836-43-1Relevant academic research and scientific papers
A Bifunctional Copper Catalyst Enables Ester Reduction with H2: Expanding the Reactivity Space of Nucleophilic Copper Hydrides
Kaicharla, Trinadh,Ngoc, Trung Tran,Teichert, Johannes F.,Tzaras, Dimitrios-Ioannis,Zimmermann, Birte M.
supporting information, p. 16865 - 16873 (2021/10/20)
Employing a bifunctional catalyst based on a copper(I)/NHC complex and a guanidine organocatalyst, catalytic ester reductions to alcohols with H2 as terminal reducing agent are facilitated. The approach taken here enables the simultaneous activation of esters through hydrogen bonding and formation of nucleophilic copper(I) hydrides from H2, resulting in a catalytic hydride transfer to esters. The reduction step is further facilitated by a proton shuttle mediated by the guanidinium subunit. This bifunctional approach to ester reductions for the first time shifts the reactivity of generally considered "soft"copper(I) hydrides to previously unreactive "hard"ester electrophiles and paves the way for a replacement of stoichiometric reducing agents by a catalyst and H2.
Oxoammonium-Mediated Allylsilane–Ether Coupling Reaction
Carlet, Federica,Bertarini, Greta,Broggini, Gianluigi,Pradal, Alexandre,Poli, Giovanni
supporting information, p. 2162 - 2168 (2021/04/02)
A new C(sp3)?H functionalization reaction consisting of the oxidative α-allylation of allyl- and benzyl- methyl ethers has been developed. The C?C coupling could be carried out under mild conditions thanks to the use of cheap and green oxoammonium salts. The scope of the reaction was studied over 27 examples, considering the nature of the substituents on the two coupling partners.
α-Lithiobenzyloxy as a Directed Metalation Group in ortho-Lithiation Reactions
Sedano, Carlos,Velasco, Rocío,Feberero, Claudia,Suárez-Pantiga, Samuel,Sanz, Roberto
supporting information, p. 6365 - 6369 (2020/08/24)
The α-lithiobenzyloxy group, easily generated from aryl benzyl ethers by selective α-lithiation with t-BuLi at low temperature, behaves as a directed metalation group (DMG) providing a direct access to o-lithiophenyl α-lithiobenzyl ethers. This ortho-directing effect is reinforced in substrates bearing an additional methoxy group at the meta position. The generated dianions can be reacted with a selection of electrophiles including carboxylic esters and dihalosilanes or germanes, which afford interesting benzofuran, sila(germa)dihydrobenzofuran, and silachroman derivatives from simple aryl benzyl ethers.
Fumarate related impurity and preparation method and application thereof (by machine translation)
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Paragraph 0091-0094, (2020/02/04)
The preparation method of the related impurities comprises the following steps: No.No.No. STR8No.No. wherein the (I) preparation method, of ,R the related impurities is. shown, in the specification, and the preparation method of, the 1 present, application, further, discloses, the preparation method, and of the related impurities. (by machine translation)
Tuning Cu Overvoltage for a Copper-Telluride System in Electrocatalytic Water Reduction and Feasible Feedstock Conversion: A New Approach
Johny, Jinta Merlin,Karthick, Kannimuthu,Kumaravel, Sangeetha,Kundu, Subrata,Sankar, Selvasundarasekar Sam,Thiruvengetam, Prabaharan
supporting information, (2020/08/12)
Highly efficient and earth-abundant elements capable of water reduction by electrocatalysis and are attractive for the sustainable generation of fuels. Among the earth-abundant metals, copper is one of the cheapest but often the most neglected choice for the hydrogen evolution reaction (HER) due to its high overvoltage. Herein, for the first time we have tuned the overpotential of copper by tellurizing it by two different methodologies, viz. hydrothermal and wet chemical methods, which form copper telluride nanochains and aggregates. The application of copper telluride as an electrocatalyst for the HER gave fruitful results in terms of both activity and stability. The hydrothermally synthesized catalyst Cu2-xTe/hyd shows a low overpotential (347 mV) at 10 mA cm-2 toward the HER. In addition, the catalyst showed a very low charge transfer resistance (Rct) of 24.4 ω and, as expected, Cu2-xTe/hyd exhibited a lower Tafel slope value of 188 mV/dec in comparison to Cu2-xTe/wet (280 mV/dec). A chronoamperometry study reveals the long-term stability of both catalysts even up to 12 h. The Faradaic efficiency of Cu2-xTe/hyd was calculated and found to be 95.06percent by using gas chromatographic (GC) studies. Moreover, with the idea of utilizing produced hydrogen (H2) from electrocatalysis, for the first time we have carried out feedstock conversion to platform chemicals in water under eco-friendly green conditions. We have chosen cinnamaldehyde, 2-hydroxy-1-phenylethanone, 4-(benzyloxy)benzaldehyde, and 2-(3-methoxyphenoxy)-1-phenylethanone (β-O-4) as model compounds for feedstock conversion by hydrogenation and/or hydrogenolysis reactions in aqueous medium using external hydrogen pressure. This protocol could also be scaled up for large-scale conversion and the catalyst is likely to find industrial application since it requires an inexpensive catalyst and an easily available, mild reducing agent. The robustness of the developed catalyst is proven by recyclability experiments and its possibility of use in real-life applications.
Combined KOH/BEt3Catalyst for Selective Deaminative Hydroboration of Aromatic Carboxamides for Construction of Luminophores
Li, Jinshan,Wang, Jiali,Yang, Jianguo,Yao, Wubing,Zhong, Aiguo
, p. 8086 - 8090 (2020/11/03)
The selective catalytic C-N bond cleavage of amides into value-added amine products is a desirable but challenging transformation. Molecules containing iminodibenzyl motifs are prevalent in pharmaceutical molecules and functional materials. Here we established a combined KOH/BEt3 catalyst for deaminative hydroboration of acyl-iminodibenzyl derivatives, including nonheterocyclic carboxamides, to the corresponding amines. This novel transition-metal-free methodology was also applied to the construction of Clomipramine and luminophores.
Manganese-catalysed transfer hydrogenation of esters
Oates, Conor L.,Widegren, Magnus B.,Clarke, Matthew L.
supporting information, p. 8635 - 8638 (2020/08/21)
Manganese catalysed ester reduction using ethanol as a hydrogen transfer agent in place of dihydrogen is reported. High yields can be achieved for a range of substrates using 1 mol% of a Mn(i) catalyst, with an alkoxide promoter. The catalyst is derived from a tridentate P,N,N ligand.
A General Method for Photocatalytic Decarboxylative Hydroxylation of Carboxylic Acids
Khan, Shah Nawaz,Zaman, Muhammad Kashif,Li, Ruining,Sun, Zhankui
, p. 5019 - 5026 (2020/05/01)
A general and practical method for decarboxylative hydroxylation of carboxylic acids was developed through visible light-induced photocatalysis using molecular oxygen as the green oxidant. The addition of NaBH4 to in situ reduce the unstable peroxyl radical intermediate much broadened the substrate scope. Different sp3 carbon-bearing carboxylic acids were successfully employed as substrates, including phenylacetic acid-type substrates, as well as aliphatic carboxylic acids. This transformation worked smoothly on primary, secondary, and tertiary carboxylic acids.
New convergent one pot synthesis of amino benzyl ethers bearing a nitrogen-containing bicycle
López, Jhon J.,Pérez, Edwin G.
, p. 715 - 723 (2019/02/19)
We report herein a new convergent one pot method for the synthesis of amino benzyl ethers containing a bicyclic amine, derived from different substituted benzyl alcohols and bicyclic amino alcohols such as tropine, pseudotropine, and 3-quinuclidinol, using chlorotrimethylsilane and sodium iodide. In order to avoid the competitive reaction with the nitrogen atom, a solution of the separately prepared alkoxide of tropine, pseudotropine, and 3-quinuclidinol was added to the preformed substituted benzyl iodides and allowed to reflux at 90 °C for 15 h under nitrogen atmosphere. This method provides an efficient alternative of the preparation of amino benzyl ethers in organic synthesis with good yields in comparison with existed methods.
Controlled Reduction of Carboxamides to Alcohols or Amines by Zinc Hydrides
Ong, Derek Yiren,Yen, Zhihao,Yoshii, Asami,Revillo Imbernon, Julia,Takita, Ryo,Chiba, Shunsuke
supporting information, p. 4992 - 4997 (2019/03/13)
New protocols for controlled reduction of carboxamides to either alcohols or amines were established using a combination of sodium hydride (NaH) and zinc halides (ZnX2). Use of a different halide on ZnX2 dictates the selectivity, wherein the NaH-ZnI2 system delivers alcohols and NaH-ZnCl2 gives amines. Extensive mechanistic studies by experimental and theoretical approaches imply that polymeric zinc hydride (ZnH2)∞ is responsible for alcohol formation, whereas dimeric zinc chloride hydride (H?Zn?Cl)2 is the key species for the production of amines.
