- (4E,8Z)-12-methyloxacyclotetradeca-4,8-dien-2-one and its 7a-homologue: Conformationally constrained double-unsaturated macrocyclic musks by ring-closing alkyne metathesis
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The double-unsaturated macrocyclic lactones (4E,8Z)-12- methyloxacyclotetradeca-4,8-dien-2-one and its 7a-homologue (4E,9Z)-13- methyloxacyclopentadeca-4,9-dien-2-one, designed as new potent musk odorants by molecular modeling, were synthesized by ring-closing alkyne metathesis in the presence of 10 mol% of Schrock's alkylidyne catalyst, and subsequent Lindlar hydrogenation. Demethylation of citronellol, induced by nitrous acid, afforded the 3-methyloct-6-yn-1-ol building block. The substrates for the alkyne metathesis were prepared by Steglich esterification of citronellol with the 3E-configured non-3-en-7-ynoic and dec-3-en-8-ynoic acids, accessible by β,γ-selective Knoevenagel condensation from the corresponding alkynals hept-5-ynal and oct-6-ynal, which were synthesized by Eschenmoser-Ohloff fragmentation of the epoxide of 2-methylcyclohex-2-enone, and methylation of hex-5-yn-1-ol, respectively. Both target structures, (4E,8Z)-12-methyloxacyclotetradeca-4,8-dien-2-one and its 7a-homologue, emanated most pleasant and powerful musk odors. Georg Thieme Verlag Stuttgart.
- Kraft, Philip,Berthold, Carola
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- An Alkyne-Metathesis-Based Approach to the Synthesis of the Anti-Malarial Macrodiolide Samroiyotmycin A
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We report the first total synthesis of samroiyotmycin A (1), a C2-symmetric 20-membered anti-malarial macrodiolide isolated from Streptomyces sp. The convergent synthetic strategy orchestrates bisalkyne fragment-assembly using an unprecedented Sch?llkopf-type condensation on a substituted β-lactone and an ambitious late-stage one-pot alkyne cross metathesis–ring-closing metathesis (ACM–RCAM) reaction. The demanding alkyne metathesis sequence is achieved using the latest generation of molybdenum alkylidynes endowed with a tripodal silanolate ligand framework. Subsequent conversion to the required E-alkenes uses contemporary hydrometallation chemistry catalysed by tetrameric cluster [{Cp*RuCl}4].
- Fürstner, Alois,Grimes, Mark I.,Hulme, Alison N.,Whitelegge, James T.,Yiannakas, Ektoras
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- The (5Z)-5-Pentacosenoic and 5-Pentacosynoic Acids Inhibit the HIV-1 Reverse Transcriptase
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The natural fatty acids (5Z)-5-pentacosenoic and (9Z)-9-pentacosenoic acids were synthesized for the first time in eight steps starting from either 4-bromo-1-butanol or 8-bromo-1-butanol and in 20-58 % overall yields, while the novel fatty acids 5-pentacosynoic and 9-pentacosynoic acids were also synthesized in six steps and in 34-43 % overall yields. The ?5 acids displayed the best IC50's (24-38 μM) against the HIV-1 reverse transcriptase (RT) enzyme, comparable to nervonic acid (IC50 = 12 μM). The ?9 acids were not as effective towards HIV-RT with the (9Z)-9-pentacosenoic acid displaying an IC50 = 54 μM and the 9-pentacosynoic acid not inhibiting the enzyme at all. Fatty acid chain length and position of the unsaturation was important for the observed inhibition. None of the synthesized fatty acids were toxic (IC50 > 500 μM) towards peripheral blood mononuclear cells. Molecular modeling studies indicated the structural determinants underlying the biological activity of the most potent compounds. These results provide new insights into the structural requirements that must be present in fatty acids so as to enhance their inhibitory potential towards HIV-RT.
- Moreira, Lizabeth Giménez,Orellano, Elsie A.,Rosado, Karolyna,Guido, Rafael V. C.,Andricopulo, Adriano D.,Soto, Gabriela Ortiz,Rodríguez, José W.,Sanabria-Ríos, David J.,Carballeira, Néstor M.
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Read Online
- A Tandem Synthesis of (+/-)-Euphococcinine and (+/-)-Adaline
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Intramolecular hydroxylamine-alkyne cyclisation of the hydroxylamines 8 and 9 afforded six-membered cyclic nitrones which without isolation underwent a tandem intramolecular dipolar cycloaddition to produce the tricyclic isoxazolidines 6 and 7 respectively.These were converted in two steps into the ladybird defence alkaloids (+/-)-euphococcinine 4 and (+/-)-adaline 5.
- Davison, Edwin C.,Holmes, Andrew B.,Forbes, Ian T.
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- Scope and Mechanism of Stannylalumination of 1-Alkynes
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Terminal acetylenes react with Bu3SnAlEt2 in the presence of Cu+ or Pd0 catalysts to give 1,2-dimetallo-1-alkenes in highly regio- and stereoselective reactions.These intermediates can be selectively functionalized at the vinyl-aluminum bond to provide vinylstannanes, which upon transmetalation and further reaction with electrophiles give stereodefined trisubstituted olefins.In sharp contrast to the normal behavior of alkylaluminum reagents, this process tolerates a number of functional groups including OH, OAc, OTHP, and Br.Mechanistic investigations suggest that the addition of Bu3SnAlEt2 to 1-alkynes proceeds via stannylcupration followed by capture of the stannylcuprate adduct by electrophilic aluminum.
- Sharma, Sunaina,Oehlschlager, Allan C.
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- Additions of CuCN-Derived Stannylcuprates to Terminal Alkynes: A Comparative Spectroscopic and Chemical Study
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The stannylcupration of terminal alkynes 4a,b with cuprates 1-3 proceeds rapidly and reversibly above -35 deg C to afford stannylcuprate intermediates 5a,b and 6a,b.These intermediates have been characterized by 2H and 13C NMR labelling experiments.Corroborating evidence for this reversible addition comes from further chemical tests and cross-over experiments that show the thermodynamic favorability of the adducts.Further comparative study of reaction products and byproducts shows 2 to be the stannylcuprate of choice for the preparation of vinylstannates from terminal alkynes.
- Singer, Robert, D.,Hutzinger, Michael W.,Oehlschlager, Allan C.
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Read Online
- PYRAZOLO[1,5-D][1,2,4]TRIAZINE-5(4H)-ACETAMIDES AS INHIBITORS OF THE NLRP3 INFLAMMASOME PATHWAY
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The invention relates to novel compounds for use as inhibitors of NLRP3 inflammasone production, wherein such compounds are as defined by compounds of formula (I) and wherein the integers R1, R2 and R3 are defined in the description, and where the compounds may be useful as medicaments, for instance for use in the treatment of a disease or disorder that is associated with NLRP3 inflammasome activity.
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(2021/10/22)
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- FATTY ACID COMPOUND, PREPARATION METHOD THEREFOR AND USE THEREFOR
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The present invention relates to a class of fatty acid compounds, a preparation method thereof and use thereof. The fatty acid compounds have the structure of the formula I, which has the ability to activate APMK and inhibit the glucose output in mouse primary hepatocytes. The fatty acid compounds can be used in preparing a medicament for the treatment of obesity or diabetes.
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Paragraph 0117-0119
(2019/02/19)
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- Efficient synthesis of (5Z,7E)-Dodecadienal, the sex pheromone of the european pine moth dendrolimus pini
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Efficient synthesis of (5Z,7E)-dodecadienal, the sex pheromone of European pine moth Dendrolimus pini, was stereoselectively accomplished via Pd- and Fe- catalyzed cross-coupling reactions in the key steps. The very simple and practical method developed herein provides a general synthetic approach to other (Z,E)-diene compounds.
- T?t?s, ?tefania,Vasian, Iuliana,Gorgan, Monica,T?t?s, Róbert,Lar, Claudia
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p. 315 - 319
(2018/10/20)
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- Synthetic method for attractant component namely cis,trans-5,7-dodecadiene derivative in Dendrolimus sex pheromone
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The invention discloses a synthetic method for an attractant component namely a cis,trans-5,7-dodecadiene derivative in Dendrolimus sex pheromone. With the synthetic method provided by the invention,5-hexyne-1-ol and 3, 4-dihydro-2H-pyran used as starting materials are successively subjected to an addition reaction, a condensation reaction, an elimination reaction, a hydrogenation reaction, a deprotection reaction and a derivatization reaction to obtain the cis,trans-5,7-dodecadiene derivative. The synthetic method provided by the invention has the advantages of short route, high reaction yield in each step, simple operation and convenience in mass production.
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Paragraph 0015; 0027-0030
(2019/01/08)
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- Synthesis of isocoumarin compounds, 8-Hydroxy-6-Methoxy-3-Pentyl-1H-Isochromen-1-One and Fusariumin analog using palladium-Catalyzed carbonylation trapping with O-enolate
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Concise synthesis of 6,8-dialkoxyisocoumarin framework was achieved using Pd-catalyzed carbonylation trapping with O-enolate. This methodology was applied to the synthesis of 8-hydroxy-6-methoxy-3-pentyl-1H-isochromen-1-one isolated from Tessmannia densiflora and fusariumin analog.
- Asai, Masaki,Hattori, Yasunao,Makabe, Hidefumi
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p. 1542 - 1553
(2017/08/02)
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- Supported Gold Nanoparticle-Catalyzed Hydration of Alkynes under Basic Conditions
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TiO2-supported nanosize gold particles catalyze the hydration of alkynes using morpholine as a basic cocatalyst. Unlike most homogeneous cationic gold catalysts, the TiO2-Au/morpholine system is weakly basic and is compatible with acid-sensitive functional groups (e.g., silyl ethers, ketals) or with a strongly coordinating group such as pyridine. What's more, this gold catalyst can be recycled by simple filtration and works well in flow reactors. (Chemical Equation Presented).
- Liang, Shengzong,Jasinski, Jacek,Hammond, Gerald B.,Xu, Bo
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supporting information
p. 162 - 165
(2015/07/28)
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- Asymmetric total synthesis of all four isomers of 6-acetoxy-5- hexadecanolide: The major component of mosquito oviposition attractant pheromones
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An asymmetric total synthesis of (5S,6R)-(+)-erythro-6-acetoxy-5- hexadecanolide 1a has been accomplished from readily available hex-5-yn-1-ol via Shi's asymmetric epoxidation as the key step, in eight steps with an overall yield of 33.5%. In addition, the stereoselective synthesis of all four isomers of 6-acetoxy-5-hexadecanolide 1a-1d were obtained via Sharpless asymmetric dihydroxylation and Mitsunobu reaction as the key steps with overall yields of 16.5-21.2%, respectively.
- Dong, Hong-Bo,Yang, Ming-Yan,Zhang, Xiao-Teng,Wang, Ming-An
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p. 610 - 616
(2014/05/20)
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- The intramolecular allenolate rauhut-currier reaction
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An intramolecular Rauhut-Currier reaction utilizing alkynoates as the initial conjugate acceptor affords densely functionalized 5- and 6-membered rings from ynoate-enoate, ynoate-enenitrile, and alkynyl sulfone-enenitrile substrates. Trialkylphosphines ca
- MacKay, James A.,Landis, Zachary C.,Motika, Stephen E.,Kench, Margaret H.
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p. 7768 - 7774
(2012/11/06)
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- Synthesis of deuterated 5(Z),11(Z)-eicosadienoic acid as a biomarker for trophic transfer
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The poly-methylene interrupted fatty acid 5(Z),11(Z)-eicosadienoic acid and its tetradeuterated analogue were prepared via a convergent synthetic sequence.
- Albu, Siliva,Sverko, Ed,Arts, Michael T.,Capretta, Alfredo
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scheme or table
p. 787 - 788
(2011/03/21)
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- Synthetic applications of the nickel-catalyzed cyclization of alkynes combined with addition reactions in a domino process
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Carbonickelations of alkynes and functionalization of the resulting vinylnickel moiety have been performed efficiently in a nickel-catalyzed domino cyclization-condensation process. This reaction, which does not require the preparation of any other organometallic reagent, proceeds only by exo-dig cyclization. This convenient and mild method constitutes a one-pot synthesis of substituted dihydrobenzofurans, chromans, isochromans, indoles, or indanes. Theses valuable products are generally obtained in good yields and high stereoselectivity. They are shown to be useful synthons for rapid access to functionalized polycyclic skeletons. Yes nickel can! Carbonickelation of alkynes and functionalization of the resulting vinylnickel moiety occurs efficiently. Overall, a domino cyclization-condensation process propagated by substoichiometric nickel catalysis takes place (see scheme). This one-pot synthesis provides substituted polyheterocyclic compounds in good yields and high stereoselectivity.
- Durandetti, Muriel,Hardou, Lucie,Lhermet, Rudy,Rouen, Mathieu,Maddaluno, Jacques
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supporting information; experimental part
p. 12773 - 12783
(2011/12/04)
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- Spiroacetal biosynthesis in fruit flies is complex: Distinguishable origins of the same major spiroacetal released by different Bactrocera spp.
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The major spiroacetal ((E,E)-1) of the pestiferous fruit flies, Bactrocera tryoni and Bactrocera cucumis, is biosynthesised from fatty acids by distinguishable pathways which utilise modified β-oxidation and C-H hydroxylation, generating a putative ketodiol which cyclises. The Royal Society of Chemistry 2010.
- Schwartz, Brett D.,Booth, Yvonne K.,Fletcher, Mary T.,Kitching, William,De Voss, James J.
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supporting information; experimental part
p. 1526 - 1528
(2010/06/12)
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- MACROCYCLIC LACTONES AS FRAGRANCES
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The present invention refers to methyl-substituted double-unsaturated macrocyclic lactones comprising 14 to 17 ring atoms of formula (I) wherein n and m are independently selected from 1, 2, 3 and 4 with the proviso that 3 ≤ n + m ≤ 6. The invention relates furthermore to their use as odorant and fragrance composition comprising them.
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Page/Page column 7
(2009/05/29)
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- Regio- and stereoselective hydroamidation of 1-alkynylphosphine sulfides catalyzed by cesium base
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(Chemical Equation Presented) Regio- and stereoselective hydroamidation of 1-alkynylphosphine sulfides proceeds in the presence of cesium carbonate to provide (E)-2-amino-1-thiophosphinyl-1-alkenes. Asymmetric hydrogenation of the adducts catalyzed by an
- Kondoh, Azusa,Yorimitsu, Hideki,Oshima, Koichiro
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supporting information; experimental part
p. 3093 - 3095
(2009/05/27)
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- Efficient synthesis of 8,11-dimethylene-bicyclo[5.3.1]undecan-2-one
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We report here, an effective methodology for the preparation of 8,11-dimethylene-bicyclo[5.3.1]undecan-2-one. The key steps in these reactions were chloromethylation, cationic-alkyne cyclization and anionic fragmentation sequence.
- Gu, Haining,Xu, Wei Ming,Kinstle, Thomas H.
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p. 6449 - 6451
(2007/10/03)
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- Palladium(II)-catalyzed enyne coupling reaction initiated by acetoxypalladation of alkynes and quenched by protonolysis of the carbon-palladium bond
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Divalent palladium-catalyzed inter- and intramolecular enyne coupling reactions initiated by acetoxypalladation of alkynes were developed. The reaction involves the acetoxypalladation of the alkyne, followed by the insertion of the alkene and the protonolysis of the carbon-palladium bond. The protonolysis of the carbon-palladium bond in the presence of bidentate nitrogen containing ligands is the key step in completing the Pd(II) catalytic cycle. The nitrogen-containing ligands, like halides, served to favor the protonolysis of the carbon-palladium bond over the β-H elimination in the Pd(II)-mediated reactions. The intermolecular coupling reactions provide an efficient method for synthesizing γ,δ-unsaturated carbonyls. The intramolecular coupling reactions offer a method to construct a variety of synthetically important carbo- and heterocycles. The asymmetric version of such a cyclization was developed with moderate enantioselectivity when employing pymox (pyridyl monooxazoline) as the ligand.
- Zhao, Ligang,Lu, Xiyan,Xu, Wei
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p. 4059 - 4063
(2007/10/03)
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- Rh(I)-catalyzed CO gas-free cyclohydrocarbonylation of alkynes with formaldehyde to α,β-butenolides
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The rhodium(I)-catalyzed reaction of alkynes with formaldehyde proceeds via the double incorporation of a carbonyl moiety from formaldehyde, resulting in a CO gas-free cyclohydrocarbonylation leading to α,β-butenolides. The Royal Society of Chemistry 2005.
- Fuji, Koji,Morimoto, Tsumoru,Tsutsumi, Ken,Kakiuchi, Kiyomi
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p. 3295 - 3297
(2007/10/03)
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- Anomeric oxygen to carbon rearrangements of alkynyl tributylstannane derivatives of furanyl (γ)- and pyranyl (δ)-lactols
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Tetrahydropyran and tetrahydrofuran containing natural products, drugs and agrochemicals often possess carbon-carbon bonds adjacent to the heteroatom. Consequently, new methods for the construction of anomeric carbon-carbon bonds are of considerable importance. We have devised a new strategy to access these systems that requires the treatment of O-glycoside alkynyl tributylstannane derivatives of furanyl and pyranyl lactols with Lewis acid to effect oxygen to carbon rearrangements. This leads to the formation of the corresponding carbon linked alkynol products that can be further manipulated to produce key structural motifs and building blocks for the assembly of complex molecules.
- Buffet, Marianne F.,Dixon, Darren J.,Ley, Steven V.,Reynolds, Dominic J.,Storer, R. Ian
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p. 1145 - 1154
(2007/10/03)
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- Rapid methylation of terminal acetylenes by the Stille coupling of methyl iodide with alkynyltributylstannanes: A general protocol potentially useful for the synthesis of short-lived 11CH3-labeled PET tracers with a 1-propynyl group
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The Pd(0)-mediated rapid coupling (trapping) reaction of methyl iodide with an excess amount of alkynyltributyl-stannane has been developed with the aim to incorporate a short-lived 11C-labeled methyl group into biologically active organic compounds with a 1-propynyl structural unit.
- Hosoya, Takamitsu,Wakao, Masahiro,Kondo, Yurie,Doi, Hisashi,Suzuki, Masaaki
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- Total synthesis and assignment of the double-bond position and absolute configuration of (-)-pyrinodemin A
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(Matrix presented) The first asymmetric total synthesis of a structurally novel cis-cyclopent[c]isoxazolidine alkaloid, (-)-pyrinodemin A (3), which exhibits potent cytotoxicity, has been accomplished through a highly diastereoselective intramolecular nitrone - olefin cycloaddition reaction as the key step. Thus, it has been found that the hitherto unknown absolute configuration of pyrinodemin A is as indicated in the structural formula 3.
- Morimoto, Yoshiki,Kitao, Satoru,Okita, Tatsuya,Shoji, Takamasa
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p. 2611 - 2614
(2007/10/03)
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- Electrotelluration: A new approach to tri- and tetrasubstituted alkenes
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A novel electrotelluration process is described in which a Michael addition of an alkyl or aryl tellurolate anion occurs onto an activated alkyne with subsequent trapping of a vinyl anion with electrophiles (aldehydes and ketones) other than a proton. This process provides an efficient regio-and stereospecific route to tri- and tetrasubstituted alkenes. Methodologically significant examples of this chemistry were studied in which aryl and alkyl tellurolate anions were added to ω-keto alkynyl esters in a Michael reaction, and the incipient vinyl anions were trapped intramolecularly by the internal aldehydes. The reactive centers were tethered by different lengths of alkyl chains to form highly functionalized five-, six-, seven-, and eight-membered rings in modest to good yields.
- Marino, Joseph P.,Nguyen, Hanh Nho
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p. 6291 - 6296
(2007/10/03)
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- Study of the regioselectivity in the hydrotelluration of hydroxy alkynes
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Vinylic tellurides were synthesized by the addition of organotellurols to acetylenic alcohols and the regioselectivity of the reaction was evaluated.
- Stefani, Hélio A.,Cardoso, Lincoln D. G.,Valduga, Claudéte J.,Zeni, Gilson
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p. 167 - 172
(2007/10/03)
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- Acid-catalyzed cyclization of vinylsilanes bearing a hydroxy group: A new method for stereoselective synthesis of disubstituted tetrahydrofurans
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In the presence of a catalytic amount of TsOH or TiCl4, (Z)-5-silyl-4-penten-1-ols ((Z)-1) are smoothly cyclized to 2-silylmethyl-substituted tetrahydrofurans. This cyclization is applicable to the construction of a tetrahydropyran ring. The silyl group and the geometry of the C-C double bond strongly influence the cychzation rate. TBDMS and benzyldimethylsilyl groups considerably accelerate the cyclization in comparison with a dimethylphenylsilyl group, and (E)-vinylsilanes show much lower reactivity than the corresponding (Z)-isomers. The cyclization proceeds by stereospecific syn addition of the hydroxy group. Vinylsilanes 17, 19, and 21, (Z)-5-silyl-4-penten-1-ols bearing a substituent on the methylene tether, smoothly undergo the acid-catalyzed cyclization to give trans-2,5-, cis-2,4-, and trans-2,3-disubstituted tetrahydrofurans, respectively, with moderate to high stereoselectivity. The silyl group of some cychzed products can be easily converted into a hydroxy group with stereochemical retention.
- Miura,Okajima,Hondo,Nakagawa,Takahashi,Hosomi
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p. 11348 - 11357
(2007/10/03)
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- Inhibition of protein kinase Cα by dequalinium analogues: Dependence on linker length and geometry
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Analogues of a bipartite compound, dequalinium (DECA) (quinolinium, 1,1'-(1,10-decanediyl)bis(4-amino-2-methyl diiodide)), were tested for inhibition of protein kinase Cα (PKCα). In vitro assays of monomeric and dimeric analogues support a model in which DECA inhibits PKCα by an obligatory two-point contact, a unique mechanism among PKC inhibitors. The presence of unsaturation in the center of the C10-alkyl linker produced geometric isomers with different inhibitory potencies: cis IC50 = 52 ± 12 μM and trans IC50 = 12 ± 3 μM, where the trans isomer was equipotent to that of the saturated C10-DECA. DECA analogues with longer, saturated linkers (C12, C14, or C16) exhibited enhanced inhibitory potencies which reached a plateau with the C14-linker (IC50 = 2.6 ± 0.2 μM). Metastatic melanoma cells treated with 250 nM C12-, C14-, or C16-DECA and irradiated with long-wave UV light (which causes irreversible inhibition of PKCα by DECA) confirmed the linker-dependent inhibition of intracellular PKCα activity.
- Qin, Donghui,Sullivan, Regina,Berkowitz, William F.,Bittman, Robert,Rotenberg, Susan A.
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p. 1413 - 1417
(2007/10/03)
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- Syn-oxidative cyclizations of trishomoallylic alcohols: Stereoselective and stereospecific synthesis of trans-tetrahydropyranyl alcohols
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Trifluoroacetylperrhenate promotes the hydroxyl-directed syn-oxidative cyclization of trishomoallylic alcohols. The cyclization reaction is highly stereospecific and stereoselective, providing a novel and efficient synthesis of trans-2,6-disubstituted tetrahydropyranyl alcohols.
- McDonald, Frank E.,Singhi, Aatur D.
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p. 7683 - 7686
(2007/10/03)
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- Preparation of methyl cis-9, trans-11- and trans-9, trans-11-octadecadienoate-17,17,18,18-d4, two of the isomers of conjugated linoleic acid
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A multi-step synthesis was used to prepare the cis-9, trans-11- and trans-9, trans-11-isomers (in a ratio of 46/54) of conjugated linoleic acid (cis-9, trans-11-octadecadienoic acid) labeled with deuterium atoms on the 17- and 18-carbon atoms (17,17,18,18-d4). The methyl cis/trans-9, trans-11-octadecadienoate-17,17,18,18-d4 isomer pair were obtained from the Wittig coupling of trans-2-nonenyltriphenyl-phosphonium bromide (8,8,9,9-d4) and methyl 9-oxononanoate. To prepare the phosphonium bromide. 5-hexyn-1-o1 was reduced with deuterium gas/Wilkinson's catalyst to yield 1-hexanol-5,5,6,6-d4. The alcohol was converted to the iodide with phosphorous pentoxide/phosphoric acid/potassium iodide. Coupling of the iodide with 2-propyn-1-o1 via lithium amide in liquid ammonia gave 2-nonyn-1-o1-d4. The acetylenic alcohol was reduced with lithium metal in liquid ammonia to yield the trans-2-nonen-1-o1-d4. The alcohol was converted to the bromide (using triphenylphosphine dibromide) and then converted to the phosphonium salt. The aldehyde ester was prepared by the reductive ozonization of methyl 9-cis-octadecenoate. The two conjugated linoleic acid isomers, formed during the final Wittig coupling reaction, were readily separated by a combination of reversed-phase and silver resin chromatography. Isotopic and chemical purities were > 95% for each geometric isomer. Overall yield (both isomers) from the 8-step synthesis was 12%.
- Adlof
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p. 107 - 112
(2007/10/03)
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- Studies related to fatty acids desaturation. II. Preparation of iso-linoleic and iso-vernolic acids
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New iso-vernolic and iso-linoleic acids have been prepared in order to study their potential inhibition action during in vivo desaturation of oleic acid in vegetal sources. - Keywords: Δ12-desaturase / modified fatty acids / Z,ω-octenyl bromides / iso-linoleic acids / iso-vernolic acids
- Gruiec, Regine,Noiret, Nicolas,Patin, Henri
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p. 699 - 705
(2007/10/02)
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- N-Alkenyl Nitrone Dipolar Cycloaddition Routes to Piperidines and Indolizidines. Part 7. Hydroxylamine-Alkyne Cyclisations. Formation of Cyclic Nitrones and Application to the Synthesis of the Proposed Structure for (+/-)-Acacialactam
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The cyclisation of the alkynylhydroxylamines 2, 13, 14, 19, 27, 34, 39, 46 and 47 to give five-, six- and seven-membered cyclic nitrones is described.A concerted intramolecular ene-like pathway is proposed for the addition of the N-O-H group across the tr
- Fox, Martin E.,Holmes, Andrew B.,Forbes, Ian T.,Thompson, Mervyn
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p. 3379 - 3396
(2007/10/02)
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- First total synthesis of a barnacle hatching factor 8(R)-Hydroxy-eicosa-5(Z),9(E),11(Z),14(Z),17(Z)-pentaenoic acid
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The first total synthesis of a barnacle hatching factor (BHF) establishes its constitution and absolute stereochemistry as 8(R)-Hydroxy-eicosa-5(Z),9(E),11(Z),14(Z),17(Z)-pentaenoic acid 1.
- Shing, Tony K.M.,Gibson,Wiley, Jonathan R.,Watt, C. Ian F.
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p. 1067 - 1070
(2007/10/02)
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- Synthesis of methyl (Z)-tetracos-5-enoate and both enantiomers of ethyl (E)-6-methyltetracos-4-enoate: Possible intermediates in the biosynthesis of mycolic acids in mycobacteria
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The high molecular weight 2-alkyl-3-hydroxy mycolic acids are key structural components of the cell envelope of pathogenic mycobacteria, such as Mycobacterium tuberculosis. A prime target for drug action would be the initial stages where the biosynthetic pathways diverge from those of ordinary fatty acids. It has been postulated that the pathway for the α-mycolates, without oxygen functions in addition to the hydroxy-acid unit, appears to diverge from (Z)-tetracos-5-enoic acid. The biosynthesis of oxygenated mycolic acids is considered to possibly diverge from (E)-6-(R)-methyltetracos-4-enoic and (E)-6-(S)-methyltetracos-4-enoic acids. This communication describes the synthesis of esters of these acids in order to test their potential role in the biosynthesis of mycolic acids.
- Besra, Gurdyal S.,Minnikin, David E.,Wheeler, Paul R.,Ratledge, Colin
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- Strong-Base-Induced Intramolecular Cycloaddition of Homophthalic Anhydrides: An Efficient Synthesis of Polycyclic peri-Hydroxy Aromatic Compounds
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A strong-base-induced intramolecular cycloaddition reaction of homophthalic anhydrides has been examined as a method for preparing nonlinear polycyclic peri-hydroxy aromatic compounds.
- Kita, Yasuyuki,Okunaka, Ryuichi,Honda, Takao,Shindo, Miki,Taniguchi, Miyako,et al.
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p. 119 - 125
(2007/10/02)
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- Stereoselective Formation of trans-1,2-Disubstituted Cyclopentanes by Intramolecular Cyclisation of Allylsilane Alkylidene 1,3-Dioxo Compounds
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The alkylidene 1,3-dioxo compounds 4a-d with an allylsilane moiety undergo a fluoride-, Lewis acid- and TMSOTf-induced intramolecular cyclisation to give almost exclusively the trans-1,2-disubstituted cyclopentanes 5a-d in good to excellent yields.The dia
- Tietze, Lutz F.,Ruther, Michael
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p. 1387 - 1395
(2007/10/02)
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- Asymmetric Bioreduction of Ethyl 3-Oxobutanoate by Immobilized Baker's Yeast Entrapped in Calcium Alginate Beads. Application of the Immobilized Biocatalyst to the Synthesis of (5Z,13S)-5-Tetradecen-13-olide, Aggregation Pheromone of Cryptolestes Grain Beetle
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Immobilized baker's yeast entrapped in calcium alginate beads of 1-1.5 mm diameter was reusable more than 10 times and stereoselectively reduced ethyl 3-oxobutanoate to the corresponding (S)-hydroxy ester in high chemical and optical yields.The immobilized biocatalyst was also successfully used for an asymmetric synthesis of (5Z,13S)-5-tetradecen-13-olide, a synergist of the aggregation pheromone of the flat grain beetle.
- Naoshima, Yoshinobu,Nakamura, Akihiro,Nishiyama, Tadashi,Haramaki, Toshikatsu,Mende, Mitsuo,Munakata, Yoshihito
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p. 1023 - 1026
(2007/10/02)
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- STRONG BASE INDUCED INTRAMOLECULAR CYCLOADDITION OF HOMOPHTALIC ANHYDRIDES LEADING TO POLYCYCLIC PERI-HYDROXY AROMATIC COMPOUNDS
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A strong base-induced intramolecular cycloaddition reaction homophthalic anhydride has been examined as a method for preparing polycyclic peri-hydroxy aromatic compounds.
- Kita, Yasuyuki,Okunaka, Ryuichi,Sasho, Manabu,Taniguchi, Miyako,Honda, Takao,Tamura, Yasumitsu
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p. 5943 - 5944
(2007/10/02)
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- SYNTHESE REGIOSPECIFIQUE D'ALLENES TERMINAUX A PARTIR DE PROPARGYLTRIMETHYLSILANES SIMPLES OU FONCTIONNELS
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Protodesilylation of varied propargyltrimethylsilanes, using boron trifluoride-acetic acid as reagent, give regiospecifically terminal allenes with very good yields.Yet, particular ω-functional propargyltrimethylsilanes may lead to vinylsilanes resulting
- Pornet, J.,Damour, D.,Miginiac, L.
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p. 333 - 344
(2007/10/02)
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- SYNTHESE ET REACTIVITE DE SILANES PROPARGYLIQUES ω-FONCTIONNELS : PREPARATION DE VINYLIDENE-3 OXOLANNES, OXANNES, OXEPANNES ET OXOCANNES
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The ω-silyloxypropargyltrimethylsilanes regiospecifically react with aliphatic and aromatic aldehydes to lead to vinylidene oxigen-containing heterocycles, such as 3-vinylidene oxolanes, oxanes, oxepanes and oxocanes.
- Pornet, J.,Damour, D.,Miginiac, L.
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p. 2017 - 2024
(2007/10/02)
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- SHORT INTRAMOLECULAR DIELS-ALDER APPROACH TO FUNCTIONALIZED SPIRODECANES
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The intramolecular Diels-Alder reaction of a (5'-hexynyl)cyclopentadiene provides a 1,2-tetramethylene-bridged norbornadiene which undergoes selective monohydrogenation followed by ozonolysis to provide the title compounds.
- Nystroem, Jan-E.,McCanna, Terrence D.,Helquist, Paul,Iyer, Ramnath S.
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p. 5393 - 5396
(2007/10/02)
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- Systematic Syntheses and Charactarization of Dodecadien-1-ols with Conjugated Double Bond, Lepidopterous Sex Pheromones
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Four geometrical isomers of 5,7-, 6,8-, 7,9- and 8,10-dodecadein-1-ols were systematically synthesized by two routes.One involved the Wittig reaction between (E)-2-alkenal and a phosphorane with an appropriate carbon chain, and yielded a mixture of (E,Z)- and (E,E)-isomers in a ratio of ca. 3:2.The other route comprised of the Wittig reaction of a 2-alkynal and the stereoselective reduction of the triple bond to a (Z)-double bond via hydroboration with dicyclohexylborane to give a mixture of (Z,Z)- and (Z,E)-isomers in a ratio of 6:1 10:1.Both the mixtures were separately chromatographed on a silica gel column impregnated with silver nitrate to give four geometrically pure isomers.With 9,11-diene they were analysed by GC on a capillary column, HPLC, silver nitrate impregnated TLC, and 13C NMR.
- Ando, Tetsu,Kurotsu, Yuichi,Kaiva, Mieko,Uchiyama, Masaaki
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p. 141 - 148
(2007/10/02)
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- ALKYNE-COBALT COMPLEXES AS PROSTAGLANDIN SYNTHONS. III. IMPROVED ROUTE TO METHYL (Z)-NON-5-EN-8-YNOATE AND SYNTHESIS OF A NEW PROSTAGLANDIN E2 ANALOGUE.
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Hydrogenation of methyl 7-hydroxyhept-5-ynoate followed by formation of the p-toluene-p-sulphonate ester and reaction with ethynylmagnesium bromide leads to an improved synthesis of methyl Z-non-5-en-8-ynoate, whose hexacarbonyldicobalt complex reacts smoothly with 2,5-dihydrofuran.Conventional "mixed cuprate" methodology is used to add the "β"-side chain producing a novel, but biologically inactive bicyclic prostaglandin E2 analogue.Cobalt carbonyl complexed selectively with the terminal triple bond of a 1,3-diyne but the product proved unsuitable for similar synthetic elaboration.
- Daalman, Lachlan,Newton, Roger F.,Pauson, Peter L.,Taylor, Ronald G.,Wadsworth, Alan
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p. 3131 - 3149
(2007/10/02)
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- SYNTHESIS OF HIGHER ACETYLENIC ALCOHOLS
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The alkylation of 1-alkynes in various solvents was investigated, and the optimum conditions for the production of acetylenic alcohols were obtained.
- Kovalev, B. G.,Matveeva, E. D.,Stan, V. V.,Vovk, G. A.,Yudin, L. G.,Kost, A. N.
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p. 1728 - 1733
(2007/10/02)
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