- Assembly of two new hybrid chloride materials with potential NLO properties: Structure elucidation, empirical and computational studies
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This paper deals with the crystal structure of two new non-centrosymmetric hybrid compounds obtained from an aqueous solution by slow evaporation method and characterized by various techniques mainly single-crystal X-ray diffraction. In the atomic arrangement of 2-methylbenzylammonium chloride (1), the organic cations and the chloride anions are linked to each other via N–H…Cl hydrogen bonds; organic cations in zigzag distribution along b-axis in z = 0 and z = ? are also close enough to enable a C–H…π interaction to occur. In 3-methylbenzylammonium chloride (2), the organic cations are linked together by C–H…π interactions and through N–H…Cl and C–H…Cl hydrogen bonds to form a two-dimensional network. To support experimental results, DFT calculations have been accomplished via the B3LYP method and 6-311++G(d,p) basis set on molecular geometry, vibrational, and electronic properties. The non-covalent interactions were studied quantitatively using the Hirshfeld surfaces (HS) associated with 2D fingerprint plots. The NLO properties have been also investigated by DFT and compared to the urea reference.
- Issaoui, Noureddine,Jomaa, Ikram,Marouani, Houda,Roisnel, Thierry
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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.
- Bera, Jitendra K.,Pandey, Pragati
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supporting information
p. 9204 - 9207
(2021/09/20)
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- Phosphine-Free Manganese Catalyst Enables Selective Transfer Hydrogenation of Nitriles to Primary and Secondary Amines Using Ammonia-Borane
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Herein we report the synthesis of primary and secondary amines by nitrile hydrogenation, employing a borrowing hydrogenation strategy. A class of phosphine-free manganese(I) complexes bearing sulfur side arms catalyzed the reaction under mild reaction conditions, where ammonia-borane is used as the source of hydrogen. The synthetic protocol is chemodivergent, as the final product is either primary or secondary amine, which can be controlled by changing the catalyst structure and the polarity of the reaction medium. The significant advantage of this method is that the protocol operates without externally added base or other additives as well as obviates the use of high-pressure dihydrogen gas required for other nitrile hydrogenation reactions. Utilizing this method, a wide variety of primary and symmetric and asymmetric secondary amines were synthesized in high yields. A mechanistic study involving kinetic experiments and high-level DFT computations revealed that both outer-sphere dehydrogenation and inner-sphere hydrogenation were predominantly operative in the catalytic cycle.
- Sarkar, Koushik,Das, Kuhali,Kundu, Abhishek,Adhikari, Debashis,Maji, Biplab
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p. 2786 - 2794
(2021/03/03)
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- Benzimidazole fragment containing Mn-complex catalyzed hydrosilylation of ketones and nitriles
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The synthesis of a new bidentate (NN)–Mn(I) complex is reported and its catalytic activity towards the reduction of ketones and nitriles is studied. On comparing the reactivity of various other Mn(I) complexes supported by benzimidazole ligand, it was observed that the Mn(I) complexes bearing 6-methylpyridine and benzimidazole fragments exhibited the highest catalytic activity towards monohydrosilylation of ketones and dihydrosilylation of nitriles. Using this protocol, a wide range of ketones were selectively reduced to the corresponding silyl ethers. In case of unsaturated ketones, the chemoselective reduction of carbonyl group over olefinic bonds was observed. Additionally, selective dihydrosilylation of several nitriles were also achieved using this complex. Mechanistic investigations with radical scavengers suggested the involvement of radical species during the catalytic reaction. Stoichiometric reaction of the Mn(I) complex with phenylsilane revealed the formation of a new Mn(I) complex.
- Ganguli, Kasturi,Mandal, Adarsha,Sarkar, Bidisha,Kundu, Sabuj
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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; 0158-0161
(2020/08/18)
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- Transition metal-free catalytic reduction of primary amides using an abnormal NHC based potassium complex: Integrating nucleophilicity with Lewis acidic activation
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An abnormal N-heterocyclic carbene (aNHC) based potassium complex was used as a transition metal-free catalyst for reduction of primary amides to corresponding primary amines under ambient conditions. Only 2 mol% loading of the catalyst exhibits a broad substrate scope including aromatic, aliphatic and heterocyclic primary amides with excellent functional group tolerance. This method was applicable for reduction of chiral amides and utilized for the synthesis of pharmaceutically valuable precursors on a gram scale. During mechanistic investigation, several intermediates were isolated and characterized through spectroscopic techniques and one of the catalytic intermediates was characterized through single-crystal XRD. A well-defined catalyst and isolable intermediate along with several stoichiometric experiments, in situ NMR experiments and the DFT study helped us to sketch the mechanistic pathway for this reduction process unravelling the dual role of the catalyst involving nucleophilic activation by aNHC along with Lewis acidic activation by K ions.
- Bhunia, Mrinal,Sahoo, Sumeet Ranjan,Das, Arpan,Ahmed, Jasimuddin,Sreejyothi,Mandal, Swadhin K.
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p. 1848 - 1854
(2020/03/03)
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- Primary amides to amines or nitriles: A dual role by a single catalyst
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We report a manganese-catalyzed hydrosilylative reduction of various primary amides to amines (25 examples). On simple modification of the reaction conditions such as in the presence of a catalytic amount of secondary amide, the same catalyst can transform the primary amides into intermediate nitrile compounds (16 examples) in excellent yields. This is the first example where such a controlled catalytic transformation of primary amides to amines or nitriles with a single catalyst has been demonstrated.
- Das, Hari S.,Das, Shyamal,Dey, Kartick,Singh, Bhagat,Haridasan, Rahul,Das, Arpan,Ahmed, Jasimuddin,Mandal, Swadhin K.
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supporting information
p. 11868 - 11871
(2019/10/11)
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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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- Hydrosilane Reduction of Nitriles to Primary Amines by Cobalt-Isocyanide Catalysts
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Reduction of nitriles to silylated primary amines was achieved by combination of 1,1,3,3-tetramethyldisiloxane (TMDS) as the hydrosilane and a catalytic amount of Co(OPIV)2 (PIV = COtBu) associated with isocyanide ligands. The resulting silylated amines were subjected to acid hydrolysis or treatment with acid chlorides to give the corresponding primary amines or imides in good yields. One-pot synthesis of primary amides to primary amines with hydrosilanes was also achieved by iron-cobalt dual catalyst systems.
- Sanagawa, Atsushi,Nagashima, Hideo
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supporting information
p. 287 - 291
(2019/01/10)
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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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- Cobalt-based nanoparticles prepared from MOF-carbon templates as efficient hydrogenation catalysts
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The development of efficient and selective nanostructured catalysts for industrially relevant hydrogenation reactions continues to be an actual goal of chemical research. In particular, the hydrogenation of nitriles and nitroarenes is of importance for the production of primary amines, which constitute essential feedstocks and key intermediates for advanced chemicals, life science molecules and materials. Herein, we report the preparation of graphene shell encapsulated Co3O4- and Co-nanoparticles supported on carbon by the template synthesis of cobalt-terephthalic acid MOF on carbon and subsequent pyrolysis. The resulting nanoparticles create stable and reusable catalysts for selective hydrogenation of functionalized and structurally diverse aromatic, heterocyclic and aliphatic nitriles, and as well as nitro compounds to primary amines (>65 examples). The synthetic and practical utility of this novel non-noble metal-based hydrogenation protocol is demonstrated by upscaling several reactions to multigram-scale and recycling of the catalyst.
- Murugesan, Kathiravan,Senthamarai, Thirusangumurugan,Sohail, Manzar,Alshammari, Ahmad S.,Pohl, Marga-Martina,Beller, Matthias,Jagadeesh, Rajenahally V.
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p. 8553 - 8560
(2018/11/30)
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- Cobalt-Catalyzed and Lewis Acid-Assisted Nitrile Hydrogenation to Primary Amines: A Combined Effort
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The selective hydrogenation of nitriles to primary amines using a bench-stable cobalt precatalyst under 4 atm of H2 is reported herein. The catalyst precursor was reduced in situ using NaHBEt3, and the resulting Lewis acid formed, BEt3, was found to be integral to the observed catalysis. Mechanistic insights gleaned from para-hydrogen induced polarization (PHIP) transfer NMR studies revealed that the pairwise hydrogenation of nitriles proceeded through a Co(I/III) redox process.
- Tokmic, Kenan,Jackson, Bailey J.,Salazar, Andrea,Woods, Toby J.,Fout, Alison R.
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supporting information
p. 13554 - 13561
(2017/10/05)
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- Selective Hydrogenation of Nitriles to Primary Amines Catalyzed by a Polysilane/SiO2-Supported Palladium Catalyst under Continuous-Flow Conditions
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Hydrogenation of nitriles to primary amines with heterogeneous catalysts under liquid-phase continuous-flow conditions is described. Newly developed polysilane/SiO2-supported Pd was found to be an effective catalyst and various nitriles were converted into primary amine salts in almost quantitative yields under mild reaction conditions. Interestingly, a complex mixture was obtained under batch conditions. Lifetime experiments showed that this catalyst remained active for more than 300 h (TON≥10 000) without loss of selectivity and no metal leaching from the catalyst occurred. By using this continuous-flow hydrogenation, synthesis of venlafaxine, an antidepressant drug, has been accomplished.
- Saito, Yuki,Ishitani, Haruro,Ueno, Masaharu,Kobayashi, Shū
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p. 211 - 215
(2017/04/21)
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- Exhaustive Chemoselective Reduction of Nitriles by Catalytic Hydrosilylation Involving Cooperative Si-H Bond Activation
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A chemoselective method for the catalytic hydrosilylation of nitriles to either the imine or amine oxidation level is reported. The chemoselectivity is controlled by the hydrosilane used. The usefulness of the nitrile-to-amine reduction is demonstrated for a diverse set of aromatic and aliphatic nitriles, and the amines are easily isolated after hydrolysis as their hydrochloride salts. This exhaustive nitrile reduction proceeds at room temperature.
- Wübbolt, Simon,Oestreich, Martin
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supporting information
p. 2411 - 2414
(2017/10/03)
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- APPLICATIONS OF N6-SUBSTITUTED ADENOSINE DERIVATIVE AND N6-SUBSTITUTED ADENINE DERIVATIVE TO CALMING, HYPNOSES, CONVULSION RESISTANCE, EPILEPTIC RESISTANCE, PARKINSON DISEASE RESISTANCE, AND DEMENTIA PREVENTION AND TREATMENT
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PROBLEM TO BE SOLVED: To prepare analgesics, hypnotic agents, anticonvulsant agents, antiepileptics, antiparkinson drugs, dementia prophylactics, and health care food. SOLUTION: The present invention relates to an N6-substituted adenosine derivative and an N6-substituted adenine derivative selected from the group consisting of specific compounds. The present invention also relates to a pharmaceutical composition at least comprising a therapeutically effective amount of the compounds and a pharmaceutically acceptable carrier. The invention further relates to the compounds used in preparation of analgesics, hypnotic agents, anticonvulsant agents, antiepileptics, antiparkinson drugs, dementia prophylactics, and health care food. COPYRIGHT: (C)2016,JPO&INPIT
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Paragraph 0097
(2018/10/27)
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- N6-SUBSTITUTED ADENOSINE DERIVATIVES AND N6-SUBSTITUTED ADENINE DERIVATIVES AND USES THEREOF
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The present invention provides N6-substituted adenosine derivatives and N6-substituted adenine derivatives, manufacturing methods thereof, a pharmaceutical composition comprising the said compounds above, and uses of these compounds in manufacturing medicaments and health-care products for treating insomnia, convulsion, epilepsy, and Parkinson's diseases, and preventing and treating dementia.
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Paragraph 0097
(2013/03/26)
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- TBAF-catalyzed hydrosilylation for the reduction of aromatic nitriles
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The selective catalytic hydrosilylation of functional groups is becoming an interesting tool for organic synthesis. In the present study, fluoride-catalyzed hydrosilylations of aromatic nitriles have been examined in detail. Using catalytic amounts of inexpensive tetra-n-butylammonium fluoride (TBAF) various aromatic nitriles are reduced in good yields under mild conditions.
- Bornschein, Christoph,Werkmeister, Svenja,Junge, Kathrin,Beller, Matthias
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supporting information
p. 2061 - 2065
(2013/10/08)
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- N6-SUBSTITUTED ADENOSINE DERIVATIVES, N6-SUBSTITUTED ADENINE DERIVATIVES AND USES THEREOF
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The present invention provides N6-substituted adenosine derivatives and N6-substituted adenine derivatives, manufacturing methods thereof, a pharmaceutical composition comprising the said compounds above, and uses of of these compounds in manufacturing medicaments and health-care products for treating insomnia, convulsion, epilepsy, and Parkinson's diseases, and preventing and treating dementia.
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Page/Page column 40
(2012/11/06)
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- Substituent effects. 14. Anomalous dissociation constants in water-organic solvent mixtures: benzylammonium ions and related systems
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Thermodynamic dissociation constants in various water-organic solvent mixtures are given for benzylammonium, benzyldialkylammonium, and (2-phenylethyl)ammonium ions.Deviations from the Hammett equation (Eqn. 1) are similar to those observed for carboxylic acids, but of opposite sign.The extended Hammett equation (Eqn. 3), containing the hydrophobic constant, ?, yields good correlations.Derived secondary normal sigma values are exemplified.
- Hoefnagel, A. J.,Vos, R. H. de,Wepster, B. M.
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