Epoxidation of sesquiterpene lactones tourneforin and ludartin

Epoxy derivatives of the sesquiterpene lactones ludartin and tourneforin were synthesized. Their structures were elucidated using spectral data and x-ray structure analysis.     

Synthetic transformations of sesquiterpene lactones. IV.* Synthesis and transformations of <Emphasis Type="Italic">gem</Emphasis>-dichlorocyclopropyl-substituted isoalantolactone derivatives

Chloro-containing compounds, the ratio of which depended on the reaction time, were formed via reaction of isoalantolactone and CHCl₃ through the action of a phase-transfer catalyst. 4,15-(2,2-Dichlorocycloprop1-yl)isoalantolactone exhibited high activity and selectivity in the Heck reaction with arylhalides. Data for the cytotoxicity of the synthesized chloro-derivatives of isoalantolactone in CEM-13, MT-4, and U-937 cell tumor models were obtained. The doses of the most active compounds inhibiting the viability of tumor cells by 50 % (CCID₅₀) were 3.2–11.1 1 M.     

Synthetic transformations of sesquiterpene lactones 6. Alantolactone and isoalantolactone derivatives in the Heck reaction

The Heck reaction of the eudesman-type methylidenelactones (alantolactone, alloalantolactone, and 4,15-epoxyisoalantolactone) with haloarenes afforded the corresponding (E)-13-aryleudesma-4(15),11(13)-dien-8β,12-olides and 11-arylmethyl-13-noreudesma-4(15),7(11)-dien-8α,12-olides. The yields and the ratios of the arylation products depended on the reaction conditions and the structure of lactone. Certain side processes were found to take place.     

Synthetic transformations of sesquiterpene lactones. Controllable synthesis of 11,13-dihydroisoalantolactone azides and 13-(1,2,3-triazolyl)eudesmanolides based on sesquiterpene lactones

Chemistry of Heterocyclic Compounds - Modification of eudesmane-type lactones isoalantolactone and 4,15-epoxyisoalantolactone was carried out at the active methylene group. The reaction of...     

Synthetic transformations of sesquiterpene lactones: VII. Palladium-catalyzed cross-coupling of isoalantolactone with 5-halouracils

Palladium-catalyzed cross-coupling of isoalantolactone with 1,3-disubstituted or 1-substituted 5-bromo(iodo)uracils afforded mainly (13E)-13-(2,4-dioxotetrahydropyrimidin-5-yl)eudesma-4(15),11(13)-dien-8β,12-olides whose yields depended on the composition of the catalytic system, base, and additive. The structure of (13E)-13-[3-(2-cyanoethyl)-2,4-dioxotetrahydropyrimidin-5-yl]eudesma-4(15),11(13)-dien-8β,12-olide was proved by X-ray analysis.     

Synthetic transformations of isoquinoline alkaloids. Synthesis of new dihydrothebaine-hydroquinone derivatives

1-Bromo-and 1-iodo-6,14-endo-ethenodihydrothebaine-hydroquinones were obtained. The Heck reactions of these halides with various olefins were studied. Dedicated to the memory of Academician N. N. Vorozhtsov on the 100th anniversary of his birth. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1206–1214, June, 2007.     

A study of sesquiterpene lactones by13C NMR spectroscopy. I.13C NMR spectra of badkhyzin and its derivatives

The¹³C NMR spectra of badkhyzin and its derivatives have been studied.     

Synthesis and some transformations of 4-aryl-substituted amines of the tetrahydropyran series

The reaction of 2-isopropyltetrahydropyran-4-one [obtained by isomerization and hydration of 3-isopropylpent-1-en-4-yn-3-ol in the presence of 5% sulfuric acid and mercury(II) sulfate] with ethyl cyanoacetate gave ethyl cyano(2-isopropyltetrahydropyran-4-ylidene)acetate which was treated with 4-tolylmagnesium chloride. The resulting ethyl cyano[2-isopropyl-4-(4-tolyl)tetrahydropyran-4-yl]acetate was subjected to decarbethoxylation to obtain 2-isopropyl-4-(4-tolyl)tetrahydropyran-4-ylacetonitrile. The latter was reduced to the corresponding amine with lithium tetrahydridoaluminate, and the reduction product was brought into condensation with aromatic aldehydes. The Schiff bases thus formed were reduced with sodium tetrahydridoborate, followed by N-acylation with acetyl and propionyl chlorides.     

Synthesis and some transformations of functionally substituted lactones

Reactions of functionally substituted unsaturated five- and six-membered cyanolactones with α- and β-hydroxy ketones in the presence of sulfuric acid gave substituted 2-oxofuran- and 2-oxopyran-3-carboxamides. Hydrolysis of some keto amides thus obtained afforded the corresponding carboxylic acids, and reactions with hydrazines and semicarbazides led to hydrazones and semicarbazones at the side-chain oxo group.     

Investigation of sesquiterpene lactones by13C NMR spectroscopy. III.13C MNR spectra of artemin and its derivatives

The¹³C NMR spectra obtained under conditions of complete and incomplete decoupling from protons of the sesquiterpene lactone artemin (I), its dihydro derivative (II), and its acetyl derivative (III) have been studied. An assignment has been made of the chemical shifts of all the carbon atoms by comparison of the¹³C NMR spectra of (I), (II), and (III) with one another and also by comparison with literature information.V. L. Komarov Institute of Botany, Academy of Sciences of the AzSSR, Baku, Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 576–578, September–October, 1983.     

Synthetic transformations of higher terpenoids: XVIII. Synthesis of optically active 9,10-anthraquinone derivatives

Retro-Diels-Alder decomposition of dodecahydro-endo-4b,12-ethenochrysene-1,4-diones obtained from a tricyclic diterpenoid, levopimaric acid, gave optically active 5-[2-(6-vinyl-2,6-dimethyl-2-carboxycyclohexyl) ethyl]-7-isopropyl-1,4-naphthoquinones which reacted with silyloxybutadienes to produce the corresponding 6- and 7-hydroxyanthraquinones, 5-furyl-7-hydroxytetrahydroanthraquinones, or 5-furyl-7-oxohexahydroanthraquinones. Condensation of the naphthoquinone derivatives with 5-isopropenyl-2,3-dihydrothiophene 1,1-dioxide resulted in the formation of 6,11-dioxodihydro- and 6,11-dioxohexahydroanthra[2,1-b]thiophene 3,3-dioxides. 6- and 7-Hydroxyanthraquinones were also obtained by reaction of dodecahydro-endo-4b,12-ethenochrysene-1,4-diones with Danishevsky diene, followed by cleavage of the polycyclic adducts. The cycloaddition of 5-[2-(-2-carboxy-2,6-dimethyl-6-vinylcyclohexyl)ethyl]-7-isopropyl-1,4-naphthoquinones in the presence of Lewis acids was characterized by increased regioselectivity.     

A new lanostane-type triterpene and sesquiterpene lactones from Vernonia leopoldii and their in vitro cytotoxicity

Investigation of the aerial parts of Vernonia leopoldii (Sch. Bip.) Vatke afforded a new lanostane-type triterpene along with known hirsutinolide-type sesquiterpene lactones and flavonoid glycosides, all are identified for the first time in this species. The new compound was identified as lanost-3β, 23S-dihydroxy-22(31)-ene. The structures of the isolated compounds were elucidated based on spectroscopic evidence. The hirsutinolides and the triterpene were evaluated for their cytotoxicity against four human cancer cell lines using MTT assay.     

Synthesis of hybrid molecules containing fragments of sesquiterpene lactones and plant alkaloids

The Pd-catalyzed arylation of isoalantolactone by deoxyvasicinone and lappaconitine halides occurred with formation mainly of cross-coupling products with the (E)-configuration of the double bond. Another three compounds were isolated from the reaction of isoalantolactone with 6-bromodeoxyvasicinone. These were the lactone diarylation product, a compound with the (Z)-configuration of the double bond, and a product with a shift of the C(11,13) double bond and configuration inversion at C(8). The new compounds are interesting as potential biologically active agents.     

Synthesis and transformations of furan derivatives

Condensation of thiosemicarbazones of furfural, 3-(2-furyl)acrolein, as well as their 5-nitro derivatives with chloroacetone by boiling in alcohol or acetic acid gives the corresponding 4-methylthiazolyl-(2)hydrazones. 4-Methylthiazolyl-(2)-hydrazones of 5-nitro-2-acetylfuran and 5-nitro-2-furfurilydeneacetone can be prepared by condensing the corresponding thiosemicarbazones with chloroacetone by heating with glacial acetic acid containing fused sodium acetate.For Part IV see [1].     

Synthesis and transformations of pyrimidine derivatives

A methoxyl group in the 4 and 6 positions has a passivating effect on the ability of the methyl group in monomethoxymethylpyrimidine derivatives to enter into azo coupling; at the same time, a methoxyl group in the 2 position does not have an appreciable effect on the activity of the methyl group because the conjugation effect of the methoxyl group in this position is less than in the 4 and 6 positions.See [1] for Communication XVIII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1573–1574, November, 1970.