32231-50-8Relevant academic research and scientific papers
Sinapyl alcohol derivatives from the lipo-soluble part of Dichrocephala benthamii C. B. Clarke
Tian, Xinhui,Ding, Gang,Peng, Chaozhong,Hu, Yanbao,Li, Li,Chen, Hong,Zou, Zhongmei
, p. 1720 - 1727 (2013)
Four new sinapyl alcohol derivatives dichrocephols A-D (compounds 1-4) were isolated from the lipo-soluble part of the whole herb of Dichrocephala benthamii C. B. Clarke, together with the known compound syringenin isovalerate (5). Their structures were elucidated on the basis of spectroscopic analysis. Their absolute configurations were established by the method of alkaline hydrohysis. Compounds 1-3 showed moderate cytotoxity against HeLa cells, with IC50 values of 14.8 μM, 51.6 μM and 81.6 μM, respectively. This is the first time that sinapyl alcohol derivatives were isolated from the genus Dichrocephala.
Asymmetric hydrogenation of an α-unsaturated carboxylic acid catalyzed by intact chiral transition metal carbonyl clusters-diastereomeric control of enantioselectivity
Abdel-Magied, Ahmed F.,Doverbratt, Isa,Haukka, Matti,Nordlander, Ebbe,Raha, Arun K.,Rahaman, Ahibur,Richmond, Michael G.,Singh, Amrendra K.,Theibich, Yusuf
, p. 4244 - 4256 (2020/04/17)
Twenty clusters of the general formula [(μ-H)2Ru3(μ3-S)(CO)7(μ-P-P?)] (P-P? = chiral diphosphine of the ferrocene-based Walphos or Josiphos families) have been synthesised and characterised. The clusters have be
Electrocatalytic asymmetric hydrogenation of α,β-unsaturated acids in a PEM reactor with cinchona-modified palladium catalysts
Atobe, Mahito,Fukazawa, Atsushi,Hashimoto, Yasushi,Sato, Yasushi,Tanaka, Kenta
, (2020/04/28)
We have developed an electrocatalytic asymmetric hydrogenation reaction using a proton-exchange membrane (PEM) reactor that employs a polymer electrolyte fuel cell and industrial electrolysis technologies. Reasonable enantioselectivities and excellent current efficiencies were obtained in the asymmetric hydrogenation of α-phenylcinnamic acid under mild conditions without adding a supporting electrolyte. The current density was crucial to achieving the improved results observed.
Effect of particle restructuring during reduction processes over polydopamine-supported Pd nanoparticles
Gazdag, Tamás,Baróthi, ádám,Juhász, Koppány Levente,Kunfi, Attila,Németh, Péter,Sápi, András,Kukovecz, ákos,Kónya, Zoltán,Szori, Kornél,London, Gábor
, p. 484 - 491 (2018/12/13)
The effect of catalyst restructuring on the polydopamine-supported Pd catalyzed transfer hydrogenation of ethyl 4-nitrobenzoate and the catalytic hydrogenation of (E)-2-methyl-2-butenoic acid is reported. Transmission electron microscopy investigation of different catalyst pre-treatment and reaction conditions revealed high catalytic activity in both reactions unless drastic aggregation of the active metal occurred. In the transfer hydrogenation reaction aggregation was primarily dependent on the H-source used, while in the catalytic hydrogenation additives in combination with the reductive environment led to extensive Pd aggregation and thus decreased catalytic activity. The enantioselective hydrogenation of (E)-2-methyl-2-butenoic acid showed increased enantioselectivity and decreased conversion with increased particle size.
Hydrogen/deuterium isotopic labeling study of enantioselective hydrogenation of (E)-2-Methyl-2-butenoic acid over a cinchonidine-modified Pd/C catalyst
Sugimura, Takashi,Tomatsuri, Satoshi,Fujita, Morifumi,Okamoto, Yasuaki
, p. 1737 - 1742 (2019/10/01)
In the enantioselecitve hydrogenation of (E)-2-methyl-2butenoic acid (1) over a cinchonidine-modified Pd/C catalyst, the addition of hydrogen preferentially proceeds from the Re-Si enantioface of the C=C double bond of 1 to yield (S)-2methylbutanoic acid ((S)-3). Double bond migration of 1 takes place under the reaction conditions and is followed by immediate hydrogenation to yield 3 in a poor enantiomeric purity. Deuterium labeling experiments at 0.1 MPa and 1.9 MPa of D2verified the previous assumption of competitive double bond migration. The combination of isotopic labeling experiments and chiral analysis revealed that the double bond migration of 1 proceeds with the same enantiofacial differentiation as the hydrogenation of 1. Thus, interaction of 1 with cinchonidine adsorbed on the Pd surface may control the configuration of the double bond migration and the hydrogenation.
Chemoenzymatic Cascade Synthesis of Optically Pure Alkanoic Acids by Using Engineered Arylmalonate Decarboxylase Variants
Enoki, Junichi,Mügge, Carolin,Tischler, Dirk,Miyamoto, Kenji,Kourist, Robert
, p. 5071 - 5076 (2019/03/17)
Arylmalonate decarboxylase (AMDase) catalyzes the cofactor-free asymmetric decarboxylation of prochiral arylmalonic acids and produces the corresponding monoacids with rigorous R selectivity. Alteration of catalytic cysteine residues and of the hydrophobic environment in the active site by protein engineering has previously resulted in the generation of variants with opposite enantioselectivity and improved catalytic performance. The substrate spectrum of AMDase allows it to catalyze the asymmetric decarboxylation of small methylvinylmalonic acid derivatives, implying the possibility to produce short-chain 2-methylalkanoic acids with high optical purity after reduction of the nonactivated C=C double bond. Use of diimide as the reductant proved to be a simple strategy to avoid racemization of the stereocenter during reduction. The developed chemoenzymatic sequential cascade with use of R- and S-selective AMDase variants produced optically pure short-chain 2-methylalkanoic acids in moderate to full conversion and gave both enantiomers in excellent enantiopurity (up to 83 % isolated yield and 98 % ee).
Convenient enzymatic resolution of (R,S)-2-methylbutyric acid catalyzed by immobilized lipases
Mittersteiner, Mateus,Linshalm, Bruna Luiza,Vieira, Ana Paula Furlan,Brondani, Patrícia Bulegon,Scharf, Dilamara Riva,de Jesus, Paulo Cesar
, p. 106 - 111 (2017/11/14)
The application of several immobilized lipases has been explored in the enantioselective esterification of (R,S)-2-methylbutyric acid, an insect pheromone precursor. With the use of Candida antarctica B, using hexane as solvent, (R)-pentyl 2-methylbutyrat
Pentasaccharide resin glycosides with multidrug resistance reversal activities from the seeds of: Pharbitis nil
Li, Jun,Wang, Wen-Qiong,Tang, Shuai,Song, Wei-Bin,Huang, Min,Xuan, Li-Jiang
supporting information, p. 52001 - 52009 (2017/11/22)
Resin glycosides are novel P-glycoprotein inhibitors. In order to evaluate their multidrug resistance (MDR) reversal activities, we isolated seven new resin glycosides, pharbitins A-G (1-7) from the seeds of Pharbitis nil. Their chemical structures were determined by extensive application of high resolution 2D NMR techniques, HRESIMS and chemical methods. Compounds 1-4 and 6 were evaluated for their MDR reversal activities in KB/VCR, A549/T and K562/ADR cells. Among them, compound 2 showed moderate MDR reversal activity in KB/VCR cells, and increased the cytotoxicity of vincristine by 2.2-fold when incorporated at 25 μM. A structure-activity relationship study revealed that substituting Rha′′ C-3 with a trans-cinnamoyl group improves the MDR reversal activity. Also, an intracellular Rh123 accumulation assay demonstrated that compound 2 could inhibit the function of P-gp.
Hydrogenation of (E)-2-methyl-2-butenoic acid over cinchona-modified Pd catalyst in the presence of achiral amines: Solvent and modifier effect
Makra, Zsolt,Szollosi, Gy?rgy
, p. 113 - 117 (2014/01/17)
The effect of the solvent, modifier structure and concentration on the enantioselective hydrogenation of (E)-2-methyl-2-butenoic acid over Pd/Al 2O3 modified by cinchona alkaloids was influenced by the addition of achiral amines to t
Diastereomeric control of enantioselectivity: Evidence for metal cluster catalysis
Abdel-Magied, Ahmed F.,Singh, Amrendra K.,Haukka, Matti,Richmond, Michael G.,Nordlander, Ebbe
supporting information, p. 7705 - 7708 (2014/07/08)
Enantioselective hydrogenation of tiglic acid effected by diastereomers of the general formula [(μ-H)2Ru3(μ3-S)(CO) 7(μ-P-P*)] (P-P* = chiral Walphos diphosphine ligand) strongly supports catalysis by intact Ru
