79898-17-2Relevant articles and documents
Efficient synthesis of (-)-clausenamide
He, Guantao,Lin, Hansen,Rao, Yu,Su, Jinlong,Yan, Yixiao,Zhu, Senmei
, (2021/06/17)
A new method for the synthesis of (-)-clausenamide was reported. (-)-clausenamide was obtained from the inexpensive material of trans-cinnamic acid within five steps with overall yields of 8.9% and ee 99.5%. Compared with the multi-step asymmetric synthes
The preparation of optically active epineoclausenamide and enantiomeric separation of its racemate
Yan, Yixiao,Zhu, Senmei,Luo, Xuna,Rao, Yu,Su, Jinlong,He, Guantao,Lin, Hansen
, p. 643 - 651 (2021/08/24)
We synthesized the optically active epineoclausenamide by utilizing chiral reagents, such as R-α-methylbenzylamine and S-α-methylbenzylamine, for the resolution of the intermediate (trans-3-phenyl-oxiranecarboxylic acid 12), followed by amide exchange, cy
Intermolecular Amine Transfer to Enantioenriched trans-3Phenylglycidates by an α/β-Aminomutase to Access Both anti-Phenylserine Isomers
Shee, Prakash K.,Yan, Honggao,Walker, Kevin D.
, p. 15071 - 15082 (2020/12/21)
β-Hydroxy-α-amino acids are noncanonical amino acids with two stereocenters and with useful applications in the pharmaceutical and agrochemical sectors. Here, a 5-methylidene-3,5-dihydro-4H-imidazol-4-one-dependent aminomutase from Taxus canadensis (TcPAM) was repurposed to transfer the amino group irreversibly from (2S)-styryl-α-alanine to exogenously supplied trans-3-phenylglycidate enantiomers, producing anti-phenylserines stereoselectively. TcPAM catalysis inverted the intrinsic regioselective chemistry from amination at Cβ to Cα of enantioenriched trans-3-phenylglycidates to make phenylserine predominantly (97%)phenylisoserine (~3% relative abundance). Gas chromatography?mass spectrometry analysis of the chiral auxiliary derivatives of the biocatalyzed products confirmed that the amine transfer was stereoselective for each glycidate enantiomer. TcPAM converted (2S,3R)-3-phenylglycidate to (2S)-anti-phenylserine predominantly (89%) and (2R,3S)-3-phenylglycidate to (2R)-anti-phenylserine (88%)their antipodes, with inversion of the configuration at Cα in each case. Both glycidate enantiomers formed a small amount (~10%) of syn-phenylserine by retaining the configuration at Cα. The minor syn-isomer likely came from a β-hydroxy oxiranone intermediate formed by intramolecular ring opening of the oxirane ring by the carboxylate before amine transfer. TcPAM had a slight preference toward (2S,3R)-3-phenylglycidate, which was turned(kcat = 0.3 min?1) 1.5 times faster than the (2R,3S)-glycidate (kcat = 0.2 min?1). The catalytic efficiencies (kcatapp/KMapp ≈ 20 M?1s?1) of TcPAM for the antipodes were similar. The kinetic data supported a two-substrate ping-pong mechanism for the amination of the phenylglycidates, with competitive inhibition at higher glycidate substrate concentrations.
An optical active wampi amide alkone and its derivatives
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Paragraph 0073; 0076-0078, (2019/05/16)
The invention discloses an optical active wampi amide alkone and its derivatives of the preparation method. The optical active wampi amide alkone preparation method comprises the following steps: S1. Racemic epoxy cinnamic acid synthesizing and; S2. (+) -
Regio- and stereoselective methods for the conversion of (2S,3R)-β-phenylglycidic acid esters to taxoids and other enantiopure (2R,3S)-phenylisoserine esters
Afon'Kin,Kostrikin,Shumeiko,Popov,Matveev,Matvienko,Zabudkin
, p. 2149 - 2162 (2013/10/01)
A novel efficient method was proposed for the synthesis of enantiopure precursors of taxane-containing cytostatics, i.e., methyl esters of (2R,3S)- and (2S,3R)-N-benzoylphenylisoserine and similar taxoid esters. The method is based on the regio- and stereoselective hydrobromolysis of the corresponding trans-β-phenyl glycidate enatiomers, consecutive reactions of O-acylcarbamoylation of the obtained 3-bromohydrins, intramolecular cyclization to 4-phenyloxazolidin-2-one-5-carboxylic acid derivatives, and oxazolidinone ring opening.
Lipase activity of Lecitase Ultra: characterization and applications in enantioselective reactions
Mishra, Mithilesh Kumar,Kumaraguru, Thenkrishnan,Sheelu, Gurrala,Fadnavis, Nitin W.
experimental part, p. 2854 - 2860 (2010/04/05)
The general properties of Lecitase Ultra, a phospholipase manufactured and marketed by Novozymes, Denmark, have been studied after purification by ultrafiltration. The enzyme has a molecular mass of 35 KD, pH-optimum of 8.5, and appears to possess a single active site which exhibits both the lipase and phospholipase activities that increase in the presence of Ca2+ and Mg2+ ions. The enzyme is inhibited by heavy metal ions and surfactants, and does not accept p-nitrophenyl acetate and glycerol triacetate. Substrates, such as glycerol tributyrate and p-nitrophenyl palmitate, esters of N-acetyl-α-amino acids and α-hydroxy acids are readily accepted. Amino acids with aliphatic residues, such as alanine, isoleucine, and methionine, are hydrolyzed with high enantioselectivity for the l-enantiomer (E >100), but amino acids with aromatic residues such as phenylalanine and phenylglycine, and esters of α-hydroxy acids are hydrolyzed with low enantioselectivity (E = 1-5). Immobilization of the enzyme in a gelatin matrix (gelozyme) leads to a marginal improvement in the enantioselectivity for these substrates. However, a dramatic improvement in enantioselectivity is observed for ethyl 2-hydroxy-4-oxo-4-phenylbutyrate (E value increases from 4.5 to 19.5 with S-selectivity). Similarly, glycidate esters, such as ethyl trans-(±)-3-phenyl glycidate and methyl trans-(±)-3-(4-methoxyphenyl) glycidate, are selectively hydrolyzed with a remarkable selectivity towards the (2S,3R)-enantiomer providing unreacted (2R,3S)-glycidate esters (ee >99%, conversion 52-55%) by the immobilized enzyme.
Improved enantioselectivity in the epoxidation of cinnamic acid derivatives with dioxiranes from keto bile acids
Bortolini, Olga,Fantin, Giancarlo,Fogagnolo, Marco,Forlani, Roberto,Maietti, Silvia,Pedrini, Paola
, p. 5802 - 5806 (2007/10/03)
The asymmetric epoxidation of substituted cinnamic acids has been obtained in the presence of different keto bile acid derivatives as optically active carbonyl inducers and Oxone as oxygen source. Predominant or almost exclusive formation of both enantiomeric epoxides is obtained (ee up to 95%) depending on the specific substitution at carbons C(7) and C(12) of the bile acid.
Catalytic asymmetric synthesis of epoxides from aldehydes using sulfur ylides with in situ generation of diazocompounds
Aggarwal, Varinder K.,Alonso, Emma,Hynd, George,Lydon, Kevin M.,Palmer, Matthew J.,Porcelloni, Marina,Studley, John R.
, p. 1430 - 1433 (2007/10/03)
A practical, general, and convergent to epoxides with control of the relative and absolute stereochemistry has been achieved by generating the reactive intermediate (the diazo compound) in situ from tosylhydrazone salts (see scheme, PTC = phase-transfer catalyst, Ts = toluene-4-sulfonyl). High yields (58-82%), high d.r. (88:12-98:2), and high ee values (87-94%) have been obtained using a new class of stable chiral sulfides at low catalyst loading (5 mol%) and [Rh2(OAc)4] (0.5 mol%).