- C H Bond Arylation of Diamondoids Catalyzed by Palladium(II) Acetate
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We have developed an effective approach to 1,2-disubstituted diamondoids by palladium(II) acetate catalyzed functionalization of C H bond. Selective mono-arylation of the adamantane framework was achieved using picolylamide as a directing group in yields up to 87 %. Kinetic studies in combination with deuterium labeling experiments, competitive experiments and mass spectrometry contribute to the mechanistic understanding of the arylation process of alkanes with number of C H bonds neighboring the directing group. Triflic anhydride promoted cyclization of the directing group generates imidazo[1,5-a]pyridine derivatives. Acid-mediated removal of the directing group provides access to 2-aryl diamondoid carboxylic acids, which are common precursors for the synthesis of various bioactive compounds (drug candidates). (Figure presented.) .
- Larrosa, Marta,Heiles, Sven,Becker, Jonathan,Spengler, Bernhard,Hrdina, Radim
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- Hydrosilylative reduction of primary amides to primary amines catalyzed by a terminal [Ni-OH] complex
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A terminal [Ni-OH] complex1, supported by triflamide-functionalized NHC ligands, catalyzes the hydrosilylative reduction of a range of primary amides into primary amines in good to excellent yields under base-free conditions with key functional group tolerance. Catalyst1is also effective for the reduction of a variety of tertiary and secondary amides. In contrast to literature reports, the reactivity of1towards amide reduction follows an inverse trend,i.e., 1° amide > 3° amide > 2° amide. The reaction does not follow a usual dehydration pathway.
- Pandey, Pragati,Bera, Jitendra K.
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supporting information
p. 9204 - 9207
(2021/09/20)
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- Silicon hydrogenation reaction method of organic boron and inorganic alkali catalysis amide (by machine translation)
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The method is characterized in that organic boron and inorganic bases are used as catalysts, silane is used as a reducing agent, primary amide is reduced to primary amine or dehydration dinitrile, the secondary amide is reduced to a secondary amine or aldimine, and the tertiary amide is reduced to tertiary amine. The method has the advantages of simple operation, mild reaction conditions, wide substrate universality, good functional group compatibility and the like, and has the characteristics of good stability, cheap and accessible catalyst, simple and convenient operation, high practicality and the like. (by machine translation)
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Paragraph 0134-0140; 0178-0181
(2020/08/18)
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- ADAMANTANYL-SUBSTITUTED BENZAMIDE COMPOUNDS AND THEIR USE AS P2X7 RECEPTOR ANTAGONISTS
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The present invention relates to adamantanyl-substituted benzamide compounds and their use as antagonists of the P2X7 purinoreceptor. The invention further relates to methods for the treatment of disease and conditions associated with the P2X7 purinoreceptor.
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- A cobalt phosphide catalyst for the hydrogenation of nitriles
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The study of metal phosphide catalysts for organic synthesis is rare. We present, for the first time, a well-defined nano-cobalt phosphide (nano-Co2P) that can serve as a new class of catalysts for the hydrogenation of nitriles to primary amines. While earth-abundant metal catalysts for nitrile hydrogenation generally suffer from air-instability (pyrophoricity), low activity and the need for harsh reaction conditions, nano-Co2P shows both air-stability and remarkably high activity for the hydrogenation of valeronitrile with an excellent turnover number exceeding 58000, which is over 20- to 500-fold greater than that of those previously reported. Moreover, nano-Co2P efficiently promotes the hydrogenation of a wide range of nitriles, which include di- and tetra-nitriles, to the corresponding primary amines even under just 1 bar of H2 pressure, far milder than the conventional reaction conditions. Detailed spectroscopic studies reveal that the high performance of nano-Co2P is attributed to its air-stable metallic nature and the increase of the d-electron density of Co near the Fermi level by the phosphidation of Co, which thus leads to the accelerated activation of both nitrile and H2. Such a phosphidation provides a promising method for the design of an advanced catalyst with high activity and stability in highly efficient and environmentally benign hydrogenations. This journal is
- Jitsukawa, Koichiro,Mitsudome, Takato,Mizugaki, Tomoo,Nakata, Ayako,Sheng, Min,Yamasaki, Jun
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p. 6682 - 6689
(2020/08/24)
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- A BEt3-Base catalyst for amide reduction with silane
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Reported herein is the development of a simple but practical catalytic system for the selective reduction of amides with hydrosilane or hydrosiloxane. Low-cost and readily available triethylborane (1.0 M in THF), in combination with a catalytic amount of an alkali metal base, was found to catalyze the reduction of all three amide classes (tertiary, secondary, and primary amides) to form amines under mild conditions. In addition, the selective transformation of secondary amides to aldimines and primary amides to nitriles can also be achieved by using a proper combination of BEt3 and base. The scope of these BEt3-base-catalyzed amide hydrosilylation reactions has been explored in depth. Preliminary results of mechanistic studies suggest a modified Piers' silane Si-H···B activation mode wherein the hydride abstraction by BEt3 is promoted by the coordination of an alkoxide or hydroxide anion to the Si center.
- Yao, Wubing,Fang, Huaquan,He, Qiaoxing,Peng, Dongjie,Liu, Guixia,Huang, Zheng
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- A BEt3-Base Catalyst for Amide Reduction with Silane
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Reported herein is the development of a simple but practical catalytic system for the selective reduction of amides with hydrosilane or hydrosiloxane. Low-cost and readily available triethylborane (1.0 M in THF), in combination with a catalytic amount of an alkali metal base, was found to catalyze the reduction of all three amide classes (tertiary, secondary, and primary amides) to form amines under mild conditions. In addition, the selective transformation of secondary amides to aldimines and primary amides to nitriles can also be achieved by using a proper combination of BEt3 and base. The scope of these BEt3-base-catalyzed amide hydrosilylation reactions has been explored in depth. Preliminary results of mechanistic studies suggest a modified Piers' silane Si-H···B activation mode wherein the hydride abstraction by BEt3 is promoted by the coordination of an alkoxide or hydroxide anion to the Si center.
- Yao, Wubing,Fang, Huaquan,He, Qiaoxing,Peng, Dongjie,Liu, Guixia,Huang, Zheng
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p. 6084 - 6093
(2019/05/24)
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- Liquid-phase hydrogenation of nitriles to amines facilitated by a co(ii)/zn(0) pair: a ligand-free catalytic protocol
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The given report introduces a simple and user-friendly in situ method for the production of catalytically active cobalt particles. The approach circumvents the use of air-and moisture-sensitive reductants as well as the application of anhydrous Co-precursor salts. Accordingly, the described catalytic system is readily assembled under open-flask conditions by simply combining the components in the reaction vessel. Therefore, the arduous charging procedure of the reaction autoclave in a glovebox under an inert gas atmosphere is no longer necessary. In fact, the catalytically active material is obtained upon treatment of readily available Co(OAc)2·4 H2O with benign commercial Zn powder. The catalytic performance of the resultant material was tested in the heterogeneous hydrogenation of nitriles to the corresponding primary amines. Both activity and selectivity of the cobalt catalyst are significantly enhanced if a triflate-based Lewis acid and ammonia is added to the reaction mixture.
- Timelthaler, Daniel,Topf, Christoph
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p. 11604 - 11611
(2019/10/02)
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- Catalytic Reduction of Nitriles by Polymethylhydrosiloxane Using a Phenalenyl-Based Iron(III) Complex
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The reduction of nitriles to primary amines using an inexpensive silane such as polymethylhydrosiloxane (PMHS) is an industrially important reaction. Herein we report the synthesis of an earth-abundant Fe(III) complex bearing a phenalenyl-based ligand that was characterized by mass spectroscopy, elemental analysis, cyclic voltammetry, and single-crystal X-ray diffraction. The complex showed excellent catalytic activity toward reduction of aromatic, heteroaromatic, aliphatic, and sterically crowded nitriles to produce primary amines using polymethylhydrosiloxane (PMHS).
- Das, Shyamal,Das, Hari Sankar,Singh, Bhagat,Haridasan, Rahul Koottanil,Das, Arpan,Mandal, Swadhin K.
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supporting information
p. 11274 - 11278
(2019/09/10)
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- Manganese-Catalyzed Transfer Hydrogenation of Nitriles with 2-Butanol as the Hydrogen Source
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We report herein the first example of a homogeneous manganese catalyzed transfer hydrogenation of nitriles using 2-BuOH as the hydrogen source. Compound fac-[(CO)3Mn{iPr2P(CH2)2PiPr2}Br] (Mn-1, 3 mol %) exhibited catalytic activity in the presence of KOtBu (10 mol %) for the transfer hydrogenation of benzonitrile to yield a mixture of benzylamine (BA) and N-sec-butylidenebenzylamine (SBA). Subsequent acidic hydrolysis yielded isolated benzylamine hydrochloride in 96 %. The title system featured reversible formation of N-benzylidenebenzylamine (BBA) prior to formation of SBA. A series of amine hydrochlorides was prepared following this methodology (39–92 % isolated yields, 4 examples). Best substrates for this transformation are electron-rich aromatic nitriles, nonetheless electron-deficient aromatic as well as aliphatic nitriles were also hydrogenated. Mechanistic studies suggested coordinatively unsaturated Mn-hydride species performing catalytic turnover.
- Gardu?o, Jorge A.,Flores-Alamo, Marcos,García, Juventino J.
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p. 5330 - 5338
(2019/11/03)
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- Stable and Inert Cobalt Catalysts for Highly Selective and Practical Hydrogenation of C≡N and C=O Bonds
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Novel heterogeneous cobalt-based catalysts have been prepared by pyrolysis of cobalt complexes with nitrogen ligands on different inorganic supports. The activity and selectivity of the resulting materials in the hydrogenation of nitriles and carbonyl compounds is strongly influenced by the modification of the support and the nitrogen-containing ligand. The optimal catalyst system ([Co(OAc)2/Phenα-Al2O3]-800 = Cat. E) allows for efficient reduction of both aromatic and aliphatic nitriles including industrially relevant dinitriles to primary amines under mild conditions. The generality and practicability of this system is further demonstrated in the hydrogenation of diverse aliphatic, aromatic, and heterocyclic ketones as well as aldehydes, which are readily reduced to the corresponding alcohols.
- Chen, Feng,Topf, Christoph,Radnik, J?rg,Kreyenschulte, Carsten,Lund, Henrik,Schneider, Matthias,Surkus, Annette-Enrica,He, Lin,Junge, Kathrin,Beller, Matthias
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supporting information
p. 8781 - 8788
(2016/08/02)
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- Hydrogenation of Aliphatic and Aromatic Nitriles Using a Defined Ruthenium PNP Pincer Catalyst
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Selective catalytic reductions of nitriles are presented using the commercially available Ru-Macho-BH complex. A variety of aliphatic, aromatic and (hetero)cyclic nitriles including industrially important adipodinitrile are hydrogenated to the corresponding primary amines. Modelling suggests the reaction follows an outer sphere hydrogenation mechanism. An efficient and selective catalytic reduction of nitriles is presented using the commercially available Ru-Macho-BH complex. A variety of aliphatic, aromatic and (hetero)cyclic nitriles including the industrially important adipodinitrile are hydrogenated to the corresponding primary amines. The reaction follows an outer-sphere mechanism.
- Neumann, Jacob,Bornschein, Christoph,Jiao, Haijun,Junge, Kathrin,Beller, Matthias
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p. 5944 - 5948
(2015/09/22)
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- NEW ADAMANTANE DERIVATIVES AS DIPEPTIDYL, PEPTIDASE IV INHIBITORS, PROCESSES FOR THEIR PREPARATION, AND PHARMACEUTICAL COMPOSITIONS CONTAINING THEM
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The present invention relates to dipeptidyl peptidase IV (DPP-IV) inhibitors of the formula (A): wherein R1, R2, Y, and n are as defined herein, pharmaceutical compositions containing the same, processes for their preparation, and methods for treating disorders mediated by DPP-IV inhibition, such as diabetes, especially Type II diabetes, with them.
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Page/Page column 28
(2008/06/13)
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