87586-97-8Relevant academic research and scientific papers
Chiral bisphosphine ligands based on quinoline oligoamide foldamers: application in asymmetric hydrogenation
Zheng, Lu,Zheng, Dan,Wang, Yanru,Yu, Chengyuan,Zhang, Kun,Jiang, Hua
, p. 9573 - 9577 (2019/11/20)
A series of chiral bisphosphine ligands were designed and synthesized based on single-handed quinoline oligoamide foldamers. The bisphosphine ligands can coordinate with Rh(cod)2BF4 in a 1 : 1 stoichiometry and the resulted chiral Rh(i) catalysts were applied in the asymmetric hydrogenation of α-dehydroamino acid esters, in which excellent conversions and promising levels of enantioselectivity were achieved.
Site- and Stereoselective Chemical Editing of Thiostrepton by Rh-Catalyzed Conjugate Arylation: New Analogues and Collateral Enantioselective Synthesis of Amino Acids
Key, Hanna M.,Miller, Scott J.
supporting information, p. 15460 - 15466 (2017/11/06)
The synthesis of complex, biologically active molecules by catalyst-controlled, selective functionalization of complex molecules is an emerging capability. We describe the application of Rh-catalyzed conjugate arylation to the modification of thiostrepton, a complex molecule with potent antibacterial properties for which few analogues are known. By this approach, we achieve the site- and stereoselective functionalization of one subterminal dehydroalanine residue (Dha16) present in thiostrepton. The broad scope of this method enabled the preparation and isolation of 24 new analogues of thiostrepton, the biological testing of which revealed that the antimicrobial activity of thiostrepton tolerates the alteration of Dha16 to a range of amino acids. Further analysis of this Rh-catalyzed process revealed that use of sodium or potassium salts was crucial for achieving high stereoselectivity. The catalyst system was studied further by application to the synthesis of amino esters and amides from dehydroalanine monomers, a process which was found to occur with up to 93:7 er under conditions milder than those previously reported for analogous reactions. Furthermore, the addition of the same sodium and potassium salts as applied in the case of thiostrepton leads to a nearly full reversal of the enantioselectivity of the reaction. As such, this study of site-selective catalysis in a complex molecular setting also delivered synergistic insights in the arena of enantioselective catalysis. In addition, these studies greatly expand the number of known thiostrepton analogues obtained by any method and reveal a high level of functional group tolerance for metal-catalyzed, site-selective modifications of highly complex natural products.
Chiral Rh phosphine-phosphite catalysts immobilized on ionic resins for the enantioselective hydrogenation of olefins in water
Kleman,Barbaro,Pizzano
supporting information, p. 3826 - 3836 (2015/07/15)
The asymmetric hydrogenation of prochiral enamides with Rh complexes bearing chiral phosphine-phosphite ligands (P-OP) supported on sulphonated polystyrene resins has been studied. The complexes have been supported by simple treatment of preformed [Rh(dio
The Heck-Matsuda arylation of 2-hetero-substituted acrylates
De Azambuja, Francisco,Correia, Carlos Roque Duarte
supporting information; experimental part, p. 42 - 45 (2011/02/25)
The Heck-Matsuda arylation of 2-aza and 2-oxo-substituted acrylates is described. Several reaction conditions were evaluated including the influence of solvents, temperature, catalysts, and stoichiometry. While the oxygenated system was successfully aryla
Synthesis of unnatural amino acid derivatives via palladium-catalyzed 1,4-addition of boronic acids
Ray, Devalina,Nyong, Abijah M.,Natarajan, Amarnath
experimental part, p. 2655 - 2656 (2010/06/19)
Aryl and alkenyl amino acid derivatives were synthesized by a palladium-catalyzed 1,4-addition of the corresponding boronic acids to 2-acetamidoacrylate.
Substituted cyclic carbonyls and derivatives thereof useful as retroviral protease inhibitors
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, (2008/06/13)
This invention relates to substituted cyclic carbonyls and derivatives thereof useful as retroviral protease inhibitors, to pharmaceutical compositions comprising such compounds, and to methods of using these compounds for treating viral infection. A representative compound of the invention is the compound of formula: STR1 wherein R22 and R23 are allyl.
Synthesis of (S)-3,4-dihydroxyphenylalanine (L-DOPA) and unnatural α-amino acids via enzymatic resolution using alcalase
Tyagi, O D,Boll, P M,Parmar, V S,Taneja, Poonam,Singh, S K
, p. 851 - 854 (2007/10/02)
Enzymatic resolution has been used for the synthesis of L-DOPA with high optical purity.N-Acetyl-(R,S)-3,4-methylenedioxyphenylalanine methyl ester (2b) on enzymatic resolution by alcalase (Subtilisin Carlsberg) yields N-acetyl-(S)-3,4-methylenedioxyphenylalanine (3b) which upon acid treatment affords (S)-3,4-dihydroxyphenylalanine (L-DOPA) (4).Several optically active unnatural N-acetylated and N-benzoylated α-amino acids have been prepared by similar enzymatic resolution.
