- The total synthesis of (±)-ginkgolide B
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The total synthesis of the potent PAF antagonist ginkgolide B has been accomplished. The complex architecture of ginkgolide B which includes six rings, eleven stereogenic centers, ten oxygenated carbons, and four contiguous fully substituted carbons is a
- Crimmins, Michael T.,Pace, Jennifer M.,Nantermet, Philippe G.,Kim-Meade, Agnes S.,Thomas, James B.,Watterson, Scott H.,Wagman, Allan S.
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- Facile Synthesis of Chiral Arylamines, Alkylamines and Amides by Enantioselective NiH-Catalyzed Hydroamination
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Regio- and enantioselective hydroarylamination, hydroalkylamination and hydroamidation of styrenes have been developed by NiH catalysis with a simple bioxazoline ligand under mild conditions. A wide range of enantioenriched benzylic arylamines, alkylamines and amides can be easily accessed by nitroarenes, hydroxylamines and dioxazolones, respectively as amination reagents. The chiral induction in these reactions is proposed to proceed through an enantiodifferentiating syn-hydronickellation step.
- Meng, Lingpu,Yang, Jingjie,Duan, Mei,Wang, You,Zhu, Shaolin
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supporting information
p. 23584 - 23589
(2021/09/28)
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- Preparation method of (E)-3-(3-furyl) acrylic acid
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The invention belongs to the technical field of medical intermediates, and provides a preparation method of a nalfurafine intermediate (E)-3-(3-furyl) acrylic acid. The method comprises the followingsteps: generating the nalfurafine intermediate (E)-3-(3-furyl) acrylic acid from a 3-substituted furan compound and an acrylate compound under the action of a catalyst; the method is mild in reactioncondition, simple and convenient to operate and high in reaction yield, and the obtained product is high in isomerization purity; a refining process and a waste liquid treatment process are avoided sothat the production cost is reduced, and the environmental protection pressure is reduced.
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Paragraph 0048-0071; 0080-0081
(2020/08/30)
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- Bioactivity and structure–activity relationship of cinnamic acid derivatives and its heteroaromatic ring analogues as potential high-efficient acaricides against Psoroptes cuniculi
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A series of cinnamic acid derivatives and its heteroaromatic ring analogues were synthesized and evaluated for acaricidal activity in vitro against Psoroptes cuniculi, a mange mite. Among them, eight compounds showed the higher activity with median lethal concentrations (LC50) of 0.36–1.07 mM (60.4–192.1 μg/mL) and great potential for the development of novel acaricidal agent. Compound 40 showed both the lowest LC50 value of 0.36 mM (60.4 μg/mL) and the smallest median lethal time (LT50) of 2.6 h at 4.5 mM, comparable with ivermectin [LC50 = 0.28 mM (247.4 μg/mL), LT50 = 8.9 h], an acaricidal drug standard. SAR analysis showed that the carbonyl group is crucial for the activity. The type and chain length of the alkoxy in the ester moiety and the steric hindrance near the ester group significantly influence the activity. The esters were more active than the corresponding thiol esters, amides, ketones or acids. Replacement of the phenyl group of cinnamic esters with α-pyridyl or α-furanyl significantly increase the activity. Thus, a series of cinnamic esters and its heteroaromatic ring analogues with excellent acaricidal activity emerged.
- Chen, Dong-Dong,Zhang, Bing-Yu,Liu, Xiu-Xiu,Li, Xing-Qiang,Yang, Xin-Juan,Zhou, Le
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supporting information
p. 1149 - 1153
(2018/03/05)
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- Iridium-Catalyzed Enantioselective Allylic Substitution of Aliphatic Esters with Silyl Ketene Acetals as the Ester Enolates
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Enantioselective allylic substitution with enolates derived from aliphatic esters under mild conditions remains challenging. Herein we report iridium-catalyzed enantioselective allylation reactions of silyl ketene acetals, the silicon enolates of esters, to form products containing a quaternary carbon atom at the nucleophile moiety and a tertiary carbon atom at the electrophile moiety. Under relatively neutral conditions, the allylated aliphatic esters were obtained with excellent regioselectivity and enantioselectivity. These products were readily converted into primary alcohols, carboxylic acids, amides, isocyanates, and carbamates, as well as tetrahydrofuran and γ-butyrolactone derivatives, without erosion of enantiomeric purity.
- Jiang, Xingyu,Hartwig, John F.
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supporting information
p. 8887 - 8891
(2017/07/17)
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- Intramolecular Didehydro-Diels-Alder Reaction for the Synthesis of Benzo- and Dihydrobenzo-Fused Heterocycles
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Using an intramolecular didehydro-Diels-Alder reaction, ene-yne substituted pyrroles, thiophenes, and furans afford functionalized indoles, benzothiophenes, and benzofurans and the corresponding dihydroaromatic products. Product selectivity for the aromatic or dihydroaromatic product is controlled by the reaction conditions, which vary depending upon the substrate.
- Bober, Ashley E.,Proto, Justin T.,Brummond, Kay M.
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supporting information
p. 1500 - 1503
(2017/04/13)
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- Piperlongumine derived cyclic sulfonamides (sultams): Synthesis and in?vitro exploration for therapeutic potential against HeLa cancer cell lines
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A novel modification of piperlongumine is designed, bearing a cyclic sulphonamide (sultam) and its synthesis is described. For the first time herein we report the synthesis and biological evaluation of the natural product derived cyclic sulfonamides using Grubbs second generation catalyst (Grubbs II) via ring closing metathesis approach. Synthesis of a series of piperlongumine derived sultams is done in a moderate to good yield using Wittig reaction, Ring-Closing Metathesis (RCM) and, amide synthesis by using mixed anhydride, approach. All synthesized compounds were evaluated for anticancer activity and some demonstrated dose dependent reduction in HeLa cell growth. Of these 7, 10 and 14 significantly reduced the cell growth. Consequently their calculated GI50values were found to be 0.1 or 0.1?μM.
- Lad, Nitin P.,Kulkarni, Sarang,Sharma, Rajiv,Mascarenhas, Malcolm,Kulkarni, Mahesh R.,Pandit, Shivaji S.
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p. 870 - 878
(2016/12/18)
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- Silver-Catalyzed Cross-Olefination of Donor and Acceptor Diazo Compounds: Use of N-Nosylhydrazones as Diazo Surrogate
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The cross-olefination reaction of donor and acceptor diazo compounds was explored. The use of N-nosylhydrazones as diazo surrogates and the dependence on silver catalysis were crucial for the reaction development. A variety of (hetero)aryl N-nosylhydrazones and α-diazo esters, amides, and phosphonates were compatible, and the functionalized alkene products were afforded in good to high yields with moderate (Z)/(E) selectivities. The experimental and DFT calculation results suggest that the cross-selectivity is due to selective activation of the silver catalyst for donor diazo compounds.
- Liu, Zhaohong,Liu, Binbin,Zhao, Xue-Feng,Wu, Yan-Bo,Bi, Xihe
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supporting information
p. 928 - 932
(2017/02/15)
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- BF3·OEt2-mediated: Syn -selective Meyer-Schuster rearrangement of phenoxy propargyl alcohols for Z -β-aryl-α,β-unsaturated esters
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Synthesis of Z-β-aryl-α,β-unsaturated esters from readily available 1-aryl-3-phenoxy propargyl alcohols is achieved via a BF3-mediated syn-selective Meyer-Schuster rearrangement under ambient conditions. The reaction mechanism is postulated to involve an electrophilic borylation of an allene intermediate as the key step to kinetically control the stereoselectivity.
- Puri, Surendra,Hari Babu, Madala,Sridhar Reddy, Maddi
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p. 7001 - 7009
(2016/07/30)
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- Chiral Cyclopentadienyl Iridium(III) Complexes Promote Enantioselective Cycloisomerizations Giving Fused Cyclopropanes
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The cyclopentadienyl (Cp) group is a very important ligand for many transition-metal complexes which have been applied in catalysis. The availability of chiral cyclopentadienyl ligands (Cpx) lags behind other ligand classes, thus hampering the investigation of enantioselective processes. We report a library of chiral CpxIrIII complexes equipped with an atropchiral Cp scaffold. A robust complexation procedure reliably provides CpxIrIII complexes with tunable counterions. In a proof-of-concept application, the iodide-bearing members are shown to be highly selective for enyne cycloisomerization reactions. The dehydropiperidine-fused cyclopropane products are formed in good yields and enantioselectivities.
- Dieckmann, Michael,Jang, Yun-Suk,Cramer, Nicolai
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supporting information
p. 12149 - 12152
(2015/10/12)
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- C-H alkenylation of azoles with enols and esters by nickel catalysis
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Rather u(Ni)que: Two new C-H alkenylation reactions, that is C-H/Ci£O alkenylation and decarbonylative C-H alkenylation, of azoles are uniquely catalyzed by Ni/dcype. These azole alkenylation reactions are successfully applied to the convergent formal synthesis of siphonazoleB.
- Meng, Lingkui,Kamada, Yuko,Muto, Kei,Yamaguchi, Junichiro,Itami, Kenichiro
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supporting information
p. 10048 - 10051
(2013/10/01)
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- The first enantioselective synthesis of palinurin
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The first enantioselective synthesis of palinurin has been accomplished starting from commercially available furaldehyde and (R)-methyl-3-hydroxy-2- methylpropionate; the key steps of the synthesis include the use of a chiral pyrrolidine to create the chiral tetronic moiety, and Horner-Wadsworth-Emmons, Wittig and Wittig-Horner reactions to construct the alkene units.
- Perez, Manuel,Perez, Daniel I.,Martinez, Ana,Castro, Ana,Gomez, Generosa,Fall, Yagamare
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supporting information; experimental part
p. 3252 - 3254
(2009/12/01)
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- Diazo reagents in copper(I)-catalyzed olefination of aldehydes
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The olefination of aldehydes to synthesize unsaturated ketones, esters, amides and phosphonates using diazo reagents and triphenylphosphine in the presence of copper(I) iodide as catalyst, is described. Good to excellent E:Z selectivities as well as yields were obtained for a large variety of aliphatic, aromatic and heteroaromatic aldehydes. The reaction showed also an excellent functional group compatibility and aldehydes were selectively reacted in the presence of ketone, nitro, amine, ether, acetal, thioether and halide groups. The use of a cost-effective copper salt as a catalyst is advantageous compared to previously reported expensive transition metal complexes. The method was used in the total synthesis of the scutifoliamide A, a biologically active compound that exhibits antifungal activity.
- Lebel, Helene,Davi, Michael
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supporting information; experimental part
p. 2352 - 2358
(2009/10/02)
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- Addition/oxidative rearrangement of 3-furfurals and 3-furyl imines: New approaches to substituted furans and pyrroles
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Furans and pyrroles are important synthons in chemical synthesis and are commonly found in natural products, pharmaceutical agents, and materials. Introduced herein are three methods to prepare 2-substituted 3-furfurals starting from 3-furfural, 3-bromofuran, and 3-vinylfurans. Addition of a variety of organofithium, Grignard, and organozinc reagents (M-R) to 3-furfural provides 3-furyl alcohols in high yields. Treatment of these intermediates with NBS initiates a novel oxidative rearrangement that results in the installation of the R group in the 2 position of the 2-substituted 3-furfurals. Likewise, metalation of 3-bromofuran with n-BuLi and addition to benzaldehyde provides a furyl alcohol that is converted to 2-phenyl 3-furfural upon oxidative rearrangement. Enantioenriched disubstituted furans can be prepared starting with the Sharpless asymmetric dihydroxylation of 3-vinylfurans. The resulting enantioenriched diols undergo the oxidative rearrangement to furnish enantioenriched 2-substituted 3-furfurals with excellent transfer of asymmetry. This later method has been applied to the enantioselective preparation of an intermediate in Honda's synthesis of the natural product (-)-canadensolide. Mechanistic studies involving deuterium-labeled furyl alcohol suggest that the oxidative rearrangement proceeds through an unsaturated 1,4-dialdehyde intermediate. The alcohol then cyclizes onto an aldehyde, resulting in the elimination of water and rearomatization. On the basis of this proposed mechanism, we found that 3-furyl imines undergo the addition of organometallic reagents to provide furyl sulfonamides. Under the oxidative rearrangement conditions, 2-substituted 3-formyl pyrroles are formed, providing a novel route to these heterocycles. In contrast to the metalation of heterocycles, which often lead to mixtures of regioisomeric products, these new oxidative rearrangements of furyl alcohols and furyl sulfonamides generate only one regioisomer in each case.
- Kelly, Ann Rowley,Kerrigan, Michael H.,Walsh, Patrick J.
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p. 4097 - 4104
(2008/09/21)
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- Furan derivatives, method of synthesis and uses thereof
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The present invention relates to furan derivatives of formula (I), their method of synthesis and uses thereof. Concretely, the compounds disclosed have proved to be inhibitors of glycogen synthase kinase 3β, GSK-3 β, which is known to be involved in different disease and conditions, such as Alzheimer's disease or non-insulin dependent diabetes mellitus. The present invention also relates to pharmaceutical compositions comprising the same. Further, the present invention is directed to the use of the compounds in the manufacture of a medicament for the treatment and/or prevention of a GSK-3 mediated disease or condition.
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Page/Page column 19-20
(2008/12/06)
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- Novel Compounds
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There is provided a compound of formula (I): processes for the manufacture thereof, pharmaceutical compositions thereof and uses in therapy.
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Page/Page column 111
(2008/06/13)
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- The interaction of heteroaryl-acrylates and alanines with phenylalanine ammonia-lyase from parsley
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Acrylic acids and alanines substituted with heteroaryl groups at the β-position were synthesized and spectroscopically characterized (UV, HRMS, 1H NMR, and 13C NMR spectroscopy). The heteroaryl groups were furanyl, thiophenyl, benzofuranyl, and benzothiophenyl and contained the alanyl side chains either at the 2- or 3-positions. While the former are good substrates for phenylalanine ammonia lyase (PAL), the latter compounds are inhibitors. Exceptions are thiophen-3-yl-alanine, a moderate substrate and furan-3-yl-alanine, which is inert. Possible reasons for these exceptions are discussed. Starting from racemic het eroaryl-2-alanines their D-enantiomers were prepared by using a stereodestructive procedure. From the heteroaryl-2- acrylates, the L-enantiomers of the heteroaryl-2-alanines were prepared at high ammonia concentration. These results can be best explained by a Friedel - Crafts-type electrophilic attack at the aromatic part of the substrates as the initial step of the PAL reaction.
- Paizs, Csaba,Katona, Adrian,Retey, Janos
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p. 2739 - 2744
(2008/02/03)
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- Microwave-mediated claisen rearrangement followed by phenol oxidation: A simple route to naturally occurring 1,4-benzoquinones. The first syntheses of verapliquinones A and B and panicein A
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The naturally occurring 1,4-benzoquinones 2-methoxy-6-propyl-1,4- benzoquinone (1), 2-methoxy-6-pentyl-1,4-benzoquinone (primin 2), 2-methoxy-6-pentadecyl-1,4-benzoquinone (3), 2-methoxy-6-heptadecyl-l,4- benzoquinone (dihydroirisquinone, pallasone B; 4) were synthesized by a simple protocol involving microwave accelerated Claisen rearrangement of allyl ethers 10, followed by hydrogenation of the side chain alkene, and oxidation to the quinone. The Claisen-based methodology was extended to the first synthesis of the marine benzoquinones verapliquinones A and B (5 and 6), and panicein A (7). Isoarnebifuranone (9) was also synthesized by a similar strategy.
- Davis, Christopher J.,Hurst, Timothy E.,Jacob, Aouregan M.,Moody, Christopher J.
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p. 4414 - 4422
(2007/10/03)
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- A highly convergent enantioselective total synthesis of marine natural product, furanoterpene
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The enantioselective total convergent synthesis of marine furanoterpene 1 is achieved and the absolute configuration of the only existing quaternary stereogenic centre is found to be S.
- Bando, Toshikazu,Shishido, Kozo
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p. 1357 - 1358
(2007/10/03)
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- Total syntheses of strychnan- and aspidospermatan-type alkaloids. 2. Generation of 15-(3-furanyl) ABCE tetracyclic intermediates
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The synthesis of Nb-benzyl-2-(dimethyl 2-malonyl)- and 2-(methyl 2- acetyl)tryptamines (21, 25) provides access to methyl 4-(3-furanyl)- 1,2,3,4,5,6-hexahydroazepino[4,5-b]indole-5-carboxylate (12) and methyl 3- benzyl-5-(3-furanyl)-2,3,3a,4,5,
- Parsons,Berk,Kuehne
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p. 7482 - 7489
(2007/10/02)
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- Palladium-Catalyzed Cyclocarbonylation of 3-(Heteroaryl)allyl Acetates1
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Acetoxybenzofurans, acetoxybenzothiophenes, acetoxyindoles, and acetoxycarbazoles were obtained in high yields by cyclocarbonylation of 3-furyl-, 3-thienyl-, 3-pyrrolyl-, and 3-indolylallyl acetates, respectively, in the presence of Ac2O, NEt3, and a catalytic amount of PdCl2(PPh3)2 at 130 - 170 deg C under 50 - 70 atm of CO. 3-(3-Furyl)allyl and 3-(3-thienyl)allyl acetates cyclized selectively at the 2-position of the heterocyclic nucleus to give 7-acetoxybenzofuran and 7-acetoxybenzothiophene, respectively.The synthetic utility of the reaction was demonstrated by the synthesis of canabifuran from isothymol.
- Iwasaki, Masakazu,Kobayashi, Yoshihiro,Li, Ji-Ping,Matsuzaka, Hiroyuki,Ishii, Youichi,Hidai, Masanobu
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p. 1922 - 1927
(2007/10/02)
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