- Oxidation of α-Hydroxy Acids by an Oxidation-active Flavin Mimic bearing a Bipyridin-6-ylmethyl Moiety in the Presence of Zn2+ and a Base in tert-Butyl Alcohol
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A benzo-dipteridine (BDP) having a bipyridin-6-ylmethyl moiety oxidizes α-hydroxy acids to give α-keto acids in the presence of Zn2+ and Et3N in t-BuOH, whereas a BDP bearing a bipyridin-5-ylmethyl moiety is unable to oxidize them under the sam
- Yano, Yumihiko,Mitsui, Keita,Ohsawa, Youichi,Kobayashi, Toshitada,Nabeshima, Tatsuya
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Read Online
- Biosynthesis of Phenylglyoxylic Acid by LhDMDH, a Novel d -Mandelate Dehydrogenase with High Catalytic Activity
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d-Mandelate dehydrogenase (DMDH) has the potential to convert d-mandelic acid to phenylglyoxylic acid (PGA), which is a key building block in the field of chemical synthesis and is widely used to synthesize pharmaceutical intermediates or food additives.
- Tang, Cun-Duo,Shi, Hong-Ling,Xu, Jian-He,Jiao, Zhu-Jin,Liu, Fei,Ding, Peng-Ju,Shi, Hong-Fei,Yao, Lun-Guang,Kan, Yun-Chao
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Read Online
- One-Pot Synthesis of Phenylglyoxylic Acid from Racemic Mandelic Acids via Cascade Biocatalysis
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Phenylglyoxylic acid (PGA) are key building blocks and widely used to synthesize pharmaceutical intermediates or food additives. However, the existing synthetic methods for PGA generally involve toxic cyanide and complex processes. To explore an alternati
- Tang, Cun-Duo,Ding, Peng-Ju,Shi, Hong-Ling,Jia, Yuan-Yuan,Zhou, Mao-Zhi,Yu, Hui-Lei,Xu, Jian-He,Yao, Lun-Guang,Kan, Yun-Chao
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Read Online
- Photoinduced homolytic decarboxylative acylation/cyclization of unactivated alkenes with α-keto acid under external oxidant and photocatalyst free conditions: access to quinazolinone derivatives
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A novel and green strategy for the synthesis of acylated quinazolinone derivativesviaphoto-induced decarboxylative cascade radical acylation/cyclization of quinazolinone bearing unactivated alkenes has been developed. The protocol provides a novel route to access acyl radicals from α-keto acids through a self-catalyzed energy transfer process. Most importantly, the reaction proceeded smoothly without any external photocatalyst, additive or oxidant, and could be easily scaled-up in flow conditions with sunlight irradiation.
- Sun, Bin,Shi, Rongcheng,Zhang, Kesheng,Tang, Xiaoli,Shi, Xiayue,Xu, Jiayun,Yang, Jin,Jin, Can
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supporting information
p. 6050 - 6053
(2021/06/21)
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- Hypervalent Iodine(III)-Promoted Radical Oxidative C-H Annulation of Arylamines with α-Keto Acids
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A novel catalyst-free radical oxidative C-H annulation reaction of arylamines with α-keto acids toward benzoxazin-2-ones synthesis under mild conditions was developed. This hypervalent iodine(III)-promoted process eliminated the use of a metal catalyst or additive with high levels of functional group tolerance. Hypervalent iodine(III) was both an oxidant and a radical initiator for this reaction. The synthetic utility of this method was confirmed by the synthesis of the natural product cephalandole A.
- Long, Lipeng,Wang, Jieyan,Gu, Liuqing,Yang, Shiguang,Qiao, Liang,Luo, Guotian,Chen, Zhengwang
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supporting information
p. 12084 - 12092
(2021/08/24)
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- Novel peptidomimetic peptide deformylase (PDF) inhibitors of Mycobacterium tuberculosis
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Emergence of MDR-TB and XDR-TB led to the failure of available anti-tubercular drugs. In order to explore, identify and develop new anti-tubercular drugs, novel peptidomimetic series of Mtb–peptide deformylase (PDF) inhibitors was designed and synthesized. In vitro antimycobacterial potential of compounds was established by screening of compounds against Mycobacterium tuberculosis H37Rv strain using MABA. Among them, ester series of compounds 4a, 4b, 4c, 4d, and 4e were found most active, with compound 4c being highly active and exhibiting minimum inhibitory concentration of 6.25?μg/ml against M.?tb H37Rv strain. Additionally, the compounds were docked to determine the probable binding interactions and understand the mechanism of action of most active molecules on Mtb-peptide deformylase (PDF), which is involved in the mycobacterium protein synthesis.
- Gokhale, Kunal M.,Telvekar, Vikas N.
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p. 148 - 156
(2020/08/26)
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- Possible competitive modes of decarboxylation in the annulation reactions ofortho-substituted anilines and arylglyoxylates
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Annulation reactions ofortho-substituted anilines and arylglyoxylates in the presence of K2S2O8at 80 °C under metal-free neutral conditions have been investigated, which extended a platform for the tandem synthesis of nitrogen heterocycles. While arylglyoxylic acids are known to undergo decarboxylation to form an acyl radical in the presence of K2S2O8and used in the Minisci acylation of electron-deficient (hetero)aromatics, their reactions with electron-richortho-substituted anilines to form nitrogen heterocycles have recently been studied. Depending upon the experimental conditions used in the reactions, the mechanism of the formation of heterocycles involving reactions of an acyl radical or aryl iminocarboxylic acids has been postulated. Given the subtle understanding of the mechanisms of annulation reactions of 2-substituted anilines and arylglyoxylates in the presence of K2S2O8, an extensive mechanistic investigation was undertaken. In the current study, the various mechanistic pathways including the generation of acyl, imidoyl, aminal, and N,O-hemiketal radicals have been postulated based on different possible decarboxylation modes. Some of the proposed intermediates are supported based on the available analytical data. The protocol uses a single, inexpensive reagent K2S2O8, which offers not only transition-metal-free conditions but also serves as the reagent for the key decarboxylation step. Taken together, this study complements the current development of the annulation reactions of 2-substituted anilines and arylglyoxylates in terms of synthesis and mechanistic understanding.
- Laha, Joydev K.,Panday, Surabhi,Tomar, Monika,Patel, Ketul V.
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supporting information
p. 845 - 853
(2021/02/09)
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- K2S2O8mediated synthesis of 5-Aryldipyrromethanes and meso-substituted A4-Tetraarylporphyrins
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The synthesis of dipyrromethanes from pyrrole and arylglyoxylic acids in the presence of K2S2O8at 90 C is reported affording dipyrromethanes in very good yields. Unlike an excess pyrrole traditionally used in dipyrromethane synthesis, the current method uses a stoichiometric amount of pyrrole avoiding any use of Br?nsted or Lewis acid. A gram scale synthesis of 5-phenyldipyrromethane is also achieved demonstrating potential scale up of dipyrromethanes using this method feasible. Subsequently, dipyrromethanes were converted to A4tetraarylporphyrins also in the presence of K2S2O8at 90C. A direct synthesis of A4-tetraphenylporphyrin from excess pyrrole and phenylglyoxylic acid in the presence of K2S2O8 at 90C is also reported.
- Laha, Joydev K.,Hunjan, Mandeep Kaur
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p. 664 - 673
(2021/06/03)
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- K2S2O8activation by glucose at room temperature for the synthesis and functionalization of heterocycles in water
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While persulfate activation at room temperature using glucose has primarily been focused on kinetic studies of the sulfate radical anion, the utilization of this protocol in organic synthesis is rarely demonstrated. We reinvestigated selected K2S2O8-mediated known organic reactions that invariably require higher temperatures and an organic solvent. A diverse, mild functionalization and synthesis of heterocycles using the inexpensive oxidant K2S2O8 in water at room temperature is reported, demonstrating the sustainability and broad scope of the method. Unlike traditional methods used for persulfate activation, the current method uses naturally abundant glucose as a K2S2O8 activator, avoiding the use of higher temperature, UV light, transition metals or bases.
- Hunjan, Mandeep Kaur,Laha, Joydev K.
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supporting information
p. 8437 - 8440
(2021/09/02)
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- Diazotrifluoroethyl Radical: A CF3-Containing Building Block in [3 + 2] Cycloaddition
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We present herein a visible-light-induced [3 + 2] cycloaddition of a hypervalent iodine(III) reagent with α-ketoacids for the construction of 5-CF3-1,3,4-oxadiazoles that are of importance in medicinal chemistry. The reaction proceeds smoothly without a photocatalyst, metal, or additive under mild conditions. Different from the well-established trifluorodiazoethane (CF3CHN2), the diazotrifluoroethyl radical [CF3C(·)N2], a trifluoroethylcarbyne (CF3C?:) equivalent and an unusual CF3-containing building block, is involved in the present reaction system.
- Zhao, Wen-Wen,Shao, Yong-Chao,Wang, An-Ni,Huang, Jia-Li,He, Chun-Yang,Cui, Bao-Dong,Wan, Nan-Wei,Chen, Yong-Zheng,Han, Wen-Yong
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supporting information
p. 9256 - 9261
(2021/12/06)
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- Minisci aroylation of N-heterocycles using choline persulfate in water under mild conditions
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Metal persulfate mediated thermal oxidative organic transformations invariably require a higher temperature and frequently use an organic solvent. The objective of this work was to develop persulfate mediated oxidative transformations that can be performed nearly at room temperature using water as a solvent. This report describes modified Minisci aroylation of isoquinolines with arylglyoxylic acids using choline persulfate and its pre-composition (choline acetate and K2S2O8) in water at 40 °C. A few other nitrogen heterocycles were also utilized affording various aroylated products in good to excellent yields. Unlike metal persulfate that could produce metal salt byproducts, a key feature of the chemistry reported herein includes the use of environmentally benign choline persulfate containing biodegradable choline as a counter-cation, the Minisci reaction demonstrated at 40 °C in water as the only solvent, and unconventional activation of persulfate. This journal is
- Hunjan, Mandeep Kaur,Laha, Joydev K.,Tinwala, Ummehani
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p. 22853 - 22859
(2021/12/24)
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- Synthesis of α-Keto Acids via Oxidation of Alkenes Catalyzed by a Bifunctional Iron Nanocomposite
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An efficient methodology for synthesis of α-keto acids via oxidation of alkenes using TBHP as oxidant catalyzed by a bifunctional iron nanocomposite has been established. A variety of alkenes with different functional groups were smoothly oxidized into their corresponding α-keto acids in up to 80% yield. Moreover, the bifunctional iron nanocomposite catalyst showed outstanding catalytic stability for successive recycles without appreciable loss of activity.
- Song, Tao,Ma, Zhiming,Wang, Xiaoxue,Yang, Yong
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supporting information
p. 5917 - 5921
(2021/07/31)
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- Silyl Cyanopalladate-Catalyzed Friedel-Crafts-Type Cyclization Affording 3-Aryloxindole Derivatives
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3-Aryloxindole derivatives were synthesized through a Friedel-Crafts-type cyclization. The reaction was catalyzed by a trimethylsilyl tricyanopalladate complex generated in situ from trimethylsilyl cyanide and Pd(OAc) 2. Wide varieties of diethyl phosphates derived from N -arylmandelamides were converted almost quantitatively into oxindoles. When N, N -dibenzylamide was used instead of an anilide substrate, a benzo-fused δ-lactam was obtained. An oxindole product was subjected to substitution reactions to afford 3,3-diaryloxindoles with two different aryl groups.
- Ece, Hamdiye,Tange, Yuji,Yurino, Taiga,Ohkuma, Takeshi
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p. 935 - 939
(2021/02/22)
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- Structure-Activity Relationship Studies of α-Ketoamides as Inhibitors of the Phospholipase A and Acyltransferase Enzyme Family
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The phospholipase A and acyltransferase (PLAAT) family of cysteine hydrolases consists of five members, which are involved in the Ca2+-independent production of N-acylphosphatidylethanolamines (NAPEs). NAPEs are lipid precursors for bioactive N-acylethanolamines (NAEs) that are involved in various physiological processes such as food intake, pain, inflammation, stress, and anxiety. Recently, we identified α-ketoamides as the first pan-active PLAAT inhibitor scaffold that reduced arachidonic acid levels in PLAAT3-overexpressing U2OS cells and in HepG2 cells. Here, we report the structure-activity relationships of the α-ketoamide series using activity-based protein profiling. This led to the identification of LEI-301, a nanomolar potent inhibitor for the PLAAT family members. LEI-301 reduced the NAE levels, including anandamide, in cells overexpressing PLAAT2 or PLAAT5. Collectively, LEI-301 may help to dissect the physiological role of the PLAATs.
- Zhou, Juan,Mock, Elliot D.,Al Ayed, Karol,Di, Xinyu,Kantae, Vasudev,Burggraaff, Lindsey,Stevens, Anna F.,Martella, Andrea,Mohr, Florian,Jiang, Ming,Van Der Wel, Tom,Wendel, Tiemen J.,Ofman, Tim P.,Tran, Yvonne,De Koster, Nicky,Van Westen, Gerard J.P.,Hankemeier, Thomas,Van Der Stelt, Mario
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p. 9340 - 9359
(2020/10/19)
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- 1D Fe3O4&at;CuSiO3 composites catalyzed decarboxylative A3-coupling for propargylamine synthesis
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Highly active and stable magnetic copper catalysts were successfully achieved by magnetic induced St?ber method and subsequent hydrothermal reaction with copper ions in alkaline condition. The high content of Cu2+ as well as the unique structures of hierarchical copper silicate in the as-prepared catalysts endowed their outstanding catalytic performance. Efficient decarboxylative A3-coupling of α-keto acid, amine and alkyne was realized with the low Fe3O4&at;CuSiO3 loading. A range of propargylamines were produced in good to excellent yields under solvent-free condition. Moreover, the catalyst can be easily separated from the final organic product with an external magnet. Also, this kind of catalyst could be recycled up to six times while maintaining its activity.
- Cao, Tiantian,Feng, Huangdi,Li, Huiqiong,Miao, Teng,Wang, Fang,Zhang, Min
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supporting information
p. 1558 - 1563
(2020/07/30)
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- Photoredox Catalysis Enables Decarboxylative Cyclization with Hypervalent Iodine(III) Reagents: Access to 2,5-Disubstituted 1,3,4-Oxadiazoles
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A novel approach to 2,5-disubstituted 1,3,4-oxadiazoles derivatives via a decarboxylative cyclization reaction by photoredox catalysis between commercially available α-oxocarboxylic acids and hypervalent iodine(III) reagent is described. This powerful transformation involves the coupling reaction between two different kinds of radical species and the formation of C-N and C-O bonds.
- Li, Jian,Lu, Xue-Chen,Xu, Yue,Wen, Jin-Xia,Hou, Guo-Quan,Liu, Li
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supporting information
p. 9621 - 9626
(2020/12/21)
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- Aroylation of Electron-Rich Pyrroles under Minisci Reaction Conditions
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The development of Minisci acylation on electron-rich pyrroles under silver-free neutral conditions has been reported featuring the regioselective monoacylation of (NH)-free pyrroles. Unlike conventional Minisci conditions, the avoidance of any acid that could result in the polymerization of pyrroles was the key to success. The umpolung reactivity of the nucleophilic acyl radical, generated in situ from arylglyoxylic acid, could help explain the mechanism of product formation with electron-rich pyrroles. Alternatively, the nucleophilic substitution of the acyl radical on the electron-deficient pyrrole radical cation is proposed.
- Laha, Joydev K.,Kaur Hunjan, Mandeep,Hegde, Shalakha,Gupta, Anjali
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supporting information
p. 1442 - 1447
(2020/02/22)
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- Selective photoredox decarboxylation of α-ketoacids to allylic ketones and 1,4-dicarbonyl compounds dependent on cobaloxime catalysis
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A photoredox/cobaloxime co-catalyzed coupling reaction of α-ketoacids and methacrylates to obtain allylic ketones is described. Without the cobaloxime catalyst, 1,4-dicarbonyl compounds are generated. The cobaloxime catalyst enables dehydrogenation to generate the formation of new olefins. The generality, good substrate scope and mild conditions are good features in the photoredox/cobaloxime catalysis protocol, and this method will provide new opportunities for the functionalization of more olefins.
- Zhang, Hong,Xiao, Qian,Qi, Xu-Kuan,Gao, Xue-Wang,Tong, Qing-Xiao,Zhong, Jian-Ji
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supporting information
p. 12530 - 12533
(2020/11/02)
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- Visible-Light-Induced Decarboxylative Cyclization/Hydrogenation Cascade Reaction to Access Phenanthridin-6-yl(aryl)methanol by an Electron Donor-Acceptor Complex
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A novel and efficient visible-light-induced decarboxylative cyclization/hydrogenation cascade reaction of α-oxocarboxylic acids and 2-isocyanobiaryls has been developed. Without the need of any external photosensitizer, oxidant, and reductant, this method offers a mild and green approach for the synthesis of diverse alcohols in moderate to good yields. A mechanism indicated that an electron donor-acceptor complex-driven decarboxylation, radical addition/cyclization, and in situ photochemical reduction of ketones to alcohols could be involved in the reaction.
- Shi, Wei,Ma, Fang,Li, Pinhua,Wang, Lei,Miao, Tao
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p. 13808 - 13817
(2020/11/20)
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- Metal-free benzoylation of imidazoheterocycles by oxidative decarboxylation of arylglyoxylic acids
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A simple and straightforward approach has been realized for the direct benzoylation of imidazoheterocycles by oxidative decarboxylation of arylglyoxylic acids in the presence of K2S2O8 as an oxidant. Various functional groups were tolerated on both imidazoheterocycles and arylglyoxylic acids and a wide range of C5-benzoyl-imidazoheterocycles were obtained in good to high yields (50-84%). Radical trapping experiments confirmed the involvement of the radical pathway. The developed protocol is amenable for a scale-up reaction. This journal is
- Jaspal, Sonam,Shinde, Vikki N.,Meena, Neha,Nipate, Dhananjay S.,Rangan, Krishnan,Kumar, Anil
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p. 9072 - 9080
(2020/11/27)
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- METHOD FOR PRODUCING BENZOYL FORMIC ACID COMPOUND AND PYRIDAZINE COMPOUND
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The present invention provides an industrially-advantageous process for preparing a benzoyl formic acid compound, and an efficient process for preparing a pyridazine compound using the same process. Specifically, the present invention provides a process for preparing a compound represented by formula (2), which comprises a step (B): a step of reacting a compound represented by formula (1) with a nitrosyl sulfuric acid in water to produce the compound represented by formula (2).
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Paragraph 0099
(2020/12/18)
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- A Bifunctional Iron Nanocomposite Catalyst for Efficient Oxidation of Alkenes to Ketones and 1,2-Diketones
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We herein report the fabrication of a bifunctional iron nanocomposite catalyst, in which two catalytically active sites of Fe-Nx and Fe phosphate, as oxidation and Lewis acid sites, were simultaneously integrated into a hierarchical N,P-dual doped porous carbon. As a bifunctional catalyst, it exhibited high efficiency for direct oxidative cleavage of alkenes into ketones or their oxidation into 1,2-diketones with a broad substrate scope and high functional group tolerance using TBHP as the oxidant in water under mild reaction conditions. Furthermore, it could be easily recovered for successive recycling without appreciable loss of activity. Mechanistic studies disclose that the direct oxidation of alkenes proceeds via the formation of an epoxide as intermediate followed by either acid-catalyzed Meinwald rearrangement to give ketones with one carbon shorter or nucleophilic ring-opening to generate 1,2-diketones in a cascade manner. This study not only opens up a fancy pathway in the rational design of Fe-N-C catalysts but also offers a simple and efficient method for accessing industrially important ketones and 1,2-diketones from alkenes in a cost-effective and environmentally benign fashion.
- Ma, Zhiming,Ren, Peng,Song, Tao,Xiao, Jianliang,Yang, Yong,Yuan, Youzhu
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p. 4617 - 4629
(2020/05/19)
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- F--Free Deoxyhydrotrifluoromethylation of α-Keto Esters with Ph3P+CF2CO2-: Synthesis of α-CF3-Substituted Esters
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Trifluoromethylated compounds are usually obtained via trifluoromethylation reaction by the use of CF3SiMe3 and NaSO2CF3, Umemoto's and Togni's reagents. Here, an external fluorine anion-free direct deoxyhydrotrifluoromethylation of α-keto esters with a d
- Jia, Yimin,Jiang, Zhong-Xing,Yang, Zhigang,Yuan, Yuan,Zheng, Ying
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p. 10913 - 10923
(2020/09/23)
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- Acid-promoted cleavage of the C–C double bond of N-(2-Hydroxylphenyl)enaminones for the synthesis of benzoxazoles
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An acid-mediated selective cleavage of C–C double bond of N-(2-hydroxylphenyl)enaminones with formation a new C–O bond for the synthesis of 2-substituted benzoxazoles has been developed. This protocol proceeds under transition metal- and oxidant-free conditions with broad functional group tolerance. The oxidative cleavage of C–C double bond of N-(2-hydroxylphenyl)enaminone is also realized using NCS or NFSI as oxidants with release of 2,2-dihalogen-acetophenone fragments.
- Ge, Bailu,Peng, Yanling,Liu, Jing,Wen, Si,Peng, Cheng,Cheng, Guolin
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- Arylglyoxylic acid as well as preparation method and application thereof
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The invention relates to arylglyoxylic acid as well as a preparation method and application thereof, and the method comprises the following steps: carrying out hydrolysis reaction on arylglyoxylonitrile oxime as shown in a formula (I) under the catalysis of an inorganic acid to obtain arylglyoxylic acid as shown in a formula (II). The arylglyoxylic acid prepared by the preparation method is high in yield, high in product purity, simple to operate, environment-friendly and pollution-free. The arylglyoxylic acid is used as a fine chemical synthesis intermediate.
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Paragraph 0063-0067
(2021/01/15)
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- Method for preparing aromatic glyoxylic acid by oxidizing aromatic ethyl ketone with selenium dioxide
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The invention discloses a method for preparing aromatic glyoxylic acid by oxidizing aromatic ethyl ketone with selenium dioxide. The method comprises the following steps: dissolving aromatic ethyl ketone in an alkaline organic solvent, carrying out stirri
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Paragraph 0019-0020
(2020/01/03)
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- Novel α-ketoamide based diazeniumdiolates as hydrogen peroxide responsive nitric oxide donors with anti-lung cancer activity
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A novel type of hydrogen peroxide (H2O2)-activated diazeniumdiolate based on an α-ketoamide moietey was developed as a nitric oxide (NO) donor. KA-NO-4 inhibited lung cancer cells with submicromolar activity. The H2O2
- Fu, Junjie,Han, Jing,Meng, Tingting,Hu, Jing,Yin, Jian
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supporting information
p. 12904 - 12907
(2019/11/05)
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- Iron-catalyzed Minisci acylation of N-heteroarenes with α-keto acids
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An efficient and mild protocol has been developed for the Minisci acylation reactions of nitrogen-containing heteroarenes with α-keto acids. Distinct from the conventional Minisci acylation conditions, the chemistry was performed using non-noble metal Fe(II), instead of expensive Ag(I) salt, as catalyst. A wide range of substrates, including aliphatic or aromatic α-keto acids, as well as various N-heteroarenes, proved to be compatible with the protocol. Scale-up experiment also demonstrates the practicality of the approach.
- Wang, Xiu-Zhi,Zeng, Cheng-Chu
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supporting information
p. 1425 - 1430
(2019/02/01)
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- Palladium-Catalyzed Primary Amine-Directed Decarboxylative Annulation of α-Oxocarboxylic Acids: Access to Indolo[1,2-a]quinazolines
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An efficient protocol for the preparation of indolo[1,2-a]quinazolines via palladium-catalyzed decarboxylative annulation of indols with α-oxocarboxylic acids has been realized by using primary amine as a directing group (DG). This transformation proceeds smoothly with exclusive regioselectivity and represents an one-pot Domino synthesis of indo-lo[1,2-a]quinazolines from α-oxocarboxylic acids. (Figure presented.).
- Jiang, Guangbin,Wang, Shoucai,Zhang, Jun,Yu, Jianwen,Zhang, Ziang,Ji, Fanghua
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supporting information
p. 1798 - 1802
(2019/03/13)
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- Electrochemical synthesis of enaminones: Via a decarboxylative coupling reaction
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An environmentally benign and efficient electrochemical synthesis of enaminones via a decarboxylative coupling reaction of α-keto acids using n-Bu4NI as a redox catalyst and electrolyte under constant current electrolysis in an undivided cell is reported. A broad vinyl azide substrate scope and high functional group tolerance are observed. A gram-scale reaction further demonstrates the practicability of the protocol. The results of cyclic voltammetry and control experiments indicate that I2 is likely the active species to initiate the oxidative decarboxylation via an acyl hypoiodite intermediate.
- Kong, Xianqiang,Liu, Yulong,Lin, Long,Chen, Qianjin,Xu, Bo
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supporting information
p. 3796 - 3801
(2019/07/31)
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- Pd(OAc)2-Catalyzed Asymmetric Hydrogenation of α-Iminoesters
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An efficient Pd(OAc)2-catalyzed asymmetric hydrogenation of α-iminoesters was realized for the first time at 1 atm hydrogen pressure and room temperature. Pd(OAc)2, a less expensive Pd salt with low toxicity, was found to be the most suitable catalyst precursor rather than Pd(TFA)2 which is usually the catalyst of choice for homogeneous asymmetric hydrogenation. The chiral α-arylglycine fragments are widely found in many chiral products and bioactive molecules.
- Chen, Jianzhong,Li, Feilong,Wang, Fang,Hu, Yawen,Zhang, Zhenfeng,Zhao, Min,Zhang, Wanbin
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supporting information
p. 9060 - 9065
(2019/11/19)
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- Preparation method of aryl formyl formate and aryl formyl formic acid
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The invention discloses a preparation method of aryl formyl formate. The method comprises the following steps that mandelic acid and a derivative thereof are a compound I, the compound I reacts underthe conditions of a solvent, a catalyst and an oxidizing
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Paragraph 0050-0135
(2019/07/16)
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- Amino-TEMPO Grafted on Magnetic Multi-Walled Nanotubes: An Efficient and Recyclable Heterogeneous Oxidation Catalyst
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An efficient and easy recyclable heterogeneous oxidation catalyst was prepared by grafting TEMPO–NH2 moieties on the surface of magnetic multi-walled carbon nanotubes (MWCNT), first by a radical reaction introducing butyric acid moieties on carbon nanotube surface. Subsequently, carboxylic acid moieties were submitted for amidation using TEMPO–NH2. The functionalized nanotubes [MWCNT-{(CH2)3-CO-NH-TEMPO}n] were investigated as a (pre-)catalyst for the oxidation of primary and secondary alcohols for the production of aldehydes and ketones in a Montanari-type catalytic oxidation using the cheap and readily available 1,3-dichloro-5,5-dimethylhydantoin as the terminal oxidant.
- Gambarotti, Cristian,Bj?rsvik, Hans-René
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p. 1405 - 1412
(2019/01/04)
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- Studies on the L-2-hydroxy-acid oxidase 2 catalyzed metabolism of S-mandelic acid and its analogues
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Mandelic acid (MA) is generally used as a biomarker of the exposure of styrene, which is classified as a class of hazardous environmental pollutants, and also used as an important chiral intermediate in pharmaceutical industry. The previous studies have found the excretion of phenylglyoxylic acid (PGA) in human and rat, a metabolite of MA, was mainly from S-MA rather than R-MA. The metabolic mechanism, however, is not clear. In order to explore the possible metabolic mechanism, the enzyme types involved in the stereoselectivity metabolism of MA were firstly studied, and then human and rat long-chain 2-hydroxy-acid oxidase 2 (HAO2) were recombinantly expressed to study the metabolic profiles of S-MA and its analogues. The results indicated that HAO2 might catalyze the stereoselectivity metabolism of S-MA in rats. Human HAO2 (hHAO2) and rat HAO2 (rHAO2) isozymes β1 and β2 were successfully cloned and expressed with high purity and good enzyme activities. The enzyme kinetic profiles of these enzymes were different for S-MA and analogues. The order of catalytic efficiency for hHAO2 and rHAO2, however, was reverse. It might be relevance to the difference in active amino acid residues and loop 4 in human and rat L-2-hydroxy acid oxidase isozyme B crystal structures.
- Zhang, Yang,Su, Chen,Lei, Jinxiu,Chen, Lu,Hu, Haihong,Zeng, Su,Yu, Lushan
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p. 187 - 193
(2019/03/14)
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- Acyl Radicals from Terminal Alkynes: Photoredox-Catalyzed Acylation of Heteroarenes
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A photoredox-mediated acylation reaction of electron deficient heteroarenes with terminal alkynes is reported. The method relies on oxidative cleavage of phenylacetylenes for generation of acyl radicals as a key enabling feature. The reaction is regiosele
- Sultan, Shaista,Rizvi, Masood Ahmad,Kumar, Jaswant,Shah, Bhahwal Ali
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p. 10617 - 10620
(2018/07/31)
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- Visible-Light-Induced Decarboxylation Coupling/Intramolecular Cyclization: A One-Pot Synthesis for 4-Aryl-2-quinolinone Derivatives
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A visible-light-induced decarboxylation coupling/intramolecular cyclization is reported. The one-pot synthesis system provides mild, efficient, and atom economical access to the synthesis of 4-aryl-2-quinolinone derivatives. It is notable that the necessa
- Wang, Chenglong,Qiao, Jingyi,Liu, Xiaochong,Song, He,Sun, Zhizhong,Chu, Wenyi
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p. 1422 - 1430
(2018/02/09)
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- Copper/Persulfate-Promoted Oxidative Decarboxylative C?H Acylation of Pyrazolones with α-Oxocarboxylic Acids: Direct Access to 4-Acylpyrazolones under Mild Conditions
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A facile and efficient oxidative C?H acylation of N-substituted pyrazolones using α-oxocarboxylic acids as an acyl group source was developed. A combination of Cu(OAc)2 and K2S2O8 enables the reaction to proceed smoothly under air and provides a wide array of 4-acylpyrazolone products in moderate to excellent yields. The mechanism of this transformation is believed to proceed via a copper-induced decarboxylation to form the acyl-copper species. This method provides a convenient and useful route for a direct installation of an acyl moiety into bioactive pyrazolone derivatives, which can be further utilized in many applications. (Figure presented.).
- Kittikool, Tanakorn,Thupyai, Akkharaphong,Phomphrai, Khamphee,Yotphan, Sirilata
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supporting information
p. 3345 - 3355
(2018/09/10)
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- Silver-catalyzed Double Decarboxylative Radical Alkynylation/Annulation of Arylpropiolic Acids with α-keto Acids: Access to Ynones and Flavones under Mild Conditions
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Ynones are privileged building blocks in various organic syntheses of heterocyclic derivatives due to their multifunctional nature, and flavones are an important class of natural products with a wide range of biological activities. We describe the catalytic double decarboxylative alkynylation of arylpropiolic acids with α-keto acids. With Ag(I)/persulfate as the catalysis system, the valuable ynones bearing various substituents could be easily obtained. The introduction of hydroxyl substituent on ortho-site of α-keto acids make this strategy further applicable to the construction of flavone derivatives via heteroannulation in moderate to good yields with a similar silver-catalyzed system. The reactions proceed under relatively mild reaction conditions and tolerate a wide variety of functional groups. Control experiments indicated that both the reactions undergo radical processes. (Figure presented.).
- Meng, Mengting,Wang, Guofang,Yang, Liangfeng,Cheng, Kai,Qi, Chenze
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supporting information
p. 1218 - 1231
(2018/02/16)
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- Selectfluor-mediated mono-C–H activation: The syntheses of mono-ortho-substituted anilides
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The C–H activation of aryl amide using readily available Pd(OAc)2 in the presence of selectfluor is reported. The highly mono-selective introduction of sp2 hybridized functional groups have been realized. A broad range of aryl-, alke
- Zhu, Ranran,Lu, Shaonan,Wang, Qing,Bai, Jinshan,Wang, Yuntao,Yu, Qingzhen,Huang, Jianhui
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p. 3879 - 3887
(2018/06/15)
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- Highly enantioselective aza-henry reaction of ketimines catalyzed by a chiral bifunctional thiourea-tertiary amine derived from quinine
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We have developed a highly enantioselective aza-Henry reaction of aryl α-ketoester-derived N-Ts ketimines with a wide range of substrate scope by a simpler bifunctional thiourea-tertiary amine catalyst derived from quinine. A variety of ketimines were investigated and corresponding products were obtained in excellent yields (up to 99% yield) with excellent enatioselectivities (up to 99% ee).
- Fang, Yanhong,Lu, Ning,Wei, Zhonglin,Cao, Jungang,Liang, Dapeng,Lin, Yingjie,Duan, Haifeng
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supporting information
p. 4371 - 4375
(2018/11/25)
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- Domino Synthesis of α,β-Unsaturated γ-Lactams by Stereoselective Amination of α-Tertiary Allylic Alcohols
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Tertiary allylic alcohols equipped with a carboxyl group can be smoothly aminated under ambient conditions by a conceptually new and stereoselective protocol under palladium catalysis. The in situ formed Z-configured γ-amino acid cyclizes to afford an α,β-unsaturated γ-lactam, releasing water as the only byproduct. This practical catalytic transformation highlights the use of a carboxyl group acting as an activating and stereodirecting functional group to provide a wide series of pharma-relevant building blocks. Various control reactions support the crucial role of the carboxyl group in the substrate to mediate these transformations.
- Xie, Jianing,Xue, Sijing,Escudero-Adán, Eduardo C.,Kleij, Arjan W.
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supporting information
p. 16727 - 16731
(2018/11/23)
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- Bis(methoxypropyl) ether-promoted oxidation of aromatic alcohols into aromatic carboxylic acids and aromatic ketones with O2 under metal- and base-free conditions
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We describe an eco-friendly, practical and operationally simple procedure for the bis(methoxypropyl) ether-promoted oxidation of aromatic alcohols into aromatic carboxylic acids and aromatic ketones with atmospheric dioxygen as the sole oxidant. This chemical process is clean with high conversion and good selectivity, and an external initiator, catalyst, additive and base are not required. The virtue of this reaction is highlighted by its easily available and economical raw materials and excellent functional group tolerance (acid-, base- and oxidant-labile groups).
- Liu, Kai-Jian,Jiang, Si,Lu, Ling-Hui,Tang, Ling-Li,Tang, Shan-Shan,Tang, Hai-Shan,Tang, Zilong,He, Wei-Min,Xu, Xinhua
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supporting information
p. 3038 - 3043
(2018/07/13)
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- BENZO RING DERIVATIVE WITH B2 RECEPTOR AGONIST AND M3 RECEPTOR ANTAGONIST ACTIVITIES AND USE THEREOF IN MEDICINE
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A compound represented by general formula (I), or a stereoisomer, a hydrate, a metabolite, a solvate, a pharmaceutically acceptable salt, a cocrystal, or a prodrug thereof, the preparation method thereof, and use thereof in the manufacture of a medicament for treatment of an airway obstructive disease, wherein the substituents are defined as in the specification.
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Paragraph 0068-0070
(2018/09/29)
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- Promising fungicides from allelochemicals: Synthesis of umbelliferone derivatives and their structure–activity relationships
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Umbelliferone was discovered to be an important allelochemical in our previous study, but the contribution of its activity and structure has not yet been revealed. In this study, a series of analogues were synthesized to determine the skeleton of umbelliferone and examine its fungicidal activity. Furthermore, targeted modifications were conducted with three plant parasitic fungi to examine the lead compounds. Among those tested, compounds 2f and 10 were found to show excellent antifungal activity with an inhibitory rate over 80% at 100 ug/mL. The study proves that umbelliferone can be a promising skeleton for fungicides discovery. In addition, the primary structure–activity relationship provides a good guidance for the discovery of novel fungicides based on natural products in the future.
- Pan, Le,Lei, Dongyu,Jin, Lu,He, Yuan,Yang, Qingqing
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- Pharmaceutical intermediate benzoylformic acid synthesis method
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The invention relates to a pharmaceutical intermediate benzoylformic acid synthesis method, which mainly comprises: adding 3 mol 1-phenyl-2-bromoethanol and 6-8 mol beta-propiolactone solution into areaction container, increasing the temperature of the solution to 50-60 DEG C, controlling the stirring speed at 190-230 rpm, and adding tetraethyl titanate in 2-4 times every 30-40 min, wherein eachadding time is 5-8 min; and carrying out a reaction for 90-120 min, precipitating the precipitate, filtering, washing with a sodium bromide solution, combining the filtrate and the washing liquid, adding a sodium hydrogen sulfate solution, adjusting the pH value to 4-6, extracting 3-6 times with a 2-methyl-3-pentanone solution, extracting 5-8 times with a 2-methylpentane solution, re-crystallizingin a 1-methylnaphthalene solution, and dehydrating with a dehydrating agent to obtain the finished product benzoylformic acid.
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Paragraph 0006; 0009-0014
(2018/07/30)
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- Umpolung Reactivity of Aldehydes toward Carbon Dioxide
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Carbon dioxide is an intrinsically stable molecule. Therefore, its activation requires extra energy input in the form of reactive reagents and/or activated catalysts and, often, harsh reaction conditions. Reported here is a direct carboxylation reaction of aromatic aldehydes with carbon dioxide to afford α-keto acids as added-value products. In situ generation of a reactive cyanohydrin was the key to the successful carboxylation reaction under operationally mild reaction conditions (25–40 °C, 1 atm CO2). The resulting α-keto acids served as a platform for α-amino acid synthesis by reductive amination reactions, illustrating the chemical synthesis of essential bioactive molecules from carbon dioxide.
- Juhl, Martin,Lee, Ji-Woong
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supporting information
p. 12318 - 12322
(2018/09/10)
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- Efficient and Enantioselective Rhodium(I)-Catalyzed Arylation of α-Ketoesters: Synthesis of (S)-Flutriafol
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An enantioselective addition of arylboronic acids and α-ketoesters promoted by a Rhodium(I)-chiral diene catalyst is reported. The transformation proceeds regioselectively in the presence of as low as 0.5 mol% of the catalyst generated in situ from a Rhod
- Chang, Chiung-An,Uang, Tsung-Ying,Jian, Jia-Hong,Zhou, Meng-Yi,Chen, Ming-Liang,Kuo, Ting-Shen,Wu, Ping-Yu,Wu, Hsyueh-Liang
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p. 3381 - 3390
(2018/08/06)
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- The Synthesis of Chiral α-Aryl α-Hydroxy Carboxylic Acids via RuPHOX-Ru Catalyzed Asymmetric Hydrogenation
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A ruthenocenyl phosphino-oxazoline-ruthenium complex (RuPHOX?Ru) catalyzed asymmetric hydrogenation of α-aryl keto acids has been successfully developed, affording the corresponding chiral α-aryl α-hydroxy carboxylic acids in high yields and with up to 97% ee. The reaction could be performed on a gram scale with a relatively low catalyst loading (up to 5000 S/C) and the resulting products can be transformed to several chiral building blocks, biologically active compounds and chiral drugs. (Figure presented.).
- Guo, Huan,Li, Jing,Liu, Delong,Zhang, Wanbin
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supporting information
p. 3665 - 3673
(2017/09/11)
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- Synthesis of enaminones via copper-catalyzed decarboxylative coupling reaction under redox-neutral conditions
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A novel copper-catalyzed C(sp3)-H oxidative functionalization of aromatic oxime acetates with α-oxocarboxylic acids was reported. This process involved N-O/C-C bond cleavages and C-C bond formations to furnish substituted enaminones under redox-neutral conditions. The oxime acetates served as both reactants and internal oxidants. Furthermore, this transformation also features good functional group tolerance and needs no ligands or additional bases.
- Zhu, Zhongzhi,Tang, Xiaodong,Li, Jianxiao,Li, Xianwei,Wu, Wanqing,Deng, Guohua,Jiang, Huanfeng
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supporting information
p. 3228 - 3231
(2017/03/20)
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- Copper-catalyzed oxidative decarboxylative coupling of α-keto acids and sulfoximines
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A copper-catalyzed oxidative decarboxylative coupling of α-keto acids with NH-sulfoximines has been developed. With CuBr as the catalyst and K2S2O8 as the oxidant, this reaction enables the formation of a C-N bond and gives N-aroylsulfoximine products in moderate to excellent yields. The reaction mechanism is likely to involve the generation of a reactive aroyl radical intermediate.
- Pimpasri, Chaleena,Sumunnee, Ladawan,Yotphan, Sirilata
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supporting information
p. 4320 - 4327
(2017/07/10)
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- α-Keto Acids as Acylating Agents in the Synthesis of 2-Substituted Benzothiazoles and Benzoselenazoles
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Herein, we report the first decarboxylative oxidation of α-keto acids that is promoted by sodium metabisulfite (Na2S2O5) to obtain 2-substituted benzothiazoles and benzoselenazoles. Diaryl disulfides and diselenides were used as chalcogen sources, and the desired products were obtained in moderate to excellent yields. This protocol does not require an inert gas, transition metals, or harsh reaction conditions, and CO2 is released as an environmentally benign coproduct. The presence of Na2S2O5 was essential to guarantee that the reaction reached completion and afforded maximum product yields.
- Lima, David B.,Penteado, Filipe,Vieira, Marcelo M.,Alves, Diego,Perin, Gelson,Santi, Claudio,Lenard?o, Eder J.
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supporting information
p. 3830 - 3836
(2017/07/22)
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