a highly attractive synthetic strategy in the synthesis of aromatic molecules. In this paper, we report a novel aromatic carbon-nitrogen bond functionalization reaction by using a simple dearomatization strategy. Through this process para-substituted anilines serve as a potential aryl source in the construction of a range of functionalized aromatic molecules, such as quaternary carbon centers, α-keto esters, and aldehydes.
- Wang, Shuo-En,Wang, Linfei,He, Qiuqin,Fan, Renhua
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p. 13655 - 13658
(2015/11/11)
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- Rhodium(iii)-catalyzed C-H allylation of electron-deficient alkenes with allyl acetates
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Rhodium-catalyzed C-H allylation of acrylamides with allyl acetates is reported. The use of weakly coordinating directing group resulted in high reaction efficiency, broad functionality tolerance and excellent γ-selectivity, which opens a new synthetic pathway for the access of 1,4-diene skeletons.
- Feng, Chao,Feng, Daming,Loh, Teck-Peng
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supporting information
p. 342 - 345
(2015/01/09)
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- Rhodium(III)-catalyzed olefinic C-H alkynylation of acrylamides using tosyl-imide as directing group
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The Rh(III)-catalyzed C-H alkynylation of acrylamide derivative is realized using a hypervalent alkynyl iodine reagent. The use of a weakly coordinating directing group proved to be of critical importance. This reaction displays broad functional group tolerance and high efficiency, which opens a new synthetic pathway to access functionalized 1,3-enyne skeletons.
- Feng, Chao,Feng, Daming,Luo, Yang,Loh, Teck-Peng
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supporting information
p. 5956 - 5959
(2015/01/08)
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- Cationic Ir/Me-BIPAM-catalyzed asymmetric intramolecular direct hydroarylation of α-ketoamides
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Asymmetric intramolecular direct hydroarylation of α-ketoamides gives various types of optically active 3-substituted 3-hydroxy-2-oxindoles in high yields with complete regioselectivity and high enantioselectivities (84-98 % ee). This is realized by the use of the cationic iridium complex [Ir(cod) 2](BArF4) and the chiral O-linked bidentate phosphoramidite (R,R)-Me-BIPAM. Carbon's got a brand new bond: Asymmetric intramolecular direct hydroarylation of α-ketoamides gives various optically active 3-substituted 3-hydroxy-2-oxindoles in high yields with complete regioselectivity and high enantioselectivities. This is realized by the use of an asymmetric cationic iridium complex formed in situ (see Scheme).
- Shirai, Tomohiko,Ito, Hajime,Yamamoto, Yasunori
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supporting information
p. 2658 - 2661
(2014/03/21)
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- Directing-group-assisted copper-catalyzed olefinic trifluoromethylation of electron-deficient alkenes
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Assistance provided: The directing group in the title reaction not only activates the substrates but also allows the stereospecific formation of cis-trifluoromethylated products. The reaction is operationally simple and tolerates a wide variety of functional groups, thus providing an efficient method for the stereoselective synthesis of β-CF3-functionalized acrylamide derivatives. Copyright
- Feng, Chao,Loh, Teck-Peng
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supporting information
p. 122414 - 122417
(2013/12/04)
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- Direct asymmetric aldol addition-isomerization of α,β- unsaturated γ-butyrolactam with aryl α-ketoesters: Synthesis of MBH-type products
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A highly efficient direct asymmetric aldol addition-isomerization reaction at the α-position of α,β-unsaturated γ-butyrolactam and aryl α-ketoesters by using a bifunctional thiourea catalyst was achieved. Morita-Baylis-Hillman type adducts containing a quaternary stereocenter can be obtained in high yields and with excellent enantioselectivities (up to 99% ee). The Royal Society of Chemistry 2013.
- Zhang, Jinlong,Liu, Xihong,Ma, Xiaojuan,Wang, Rui
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supporting information
p. 3300 - 3302
(2013/06/04)
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- An efficient and practical synthesis of aryl and hetaryl α-keto esters
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A general and highly efficient method was developed for the synthesis of -keto esters by oxidative esterification of 2,2-dibromo-1-(het)arylethanones by sequential treatment with dimethyl sulfoxide and an alkanol. The versatility of the reaction was established by synthesizing a range of -keto esters by treatment of 2,2-dibromoethanones, derived from aryl or hetaryl ketones, with di-methyl sulfoxide and a cyclic or acyclic primary or secondary alcohol. The mechanism of the reaction was established by means of a detailed study. Georg Thieme Verlag Stuttgart · New York.
- Raghunadh, Akula,Meruva, Suresh Babu,Kumar, Nuka Anil,Kumar, Gudla Santosh,Rao, L. Vaikunta,Syamkumar
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supporting information; experimental part
p. 283 - 289
(2012/03/26)
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- Direct synthesis of α-keto esters from ethylbenzenes using 48% aqueous HBr by aerobic visible light photooxidation
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We report that ethylbenzenes can be directly oxidized to the corresponding -keto esters with molecular oxygen in the presence of 48% aqueous HBr under visible light irradiation. This synthetic procedure is the first example for direct preparation of the corresponding α-keto esters from ethylbenzenes. Georg Thieme Verlag Stuttgart - New York.
- Tada, Norihiro,Ban, Kazunori,Nobuta, Tomoya,Hirashima, Shin-Ichi,Miura, Tsuyoshi,Itoh, Akichika
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experimental part
p. 1381 - 1384
(2011/07/31)
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- MONOACYLGLYCEROL LIPASE INHIBITORS FOR MODULATION OF CANNABINOID ACTIVITY
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Disclosed are compounds and compositions that inhibit the action of monoacylglycerol lipase (MGL) and fatty acid amide hydrolase (FAAH), methods of inhibiting MGL and FAAH, methods of modulating cannabinoid receptors, and methods of treating various disorders related to the modulation of cannabinoid receptors.
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Page/Page column 140
(2009/05/28)
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- FATTY ACID AMIDE HYDROLASE INHIBITORS
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Disclosed are compounds of formula R-X-Y that may be used to inhibit the action of fatty acid amide hydrolase (FAAH). Inhibition of fatty acid amide hydrolase (FAAH) will slow the normal degradation and inactivation of endogenous cannabinoid ligands by FAAH hydrolysis and allow higher levels of those endogenous cannabinergic ligands to remain present. These higher levels of endocannabinoid ligands provide increased stimulation of the cannabinoid CBl and CB2 receptors and produce physiological effects related to the activation of the cannabinoid receptors. They will also enhance the effects of other exogenous cannabinergic ligands and allow them to produce their effects at lower concentrations as compared to systems in which fatty acid amide hydrolase (FAAH) action is hot inhibited. Thus, a compound that inhibits the inactivation of endogenous cannabinoid ligands by fatty acid amide hydrolase (FAAH) may increase the levels of endocannabinoids and, thus, enhance the activation of cannabinoid receptors. Thus, the compound may not directly modulate the cannabinoid receptors but has the effect of indirectly stimulating the cannabinoid receptors by increasing the levels of endocannabinoid ligands. It may also enhance the effects and duration of action of other exogenous cannabinergic ligands that are administered in order to elicit a cannabinergic response.
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Page/Page column 96
(2008/06/13)
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- 5,5-Disubstituted-3, 4-dihydroxy-2(5H)-furanones and methods of use therefor
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The present invention relates to synthetic methods for the production of both optically active and racemic 5,5-disubstituted-3,4-dihydroxy-2(5H)-furanones; 5-[(4-aryl)-3-butynyl]-3,4-dihydroxy-2(5H)-furanones; 5-(2-arylthio)ethyl-3,4-dihydroxy-2(5H)-furanones; and 5-(2-aryloxy)ethyl-3,4-dihydroxy-2(5H)-furanones. This invention further relates to the use of the above mentioned compounds as anti-inflammatory agents through their action as mixed inhibitors of lipid peroxidation, 5-lipoxygenase, cyclooxygenase-1 and cyclooxygenase-2. The invention further relates to the use of such compounds in the treatment of chronic inflammatory disorders such as asthma, rheumatoid arthritis, inflammatory bowel disease, atherosclerosis, acute respiratory distress syndrome, and central nervous system disorders such as Alzheimer's and Parkinson's disease wherein reactive oxygen species and inflammatory mediators are contributing deleterious factors.
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- Palladium-Catalyzed Coupling Reactions of (α-Ethoxyvinyl)trimethylstannane with Vinyl and Aryl Triflates
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The palladium-catalyzed cross-coupling reaction of vinyl triflates and halides with (α-ethoxyvinyl)trimethylstannane gives high yields of 2-ethoxy 1,3-dienes, which can be hydrolyzed to the corresponding α,β-unsaturated ketones.Aryl triflates undergo an analogous coupling reaction, providing a facile method for replacing the hydroxyl group of a phenol by an acyl group.The use of (α-ethoxyvinyl)trimethylstannane in palladium-catalyzed carbonylative coupling gives rise to vinyl and aryl α-ethoxyvinyl ketones and indirectly to the corresponding α-diketones (which result from their hydrolysis) and glyoxylates (which result from their ozonolysis).
- Kwon, Hyok Boong,McKee, Blain H.,Stille, J. K.
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p. 3114 - 3118
(2007/10/02)
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- A Study of Some Thiophene Analogues of Glycolic Acid
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Reaction of phenyl(3-thienyl)glycolic acid (1) with AlCl3 in benzene solution leads to the formation of 4H-indenothiophene-4-carboxylic acid (2) whereas analogous reaction of phenyl(2-thienyl)glycolic acid (4) produces no indenothiophene but only a mixture of 5 and 6.In the case of di-(2-thienyl)glycolic acid (14b) and di-(3-thienyl)glycolic acid (16b) analogous results are obtained, with the former leading to the formation of 15 and the latter producing 17.In the case of the (benzothienyl)phenylglycolic analogues of 1 and 4 the acids were unstable to heat so that the esters, ethyl (2-benzothienyl)phenylglycolate (21) and ethyl (3-benzothienyl)phenylglycolate (20), upon treatment with AlCl3 in benzene led to cyclized products only.The former gave 23 which was saponified and decarboxylated to yield 25 and compared with an authentic sample obtained by synthesis.Ester 20 similarly gave 22 which was similarly converted to the known 24.A mechanistic explanation of these findings is proposed.
- Jeffries, Alfred T.,Moore, Kenneth C.,Ondeyka, Debra M.,Springsteen, Arthur W.,MacDowell, Denis W.H.
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p. 2885 - 2889
(2007/10/02)
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