1730-91-2Relevant articles and documents
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)
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
Conformational study of poly(N-propargylamides) having bulky pendant groups
Tabei, Junichi,Nomura, Ryoji,Masuda, Toshio
, p. 5405 - 5409 (2002)
N-Propargylamides having chiral centers at the α-carbon of the amide groups, 1-3, were polymerized with (nbd)Rh+[η6-C6H5B-(C 6H5)3] to afford polymers with moderate molecular weights (Mn = 6000-32 000) in good yield. The 1H NMR spectra demonstrated that the polymers have stereoregular structures (cis = 100%). The polymers were proven to take a helical conformation with an excess of one- handed screw sense in CHCl3, which was supported by their intense CD effects and large optical rotations. It was confirmed that the helical structure was stabilized not only by the steric repulsion but also by the intramolecular hydrogen bonds between the pendant groups. CD spectroscopic study showed that the helical structure is more stable than that of the polymers without a branch at the α-position, which allowed the polymers to exist in the helical state in various solvents. The electronic absorption, CD effects, and optical rotations of the polymers closely correlated to the extent of the hydrogen bonding between the pendant amide groups.
Palladium nanoparticle-graphene catalysts for asymmetric hydrogenation
Sz?ri, Korne?l,Puskás, Robert,Sz?ll?si, Gyo?rgy,Bertóti, Imre,Szépv?lgyi, János,Bartók, Mihály
, p. 539 - 546 (2013)
We report for the first time the application of palladium nanoparticle-graphene (Pd/Gn) catalysts in the asymmetric hydrogenation of aliphatic α,β-unsaturated carboxylic acids using cinchonidine as chiral modifier. Pd/Gns were prepared by deposition-preci
Toosendanin relatives, trypanocidal principles from Meliae Cortex
Mifundu, Michel N.,Murakami, Nobutoshi,Kawano, Tomikazu,Tamura, Satoru
, p. 702 - 709 (2020)
Africa Trypanosomiasis remains a serious health problem, but the approved drugs for this disease are so few that novel trypanocidal compounds are demanded. In search for trypanocidal principles from medicinal plants, we found MeOH extracts of Meliae Cortex with potent activity through the screening from about 300 kinds of methanolic extract. By bioassay-guided fractionation from this extract through the liquid–liquid partition and subsequent chromatographic technique using silica gel and ODS, finally we disclosed toosendanin (1) and its relatives as active principles. These active congeners showed not only potent trypanocidal activity but also little cytotoxicity to display the excellent selective index. Taking the isolated amount as well as trypanocidal activity into consideration, 1 was disclosed to be the responsible active principle in Meliae Cortex. Additionally, the derivatives of 1 were chemically prepared from 1 and bioactivity of them were also evaluated. Through the comparison with their trypanocidal activity among the isolated relatives and the synthesized derivatives of 1, the epoxide moiety was revealed to be essential for their potent trypanocidal activity. Furthermore, 3-O-acetyl group and 7-hydroxyl group were presumed to be important functional groups and introduction of methylpropionyl group into hemiacetal hydroxy moiety was clarified to enhance their typanocidal activity.
Synthesis and evaluation of a new steroidal BINAP type phosphine
Enev,Harre,Nickisch,Schneider,Mohr
, p. 1767 - 1779 (2000)
The short and high yielding synthesis of a new cis-configured bissteroidal phosphine 7 is reported. The comparison of these new phosphines as ligands in ruthenium-based hydrogenation catalysts with the previously synthesized diastereomeric trans-configured phosphines 20 shows that the steroid backbone exerts only a minor influence on the enantioselection of the ruthenium catalysts and confirms that the bissteroidal phosphines behave as 'pseudo'-enantiomers in spite of their diastereomeric nature. Evidence is presented that the mode of catalyst preparation, i.e. catalyst structure, is the crucial reaction parameter which mainly determines the enantiomeric excess of the hydrogenation products. (C) 2000 Elsevier Science Ltd.
Anti-inflammatory and anti-oxidant potential of the root extract and constituents of doronicum austriacum
Marzocco, Stefania,Adesso, Simona,Alilou, Mostafa,Stuppner, Hermann,Schwaiger, Stefan
, (2017)
Background: Doronicum austriacum Jacq., Asteraceae, is a plant which is used in traditional alpine medicine. Historical sources describe the medical use of the root, but up until now only a few studies evaluated its pharmacological properties. The evaluation of the dichloromethane extract, and its major compounds for their anti-inflammatory and anti-oxidant potential was performed in macrophages J774A.1 and C6 astrocytes. Nitric oxide (NO) and reactive oxygen species (ROS) release, as well as nitrotyrosine formation, were evaluated. Moreover, in order to evaluate the potential anti-proliferative activity, under the same experimental conditions, 3-(4,5-dimethyltiazol-2yl)-2,5-phenyl-2H-tetrazolium bromide (MTT) assay was also performed. Our results indicate that Doronicum austriacum has a significant effect in inhibiting both pro-inflammatory and pro-oxidative mediators. All isolated compounds were able to significantly inhibit NO and ROS release both in macrophage and in astrocytes cells, even if the effect was more pronounced in macrophage. In articular, among the tested compounds, 6,12-dihydroxy-(?)-2S-tremetone exerted stronger activity. Both extract and single compounds did not affect cellular viability. This study provides evidence for the pharmacological anti-inflammatory and anti-oxidant potential of Doronicum austriacum extract. These effects could be due to the activity of its major constituents and subsequent identification of benzofurans as a promising compound class to combat inflammation and related diseases.
Anti-inflammatory components of Chrysanthemum indicum flowers
Luyen, Bui Thi Thuy,Tai, Bui Huu,Thao, Nguyen Phuong,Cha, Ji Yun,Lee, Hoon Yeon,Lee, Young Mi,Kim, Young Ho
, p. 266 - 269 (2015)
One new octulosonic acid derivative, chrysannol A (1), along with 17 known compounds (2-18), were isolated from Chrysanthemum indicum flowers. Their structures were determined from 1D NMR, 2D NMR, HR-ESI-MS spectral data, and comparisons with previous reports. The effects of these compounds on lipopolysaccharide (LPS)-induced nitric oxide (NO) and tumor necrosis factor alpha (TNF-α) production by RAW 264.7 cells were investigated. Compound 8 showed the highest inhibition of NO production of 46.09% at a concentration of 10.0 μM. Compounds 7, 10, 11, and 16 inhibited TNF-α secretion at all concentration tested (0.4, 2.0, and 10.0 μM), with inhibition values ranging from 22.27% to 33.13%. In addition, compound 8 and 9 decrease COX-2 and iNOS protein on Western blot analysis in dose dependent manner.
Asymmetric hydrogenation of α,β-unsaturated carboxylic acids in supercritical carbon dioxide
Xiao, Jianliang,Nefkens, Sylvia C. A.,Jessop, Philip G.,Ikariya, Takao,Noyori, Ryoji
, p. 2813 - 2816 (1996)
Hydrogenation of tiglic acid in supercritical CO2 catalyzed by a chiral H8-BINAP-Ru(II) complex proceeds cleanly with cis stereochemistry to afford 2-methylbutanoic acid in up to 89% ee and over 99% yield.
ASYMMETRIC SYNTHESIS BY CHIRAL RUTHENIUM COMPLEXES. XI. ASYMMETRIC HYDROGENATION OF TIGLIC ACID IN THE PRESENCE OF PHOSPHINE SUBSTITUTED RUTHENIUM CARBONYL CARBOXYLATES
Matteoli, Ugo,Menchi, Gloria,Frediani, Piero,Bianchi, Mario,Piacenti, Franco
, p. 281 - 292 (1985)
The enantioface-discriminating hydrogenation of tiglic acid in the presence of (-)-DIOP substituted carbonyl carboxylato complexes of ruthenium has been investigated in order to identify the factors affecting the stereoselectivity of this reaction.The carboxylato ligand present in the catalytic intermediate does not seem to make a significant contribution to the stereoselectivity of this process.The stereoselectivity seems to be associated with the presence of the optically active phosphine.The catalytic system develops during the reaction through intermediates having a higher enantioface-discriminating activity than the initial and the final ruthenium complexes.
Anacolosins A-F and Corymbulosins X and Y, Clerodane Diterpenes from Anacolosa clarkii Exhibiting Cytotoxicity toward Pediatric Cancer Cell Lines
Cai, Shengxin,Risinger, April L.,Petersen, Cora L.,Grkovic, Tanja,O'Keefe, Barry R.,Mooberry, Susan L.,Cichewicz, Robert H.
, p. 928 - 936 (2019)
An extract of the plant Anacolosa clarkii was obtained from the NCI Natural Products Repository, and it showed cytotoxic activity toward several types of pediatric solid tumor cell lines. Bioassay-guided fractionation led to the purification of eight new clerodane diterpenes [anacolosins A-F (1-6) and corymbulosins X and Y (7 and 8)] and two known compounds (9 and 10) that contained an isozuelanin skeleton. The structures of the new natural products were determined using 1D and 2D NMR and HRESIMS data, while the relative and absolute configurations of the compounds were assessed using a combination of 1H NMR coupling constant data, ROESY experiments, ECD (electronic circular dichroism) and VCD (vibrational circular dichroism) spectroscopy, chemical methods (including Mosher and 2-naphthacyl esterification), and chiral HPLC analyses. The purified natural products exhibited a range of cytotoxic activities against cell lines representing four pediatric cancer types (i.e., rhabdomyosarcoma, Ewing sarcoma, medulloblastoma, and hepatoblastoma) with total growth inhibitory (TGI) values in the range 0.2-4.1 μM. The rhabdomyosarcoma and medulloblastoma cell lines showed higher sensitivity to compounds 1-4, which are the first compounds reported to contain an isozuelanin skeleton and feature keto carbonyl groups at the C-6 positions. In contrast, the hepatoblastoma cell line was modestly more sensitive to 7-10, which contained a C-6 hydroxy group moiety.
Movement to the Clinic of Soluble Epoxide Hydrolase Inhibitor EC5026 as an Analgesic for Neuropathic Pain and for Use as a Nonaddictive Opioid Alternative
Hammock, Bruce D.,McReynolds, Cindy B.,Wagner, Karen,Buckpitt, Alan,Cortes-Puch, Irene,Croston, Glenn,Lee, Kin Sing Stephen,Yang, Jun,Schmidt, William K.,Hwang, Sung Hee
, p. 1856 - 1872 (2021)
This report describes the development of an orally active analgesic that resolves inflammation and neuropathic pain without the addictive potential of opioids. EC5026 acts on the cytochrome P450 branch of the arachidonate cascade to stabilize epoxides of polyunsaturated fatty acids (EpFA), which are natural mediators that reduce pain, resolve inflammation, and maintain normal blood pressure. EC5026 is a slow-tight binding transition-state mimic that inhibits the soluble epoxide hydrolase (sEH) at picomolar concentrations. The sEH rapidly degrades EpFA; thus, inhibiting sEH increases EpFA in vivo and confers beneficial effects. This mechanism addresses disease states by shifting endoplasmic reticulum stress from promoting cellular senescence and inflammation toward cell survival and homeostasis. We describe the synthesis and optimization of EC5026 and its development through human Phase 1a trials with no drug-related adverse events. Additionally, we outline fundamental work leading to discovery of the analgesic and inflammation-resolving CYP450 branch of the arachidonate cascade.
The origin of the enantioselection in the ruthenium(II)-catalyzed asymmetric hydrogenation of α,β-unsaturated carboxylic acid
Yoshikawa,Murata,Yamamoto,Inoguchi,Achiwa
, p. 1072 - 1074 (1992)
Using our chiral atropisomeric bisphosphines ruthenium(II) complexes, asymmetric hydrogenations of tiglic acid and its isomer were carried out. A possible enantioselective mechanism was considered on the basis of their different results on hydrogenation pressure effects.
Cytotoxic Nitrogenated Azaphilones from the Deep-Sea-Derived Fungus Chaetomium globosum MP4-S01-7
Chen, Jing,Cheng, Gang,Cheng, Xiang-Dong,Liao, Yan-Yan,Qin, Jiang-Jiang,Shao, Zongze,Wang, Weiyi,Yang, Jing
, (2020)
Eight new nitrogenated azaphilones (1-8) and two known compounds (chaetoviridin A and chaetoviridin E, 9, 10) were isolated from the culture of the deep-sea-derived fungus Chaetomium globosum MP4-S01-7. The absolute configurations of new compounds were elucidated by HSQC-HECADE NMR data, J-based configuration analysis, and modified Mosher's method and finally verified by comparison of recorded and computed NMR chemical shifts from quantum chemical calculations coupled with a statistical procedure (DP4+). All of the compounds were evaluated for their in vitro cytotoxicities against the gastric cancer cell lines MGC803 and AGS, and most of them showed significant inhibition on cancer cell viability at 10 μM. Among them, compounds 1, 2, and 5 exerted the most potent cytotoxic activities, with IC50 values less than 1 μM. Further studies showed that compound 2 inhibited cell cycle progression, and both compounds 1 and 2 induced apoptosis of gastric cancer cells in a concentration-dependent manner.
Simple azo dyes provide access to versatile chiroptical switches
Anger, Emmanuel,Fletcher, Stephen P.
, p. 3651 - 3655 (2015)
Azo dyes have played an important role in the development of the chemical industry for 150 years. The azo-core of these dyes can undergo trans to cis photoisomerization, which allows azobenzene derivatives to act as light triggered molecular switches. Here, we showed that simple derivatization of Sudan I provides access to chiroptical molecular switches, and that the properties of these switches can be readily tuned by modification of the molecular structure. The synthesis, characterization, photoisomerization, thermal stability, chiral HPLC resolution, determination of absolute configuration and chiroptical properties of chiroptical switches based on Sudan I are reported. ortho-difluorinated Sudan I derivatives have improved thermal stabilities and switching properties compared to switches based on Sudan I itself. Transfer of stereochemical information from a non-racemic chiral unit to the π-conjugated system of the dye and exciton-coupled circular dichroism are both observed. The chiral unit influences the geometry and hence the spectra of cis and trans-isomers differently, which is the mechanistic basis of chiroptical switching. The azo-core of dyes can undergo trans to cis photoisomerization, which allows azobenzene derivatives to act as light triggered molecular switches. Simple derivatization of Sudan I using a chiral auxiliary provides access to chiroptical molecular switches. The properties of these switches can be readily tuned by modification of the molecular structure.
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)
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
A crotofolane-type diterpenoid and a rearranged nor-crotofolane-type diterpenoid with a new skeleton from the stems of Croton cascarilloides
Kawakami, Susumu,Matsunami, Katsuyoshi,Otsuka, Hideaki,Shinzato, Takakazu,Takeda, Yoshio,Kawahata, Masatoshi,Yamaguchi, Kentaro
, p. 4320 - 4322 (2010)
From the stems of Croton cascarilloides collected in the Okinawa Islands, a structurally rare crotofolane-type diterpenoid (1) and a rearranged nor-crotofalane, a new skeletal diterpenoid (2) were isolated. The structures were determined by X-ray crystallographic analyses, establishing their absolute stereostructures for the first time. Compound 2 was probably biosynthesized from 1 through several steps, such as decarboxylation, oxidation, C-C bond migration.
Enantioselective Catalytic Transfer Hydrogenation of α,β-Unsaturated Carboxylic Acids with Formates Catalyzed by Novel Ruthenium Phosphine Complexes
Brown, John M.,Brunner, Henri,Leitner, Walter,Rose, Michael
, p. 331 - 334 (1991)
Hydrogen transfer from the formic acid/triethylamine (5:2) azeotrope to α,β-unsaturated carboxylic acids is effectively catalyzed by ruthenium complexes of general formula 3-C3H5)(diphosphine).If a chiral diphosphine is employed, the saturated acids are obtained in up to 93percent ee, the most active and selective catalyst being formed with BINAP.
Granatumins A-G, limonoids from the seeds of a Krishna mangrove, Xylocarpus granatum
Li, Min-Yi,Yang, Xiao-Bo,Pan, Jian-Yu,Feng, Gang,Xiao, Qiang,Sinkkonen, Jari,Satyanandamurty, Tirumani,Wu, Jun
, p. 2110 - 2114 (2009)
Seven new limonoids (1-7), named granatumins A-G, were isolated from seeds of an Indian mangrove (Xylocarpus granatum) collected from the wetlands of Krishna estuary, Andhra Pradesh. The known compounds khayasin T, tigloylseneganolide A, 6-deoxyswietenine
Bioactive constituents from the leaves of Croton tiglium
Duan, Li-Kun,Feng, Jin-E.,He, Hong-Ping,Huang, Chun-Qiu,Jiang, Zhi-Yong,Li, Xiao-Fei,Li, Yuan,Liu, Chun-Jiang,Shi, Sheng-Li,Zuo, Ai-Xue
, p. 65 - 72 (2022/03/15)
Fifteen compounds, including five new phorbol esters (1-5) and ten known metabolites were isolated from the leaves of Croton tiglium. The structures of new compounds 1-5 were determined by comprehensive analysis of the HRESIMS, IR, 1D and 2D NMR spectral
Enantioselective Enzymatic Reduction of Acrylic Acids
An, Chihui,Shaw, Megan H.,Tharp, Annika,Verma, Deeptak,Li, Hongming,Wang, Heather,Wang, Xiao
supporting information, p. 8320 - 8325 (2020/11/03)
An ene-reductase (ERED 36) with broad substrate specificity was identified, and optimization studies led to the development of an enzymatic protocol for the reduction of α,β-unsaturated acids under mild, aqueous conditions. The substrate scope includes aromatic- A nd aliphatic-substituted acrylic acids, as well as cyclic α,β-substituted acrylic acids, yielding chiral α-substituted acids with exquisite levels of enantioselectivity (>99% ee).
