- Thermal Stability of 2-Butynoic Acid (Tetrolic Acid)
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Work to assess the thermal properties of 2-butynoic acid (a precursor to acalabrutinib) has revealed the potential for thermal runaway on heating; testing using accelerated rate calorimetry (ARC) showed exothermic onset from 135 °C, precluding short-path distillation as a means of purification. Recrystallization was shown to be effective as an alternative technique to purify the compound and avoid the distillation procedure.
- Ashton, Hannah,Bethel, Paul A.,Cantlie, Sarah-Kate,Churchill, Trevor,Cooper, Katie,Dobson, Benjamin,Golden, Michael,Hoyle, Mark
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- Access to Triazolopiperidine Derivatives via Copper(I)-Catalyzed [3+2] Cycloaddition/Alkenyl C?N Coupling Tandem Reactions
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A copper-catalyzed [3+2] cylcoaddition/ alkenyl C?N coupling tandem reaction was demonstrated. It provided a method for the formation of triazolopiperidine skeletons. (Figure presented.).
- Xiao, Guorong,Wu, Kaifu,Zhou, Wei,Cai, Qian
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supporting information
p. 4988 - 4991
(2021/10/14)
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- Metal-Organic Framework Based on Heptanuclear Cu-O Clusters and Its Application as a Recyclable Photocatalyst for Stepwise Selective Catalysis
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Visible-light driven photoreactions using metal-organic frameworks (MOFs) as catalysts are promising with regard to their environmental friendly features such as the use of renewable and sustainable energy of visible light and potential catalyst recyclability. To develop potential heterogeneous photocatalysts, a family of three copper(II) coordination polymers bearing different Cu-O assemblies have been synthesized with the ligand 4,4-disulfo-[1,1-biphenyl]-2,2-dicarboxylate acid (H4DSDC), namely, {[Cu7(DSDC)2(OH)6(H2O)10]·xH2O}n (1), {[Cu4(DSDC)(4,4-bpy)2(OH)4]·2H2O}n (2), and {Cu2(DSDC)(phen)2(H2O)2}n (3) (4,4-bpy = 4,4-bipyridine and phen = 1,10-phenanthroline). Complex 1 represents a metal-organic framework featuring a NbO type topology constructed from the infinite linkage of heptanuclear [Cu7(μ3-OH)6(H2O)10]8+ clusters by deprotonated DSDC4- ligands, comprising one-dimensional hexagonal channels of a diameter around 11 ? that are filled with water molecules. The infinite waving {[Cu2(OH)2]2+}n ladderlike chains in complex 2 are bridged by DSDC4- and 4,4-bpy ligands into a three-dimensional framework. A two-dimensional layered structure is formed in complex 3 due to the existence of terminal phenanthroline ligands. All of the coordination polymers 1-3 are able to catalyze the visible-light driven oxidation of alcohols at mild conditions using hydrogen peroxide as an oxidant, in which complex 1 demonstrates satisfactory efficiency. Significantly for this photoreaction catalyzed by 1, the extent of oxidation over aryl primary alcohols is fully controllable with time-resolved product selectivity, giving either corresponding aldehydes or carboxylate acids in good yields. It is also remarkable that the photocatalyst could be recovered almost quantitatively on completion of the catalytic cycle without any structure change, and could be recycled for catalytic use for at least five cycles with constant efficiency. This photocatalyst with time-resolved selectivity for different products may provide new insight into the design and development of novel catalytic systems.
- Zhou, Jie,Huang-Fu, Xu,Huang, Yang-Ying,Cao, Chu-Ning,Han, Jie,Zhao, Xiao-Li,Chen, Xu-Dong
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p. 254 - 263
(2019/12/04)
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- Preparation method of 2-butynoic acid
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The invention relates to the technical field of preparation of 2-butynoic acid, in particular to a preparation method of 2-butynoic acid. The preparation method provided by the invention comprises thefollowing steps: mixing 2-butyn-1-ol, a catalyst, hypochlorite, an alkaline substance and water, carrying out an oxidation reaction, and adding an acid to obtain the 2-butyne acid. On the basis of not using a phase transfer catalyst, high yield and purity of 2-butynoic acid are ensured. According to the embodiment, the high performance liquid chromatography (HPLC) purity of the 2-butynoic acid prepared by the preparation method is more than or equal to 99.6%, and the yield is more than or equal to 52.7%.
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Paragraph 0050-0063
(2020/01/25)
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- Rh-Catalyzed Asymmetric Hydrogenation of Unsaturated Medium-Ring NH Lactams: Highly Enantioselective Synthesis of N-Unprotected 2,3-Dihydro-1,5-benzothiazepinones
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A straightforward method to prepare 1,5-benzothiazepines was reported. Catalyzed by a Rh/Zhaophos complex, unsaturated cyclic NH lactams with a medium-size ring were hydrogenated smoothly, giving remarkably high enantioselectivities. The sulfur atom in the substrates did not bring an inhibition which was observed with commercially available bisphosphine ligands. This method was successfully applied in the scale-up synthesis of (R)-(-)-thiazesim.
- Yin, Congcong,Yang, Tao,Pan, Yingmin,Wen, Jialin,Zhang, Xumu
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supporting information
p. 920 - 923
(2020/02/04)
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- Asymmetric total synthesis of naturally occurring spirocyclic tetranorsesquiterpenoid lanceolactone A
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Asymmetric total synthesis of naturally occurring γ-butenolide containing [4.4]spiro-tetrahydrofuran lanceolactone A has been reported in the present work. Bimetallic ("Pd-Cu") cascade cyclization was the crucial reaction employed for the construction of the γ-butenolide framework of the natural product. Subsequently, iodocyclization and reductive deiodination through a transfer hydrogenation reaction were applied to access the target molecule in an efficient manner.
- Acharyya, Ranjan Kumar,Nanda, Samik
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p. 5027 - 5035
(2018/07/25)
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- Carbene-catalyzed LUMO activation of alkyne esters for access to functional pyridines
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A carbene-catalyzed LUMO activation of α,β-unsaturated alkyne esters is reported. This catalytic process allows for effective reactions of alkyne esters with enamides to synthesize functional pyridines via simple protocols. A previously unexplored unsaturated alkyne acyl azolium intermediate is involved in the key step of the reaction.
- Mou, Chengli,Wu, Jichang,Huang, Zhijian,Sun, Jun,Jin, Zhichao,Chi, Yonggui Robin
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supporting information
p. 13359 - 13362
(2017/12/26)
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- Benzannulation of triynes to generate functionalized arenes by spontaneous incorporation of nucleophiles
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The thermal reaction of ester-tethered 1,3,8-triynes provides novel benzannulation products with concomitant incorporation of a nucleophile. Evidence suggests that this reaction proceeds via an allene-enyne intermediate generated by an Alder-ene reaction in the first step. Depending on the substituent of the alkyne moiety on the allene-enyne intermediate, the subsequent transformation can take one of two different paths, each leading to discrete aromatization products. The benzannulation of a silane-substituted 1,3,8-triynes provides arene products with a nucleophile incorporated onto the newly formed benzene core, whereas an aryl substituent leads to nucleophile trapping at the benzylic carbon atom connected to the aryl substituent. The formation of these two different products results from the involvement of two regioisomeric allene-enyne intermediates.
- Karmakar, Rajdip,Yun, Sang Young,Chen, Jiajia,Xia, Yuanzhi,Lee, Daesung
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supporting information
p. 6582 - 6586
(2015/06/02)
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- Copper-Catalyzed Domino Synthesis of Benzo[4,5]imidazo[1,2-a]pyrimidin-4(10H)-ones using Cyanamide as a Building Block
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An efficient and practical copper-catalyzed domino synthesis of benzo[4,5]imidazo[1,2-a]pyrimidin-4(10H)-ones has been developed. The protocol uses N-(2-halophenyl)-3-alkylpropiolamides and cyanamide as the starting materials, inexpensive copper(I) iodide and pipecolinic acid as the catalyst and ligand, and the corresponding products were obtained in moderate to good yields.
- Lou, Zhenbang,Wu, Xudong,Yang, Haijun,Zhu, Changjin,Fu, Hua
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supporting information
p. 3961 - 3968
(2016/01/25)
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- Palladium-catalyzed oxidative aminocarbonylation by decarboxylative coupling: Synthesis of alkynyl amides
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Alkynyl amides were synthesized from a palladium-catalyzed coupling reaction of alkynyl carboxylic acids and amines under carbon monoxide. The reaction was conducted with palladium(II) acetate (5 mol-%) and silver(I) oxide (1.0 equiv.) in acetonitrile at 80 °C for 1 h. This method provides good to moderate product yields and good functional group tolerance towards ketone, ester, and nitrile groups.
- Hwang, Jinil,Choi, Jinseop,Park, Kyungho,Kim, Wonyoung,Song, Kwang Ho,Lee, Sunwoo
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p. 2235 - 2243
(2015/04/14)
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- Palladium (II/IV) catalyzed cyclopropanation reactions: scope and mechanism
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This report describes detailed studies of the scope and mechanism of a new Pd-catalyzed oxidation reaction for the stereospecific conversion of enynes into cyclopropyl ketones. Unlike related PdII/0, Au, and Pt-catalyzed cyclopropane-forming reactions, these transformations proceed with net inversion of geometry with respect to the starting alkene. This result, along with other mechanistic data, is consistent with a PdII/IV mechanism in which the key cyclopropane-forming step involves nucleophilic attack of a tethered olefin onto a PdIV-C bond.
- Lyons, Thomas W.,Sanford, Melanie S.
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experimental part
p. 3211 - 3221
(2009/09/05)
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- Process for preparing alkynecarboxylic acids by oxidation of alkyne alcohols
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A process for preparing alkynecarboxylic acids includes the oxidation of an alkyne alcohol with a hypohalite in the presence of a nitroxyl compound at a pH of greater than 7 with continual addition of the alkyne alcohol and of the hypohalite to the reaction mixture.
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- Decarboxylative elimination of enol triflates as a general synthesis of acetylenes.
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The enol trifluoromethanesulfonates 4, 8, 12, 17 and 20 of tert-butyl beta-ketodiesters and beta-ketoesters can be hydrolysed to the corresponding carboxylic acids by dissolution in trifluoroacetic acid. The dicarboxylic acids undergo mild decarboxylative elimination to give the acetylenic acids 4 and 9 in aqueous sodium bicarbonate solution at room temperature. Similarly, the monocarboxylic acids give the terminal and mid-chain acetylenes 13, 18, 21, and 24 by refluxing in acetone with potassium carbonate. One of the substituents on the acetylenes can be methyl, primary alkyl, secondary alkyl or ethynyl, and the other can be a carboxylic acid, hydrogen or primary alkyl, but the enol trifluoromethanesulfonates could not be prepared when one of the substituents was tert-butyl, nor when both substituents on the precursor to the acetylene were secondary alkyl.
- Fleming, Ian,Ramarao, Chandrashekar
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p. 1504 - 1510
(2007/10/03)
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- Decarboxylative elimination of enol triflates as a general synthesis of acetylenes
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Decarboxylative elimination of a range of enol triflates of β-keto esters gives acetylenes.
- Fleming, Ian,Ramarao, Chandrashekar
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p. 1113 - 1114
(2007/10/03)
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- Synthesis of (2S,3R)- and (2S,3S)-3-Methylglutamic Acid
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Arndt-Eistert homologation of suitably protected (2S,3S)-3-methylaspartic acid occurs with retention of configuration at C-3 to give, ultimately, (2S,3R)-3-methylglutamic acid. (2S,3R)-3-Methylglutamic acid was also prepared in good yield via the conjugate addition of the lithiated anion of the bis-lactim ether of cyclo-(R-Val-Gly) to methyl (E)-butenoate.The analogous reaction performed using isopentyl (Z)-butenoate ultimately gave (2S,3S)-3-methylglutamic acid.Both conjugate additions occured with high diastereoselectivity.
- Hartzoulakis, Basil,Gani, David
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p. 2525 - 2532
(2007/10/02)
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