- Concise synthesis of the bacterial DNA primase inhibitor (+)-Sch 642305
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Figure presented A highly convergent, enantioselective synthesis of (+)-Sch 642305 is presented, which features a Mukaiyama-Michael addition followed by allylation to establish the syn-anti relationship of the three contiguous stereocenters. The 10-member
- Wilson, Erica M.,Trauner, Dirk
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- Further study on synthesis of the cyclobakuchiols
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Abstract Two results are described. First, quinic acid was transformed into the monoacetate of 2-cyclohexene-1,4-diol. The Ni-catalyzed allylic substitution of the monoacetate with CH2C(Me)MgBr/ZnCl2/TMEDA followed by oxidation of th
- Kawashima, Hidehisa,Sakai, Masahiro,Kaneko, Yuki,Kobayashi, Yuichi
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- Sulfamate-tethered aza-Wacker approach towards analogs of Bactobolin A
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Here, we describe an approach towards analogs of the potent antibiotic Bactobolin A. Sulfamate-tethered aza-Wacker cyclization reactions furnish key synthons, which we envision can be elaborated into analogs of Bactobolin A. Docking studies show that the
- Nagamalla, Someshwar,Johnson, David K.,Sathyamoorthi, Shyam
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- Temporary thio-derivatization in the synthesis of (+)-4-acetylbromoxone
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A stereocontrolled synthesis of the marine natural products (+)-bromoxone (1) and (+)-4-acetylbromoxone (2) is reported. The sequence features the enzymatic kinetic resolution of 4-hydroxycyclohexenone (6) via its S-benzyl adduct. Thereafter, a base-mediated elimination-silylation generated an optically active (-)-4S-4-tert-butyldimethylsilyoxycyclohexenone (5), which then underwent diastereoselective epoxidation. Saegusa-Ito oxidation enabled formation of the corresponding α,β-unsaturated ketone 13. Bromination-elimination and subsequent removal of the silicon protecting group afforded (+)-bromoxone (1) which was converted into (+)-(4S,5R,6R)-4-acetoxy-2- bromo-5,6-epoxycyclohex-2-enone (2) [(+)-4-acetylbromoxone]. Using a luciferase gene reporter assay ED50 for NFκB inhibition of 9 μM was determined.
- O'Byrne, Aisling,O'Reilly, Steven,Tighe, Catherine,Evans, Paul,Ciuffini, Laura,Gabriella Santoro
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- The thio-adduct facilitated, enzymatic kinetic resolution of 4-hydroxycyclopentenone and 4-hydroxycyclohexenone
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The addition of 3,4-dimethoxybenzyl thiol 8, as a benzyl thiol surrogate, to racemic 4-hydroxycyclopent-2-enone 2 and 4-hydroxycyclohex-2-enone 15 gave the corresponding cis-adducts (±)-3-(3,4-dimethoxybenzylthio)-4- hydroxycyclopentanone 4b and (±)-3-(3,4-dimethoxybenzylthio)-4- hydroxycyclohexanone 16 with good diastereocontrol. In both cases, subsequent treatment with vinyl acetate, in the presence of a lipase enabled enantiomer resolution. Thus, (+)-16 and the acetate of its enantiomer, (-)-(1R,2S)-2-(3,4- dimethoxybenzylthio)-4-oxocyclohexyl acetate, (-)-17 were isolated in 98% enantiomeric excess. Based on the 1,4-dioxygenation pattern, (-)-17 can be used to prepare both enantiomers of 4-(tert-butyldimethylsilyloxy)cyclohex-2-enone 19. Firstly, saponification, with a sub-stoichiometric amount of NaOMe, followed by a one-pot silyl ether formation-sulfide elimination sequence gave (+)-19. Then using the same starting material a 6-step sequence, featuring a diastereoselective NaBH4 reduction and a Cope-type sulfoxide elimination, gave (-)-19.
- O'Byrne, Aisling,Murray, Cian,Keegan, Dearbhla,Palacio, Carole,Evans, Paul,Morgan, Ben S.
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supporting information; experimental part
p. 539 - 545
(2010/05/11)
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- The synthesis of 2-oxyalkyl-cyclohex-2-enones, related to the bioactive natural products COTC and antheminone A, which possess anti-tumour properties
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The syntheses of five novel 2-oxyalkyl-cyclohex-2-enones, structurally related to the natural products COTC and antheminone A, are described. The target structures were selected in order to probe the influence of several key structural parameters on in vi
- Arthurs, Claire L.,Morris, Gareth A.,Piacenti, Michela,Pritchard, Robin G.,Stratford, Ian J.,Tatic, Tanja,Whitehead, Roger C.,Williams, Katharine F.,Wind, Natasha S.
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experimental part
p. 9049 - 9060
(2011/01/04)
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- (-)-Quinic acid: a versatile precursor for the synthesis of analogues of 2-crotonyloxymethyl-(4R,5R,6R)-4,5,6-trihydroxycyclohex-2-enone (COTC) which possess anti-tumour properties
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Syntheses of three novel analogues of the Streptomyces metabolite COTC are described, using the versatile chiral pool starting material, (-)-quinic acid. The results of bioassays of the target compounds against two lung cancer cell lines, A549 and H460, a
- Arthurs, Claire L.,Lingley, Katharine F.,Piacenti, Michela,Stratford, Ian J.,Tatic, Tanja,Whitehead, Roger C.,Wind, Natasha S.
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p. 2410 - 2413
(2008/09/18)
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- An efficient protocol for the enantioselective preparation of a key polyfunctionalized cyclohexane. New access to (R)- and (S)-4-hydroxy-2- cyclohexenone and (R)- and (S)-trans-cyclohex-2-ene-1,4-diol
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(Chemical Equation Presented) Starting from very accessible raw materials such as p-methoxyphenol, ethylene glycol, and thiophenol, a protocol has been developed to prepare multigram quantities of the polyfunctionalized cyclohexane (±)-7. A highly efficie
- Bayon, Pau,Marjanet, Georgina,Toribio, Gladis,Alibes, Ramon,De March, Pere,Figueredo, Marta,Font, Josep
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p. 3486 - 3491
(2008/09/21)
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- Novel preparation of (-)-4-hydroxycyclohex-2-enone: Reaction of 4-hydroxycyclohex-2-enone and 4-hydroxycyclopent-2-enone with some thiols
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A new route to (R)-4-hydroxycyclohex-2-enone from cyclohexanedione monoketal (27% yield) commences with reaction of the ketal with nitrosobenzene catalysed by l-proline. 4-Hydroxycyclohex-2-enone and 4-hydroxycyclopent-2-enone react with thiols to afford
- Bickley, Jamie F.,Evans, Paul,Meek, Alastair,Morgan, Ben S.,Roberts, Stanley M.
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p. 355 - 362
(2007/10/03)
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- Enantioselective approaches to potential MetAP-2 reversible inhibitors
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(Chemical Equation Presented) Enantioselective deprotonation of 4-substituted cyclohexanones and highly stereoselective conjugate addition of higher order mixed cuprates were the key steps in a concise synthesis of fumagalone-related molecules. The origin
- Rodeschini, Vincent,Van De Weghe, Pierre,Salomon, Emmanuel,Tarnus, Celine,Eustache, Jacques
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p. 2409 - 2412
(2007/10/03)
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- Total synthesis of (+)-apiosporamide: Assignment of relative and absolute configuration
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Antipodal relationship: A convergent synthetic pathway leading to 4-hydroxy-2-pyridinones was involved in the synthesis of apiosporamide (1) and YM-215343 (2). Both have an antipodal relationship to the natural metabolites, whose relative and absolute configurations have been established. Activated β-alanine enolate equivalents derived from β-lactams were the key to the synthesis. (Chemical Equation Presented).
- Williams, David R.,Kammler, David C.,Donnell, Andrew F.,Goundry, William R. F.
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p. 6715 - 6718
(2007/10/03)
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- Total synthesis of (+)-epiepoformin, (+)-epiepoxydon and (+)-bromoxone employing a useful chiral building block, ethyl (1R,2S)-5,5-ethylenedioxy-2-hydroxycyclohexanecarboxylate
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Enantioselective total synthesis of (+)-epiepoformin 1, (+)-epiepoxydon 2 and (+)-bromoxone 3 using a chiral building block, ethyl (1R,2S)-5,5-ethylenedioxy-2-hydroxycyclo- hexanecarboxylate 6, is described. Since the synthesis afforded intermediates 18, 2 and 25, it accomplished a formal synthesis of (-)-theobroxide 19, (-)-phyllostine 22, (+)-herveynone 27 and (-)-asperpentyn 28. The usefulness of 6 for the synthesis of natural epoxycyclohexene derivatives was demonstrated.
- Tachihara, Toru,Kitahara, Takeshi
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p. 1773 - 1780
(2007/10/03)
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- The effect of DMSO on the borohydride reduction of a cyclohexanone: A formal enantioselective synthesis of (+)-epibatidine
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An asymmetric synthesis of (+)-epibatidine is described which uses the increased stereoselectivity of a borohydride reduction induced by the presence of DMSO.
- Barros, M. Teresa,Maycock, Christopher D.,Ventura, M. Rita
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p. 557 - 560
(2007/10/03)
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