529-32-8Relevant articles and documents
Aromatic compound hydrogenation and hydrodeoxygenation method and application thereof
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Paragraph 0094-0095; 0106-0113, (2021/05/29)
The invention belongs to the technical field of medicines, and discloses an aromatic compound hydrogenation and hydrodeoxygenation method under mild conditions and application of the method in hydrogenation and hydrodeoxygenation reactions of the aromatic compounds and related mixtures. Specifically, the method comprises the following steps: contacting the aromatic compound or a mixture containing the aromatic compound with a catalyst and hydrogen with proper pressure in a solvent under a proper temperature condition, and reacting the hydrogen, the solvent and the aromatic compound under the action of the catalyst to obtain a corresponding hydrogenation product or/and a hydrodeoxygenation product without an oxygen-containing substituent group. The invention also discloses specific implementation conditions of the method and an aromatic compound structure type applicable to the method. The hydrogenation and hydrodeoxygenation reaction method used in the invention has the advantages of mild reaction conditions, high hydrodeoxygenation efficiency, wide substrate applicability, convenient post-treatment, and good laboratory and industrial application prospects.
Insights into the Substrate Promiscuity of Novel Hydroxysteroid Dehydrogenases
Bertuletti, Susanna,Ferrandi, Erica Elisa,Marzorati, Stefano,Vanoni, Marta,Riva, Sergio,Monti, Daniela
, p. 2474 - 2485 (2020/05/06)
Hydroxysteroid dehydrogenases (HSDHs) are valuable biocatalysts for the regio- and stereoselective modification of steroids, bile acids and other steroid derivatives. In this work, we investigated the substrate promiscuity of this highly selective class of enzymes. In order to reach this goal, a preliminary search of HSDH homologues in in-house or public available (meta)genomes was carried out. Eight novel NAD(H)-dependent HSDHs, showing either 7α-, 7β-, or 12α-HSDH activity, and including, for the first time, enzymes from extremophilic microorganisms, were identified, recombinantly produced, and characterized. Among the novel HSDHs, four highly active (up to 92 U mg?1) NAD(H)-dependent 7β-HSDHs showing negligible similarity towards previously described 7β-HSDHs, were discovered. These enzymes, along with previously characterized HSDHs, were tested as biocatalysts for the stereoselective reduction of a panel of substrates including two α-ketoesters of pharmaceutical interest and selected ketones that partially resemble the structural features of steroids. All the reactions were coupled with a suitable cofactor regeneration system. Regarding the α-ketoesters, nearly all of the tested HSDHs showed a good activity toward the selected substrates, yielding the reduced α-hydroxyester with up to 99% conversions and enantiomeric excesses. On the other hand, only the 7β-HSDHs from Collinsella aerofaciens and Clostridium absonum showed appreciable activity toward more complex ketones, i. e., (±)-trans-1-decalone, but with interesting as well as different selectivity. (Figure presented.).
Chemoselective Oxidation of Equatorial Alcohols with N-Ligated λ3-Iodanes
Mikhael, Myriam,Adler, Sophia A.,Wengryniuk, Sarah E.
, p. 5889 - 5893 (2019/08/26)
The site-selective and chemoselective functionalization of alcohols in complex polyols remains a formidable synthetic challenge. Whereas significant advancements have been made in selective derivatization at the oxygen center, chemoselective oxidation to the corresponding carbonyls is less developed. In cyclic systems, whereas the selective oxidation of axial alcohols is well known, a complementary equatorial selective process has not yet been reported. Herein we report the utility of nitrogen-ligated (bis)cationic λ3-iodanes (N-HVIs) for alcohol oxidation and their unprecedented levels of selectivity for the oxidation of equatorial over axial alcohols. The conditions are mild, and the simple pyridine-ligated reagent (Py-HVI) is readily synthesized from commercial PhI(OAc)2 and can be either isolated or generated in situ. Conformational selectivity is demonstrated in both flexible 1,2-substituted cyclohexanols and rigid polyol scaffolds, providing chemists with a novel tool for chemoselective oxidation.
Regioselective and Chemoselective Reduction of Naphthols Using Hydrosilane in Methanol: Synthesis of the 5,6,7,8-Tetrahydronaphthol Core
He, Yuan,Tang, Jinghua,Luo, Meiming,Zeng, Xiaoming
supporting information, p. 4159 - 4163 (2018/07/29)
A regioselective and chemoselective method for catalytic synthesis of biologically interesting 5,6,7,8-tetrahydronaphthols by reduction of naphthols was described. The side aromatic hydrocarbons in naphthols were site-selectively reduced, using hydrosilanes in methanol, allowing for retaining functional phenol scaffolds intact. It presents a rare example of using low-cost and air-stable hydrosilane for catalytic reduction of unactivated aromatic hydrocarbons under mild conditions. This reaction is scalable and proceeds in high selectivity without the formation of 1,2,3,4-tetrahydronaphthol byproducts with toleration of sensitive functionalities such as bromide, chloride, fluoride, ketone, ester, and amide.
Microwave-assisted isomerizations of epoxides to allylic alcohols
Consiglio, Gabriella Barozzino,Mordini, Alessandro
, p. 447 - 454 (2018/05/22)
The present work reports a study on the isomerization reactions of several alkyl epoxides to the corresponding allylic alcohols or bicyclic alcohols under microwave irradiation. The reaction occurred in the presence of lithium diisopropylamide as a base and different experimental conditions in terms of solvent, amount of the base, times and temperatures. The traditional heating with an oil-bath and the use of alternative organometallic bases, as the Lochmann-Schlosser bases, have been furthermore compared with the microwave heating. The results obtained show that the use of microwave irradiations on promoting the isomerization of epoxides gives access to a series of synthetically useful products, among which allylic alcohols and bicyclic alcohols, depending on the starting substrate.
Selective Catalytic Hydrogenation of Arenols by a Well-Defined Complex of Ruthenium and Phosphorus-Nitrogen PN3-Pincer Ligand Containing a Phenanthroline Backbone
Li, Huaifeng,Wang, Yuan,Lai, Zhiping,Huang, Kuo-Wei
, p. 4446 - 4450 (2017/07/24)
Selective catalytic hydrogenation of aromatic compounds is extremely challenging using transition-metal catalysts. Hydrogenation of arenols to substituted tetrahydronaphthols or cyclohexanols has been reported only with heterogeneous catalysts. Herein, we demonstrate the selective hydrogenation of arenols to the corresponding tetrahydronaphthols or cyclohexanols catalyzed by a phenanthroline-based PN3-ruthenium pincer catalyst.
A stable and practical nickel catalyst for the hydrogenolysis of C-O bonds
Cui, Xinjiang,Yuan, Hangkong,Junge, Kathrin,Topf, Christoph,Beller, Matthias,Shi, Feng
, p. 305 - 310 (2017/01/24)
The selective hydrogenolysis of C-O bonds constitutes a key step for the valorization of biomass including lignin fragments. Moreover, this defunctionalization process offers the possibility of producing interesting organic building blocks in a straightforward manner from oxygenated compounds. Herein, we demonstrate the reductive hydrogenolysis of a wide variety of ethers including diaryl, aryl-alkyl and aryl-benzyl derivatives catalyzed by a stable heterogeneous NiAlOx catalyst in the presence of a Lewis acid (LA). The special feature of this catalyst system is the formation of substituted cyclohexanols from the corresponding aryl ether.
Alkane oxidation catalysed by a self-folded multi-iron complex
Mettry, Magi,Moehlig, Melissa Padilla,Gill, Adam D.,Hooley, Richard J.
, p. 120 - 128 (2016/11/09)
A preorganised ligand scaffold is capable of coordinating multiple Fe(II) centres to form an electrophilic CH oxidation catalyst. This catalyst oxidises unactivated hydrocarbons including simple, linear alkanes under mild conditions in good yields with selectivity for the oxidation of secondary CH bonds. Control complexes containing a single metal centre are incapable of oxidising unstrained linear hydrocarbons, indicating that participation of multiple centres aids the CH oxidation of challenging substrates.
Upgrading of aromatic compounds in bio-oil over ultrathin graphene encapsulated Ru nanoparticles
Shi, Juanjuan,Zhao, Mengsi,Wang, Yingyu,Fu, Jie,Lu, Xiuyang,Hou, Zhaoyin
supporting information, p. 5842 - 5848 (2016/05/24)
Fast pyrolysis of biomass for bio-oil production is a direct route to renewable liquid fuels, but raw bio-oil must be upgraded in order to remove easily polymerized compounds (such as phenols and furfurals). Herein, a synthesis strategy for graphene encapsulated Ru nanoparticles (NPs) on carbon sheets (denoted as Ru@G-CS) and their excellent performance for the upgrading of raw bio-oil were reported. Ru@G-CS composites were prepared via the direct pyrolysis of mixed glucose, melamine and RuCl3 at varied temperatures (500-800 °C). Characterization indicated that very fine Ru NPs (2.5 ± 1.0 nm) that were encapsulated within 1-2 layered N-doped graphene were fabricated on N-doped carbon sheets (CS) in Ru@G-CS-700 (pyrolysis at 700 °C). And the Ru@G-CS-700 composite was highly active and stable for hydrogenation of unstable components in bio-oil (31 samples including phenols, furfurals and aromatics) even in aqueous media under mild conditions. This work provides a new protocol to the utilization of biomass, especially for the upgrading of bio-oil.
The Stereoselective Reductions of Ketones to the Most Thermodynamically Stable Alcohols Using Lithium and Hydrated Salts of Common Transition Metals
Kennedy, Nicole,Cohen, Theodore
, p. 8134 - 8141 (2015/09/02)
A simple method is presented for the highly stereoselective reductions of ketones to the most thermodynamically stable alcohols. In this procedure, the ketone is treated with lithium dispersion and either FeCl2·4H2O or CuCl2·2H2O in THF at room temperature. This protocol is applied to a large number and variety of ketones and is both more convenient and efficient than those commonly reported for the diastereoselective reduction of five- and six-membered cyclic ketones.
