The β-elimination route to stereodefined γ-alkylidenebutenolides

Brückner, Reinhard

doi:10.1039/b007590f

Cited by 58 publications

(24 citation statements)

References 53 publications

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“…α,β-Unsaturated lactones possessing an alkylidene appendage group at the γ-position, are frequently termed γ-alkylidenebutenolides [1][2][3]. Over the past few decades, an increasing number of these compounds has been isolated from various natural sources [4].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Cytotoxic Activity of Some 3-Benzyl-5-Arylidenefuran-2(5H)-ones

et al. 2007

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3-Benzyl-furan-2(5H)-one (2a) and 3-(4-bromobenzyl)-furan-2(5H)-one (2b) were treated with TBDMSOTf and converted into the corresponding tert-butyldimethylsilylfuran ethers. These furans were further condensed with several aromatic aldehydes affording compounds 5-14 with general 3-benzyl-5-arylidene-furan-2(5H)-one structures in 31% to 98% yields. Such compounds are analogues of the naturally occurring nostoclide lactones, reported to present moderate cytotoxic activity. Compounds 5-14 were submitted to an in vitro bioassay against the HL-60, HCT-8, SF295 and MDA-MB-435 cancer cell lines using the MTT cytotoxicity assay.

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Section: Introductionmentioning

confidence: 99%

Synthesis and Cytotoxic Activity of Some 3-Benzyl-5-Arylidenefuran-2(5H)-ones

et al. 2007

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“…These routes outline new reaction pathways in the synthesis of derivatives of ketolides molecules or sugar derivative-ylidenebutenolides, a class of well-known physiologically active moieties [4,5,32].…”

Section: Discussionmentioning

confidence: 99%

A kinetic, spectral and theoretical investigation on the role of oxygen in the radiolytic oxidation of a sorbityl cyclic acetal

Poggi

D’Angelantonio

Russo

et al. 2008

Res. Chem. Intermed.

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Abstract-The oxidation process of the cyclic acetal sorbitylfurfural (SF) has been thoroughly examined from the kinetic, spectroscopic and theoretical point of view. Oxidation has been initiated by the radiolitically produced OH radical in the presence of variable oxygen amounts. Two competing reaction pathways are evidenced which lead to quite different products, although they do not affect the acetal ring integrity. The peroxidation of the hydroxylated furanic ring (k 4 = (6.1 ± 0.9) × 10 8 M −1 s −1 ) maintains the ring structure via HO • 2 elimination (k 6 = (1.9 ± 0.4) × 10 5 s −1 ). Unlike that, the peroxidation of the pseudo-allylic radical (k 5 = (1.9 ± 0.9) × 10 9 M −1 s −1 ), formed via β-cleavage, fixes the destructured intermediate, leading to a tetroxide, which slowly decomposes through a Russell mechanism (k 8 = (2.3 ± 0.6) × 10 2 s −1 ). It is confirmed that the steady state concentration of the tetroxide is very low, which suggests a molar absorption coefficient for it around 1.2 × 10 4 M −1 cm −1 at 265 nm. The end products of the latter pathway have been characterized as carboxylic and butenal D-sorbitol derivatives. The kinetic and spectral data of every step of the process have been fitted by the above outlined mechanism. The energetics of the mechanism has been detailed by ab initio computations as well, carrying further substantiation to it. Semi-empirical calculations were also employed to describe the spectral properties of each intermediate.

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“…Derivatives of ascorbic acid with the two aliphatic hydroxy groups converted into leaving groups are known to exhibit highly regio-specific reactivity against nucleophiles (elimination at the CH-carbon atom and substitution at the CH 2 -carbon atom) [2][3][4].…”

Section: Discussionmentioning

confidence: 99%

Crystal structure of (7Z)-7-(2-azidoethylidene)-2,3-dihydrofuro[3,4-b] [1,4]dioxin-5(7H)-one, C8H7N3O4

Ries¹,

Sander²,

Neis³

et al. 2008

Zeitschrift Für Kristallographie - New Crystal Structures

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Source of materialThe title compound was obtained from 2,3-O-ethandiyl-5,6-Oditosyl-L-ascorbic acid [1], which was allowed to react with 10 equiv. of NaN 3 in DMF for aperiod of 48 hat298 K. The reaction mixture was poured into water (273 K) and the product (60 % yield) was isolated by filtration. Experimental detailsAll hydrogen atomic positions were taken from adifference Fourier map. They were refined with variable isotropic displacement parameters. The value of the Flack parameter of 0.2(8) has no evidence, because the part of the anomalous dispersion is too small (Mo-source and C,H,N,O elements). In the figure, the displacement ellipsoids are shown at the 50 %probability level. Hydrogen atoms are shown in arbitrary size. DiscussionDerivatives of ascorbic acid with the two aliphatic hydroxy groups converted into leaving groups are known to exhibit highly regio-specific reactivity against nucleophiles (elimination at the CH-carbon atom and substitution at the CH 2 -carbon atom) [2][3][4].The title compound is in further support for this proposal. The crystal structure analysis exhibited a Z-configuration for the new C=C double bond, indicative of an anti-periplanar orientation of the reactive hydrogen atom and the para-tolylsulfonyl group in the transient state of the elimination reaction. As expected, the five membered lactone ring is virtually planar (the deviation of the five ring atoms O2/C3/C4/C7/C8 from their mean plane is less than 0.002 Å), whereas the six membered dioxa-cyclohexene ring (O4/C5/C6/O3/C7/C4) is considerably puckered and has a half-chair conformation (puckering parameters: Q =0.466(3) Å, q =129.2(3)°, j =88.2(3)°) [5].

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The β-elimination route to stereodefined γ-alkylidenebutenolides

Cited by 58 publications

References 53 publications

Synthesis and Cytotoxic Activity of Some 3-Benzyl-5-Arylidenefuran-2(5H)-ones

Synthesis and Cytotoxic Activity of Some 3-Benzyl-5-Arylidenefuran-2(5H)-ones

A kinetic, spectral and theoretical investigation on the role of oxygen in the radiolytic oxidation of a sorbityl cyclic acetal

Crystal structure of (7Z)-7-(2-azidoethylidene)-2,3-dihydrofuro[3,4-b] [1,4]dioxin-5(7H)-one, C8H7N3O4

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