Synthetic transformations of higher terpenoids. XXVII.* Synthesis of 7-hydroxylabdanoids and their transformations

Kharitonov, Yu. V.; ́ts, E. E. Shul; Gatilov, Yu. V.; Bagryanskaya, I. Yu.; Шакиров, М. М.; Толстиков, Г. А.

doi:10.1007/s10600-012-0215-3

Cited by 5 publications

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“…Selenium(IV) dioxide is still used for allylic hydroxylation in several multistep syntheses and transformations of natural products, their precursors and analogues such as 6-hydrocorticosteroids, 6-β-hydroxy derivatives of progesterone and testosterone, glycospirostanes, the optically pure cyclohexenone core scyphostatin and hydroxytaxadienes [39,40,41,42,43,44,45]. Allylic oxidation of phlomisoic acid and its methyl ester by selenium(IV) dioxide occurred stereoselectively to form α-hydroxy derivatives of labdanoids [46].…”

Section: Selenium(iv) Oxide and Selenic(iv) Acid As Oxidizing Agenmentioning

confidence: 99%

Developments in Synthetic Application of Selenium(IV) Oxide and Organoselenium Compounds as Oxygen Donors and Oxygen-Transfer Agents

2015

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A variety of selenium compounds were proven to be useful reagents and catalysts for organic synthesis over the past several decades. The most interesting aspect, which emerged in recent years, concerns application of hydroperoxide/selenium(IV) oxide and hydroperoxide/organoselenium catalyst systems, as "green reagents" for the oxidation of different organic functional groups. The topic of oxidations catalyzed by organoselenium derivatives has rapidly expanded in the last fifteen years This paper is devoted to the synthetic applications of the oxidation reactions mediated by selenium compounds such as selenium(IV) oxide, areneseleninic acids, their anhydrides, selenides, diselenides, benzisoselenazol-3(2H)-ones and other less often used other organoselenium compounds. All these compounds have been successfully applied for various oxidations useful in practical organic syntheses such as epoxidation, 1,2-dihydroxylation, and α-oxyfunctionalization of alkenes, as well as for ring contraction of cycloalkanones, conversion of halomethyl, hydroxymethyl or active methylene groups into formyl groups, oxidation of carbonyl compounds into carboxylic acids and/or lactones, sulfides into sulfoxides, and secondary amines into nitrones and regeneration of parent carbonyl compounds from their azomethine derivatives. Other reactions such as dehydrogenation and aromatization, active carbon-carbon bond cleavage, oxidative amidation, bromolactonization and oxidation of bromide for subsequent reactions with alkenes are also successfully mediated by selenium (IV) oxide or organoselenium compounds. The oxidation mechanisms of ionic or free radical character depending on the substrate and oxidant are discussed. Coverage of the literature up to early OPEN ACCESSMolecules 2015, 20 10206 2015 is provided. Links have been made to reviews that summarize earlier literature and to the methods of preparation of organoselenium reagents and catalysts.

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Section: Selenium(iv) Oxide and Selenic(iv) Acid As Oxidizing Agenmentioning

confidence: 99%

Developments in Synthetic Application of Selenium(IV) Oxide and Organoselenium Compounds as Oxygen Donors and Oxygen-Transfer Agents

2015

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“…The treatment of ketoxime 22 with thionyl chloride in anhydrous dioxane according to the literature procedure [9,12] 13 C HSQC NMR spectra suggested the presence of three isolated spin systems: CH 2 CH 2 CH 2 (C-11 to C-9), CHCH 2 NH (C-7 to NH), and CHCH 3 (C-4 to C-13) (Figure 3 The migration of a double bond  4(5) in precursor 23 to  5 (12) , as a result of the reaction, has additionally generated two centres of isomerism: a geometrical centre at C-5/C-12 and an optical one at C-4. The NOESY correlations between H-12 and H 3 -16, as well as H-12 and H-11, demonstrate the trans nature of the isomer at  5 (12) .…”

Section: Resultsmentioning

confidence: 99%

Synthesis of New Drimane and Homodrimane Lactams by Beckmann Rearrangement of Some Ketoximes

Secara¹

2016

ChemJMold

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“…Yield 92%, light brown oily material stable under argon. 1 Reaction of diene VII with 1,4-benzoquinones IXa-IXc (general procedure). a. Preliminarily sublimed quinone IXa-IXc, 3.6 mmol, and L-proline, 0.041 g (0.36 mmol), were added under argon to a solution of 1.9 g (4 mmol) of diene VII in 20 ml of benzene.…”

Section: Methodsmentioning

confidence: 99%

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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Synthetic transformations of higher terpenoids. XXVII.* Synthesis of 7-hydroxylabdanoids and their transformations

Cited by 5 publications

References 13 publications

Developments in Synthetic Application of Selenium(IV) Oxide and Organoselenium Compounds as Oxygen Donors and Oxygen-Transfer Agents

Developments in Synthetic Application of Selenium(IV) Oxide and Organoselenium Compounds as Oxygen Donors and Oxygen-Transfer Agents

Synthesis of New Drimane and Homodrimane Lactams by Beckmann Rearrangement of Some Ketoximes

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

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