23434-92-6Relevant articles and documents
Systematic methodology for the development of biocatalytic hydrogen-borrowing cascades: Application to the synthesis of chiral α-substituted carboxylic acids from α-substituted α,β-unsaturated aldehydes
Knaus, Tanja,Mutti, Francesco G.,Humphreys, Luke D.,Turner, Nicholas J.,Scrutton, Nigel S.
supporting information, p. 223 - 233 (2015/02/19)
Ene-reductases (ERs) are flavin dependent enzymes that catalyze the asymmetric reduction of activated carbon-carbon double bonds. In particular, α,β-unsaturated carbonyl compounds (e.g. enals and enones) as well as nitroalkenes are rapidly reduced. Conversely, α,β-unsaturated esters are poorly accepted substrates whereas free carboxylic acids are not converted at all. The only exceptions are α,β-unsaturated diacids, diesters as well as esters bearing an electron-withdrawing group in α- or β-position. Here, we present an alternative approach that has a general applicability for directly obtaining diverse chiral α-substituted carboxylic acids. This approach combines two enzyme classes, namely ERs and aldehyde dehydrogenases (Ald-DHs), in a concurrent reductive-oxidative biocatalytic cascade. This strategy has several advantages as the starting material is an α-substituted α,β-unsaturated aldehyde, a class of compounds extremely reactive for the reduction of the alkene moiety. Furthermore no external hydride source from a sacrificial substrate (e.g. glucose, formate) is required since the hydride for the first reductive step is liberated in the second oxidative step. Such a process is defined as a hydrogen-borrowing cascade. This methodology has wide applicability as it was successfully applied to the synthesis of chiral substituted hydrocinnamic acids, aliphatic acids, heterocycles and even acetylated amino acids with elevated yield, chemo- and stereo-selectivity. A systematic methodology for optimizing the hydrogen-borrowing two-enzyme synthesis of α-chiral substituted carboxylic acids was developed. This systematic methodology has general applicability for the development of diverse hydrogen-borrowing processes that possess the highest atom efficiency and the lowest environmental impact. This journal is
Asymmetric synthesis of unnatural amino acids and tamsulosin chiral intermediate
Arava, Veera Reddy,Amasa, Srinivasulu Reddy,Goud Bhatthula, Bharat Kumar,Kompella, Laxmi Srinivas,Matta, Venkata Prasad,Subha
, p. 2892 - 2897 (2013/09/02)
An efficient and enantioselective hydrogenation of N-acetylamino phenyl acrylic acids was successfully developed by using ruthenium catalyst. This methodology is important in the field of pharmaceuticals and provides a new process for the preparation of unnatural amino acids and tamsulosin chiral intermediate.
Chemoenzymatic synthesis of a mixed phosphine-phosphine oxide catalyst and its application to asymmetric allylation of aldehydes and hydrogenation of alkenes
Boyd, Derek R.,Bell, Mark,Dunne, Katherine S.,Kelly, Brian,Stevenson, Paul J.,Malone, John F.,Allen, Christopher C. R.
experimental part, p. 1388 - 1395 (2012/03/27)
The chemoenzymatic synthesis of a Lewis basic phosphine-phosphine oxide organocatalyst from a cis-dihydrodiol metabolite of bromobenzene proceeds via a palladium-catalysed carbon-phosphorus bond coupling and a novel room temperature Arbuzov [2,3]-sigmatropic rearrangement of an allylic diphenylphosphinite. Allylation of aromatic aldehydes were catalysed by the Lewis basic organocatalyst giving homoallylic alcohols in up to 57% ee. This compound also functioned as a ligand for rhodium-catalysed asymmetric hydrogenation of acetamidoacrylate giving reduction products with ee values of up to 84%.
Synthesis and application of peripherally alkyl-functionalized dendritic pyrphos ligands: Homogeneous-supported catalysts for enantioselective hydrogenation
Yi, Bing,He, Hua-Ping,Fan, Qing-Hua
experimental part, p. 82 - 85 (2010/04/25)
A new series of dendritic ligands with a chiral diphosphine located at the focal point have been synthesized through coupling of (R,R)-3,4-bis(biphenylphosphino)pyrrolidine (pyrphos) with peripherally alkyl-functionalized benzoic acid dendrons. These ligands were employed in the Rh-catalyzed asymmetric hydrogenation of prochiral dehydroamino acids, exhibiting excellent catalytic activities and enantioselectivities. The second-generation dendritic catalyst could be recovered by simple liquid-liquid biphasic separation and reused four times without serious loss of its activity and selectivity.
Resolution of N-protected amino acid esters using whole cells of Candida parapsilosis ATCC 7330
Stella, Selvaraj,Chadha, Anju
experimental part, p. 457 - 460 (2010/06/21)
Whole cells of Candida parapsilosis ATCC 7330 were used for the resolution of N-acetyl amino acid esters. Excellent enantioselectivities (E = 40 to >500) were achieved for the resolution of N-protected protein and non-protein amino acid esters giving good yields (28-50%) and high enantiomeric excesses (up to >99%) for both enantiomers.
Novel atropisomeric bisphosphine ligands with a bridge across the 5,5′-position of the biphenyl for asymmetric catalysis
Wei, Hao,Zhang, Yong Jian,Wang, Feijun,Zhang, Wanbin
, p. 482 - 488 (2008/09/19)
A new type of atropisomeric bisphosphine ligand 2 with a bridge across the 5,5′-position of the biphenyl has been developed. The axial chirality of this type of ligands can be retained by macrocyclic ring strain produced from 5,5′-linkage of the biphenyl
Melanocortin receptor ligands
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Page/Page column 56, (2010/11/08)
Disclosed are MC-4 and/or MC-3 receptor ligands, the ligands having a structure according to Formula (I): wherein R2, R4, R4′, R5, R6, R6′, R7, R8, R8′, R9, R9′, R10, Ar, Z1, Z2, Z3, X, B, D, p, q, r and s are as described in the specification and claims, and optical isomers, diastereomers or enantiomers thereof; pharmaceutically-acceptable salts, hydrates, and biohydrolyzable esters, amides or imides thereof. Also disclosed are pharmaceutical compositions comprising the ligands of Formula (I), as well as methods of treating diseases mediate by the MC-4/MC-3 receptors, as described in the Detailed Descriptions section of the specification.
Synthesis of a novel spiro bisphosphinite ligand and its application in Rh-catalyzed asymmetric hydrogenation
Guo, Zhenqiu,Guan, Xiaoyu,Chen, Zhiyong
, p. 468 - 473 (2007/10/03)
A novel, chiral bisphosphinite ligand (R)-SpiroBIP has been synthesized. The rhodium complex of the ligand was found to be highly enantioselective in the asymmetric hydrogenation of α-dehydroamino acid derivatives.
Rh-catalyzed asymmetric hydrogenation of prochiral olefins with a dynamic library of chiral TROPOS phosphorus ligands
Monti, Chiara,Gennari, Cesare,Piarulli, Umberto,De Vries, Johannes G.,De Vries, Andre H. M.,Lefort, Laurent
, p. 6701 - 6717 (2007/10/03)
A library of 19 chiral tropos phosphorus ligands, based on a flexible (tropos) biphenol unit and a chiral P-bound alcohol (11 phosphites) or secondary amine (8 phosphoramidites), was synthesized. These ligands were screened, individually and as a combination of two, in the rhodium-catalyzed asymmetric hydrogenation of dehydro-α-amino acids, dehydro-β-amino acids, enamides and dimethyl itaconate. ee values up to 98% were obtained for the dehydro-α-amino acids, by using the best combination of ligands, a phosphite [4-P(O)2O] and a phosphora midite [13-P(O)2N]. Kinetic studies of the reactions with the single ligands and with the combination of phosphite [4-P(O)2O] and phosphoramidite [13-P(O) 2N] have shown that the phosphite, despite being less enantioselective, promotes the hydrogenation of methyl 2-acetamidoacrylate and methyl 2-acetamidocinnamate faster than the mixture of the same phosphite with the phosphoramidite, while the phosphoramidite alone is much less active. In this way, the reaction was optimized by lowering the phosphite/phosphoramidite ratio (the best ratio is 0.25 equiv phosphite/1.75 equiv phosphoramidite) with a resulting improvement of the product enantiomeric excess. A simple mathematical model for a better understanding of the variation of the enantiomeric excess with the phosphite/ phosphoramidite ratio is also presented.
H8-MonoPhos and its application in catalytic enantioselective hydrogenation of α-dehydroamino acids
Zeng, Qingle,Liu, Hui,Mi, Aiqiao,Jiang, Yaozhong,Li, Xingshu,Choi, Michael C.K,Chan, Albert S.C
, p. 8799 - 8803 (2007/10/03)
H8-MonoPhos, a new stable and readily soluble monodentate phosphoramidite ligand, has been facilely prepared from H8-BINOL. The ligand achieved up to 99.9% ee and 96.7% ee in hydrogenation of dehydroalanine and dehydrohomophenylalani
