- Isolation, structure elucidation, and synthesis of antiplasmodial quinolones from Crinum firmifolium
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Antiplasmodial bioassay guided fractionation of a Madagascar collection of Crinum firmifolium led to the isolation of seven compounds. Five of the seven compounds were determined to be 2-alkylquinolin-4(1H)-ones with varying side chains. Compounds 1 and 4 were determined to be known compounds with reported antiplasmodial activities, while 5 was believed to be a new branched 2-alkylquinolin-4(1H)-one, however, it was isolated in limited quantities and in admixture and therefore was synthesized to confirm its structure as a new antiplasmodial compound. Along with 5, two other new and branched compounds 6 and 7 were synthesized as well. Accompanying the five quinolones were two known compounds 2 and 3 which are inactive against Plasmodium falciparum. The isolation, structure elucidation, total synthesis, and biological evaluation of these compounds are discussed in this article.
- Presley, Christopher C.,Du, Yongle,Dalal, Seema,Merino, Emilio F.,Butler, Joshua H.,Rakotonandrasana, Stéphan,Rasamison, Vincent E.,Cassera, Maria B.,Kingston, David G.I.
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- Synthesis of Optically Active N -(4-Hydroxynon-2-enyl)pyrrolidines: Key Building Blocks in the Total Synthesis of Streptomyces coelicolor Butanolide 5 (SCB-5) and Virginiae Butanolide A (VB-A)
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Starting from 5-methylhexanal and (S)-configured N -propargylprolinol ethers, coupling delivered N -(4-hydroxynon-2-ynyl)prolinol derivatives as mixtures of C4 diastereomers. Resolution of the epimers succeeded after introduction of an (R)-mandelic ester derivative and subsequent HPLC separation. Alternatively, suitable oxidation gave the corresponding alkynyl ketone. Midland reagent controlled diastereoselective reduction afforded a defined configured propargyl alcohol with high selectivity. LiAlH 4reduction and Mosher analyses of the allyl alcohols enabled structure elucidation. The suitably protected products are used as key intermediates in enantioselective Streptomyces γ-butyrolactone signaling molecule total syntheses.
- Donges, Jonas,Hofmann, Sandra,Walter, Johannes C.,Reichertz, Julia,Brüggemann, Moritz,Frank, Andrea,Nubbemeyer, Udo
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supporting information
p. 2632 - 2642
(2021/04/27)
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- Sulfamyl Radicals Direct Photoredox-Mediated Giese Reactions at Unactivated C(3)-H Bonds
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Alcohol-anchored sulfamate esters guide the alkylation of tertiary and secondary aliphatic C(3)-H bonds. The transformation proceeds directly from N-H bonds with a catalytic oxidant, a contrast to prior methods which have required preoxidation of the reactive nitrogen center, or employed stoichiometric amounts of strong oxidants to obtain the sulfamyl radical. These sulfamyl radicals template otherwise rare 1,6-hydrogen-atom transfer (HAT) processes via seven-membered ring transition states to enable C(3)-H functionalization during Giese reactions.
- Kanegusuku, Anastasia L. G.,Castanheiro, Thomas,Ayer, Suraj K.,Roizen, Jennifer L.
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supporting information
p. 6089 - 6095
(2019/08/26)
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- Hydroxamic acid derivative and JHDM inhibitor
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PROBLEM TO BE SOLVED: To provide a compound capable of selectively inhibiting the function of JHDM, and a JHDM inhibitor. SOLUTION: This hydroxamic acid derivative expressed by formula (1a) [wherein, R1and R2are each independently alkyl which may have a branch; and (n) is an integer of ≥1] or general formula (1b) [wherein, ring X is a 3 to 8-membered saturated carbon ring; and (n) is an integer of ≥1], its pharmaceutically acceptable salt, hydrate, solvate or prodrug is provided. COPYRIGHT: (C)2011,JPOandINPIT
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Paragraph 0116
(2016/10/09)
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- Tandem decarboxylative hydroformylation-hydrogenation reaction of α,β-unsaturated carboxylic acids toward aliphatic alcohols under mild conditions employing a supramolecular catalyst system
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A new atom economic catalytic method for a highly chemoselective reduction of α,β-unsaturated carboxylic acids to the corresponding saturated alcohols under mild reaction conditions, compatible with a wide range reactive functional groups, is reported. The new methodology consists of a novel tandem decarboxylative hydroformylation/aldehyde reduction sequence employing a unique supramolecular catalyst system.
- Diab, Lisa,Gellrich, Urs,Breit, Bernhard
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supporting information
p. 9737 - 9739
(2013/10/21)
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- Improved syntheses of high hole mobility phthalocyanines: A case of steric assistance in the cyclo-oligomerisation of phthalonitriles
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It has been shown that the base-initiated cyclo-oligomerisation of phthalonitriles is favoured by bulky α-substituents making it possible to obtain the metal-free phthalocyanine directly and in high yield. The phthalocyanine with eight α-isoheptyl substituents gives a high time-of-flight hole mobility of 0.14 cm2·V -1·s-1 within the temperature range of the columnar hexagonal phase, that is 169-189 °C.
- Tate, Daniel J.,Anemian, Remi,Bushby, Richard J.,Nanan, Suwat,Warriner, Stuart L.,Whitaker, Benjamin J.
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supporting information; experimental part
p. 120 - 128
(2012/02/14)
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- One-pot synthesis of alcohols from olefins catalyzed by rhodium and ruthenium complexes
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The one-pot synthesis of butanol and heptanol from propene and 1-hexene, respectively, was performed using Ru3(PPh3)Cl2 and Rh(CO)2(acac) in the presence of triphenylphosphene. The effects of various reaction parameters, including catalyst concentration, gas partial pressures, and temperature, were investigated. Two methods for performing the one-pot synthesis were developed and are discussed. In the first method, stoichiometric quantities of CO and propene or 1-hexene were fed to the autoclave. It was found that residual carbon monoxide necessary for the hydroformylation poisoned the Ru catalyst used for the hydrogenation. Venting the hydroformylation gases was therefore necessary for hydrogenation of the aldehyde to proceed. In the second method, sub-stoichiometric quantities of CO relative to olefin were fed to the autoclave, and CO conversion was driven to nearly 100%. In this case, the low residual CO concentration allowed the hydrogenation to proceed readily. The optimal temperatures and gas pressures for the hydroformylation were not the optimal temperatures and pressures for the hydrogenation. A strategy is described for maximizing the performance of both steps. Under optimal conditions, 100% conversion of propene to butanol could be achieved with 97% selectivity, and 99% conversion of 1-hexene to hepatanol could be achieved with 98% selectivity. The only byproduct observed in the latter case was a small amount of 2-hexene, which did not undergo hydroformylation. A possible reaction mechanism is proposed for both the hydroformylation of the olefin and the hydrogenation of aldehyde based on spectroscopic evidence.
- Zakzeski, Joseph,Lee, Hae Ryun,Leung, Yi Ling,Bell, Alexis T.
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experimental part
p. 201 - 212
(2010/11/04)
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- PROCESS AND APPARATUS FOR THE PRODUCTION OF ALCOHOLS
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A process utilising the gases carbon monoxide, carbon dioxide and hydrogen to produce alcohols directly, comprises the steps of bringing a fluid mixture comprising carbon monoxide, carbon dioxide and hydrogen into contact with the surfaces of a supported tubular porous catalyst membrane having a range of pore sizes including micropores, mesopores and macropores, controlling the temperature of the said catalyst membrane, maintaining a pressure over said catalyst membrane of from 88 to 600 kPa, and recovering alcohol containing product formed by contact of the fluid mixture with said catalyst membrane.
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Page/Page column 4
(2010/09/05)
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- Volatile methyl esters of medium chain length from the bacterium Chitinophaga Fx7914
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The analysis of the volatiles released by the novel bacterial isolate Chitinophaga Fx7914 revealed the presence of ca. 200 compounds including different methyl esters. These esters comprise monomethyl- and dimethyl-branched, saturated, and unsaturated fatty acid methyl esters that have not been described as bacterial volatiles before. More than 30 esters of medium C-chain length were identified, which belong to five main classes, methyl (S)-2-methylalkanoates (class A), methyl (S)-2,(ω-1)-dimethylalkanoates (class B), methyl 2,(ω-2)-dimethylalkanoates (class C), methyl (E)-2-methylalk-2-enoates (class D), and methyl (E)-2,(ω-1)-dimethylalk-2- enoates (class E). The structures of the compounds were verified by GC/MS analysis and synthesis of the target compounds as methyl (S)-2-methyloctanoate (28), methyl (S)-2,7-dimethyloctanoate ((S)-43), methyl 2,6-dimethyloctanoate (49), methyl (E)-2-methylnon-2-enoate (20a), and methyl (E)-2,7-dimethyloct-2- enoate (41a). Furthermore, the natural saturated 2-methyl-branched methyl esters showed (S)-configuration as confirmed by GC/MS experiments using chiral phases. Additionally, the biosynthetic pathway leading to the methyl esters was investigated by feeding experiments with labeled precursors. The Me group at C(2) is introduced by propanoate incorporation, while the methyl ester is formed from the respective carboxylic acid by a methyltransferase using S-adenosylmethionine (SAM).
- Nawrath, Thorben,Gerth, Klaus,Mueller, Rolf,Schulz, Stefan
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experimental part
p. 2228 - 2253
(2011/05/17)
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- First total synthesis of (-)-(3S,6R)-3,6-dihydroxy-10-methylundecanoic acid
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The first total synthesis of (3S,6R)-3,6-dihydroxy-10-methylundecanoic acid was accomplished from commercially available 1-bromo-3-methylbutane in 11 steps and 25.8% overall yield. The key steps were asymmetric allylic alkylations via allyldiisopinocampheylborane and hydroboration-oxidation.
- Zhang, Xianshu,Da, Shijun,Zhang, Chaoxin,Xie, Zhixiang,Li, Ying
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p. 507 - 509
(2007/10/03)
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- Synthesis and pharmacology of the isomeric methylheptyl-Δ8-tetrahydrocannabinols
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The synthesis of the 3-heptyl, and the eleven isomeric 3-methylheptyl-Δ8-tetrahydrocannabinols (3-7, R and S methyl epimers, and 8) has been carried out. The synthetic approach entailed the synthesis of substituted resorcinols, which were subjected to acid catalyzed condensation with trans-para-menthadienol to provide the Δ8-THC analogue. The 1'-, 2'- and 3'-methylheptyl analogues (3-5) are considerably more potent than Δ8-THC. The 4'-, 5'- and 6'-methylheptyl isomers (6-8) are approximately equal in potency to Δ8-THC. Copyright (C) 1998 Elsevier Science Ltd.
- Huffman, John W.,Liddle, John,Duncan Jr., Sammy G.,Yu, Shu,Martin, Billy R.,Wiley, Jenny L.
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p. 2383 - 2396
(2007/10/03)
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- Brief syntheses of (+)-blastmycinone and related γ-lactones from an asymmetrically dihydroxylated carboxylic ester
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A method for synthesizing optically active trans,trans-configurated α,β,γ-substituted γ-lactones is presented. Asymmetric hydroxylation of ester 8 with AD mix α (AD mix β) and subsequent dehydration provided butenolide S-6 (R-6). Conjugate addition of Li2(Me2PhSi)2Cu(CN) to S-6 followed by alkylation of the resulting enolate led to the stereopure silyllactones 9-11. They furnished the title compounds after oxidative removal of the Me2PhSi group.
- Berkenbusch, Thilo,Brueckner, Reinhard
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p. 11461 - 11470
(2007/10/03)
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- SYNTHESES OF OPTICALLY ACTIVE PHEROMONES WITH AN EPOXY RING, (+)-DISPARLURE AND BOTH THE ENANTIOMERS OF (3Z,6Z)-cis-9,10-EPOXY-3,6-HENEICOSADIENE
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(+)-Disparlure 1 and both the enantiomers of (3Z,6Z)-cis-9,10-epoxy-3,6-heneicosadiene 2 were synthesized in optically pure forms employing the Sharpless asymmetric epoxidation as the key-step.The natural pheromone 2 isolated from Estigmene acrea was shown to possess (9S,10R)-stereochemistry.
- Mori, Kenji,Ebata, Takashi
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p. 3471 - 3478
(2007/10/02)
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- WAX COMPOSITION OF SARGASSUM FULVELLUM
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Sixty-seven compounds were characterized in the wax of Sargassum fulvellum.Characteristic components were the 5-methylhexyl esters of octanoic, decanoic, lauric, myristic, palmitic, palmitoleic, stearic, oleic, linoleic and linolenic, and the 2-ethylhexyl esters of the same acids.The wax of S. fulvellum contains hydrocarbons (1.6percent), esters (21.8percent), free acids (74.9percent) and free alcohols (0.3percent).The principal free alcohols range in chain length only from C6 to C7. - Key Word Index: Sargassum fulvellum; Sargassaceae; Phaeophyta; wax; 5-methylhexyl esters; 2-ethylhexyl esters; 5-methylhexanol; 2-ethylhexanol.
- Miyazawa, Mitsuo,Uematsu, Tosihisa,Kameoka, Hiromu
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p. 1788 - 1791
(2007/10/02)
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- Preparation of cis-7,8-epoxy-2-methyloctadecane
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The sexual attractant of the gypsy moth, cis-7,8-epoxy-2-methyloctadecane, is prepared by reacting isoheptyl bromide with an organometallic compound of dodecine-(1) in the presence of an anhydrous polar organic diluent at a temperature of about 20° to 150°C to produce 2-methyloctadecine-(7),hydrogenating the 2-methyloctadecine-(7) in the presence of a palladium catalyst and at a temperature of about -10° to +60°C in a diluent to produce 2-methyloctadecene-7-cis and epoxidizing the 2-methyloctadecene-7-cis to produce cis-7,8-epoxy-2-methyloctadecane. The organometallic compound of dodecine-1 is prepared by reaction of dodecine-1 with lithium, sodium or potassium amide freshly prepared in liquid ammonia or a solution of alkyl-lithium. The isoheptyl bromide is prepared by converting propargyl alcohol into 3-tetrahydropyranyloxypropine-(1), reacting the 3-tetrahydropyranyloxypropine-(1) with metallic lithium, sodium or potassium in liquid ammonia or with a Grignard compound to produce the corresponding organometallic compound, reacting the organometallic compound in an inert anhydrous organic solvent at a temperature of about -20° to +50°C with an approximately equimolar amount of freshly distilled isobutyraldehyde to produce 1-tetrahydropyranyloxy-5-methylhexin-(3)-ol-(4), hydrogenating the 1-tetrahydropyranyloxy-5-methylhexin-(3)-ol-(4) with excess Pd/carbon catalyst at a temperature of about 0° to 100°C to produce isoheptanol and converting the isoheptanol to isoheptyl bromide.
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