635-85-8Relevant academic research and scientific papers
Phosphine-Free Manganese Catalyst Enables Selective Transfer Hydrogenation of Nitriles to Primary and Secondary Amines Using Ammonia-Borane
Sarkar, Koushik,Das, Kuhali,Kundu, Abhishek,Adhikari, Debashis,Maji, Biplab
, p. 2786 - 2794 (2021/03/03)
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.
Cyclic (Alkyl)(amino)carbene Ligand-Promoted Nitro Deoxygenative Hydroboration with Chromium Catalysis: Scope, Mechanism, and Applications
Zhao, Lixing,Hu, Chenyang,Cong, Xuefeng,Deng, Gongda,Liu, Liu Leo,Luo, Meiming,Zeng, Xiaoming
supporting information, p. 1618 - 1629 (2021/01/25)
Transition metal catalysis that utilizes N-heterocyclic carbenes as noninnocent ligands in promoting transformations has not been well studied. We report here a cyclic (alkyl)(amino)carbene (CAAC) ligand-promoted nitro deoxygenative hydroboration with cost-effective chromium catalysis. Using 1 mol % of CAAC-Cr precatalyst, the addition of HBpin to nitro scaffolds leads to deoxygenation, allowing for the retention of various reducible functionalities and the compatibility of sensitive groups toward hydroboration, thereby providing a mild, chemoselective, and facile strategy to form anilines, as well as heteroaryl and aliphatic amine derivatives, with broad scope and particularly high turnover numbers (up to 1.8 × 106). Mechanistic studies, based on theoretical calculations, indicate that the CAAC ligand plays an important role in promoting polarity reversal of hydride of HBpin; it serves as an H-shuttle to facilitate deoxygenative hydroboration. The preparation of several commercially available pharmaceuticals by means of this strategy highlights its potential application in medicinal chemistry.
Synthetic method of high-purity dopamine hydrochloride
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Paragraph 0038-0039; 0046-0047, (2020/11/23)
The invention provides a synthetic method of dopamine hydrochloride, and belongs to the field of drug synthesis. The preparation method comprises the following steps: taking 3,4-dimethoxyphenylethylamine as an initial raw material, firstly reacting with an acid to form a salt, re-crystallizing and refining to obtain 3,4-dimethoxyphenylethylamine salt, reacting with hydrobromic acid to remove methyl to generate dopamine hydrobromide, and finally reacting with hydrochloric acid to form a salt so as to obtain dopamine hydrochloride. The preparation method provided by the invention has the advantages of cheap and easily available initial raw materials, simple process, no high-temperature and high-pressure hydrogenation step, low cost, high purity and high yield, and is suitable for industrialproduction.
Selective Hydrogenation of Nitriles to Primary Amines Catalyzed by a Polysilane/SiO2-Supported Palladium Catalyst under Continuous-Flow Conditions
Saito, Yuki,Ishitani, Haruro,Ueno, Masaharu,Kobayashi, Shū
, p. 211 - 215 (2017/04/21)
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.
Enhanced copper-mediated 18F-fluorination of aryl boronic esters provides eight radiotracers for PET applications
Preshlock, Sean,Calderwood, Samuel,Verhoog, Stefan,Tredwell, Matthew,Huiban, Mickael,Hienzsch, Antje,Gruber, Stefan,Wilson, Thomas C.,Taylor, Nicholas J.,Cailly, Thomas,Schedler, Michael,Collier, Thomas Lee,Passchier, Jan,Smits, René,Mollitor, Jan,Hoepping, Alexander,Mueller, Marco,Genicot, Christophe,Mercier, Jo?l,Gouverneur, Véronique
, p. 8361 - 8364 (2016/07/07)
[18F]FMTEB, [18F]FPEB, [18F]flumazenil, [18F]DAA1106, [18F]MFBG, [18F]FDOPA, [18F]FMT and [18F]FDA are prepared from the corresponding arylboronic esters and [18
