- The synthesis of methyl 4-(2-octadecylpropen-1-yl)butanoate: a possible inhibitor in mycolic acid biosynthesis
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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.It has been shown recently that (Z)-tetracos-5-enoic acid is a key initial intermediate in mycolic acid biosynthesis in extracs of Mycobacterium smegmatis.This acid is presumably formed by desaturation of tetracosanoate, and previous studies on oleic acid biosynthesis suggest that a cycloproene analogue may be a potential inhibitor.This communication describes the synthesis of methyl 4-(2-octadecylcyclopropen-1-yl)butanoate, which is shown elsewhere to be an inhibitor of the initial stages of mycolic acid synthesis. Key words: Mycobacteria; Mycolic acids; Cyclopropene fatty acid; Biosynthetic inhibitor
- Besra, Gurdyal S.,Minnikin, David E.,Simpson, Michael J.,Baird, Mark S.,Wheeler, Paul R.,Ratledge, Colin
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- Extended structural modulation of bio-inspired chiral lipidic alkynylcarbinols as antitumor pharmacophores
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The chiral alkynylcarbinol motif typically found in natural marine products, has been the subject of intense research activity for its pharmacophoric properties, in particular cytotoxicity against tumor cell lines. In a chemical synthesis-driven four-parameter structure-activity relationship (SAR) study from the (S,E)-eicos-4-en-1-yl-3-ol natural reference 1, the (S)-dialkynylcarbinol unit of the non-natural dehydro derivative 2 emerged as an unprecedented anti-tumoral pharmacophore. An extended study of lipidic alkynylcarbinol pharmacophores is presented, addressing additional structural parameters: Z→E isomerization of the alkenyl carbinol substituent of 1, variation of the lipidic chain length of 2 (C3n, n=3, 4, 6), oxidation or substitution of the carbinol unit of 2 (to ketone, tertiary methylcarbinol, or methylether), cyclomethylenation of the double bond of 1. The synthesis of these analogues is described, including the preparation of enantio-enriched chiral alkynylcarbinol derivatives using a modified Carreira procedure for Zn-mediated addition of (trialkylsilyl)acetylene substrates to ynals in the presence of (-)- or (+)-N-methylephedrine. Preliminary cytotoxicity evaluation of 12 new products against the HCT 116 tumor cell line are finally reported and the results compared with those obtained for 1 and 2. These observations support and refine the relevance of the pharmacophoric character of secondary DAC units.
- Listunov, Dymytrii,Billot, Chelmia,Joly, Etienne,Fabing, Isabelle,Volovenko, Yulian,Génisson, Yves,Maraval, Valérie,Chauvin, Remi
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p. 7920 - 7930
(2015/09/15)
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- Synthesis of elenic acid, an inhibitor of topoisomerase II
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A short, efficient synthesis of elenic acid, a marine natural product with interesting biological activity, has been completed. Critical features of the synthesis are the development of methodology for the one-pot elaboration of an alkyne to an (E)-β,γ-unsaturated ester with a stereocenter at the α-position and the use of the zipper reaction of a 1- arylalkyne. This reaction has not been previously reported with aromatic substrates. The synthesis strategy provides considerable flexibility for the preparation of structural analogues.
- Hoye,Baigorria,Danielson,Pragman,Rajapakse
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p. 2450 - 2453
(2007/10/03)
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- The synthesis of long chain dialkylalkynes, dialkyldiynes and their hydrogenation to monoenes and dienes
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Long methylenic chain dialkylalkynes have been synthesised in high yield by an improved procedure. The methodology has been extended to nonconjugated diynes. Catalytic hydrogenation with a poisoned palladium catalyst affords cis-monoenes and cis, cis-dienes respectively. An improved synthesis of cis- 9-tricosene is described.
- Fisher,Tyman
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p. 1323 - 1338
(2007/10/03)
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- IMPROVED NUCLEOPHILIC DISPLACEMENTS IN N-METHYL PYRROLIDINONE AS A SOLVENT
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The nucleophilic displacement reactions of 2- and 4-halogenonaphthalic-1,8-anhydrides and the N-imides, of 4,7-dichloroquinolines, the alkylation of lithio alkynes, the methylation of ethyl or methyl diacetylacetate and a variety of related reactions are greatly facilitated in N-methylpyrrolidinone as aprotic solvent.
- Tyman, John,Ghorbanian, Shoreh,Muir, M.,Tychopoulous, Vasiliki,Bruce, Ian,Fisher, Ian
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p. 179 - 188
(2007/10/02)
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- Plant Growth Regulators: Syntheses of n-Triacontynol, n-Triacontenol and n-Triacontanol
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Convenient syntheses of n-triacontynols (VII), n-triacontenols (VIII and IX) and n-triacontanol (X) are described.The alkynes (III) are coupled with bromo THP-ethers (VI) to yield the disubstituted n-triacontynols (VII).These on selective partial hydrogenation afford the disubstituted n-triacontenols (VIII and IX).Alkynols (VII) on complete hydrogenation give the n-triacontanol (X).Biological studies reveal that the acetylenes (VII) and olefins (VIII and IX) are better plant growth regulators than the n-triacontanol (X).
- Iyer, R. R.,Mamdapur, V. R.
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p. 1216 - 1219
(2007/10/02)
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- Total Synthesis of Naturally Occurring Mycolic Acids. (E)- and (Z)-threo-2-Docosyl-3-hydroxytetracont-21-enoate
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The ethyl esters of (E)- and (Z)-2-docosyl-3-hydroxytetracont-21-enoate (4a and 4b, respectively) have been prepared by a route involving alkylation of the dianion of ethyl 2-docosyl-3-oxobutyrate (2) with either (E)-1-iodo-17-hexatriacontene (14c) or (Z)-1-iodo-17-hexatriacontene (13c) and subsequent borohydride reduction of the intermediate β-keto esters (3a and 3b, respectively).Resolution of the 3:2 mixture of erythro and threo diastereomers of 4a and 4b was accomplished by high-performance liquid chromatography, employing phenacyl ester derivatives.The 1H NMR spectra of phenacyl (E)-threo-2-docosyl-3-hydroxytetracont-21-enoate (6a) and phenacyl (Z)-threo-2-docosyl-3-hydroxytetracont-21-enoate (6b) were identical with the spectra previously reported for the phenacyl esters of the naturally occurring monoalkene mycolic acids from Mycobacterium smegmatis (see ref 10).An examination of the phenacyl ester of the epoxide derivative of the naturally occurring mycolic acid by 1H NMR spectroscopy established that it was a 93:7 mixture of the Z and E isomers, respectively, of phenacyl threo-2-docosyl-3-hydroxytetracont-21-enoate.
- Huang, Harry C.,Rehmann, Jill K.,Gray, Gary R.
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p. 4018 - 4023
(2007/10/02)
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