- Convenient synthesis of cobalt nanoparticles for the hydrogenation of quinolines in water
-
Easily accessible cobalt nanoparticles are prepared by hydrolysis of NaBH4 in the presence of inexpensive Co(ii) salts. The resulting material is an efficient catalyst for the hydrogenation of quinoline derivatives in water. The activity and chemoselectivity of this catalyst are comparable to other cobalt-based heterogeneous catalysts.
- Beller, Matthias,Dorcet, Vincent,Fischmeister, Cedric,Hervochon, Julien,Junge, Kathrin
-
p. 4820 - 4826
(2020/08/14)
-
- Synthesis method of hydroquinine(anthraquinone-1,4-diyl)diether
-
The invention discloses a synthetic method of hydroquinine(anthraquinone-1,4-diyl)diether (CAS: 176097-24-8) as shown in a formula (f), which comprises the following steps: by using phthalic anhydrideas a raw material, carrying out Friedel-Crafts reaction and dehydration cyclization reaction to obtain a compound c; and carrying out a coupling reaction on the compound c and dihydroquinine to obtain the hydroquinine(anthraquinone-1,4-diyl)diether. The synthesis method has the advantages of short reaction route, high yield, simplicity and convenience in operation, low cost, suitability for industrial production and the like.
- -
-
Paragraph 0072; 0073; 0074; 0075; 0076
(2020/10/21)
-
- A Cinchona Alkaloid Antibiotic That Appears to Target ATP Synthase in Streptococcus pneumoniae
-
Optochin, a cinchona alkaloid derivative discovered over 100 years ago, possesses highly selective antibacterial activity toward Streptococcus pneumoniae. Pneumococcal disease remains the leading source of bacterial pneumonia and meningitis worldwide. The structure-activity relationships of optochin were examined through modification to both the quinoline and quinuclidine subunits, which led to the identification of analogue 48 with substantially improved activity. Resistance and molecular modeling studies indicate that 48 likely binds to the c-ring of ATP synthase near the conserved glutamate 52 ion-binding site, while mechanistic studies demonstrated that 48 causes cytoplasmic acidification. Initial pharmacokinetic and drug metabolism analyses of optochin and 48 revealed limitations of these quinine analogues, which were rapidly cleared, resulting in poor in vivo exposure through hydroxylation pendants to the quinuclidine and O-dealkylation of the quinoline. Collectively, the results provide a foundation to advance 48 and highlight ATP synthase as a promising target for antibiotic development.
- Wang, Xu,Zeng, Yuna,Sheng, Li,Larson, Peter,Liu, Xue,Zou, Xiaowen,Wang, Shufang,Guo, Kaijing,Ma, Chen,Zhang, Gang,Cui, Huaqing,Ferguson, David M.,Li, Yan,Zhang, Jingren,Aldrich, Courtney C.
-
p. 2305 - 2332
(2019/04/25)
-
- Catalytic Enantio- and Diastereoselective Mannich Addition of TosMIC to Ketimines
-
Chiral amines bearing a stereocenter in the α position are ubiquitous compounds with many applications in the pharmaceutical and agrochemical sectors, as well as in catalysis. Catalytic asymmetric Mannich additions represent a valuable method to access such compounds in enantioenriched form. This work reports the first enantio- and diastereoselective addition of commercially available p-toluenesulfonylmethyl isocyanide (TosMIC) to ketimines, affording 2-imidazolines bearing two contiguous stereocenters, one of which is fully-substituted, with high yields and excellent stereocontrol. The reaction, catalyzed by silver oxide and a dihydroquinine-derived N,P-ligand, is broad in scope, operationally simple, and scalable. Derivatization of the products provides enantioenriched vicinal diamines, precursors to NHC ligands and sp3-rich heterocyclic scaffolds. Computations are used to understand catalysis and rationalize stereoselectivity.
- Franchino, Allegra,Chapman, Jack,Funes-Ardoiz, Ignacio,Paton, Robert S.,Dixon, Darren J.
-
supporting information
p. 17660 - 17664
(2018/11/10)
-
- Expansion of the aromatic part of Cinchona alkaloids. Annulation of quinolines with phenoxazine motifs
-
An oxidative cross-coupling strategy for quinoline ring annulation in Cinchona alkaloids has been developed. Key-reaction optimization by changing oxidants and adjusting the nucleophilicity of the 2-aminophenols led to cupreine and cupreidine expanded with the phenoxazinone unit in 56–75% yield. The stereochemical integrity of the obtained alkaloid structures was confirmed by combined experimental and computed CD and NMR data. The conformational study revealed a fast equilibrium of the three conformers, differing in the orientation of the pyrido[a-3,2]phenoxazine moiety.
- W?sińska-Ka?wa, Ma?gorzata,Giurg, Miros?aw,Boratyński, Przemys?aw J.,Skar?ewski, Jacek
-
p. 308 - 315
(2017/12/08)
-
- Rapid “Mix-and-Stir” Preparation of Well-Defined Palladium on Carbon Catalysts for Efficient Practical Use
-
A facile direct deposition approach for the preparation of recyclable Pd/C catalysts simply by stirring a solution of tris(dibenzylideneacetone)dipalladium(0) with a suitable carbon material was evaluated. An extraordinarily rapid catalyst preparation procedure (0 centers onto the highly accessible surface area and the avoidance of ill-defined PdII/Pd0 states.
- Yakukhnov, Sergey A.,Pentsak, Evgeniy O.,Galkin, Konstantin I.,Mironenko, Roman M.,Drozdov, Vladimir A.,Likholobov, Vladimir A.,Ananikov, Valentine P.
-
p. 1869 - 1873
(2018/04/30)
-
- Stereoselective glycosylation of 2-nitrogalactals catalyzed by a bifunctional organocatalyst
-
The use of a bifunctional cinchona/thiourea organocatalyst for the direct and α-stereoselective glycosylation of 2-nitrogalactals is demonstrated for the first time. The conditions are mild, practical, and applicable to a wide range of glycoside acceptors with products being isolated in good to excellent yields. The method is exemplified in the synthesis of mucin type Core 6 and 7 glycopeptides.
- Medina, Sandra,Harper, Matthew J.,Balmond, Edward I.,Miranda, Silvia,Crisenza, Giacomo E. M.,Coe, Diane M.,McGarrigle, Eoghan M.,Galan, M. Carmen
-
supporting information
p. 4222 - 4225
(2016/09/09)
-
- Enhanced Reactivity of Aerobic Diimide Olefin Hydrogenation with Arylboronic Compounds: An Efficient One-Pot Reduction/Oxidation Protocol
-
A catalyst-free and efficient method for simultaneous olefin hydrogenation and oxidation of arylboronate esters to phenols with hydrazine hydrate and molecular oxygen is presented. The process is based on the utilization of a readily available Lewis acidic arylboron compound, which evades common problems associated with the catalyst-free aerobic hydrogenation of olefins with diimide. Using an operationally simple procedure, the protocol smoothly delivers phenol derivatives and various alkanes in excellent yields with remarkable functional group compatibility. The method allows the reaction to be scaled up to 1 g of the starting materials.
- Santra, Surojit,Guin, Joyram
-
supporting information
p. 7253 - 7257
(2015/11/25)
-
- Hydromethylation of Unactivated Olefins
-
A solution to the classic unsolved problem of olefin hydromethylation is presented. This highly chemoselective method can tolerate labile and reactive chemical functionalities and uses a simple set of reagents. An array of olefins, including mono-, di-, and trisubstituted olefins, are all smoothly hydromethylated. This mild protocol can be used to simplify the synthesis of a specific target or to directly "edit" complex natural products and other advanced materials. The method is also amenable to the simple installation of radioactive and stable labeled methyl groups.
- Dao, Hai T.,Li, Chao,Michaudel, Quentin,Maxwell, Brad D.,Baran, Phil S.
-
supporting information
p. 8046 - 8049
(2015/07/15)
-
- Synthesis of Quinuclidines by Intramolecular Silver-Catalysed Amine Additions to Alkynes
-
A new method has been developed for the synthesis of 2-alkylidenequinuclidines based on a silver triflate catalysed intramolecular hydroamination of 4-(prop-2-ynyl)piperidines. Monosubstituted piperidines reacted less efficiently than cis-disubstituted piperidines, and the reaction was selective for an alkyne moiety, even in the presence of a vinyl group at the 3-position. The hydroamination occurred readily with a terminal alkyne, as well as with an internal alkyne bearing an aliphatic or aromatic group at the terminal carbon atom. Using this silver-catalysed cyclization, a short procedure was developed for the relay synthesis of the cinchona alkaloids dihydroquinidine and dihydroquinine. We report the synthesis of (enantiomerically pure) 2-alkylidenequinuclidines by an intramolecular hydroamination reaction catalysed by silver triflate. After cyclization to the appropriate quinuclidines, the cinchona alkaloids dihydroquinidine and dihydroquinine were obtained in a two-step procedure.
- Breman, Arjen C.,Ruiz-Olalla, Andrea,Van Maarseveen, Jan H.,Ingemann, Steen,Hiemstra, Henk
-
p. 7413 - 7425
(2016/02/20)
-
- Organocatalytic asymmetric direct vinylogous Michael addition of α,β-unsaturated γ-butyrolactam to nitroolefins
-
The first organocatalytic enantioselective direct vinylogous Michael reaction of α,β-unsaturated γ-butyrolactam to nitroolefins is developed using cinchona alkaloids as the catalysts. Both product enantiomers are accessible with moderate to good enantioselectivity.
- Choudhury, Abhijnan Ray,Mukherjee, Santanu
-
supporting information; experimental part
p. 7313 - 7320
(2012/10/07)
-
- Simple enantiospecific synthesis of sulfides of Cinchona alkaloids
-
The native and epi-Cinchona alkaloids were reacted with (ArS) 2/Bu3P in toluene at 65 °C to give the corresponding arylsulfanyl derivatives (15 examples, 31-75%) with complete inversion of configuration at 9-C stereogenic centers. Similar products were also obtained in the enantiospecific nucleophilic substitution of the 9-mesylates of alkaloids with sodium thiolates (4 examples, 73-84%) and no cinchona rearrangement was observed. The chiral thioethers obtained were preliminarily tested as N(sp 3), S-donating chiral ligands in the Pd-catalyzed allylic alkylation of dimethyl malonate with rac-1,3-diphenylprop-2-enyl acetate and gave the product with up to 78% ee. Georg Thieme Verlag Stuttgart.
- Zielinska-Blajet, Mariola,Kucharska, Malgorzata,Skarzewski, Jacek
-
p. 1176 - 1182
(2007/10/03)
-
- Heterogeneous enantioselective hydrogenation of ethyl pyruvate catalyzed by cinchona-modified Pt catalysts: Effect of modifier structure
-
The effect of the structure of chiral modifiers derived from natural cinchona alkaloids on the enantioselectivity and rate of the Pt/Al2O3-catalyzed hydrogenation of ethyl pyruvate was investigated. The influence of the following structural elements was studied: The cinchonidine versus the cinchonine backbone; effect of the nature and the size of substituents attached to C9; effect of partial hydrogenation of the quinoline ring; effects of changes of the substituent at the quinuclidine moiety. The strongest effects on ee and somewhat less on rate were observed for changes in the O-C9-C8-N part of the cinchona alkaloid and for partial or total hydrogenation of the quinoline rings. The nature of the substituents in the quinuclidine part had a comparably minor influence. The solvent was found to have a significant effect on enantioselectivity and rate. In acetic acid, the best results were obtained with O-methyl-10,11-diydrocinchonidine (ee's up to 93%), whereas dihydrocinchonidine was the most effective modifier in toluene. In agreement with a basic model proposed by Pfaltz, it was concluded that the minimal-requirements for an efficient modifier for the hydrogenation of α-keto esters is the presence of a basic nitrogen center close to one or more stereogenic centers and connected to an aromatic system. The results are in qualitative agreement with mechanistic models based on hydrogen-bonding interactions between an adsorbed modifier molecule and adsorbed ethyl pyruvate or its half-hydrogenated intermediate.
- Blaser,Jalett,Lottenbach,Studer
-
p. 12675 - 12682
(2007/10/03)
-
- Process for piperidine intermediates for quinine, quinidine and analogs thereof
-
Quinine, quinidine and analogs thereof, are prepared by reacting a 4-quinolyllithium compound with a 4,5-erythro-5-ethyl(or vinyl)-quinuclidine-2ε -carboxaldehyde or the corresponding quinuclidine-2-carboxylic acid alkyl ester. Also described, inter alia, is the preparation of a 4,5-erythro-5-ethyl(or vinyl)-quinuclidine-2ε-carboxaldehyde, and a 4,5-crythro-5-ethyl(or vinyl)-quinuclidine-2ε -carboxylic acid and esters thereof. The end products are useful as antimalarial and antiarrhythmic agents.
- -
-
-
