ChemInform Abstract: Synthesis of Polycyclic Sulfones.

Толстиков, Г. А.; Шульц, Э. Э.; Vafina, G. F.; Спирихин, Л. В.; Panasenko, A. A.

doi:10.1002/chin.198941163

Cited by 4 publications

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“…Their ratio was determined from the intensities of the singlet signals of the methyl groups C 20 H 3 (δ 0.74 and 0.75 ppm) and The stereoselectivity in the reactions of dienes VII and VIII with N-methylmaleimide (XIII) is likely to be determined by the upside attack of the dienophile with formation of less sterically hindered endo-transition state. Analogous stereoselectivity was observed by us previously in the Diels-Alder reaction of 1-(furan-2-yl)-substituted siloxybutadienes with cyclic dienophiles [12,13].…”

supporting

confidence: 51%

“…In the reaction of diene VII with quinone IXa in boiling benzene under argon (the conditions were analogous to those described in [12]), followed by treatment with water, we isolated by chromatography on silica gel 8-substituted 6-hydroxy-1,4-naphthoquinone X (yield 45%) and ketone IV. When the reaction was carried out in the presence of L-proline, other conditions being equal, the yield of compound X increased to 70%.…”

Section: XIIImentioning

confidence: 98%

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Synthetic transformations of higher terpenoids: XXVIII. Diels-Alder reactions of 16-(trimethylsiloxybutadienyl) labdanoids

et al. 2012

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15,16-Epoxy-16-(3-trimethylsiloxybuta-1,3-dien-1-yl)labdanoids were synthesized, and their reactions with cyclic dienophiles (1,4-benzoquinone, 1,4-toluquinone, 2-bromo-6-methyl-1,4-benzoquinone, and N-methylmaleimide) were studied. The reactions with unsymmetrically substituted benzoquinones were not selective. Methods for the preparation of hybrid compounds containing furan diterpenoid and substituted naphthoquinone, octahydroisoindoletrione, or hexahydroisoindoledione fragments were proposed. * For communication XXVII, see [1]. Lambertianic acid (I) is a plant furanoditerpenoid produced by the Siberian pine Pinus sibirica R. Mayr.; it is used for the preparation of a number of other natural compounds [2, 3], including phlomisoic acid (II). The latter is formed as a result of enzymatic hydrolysis of glycosides in medicinal plants of the Lamiaceae family, Phlomis sp. and Eremostachys sp. [4].We previously reported on modification of the furan ring in I and II, which afforded pharmacologically important compounds exhibiting analgesic activity [5] and cytotoxicity against CEM-13, MT-4, and U-937 model tumor cells [6]; they also turned out to regulate cytostatic polychemotherapy [7]. In the present article we describe the synthesis of furanolabdanoid derivatives having an additional pharmacophoric fragment (naphthoquinone or isoindoledione) on C 16 . These compounds were synthesized by DielsAlder reactions of 16-(3-trimethylsiloxybuta-1,3-dien-1-yl)-substituted furanolabdanoids with benzoquinones and N-methylmaleimide. It should be noted that model 1-furyl-3-trimethylsiloxybuta-1,3-dienes were successfully used previously in the synthesis of a series of pharmacologically important compounds [8]. New optically active labdanoid trimethylsiloxybutadienes were obtained by silylation of the corresponding ketones synthesized by condensation of 16-formylphlomisoic acid methyl ester (III) [9] with acetone and ethyl acetoacetate.Aldol-type condensation of aldehyde III with acetone gave 94% of ketone IV, whereas Knoevenagel condensation of III with ethyl acetoacetate in the presence of piperidine and acetic acid required prolonged heating (21 h under reflux) and led to the formation of a mixture of Z/E-isomeric keto esters V and VI at a ratio of 1.3 : 1 (according to the NMR data, yield 89%; Scheme 1). When the reaction was carried out in the presence of 0.1 equiv of (+)-pseudoephedrine or L-proline [10], it was possible to use a smaller amount of ethyl acetoacetate, and the reaction time was shortened to 8 h. In this case, compounds V and VI were isolated in an overall yield of 94% (after purification by column chromatography). The ratio of compounds V and VI changed insignificantly (from 1 : 1 to 1.5 : 1), depending on the catalyst.Ketone IV reacted with excess chlorotrimethylsilane in acetonitrile in the presence of anhydrous zinc chloride and triethylamine under argon to produce 16-(3-trimethylsiloxybuta-1,3-dien-1-yl) derivative VII as an oily substance (yield 92%, Scheme 2). Compound VII was stable under argon; on expo...

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confidence: 51%

Section: XIIImentioning

confidence: 98%

Synthetic transformations of higher terpenoids: XXVIII. Diels-Alder reactions of 16-(trimethylsiloxybutadienyl) labdanoids

et al. 2012

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“…Furyl ketones are starting compounds in the synthesis of the trimethylsilyl ethers of enols, They react readily and with high yields with trimethylsilane in the presence of triethylamine in dimethylformamide [236][237][238][239] Stlyl ethers wtrh the stlyloxy group separated from the furan rtng were obtatned from the carbonyl dertvattves bv varlous methods by the actton of lrthtum dttgopropylarntde and chloro\tlanes at -78°C tn a mixture of hexaniethyl phosphorotrtamtde and tetrahydrofuran [241], by treatment of a furyl-containtng ketone w~t l i tr~methylstlyl trtflare In the presence of tr~ethylamrne 12421 or trtmerhylchlorostlane by the actron of 71nc c h l o r~d e and trtethylan~rne [243] …”

Section: P Rmentioning

confidence: 99%

Furan derivatives of group IV elements (review)

Lukevits¹,

Pudova²

1995

Chem Heterocycl Compd

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“…During these reactions, we observed the loss of CF 3 CO group. While the stability of [CF 3 CO] + group in gas phase has been reported, to the best of our knowledge reactions involving the loss of CF 3 CO are rarely reported in the literature. − …”

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confidence: 92%

Amination of CF₃-Enones with Nosyloxycarbamates

et al. 2006

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CF3-enones showed a different reactivity in amination reactions with nosyloxycarbamates. 4-Oxazolines or vinyl carbamates were obtained as unique products depending on the nature of double-bond substituents and on the choice of carbamates and bases. Starting from trans-trifluoroacetyl olefins carrying a heterocyclic residue or the p-methoxyphenyl group on the double bond, a rare loss of CF3CO was observed when the aminations were performed under heterogeneous conditions using CaO as the base.

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ChemInform Abstract: Synthesis of Polycyclic Sulfones.

Abstract: The title compounds are prepared by diene reaction between the isopropenylthiolene dioxide (III) and the corresponding quinones.

Cited by 4 publications

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Synthetic transformations of higher terpenoids: XXVIII. Diels-Alder reactions of 16-(trimethylsiloxybutadienyl) labdanoids

Synthetic transformations of higher terpenoids: XXVIII. Diels-Alder reactions of 16-(trimethylsiloxybutadienyl) labdanoids

Furan derivatives of group IV elements (review)

Amination of CF₃-Enones with Nosyloxycarbamates

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ChemInform Abstract: Synthesis of Polycyclic Sulfones.

Abstract: The title compounds are prepared by diene reaction between the isopropenylthiolene dioxide (III) and the corresponding quinones.

Cited by 4 publications

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Synthetic transformations of higher terpenoids: XXVIII. Diels-Alder reactions of 16-(trimethylsiloxybutadienyl) labdanoids

Synthetic transformations of higher terpenoids: XXVIII. Diels-Alder reactions of 16-(trimethylsiloxybutadienyl) labdanoids

Furan derivatives of group IV elements (review)

Amination of CF3-Enones with Nosyloxycarbamates

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Amination of CF₃-Enones with Nosyloxycarbamates