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1.
《Mendeleev Communications》2020,30(4):421-423
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2.
Nicolaou KC Li Y Sugita K Monenschein H Guntupalli P Mitchell HJ Fylaktakidou KC Vourloumis D Giannakakou P O'Brate A 《Journal of the American Chemical Society》2003,125(50):15443-15454
The total synthesis of apoptolidin (1) is reported together with the design, synthesis, and biological evaluation of a number of analogues. The assembly of key fragments 6 and 7 to vinyl iodide 3 via dithiane coupling technology was supplemented by a second generation route to this advanced intermediate involving a Horner-Wadsworth-Emmons coupling of fragments 22 and 25. The final stages of the synthesis featured a Stille coupling between vinyl iodide 3 and vinylstannane 2, a Yamaguchi lactonization, a number of glycosidations, and final deprotection. The developed synthetic technology was applied to the construction of several analogues including 74, 75, and 77 which exhibit significant bioactivity against tumor cells. 相似文献
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[reaction: see text] The enantioselective synthesis of a 7,11-dihydroxyguaianolide bearing the stereochemistry present in thapsigargin, a potent and selective inhibitor of the Ca(2+) SERCA-ATPase pumps, is described. Starting from (+)-dihydrocarvone, the synthesis presents two key steps. The first one involves the photochemical rearrangement of a gamma,delta-unsaturated ketone eudesmane into the corresponding guaiane. The second step consists of the regioselective oxidation of an unprotected tetrahydroxylated ketone to provide a dihydroxylactone with the required stereochemistry. 相似文献
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Paterson I Chen DY Coster MJ Aceña JL Bach J Wallace DJ 《Organic & biomolecular chemistry》2005,3(13):2431-2440
The antimitotic marine macrolide altohyrtin A/spongistatin 1 has been synthesised in a highly convergent and stereocontrolled manner, thus contributing to the replenishment of the largely exhausted material from the initial isolation work. Coupling of the AB- and CD-spiroacetal subunits by a stereoselective aldol reaction was achieved by using either a lithium (67 : 33 dr) or boron enolate (90 : 10 dr). A highly (Z)-selective Wittig coupling was used to unite the northern hemisphere aldehyde with the southern hemisphere phosphonium salt . Deprotection and subsequent regioselective macrolactonisation on a triol seco-acid completed the synthesis of altohyrtin A. Two structural analogues were also prepared and evaluated as growth inhibitory agents against a range of human tumour cell lines, including Taxol-resistant strains, alongside altohyrtin A and paclitaxel (Taxol), revealing that dehydration in the E-ring is tolerated and results in enhanced cytotoxicity (at the low picomolar level), whereas the presence of the full C44-C51 side-chain appears to be crucial for biological activity. 相似文献
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《Mendeleev Communications》2020,30(1):106-108
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6.
Novel d-seco paclitaxel analogues: synthesis, biological evaluation, and model testing 总被引:2,自引:0,他引:2
Barboni L Datta A Dutta D Georg GI Vander Velde DG Himes RH Wang M Snyder JP 《The Journal of organic chemistry》2001,66(10):3321-3329
Four new D-secopaclitaxel analogues were synthesized from paclitaxel. The key step of the synthesis involved the opening of the D-ring by Jones oxidation. Two of the compounds had been predicted to be nearly as active as paclitaxel in a minireceptor model of the binding site on tubulin, but all were biologically inactive in an in vitro cytotoxic assay and a tubulin assembly assay. The biological results identify a weakness in our predictive minireceptor model and suggest a corrective remedy in which additional amino acids are needed to accommodate ligand-protein steric effects around the oxetane ring. These changes to the model lead to correct predictions of the bioactivity. Conformational analysis and dynamics simulations of the compounds showed that the 4-acetyl substituent is as important as the oxetane in determining the A ring conformation. 相似文献
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Kseniya N. Sedenkova Dmitry A. Vasilenko Denis V. Zverev Kirill S. Sadovnikov Yulia A. Gracheva Yuri K. Grishin Tamara S. Kuznetsova Elena R. Milaeva Elena B. Averina 《Mendeleev Communications》2021,31(1):39-41
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8.
Total synthesis of gambierol: subunit coupling and completion 总被引:2,自引:0,他引:2
Johnson HW Majumder U Rainier JD 《Chemistry (Weinheim an der Bergstrasse, Germany)》2006,12(6):1747-1753
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Wiest O Harrison CB Saettel NJ Cibulka R Sax M König B 《The Journal of organic chemistry》2004,69(24):8183-8185
Two new artificial photolyase models that recognize pyrimidine dimers in protic and aprotic organic solvents as well as in water through a combination of charge and hydrogen-bonding interactions and use a mimic of the flavine to achieve repair through reductive photoinduced electron transfer are presented. Fluorescence and NMR titration studies show that it forms a 1:1 complex with pyrimidine dimers with binding constants of approximately 10(3) M(-1) in acetonitrile or methanol, while binding constants in water at pH 7.2 are slightly lower. Excitation of the complex with visible light leads to clean and rapid cycloreversion of the pyrimidine dimer through photoinduced electron transfer catalysis. The reaction in water is significantly faster than in organic solvents. The reaction slows down at higher conversions due to product inhibition. 相似文献
10.
Two components of the sex pheromone of the pink bollworm moth, (Z, Z)-7,11-hexadecadienyl acetate and its (Z, E)-isomer, were synthesized employing the Grignard coupling reaction as a key step. 相似文献
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Russian Chemical Bulletin - Barton-Zard reaction of nitrostilbenes with ethyl isocyanoacetate carried out in EtOH in the presence of K2CO3 allowed us to minimize the formation of side products and... 相似文献
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Kutasi AM Turner DR Jensen P Moubaraki B Batten SR Murray KS 《Inorganic chemistry》2011,50(14):6673-6684
The first examples of polymeric complexes that contain the polynitrile dianion hexacyanotrimethylenecyclopropanediide (HCTMCP(2-)) were isolated and their magnetic properties have been explored. Complexes of the form (n-TBA)(2)[M(HCTMCP)(2)(H(2)O)(2)] (1) (M = Mn(II), Fe(II), Co(II), Cd(II)) possess (4,4) sheet structures with large cavities that contain the tetra-n-butylammonium (n-TBA) countercations. Synthesis using sodium as the countercation yields a family of products with the general form [M(S)(4)M(S)(2)(HCTMCP)(2)] (S = EtOH, M = Fe(II) (2); S = MeOH, M = Co(II) or Zn(II) (3)). These complexes adopt a variety of two-dimensional (2D) structures. The complex [Mn(3)(HCTMCP)(2)(H(2)O)(12)](HCTMCP)·6(H(2)O) (4) contains cationic (6,3) sheets with the counteranion and solvent molecules encapsulated within the hexagonal windows. Complexes 1-4 display weak antiferromagnetic coupling in all cases. The first example of a complex that contains the CN-coordinated monoanionic radical HCTMCP (?-), [Cu(HCTMCP)(MeCN)(2)] (5) is described. This one-dimensional (1D) coordination polymer, containing tetrahedral Cu(I) centers, displays medium strength antiferromagnetic coupling that is mediated through π-interactions between the radical anions on adjacent chains. 相似文献
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Fürstner A Stelzer F Rumbo A Krause H 《Chemistry (Weinheim an der Bergstrasse, Germany)》2002,8(8):1856-1871
The first total synthesis of three naturally occurring cyclophane derivatives belonging to the turriane family of natural products is described. Their sterically hindered biaryl entity is formed by reaction of the Grignard reagent derived from aryl bromide 10 with the oxazoline derivative 18, and the macrocyclic tether of the targets is efficiently forged by ring closing metathesis. While conventional RCM catalyzed by the ruthenium-carbene complexes 33 or 34 invariably leads to the formation of mixtures of both stereoisomers with the undesirable (E)-alkene prevailing, ring closing alkyne metathesis (RCAM) followed by Lindlar reduction of the resulting cycloalkynes 37 and 38 opens a convenient and stereoselective entry into this class of compounds. RCAM can either be accomplished by using the tungsten alkylidyne complex [(tBuO)3 [triple bond] WCCMe3] or by means of a catalyst formed in situ from [Mo(CO)6] and para-trifluoromethylphenol. The latter method is significantly accelerated when carried out under microwave heating. Furthermore, the judicious choice of the protecting groups for the phenolic -OH functions turned out to be crucial. PMB-ethers were found to be compatible with the diverse reaction conditions en route to 3-5; their cleavage, however, had to be carried out under carefully optimized conditions to minimize competing O-C PMB migration. Turrianes 3-5 are shown to be potent DNA cleaving agents under oxidative conditions when administered in the presence of copper ions. 相似文献
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White JD Blakemore PR Green NJ Hauser EB Holoboski MA Keown LE Nylund Kolz CS Phillips BW 《The Journal of organic chemistry》2002,67(22):7750-7760
Rhizoxin D (2) was synthesized from four subunits, A, B, C, and D representing C3-C9, C10-C13, C14-C19, and C20-C27, respectively. Subunit A was prepared by cyclization of iodo acetal 21, which set the configuration at C5 of 2 through a stereoselective addition of the radical derived from dehalogenation of 21 at the beta carbon of the (Z)-alpha,beta-unsaturated ester. Aldehyde 29 was obtained from phenylthioacetal 24 and condensed with phosphorane 30, representing subunit B, in a Wittig reaction that gave the (E,E)-dienoate 31. This ester was converted to aldehyde 33 in preparation for coupling with subunit C. The latter in the form of methyl ketone 55 was obtained in six steps from propargyl alcohol. An aldol reaction of 33 with the enolate of 55 prepared with (+)-DIPCl gave the desired beta-hydroxy ketone 56 bearing a (13S)-configuration in a 17-20:1 ratio with its (13R)-diastereomer. After reduction to anti diol 57 and selective protection as TIPS ether 58, the C15 hydroxyl was esterified to give phosphonate 59. An intramolecular Wadsworth-Emmons reaction of aldehyde 62, derived from delta-lactone 60, furnished macrolactone 63, which was coupled in a Stille reaction with stannane 68 to give 2 after cleavage of the TIPS ether. 相似文献
18.
《Tetrahedron: Asymmetry》2005,16(9):1699-1704
A study on the synthesis of the isomers of the natural C-13 norterpenoids derivatives 7,11-epoxymegastigma-5(6)-en-9-one and 7,11-epoxymegastigma-5(6)-en-9-ols is reported. The latter compounds were prepared from readily available racemic α-ionone and then resolved by mean of lipase-mediated acetylation. The obtained enantiomerically forms were evaluated for their odour properties. 相似文献
19.
Ayub K Li R Bohne C Williams RV Mitchell RH 《Journal of the American Chemical Society》2011,133(11):4040-4045
The photochromic properties of dihydropyrenes have been substantially improved by making use of density functional theory (DFT) activation barrier calculations, which suggested that the di-isobutenylcyclophanediene 15' should have a significant barrier to thermal isomerization to the dihydropyrene (DHP) 15, which itself should resist isomerization involving migration of the internal groups to the rearranged dihydropyrene 9 (X = -CH═C(Me)(2)). As a result of these calculations, the synthesis of the colorless cyclophanediene (CPD) 15' was undertaken and achieved from the dinitrile 28 in four steps in 37% overall yield %. The cyclophanediene 15' thermally isomerized to the dihydropyrene 15 at 100 °C with t(1/2) = 4.5 h, giving an extrapolated 20 °C t(1/2) of ~16 y, consistent with the DFT calculations. No evidence for [1,5]-sigmatropic rearrangement in to 9 (X = -CH═C(Me)(2)) was observed on heating to 130 °C. The ring-opening isomerization quantum yields (?(open)) for DHP 15 in to CPD 15' were determined in cyclohexane to be 0.12 ± 0.01, which is three times greater than for the benzoDHP 1. Friedel-Crafts naphthoylation of 15 gave 70% of purple 32, which in toluene showed the largest photochemical ring-opening isomerization quantum yields (?(open)) of 0.66 ± 0.02 for any known dihydropyrene, ~nine times greater than 1 in toluene. The thermal closing of 32' to 32, although faster than for 15', gave a useful extrapolated t(1/2) of ~2 y at 20 °C. 相似文献