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Quantitative, qualitative, and group composition of resinous substances from the heartwood of larch (Larix sibirica Ledeb.), which are by-products of dihydroquercetin production, have been analyzed using highperformance liquid and gas chromatography. Isocembrol, a diterpene compound possessing the properties of a plant growth-regulating hormone, has been detected for the first time among the extractable substances from larch biomass. The chemical composition of the resinous substances implies high biological activity of the product analyzed and can be used to determine the areas of practical application of this product.

A pentachloro derivative, the structure of which was proved by x-ray structure analysis, in addition to a new dichlorocarbene derivative were obtained for the first time by dichlorocyclopropanation of arglabin guaianolide. The stereochemistry of the principal reaction product was established.

The results of studies of some terpenoids, alkaloids and phenolic derivatives isolated from Siberian plants are summarised. The structures of the compounds studied are presented and the chemical transformations of the available terpenoids and alkaloids are considered. Examples of practical application of natural compounds and their derivatives are given.

A chromatographically inseparable crystalline mixture of the previously undescribed quercetin-4′-O-β-galactopyranoside and the known quercetin-3-O-β-glucopyranoside (isoquercitrin) in a 7:5 ratio was isolated from the extract of the aerial part of Filipendula ulmaria (L.) Maxim.

The structure of the sesquiterpene ketone buddledin C isolated from Pulicaria prostrata (Gilib.) Aschers., was confirmed by XSA. The stereochemistry of its epoxide, which was formed selectively by treating it with hydrogen peroxide in alkaline solution, was proposed based on quantum-chemical and molecular-mechanical calculations.

2-Chloro-4,5α-epoxy-α-santonin and 2-chloro-α-santonin, the molecular structure of which was confirmed by an XSA, were produced by reacting α-santonin and chlorine in aqueous acetonitrile. It was found that 2-chloro-α-santonin is highly effective against trichomonas.

Four sesquiterpene lactones with the germacrane structure were isolated from the aerial part of Stizolophus balsamita. X-ray structure analyses showed that two of them were previously known balsamin derivatives. A third was a crystalline isomorphous mixture of the known lactone stizolin and 11,13-dihydrostizolin in a 53:47 ratio. The biological activities of the balsamin derivatives were investigated.

Reaction of the germacranolide stizolicin with secondary amines formed normal products of a Michael reaction at the exomethylene group and simultaneously led to solvolysis with cleavage of the acyl group. The structures of the molecules were established by XSA. Use of the HI salt of one of the resulting amines enabled the proof of its absolute configuration and that of the starting stizolicin, which had previously only been proposed. Stizolicin and the synthesized compounds were screened for antimicrobial and antitrichomonal activity.

Dibromocarbene and bisdichlorocarbene derivatives of the available sesquiterpene lactone arglabin were synthesized for the first time. The structures of the molecules were established by spectra methods and XSA.

Chemical components from the aerial part of the Kazakhstan population of Artemisia pontica, from which the rarely encountered flavonoids 7-O-methyl- and 4′,7-di-O-methyl-esters of apigenin were isolated for the first time, were identified. The complete chemical composition of the essential oil was established using GC-MS.

1,10-Dihydro-1α,10α-dinitrogrossmisin was synthesized by bubbling gaseous nitrosyl chloride through a chloroform solution of the guaianolide grossmisin. The molecular structure was determined by X-ray. It was found that the formation of similar dinitrates is accelerated by using NOCl containing nitrogen dioxide.

The stereoselective synthesis of two phosphorus-containing derivatives of the known guaianolide arglabin was carried out for the first time. The molecular structures of these products were established based on the spectroscopic data and the results of X-ray diffraction analysis of one of these compounds.

Bubbling gaseous nitrosylchloride through a chloroform solution of the guaianolide achillin produces very slowly but selectively 1,10-dihydro-1α,10α-dinitroachillin. This product rapidly, quantitatively, and irreversibly isomerizes into the dinitrocarboxylic acid with retention of the guaian carbon skeleton upon dissolution in pyridine. The structures of the new compounds were found by x-ray structural analysis

Acetonation of rhaposerin is accompanied by migration of the O-acetyl group. Acetonation of 15-O-deacetylrhaposerin afforded isomeric O-isopropylidene derivatives containing five- and six-membered rings.

As part of our continuing studies of lactones from the aerial part of the plant Rhaponticum serratuloides, 15-O-deacetylrhaposerin and new guaianolide called rhaserin were isolated along with the well-known loliolide. The configuration of the C(17) asymmetric center in 15-O-deacetylrhaposerin was established by X-ray diffraction analysis. The molecular structure of rhaserin was determined based on the data from 1H and 13C NMR spectroscopy (including 2D NMR spectroscopy) of this lactone and its 4,15-O-isopropylidene derivative.

The reaction of sesquiterpene lactone achillin with chlorine in methanol afforded four products,viz., two monochlorides and two dichlorides. One of these monochlorides is an intermediate in the formation of both dichlorides. The structures of the reaction products were established by two-dimensional NMR spectroscopy. The structure of one of the products was also established by X-ray diffraction analysis.

The oxime of artemisia ketone is smoothly converted to the pyrazole derivative by sodium nitrite and acetic acid in CHCl3. The structure of the pyrazole was found by x-ray structural analysis. The PMR and13C NMR spectra were interpreted using two-dimensional1H−13C NMR (COSY, COLOC).

Four phenolic components are isolated from the CHCl 3 extract ofEmpetrum nigrumL. Three of them are known from this plant. The fourth (6,8-dimethylpinocembrine) is isolated from crowberry for the first time. The previously proposed structure for 2'-methoxy-4'-hydroxy- α,β-dihydrochalcone is confirmed by x-ray structure analysis

Two new crystalline guaianolides,viz., rhaposerine and rhaserolide, were isolated from an ethanolic extract of the above-ground part of the plantRhaponticum serratuloides by column chromatography along with sesquiterpene lactones,viz., centaurepensin and acroptilin, which have been found in other plants. The chemical structures of the title lactones were established by1H and13C NMR spectroscopy and 2D1H−1H (COSY) and13C−1H (COSY and COLOC) NMR spectroscopy.

The new sesquiterpene lactone ajanolide A has been subjected to hydrolysis and epoxidation. The structures of the derivatives obtained have been established by x-ray structural analysis.

Adducts of dihalocarbenes generated from chloroform and bromoform were prepared by reaction with estafiatin guaianolide. Their structures were established by XSA.

A novel eudesmane sesquiterpene lactone, the structure of which was established by XSA, was isolated from Artemisia tournefortiana.

The sesquiterpene lactone pulchellin C has been epoxidized with trifluoroperacetic acid. The spatial structures 4(15)-α-epoxypulchellin and 5α, 6α-epoxyalantolactone have been established by x-ray structural analysis.

A new sesquiterpenoid lactone was isolated from terrestrial parts ofArtemisia subchrysolepis Filat. and studied by X-ray diffraction analysis and CD spectroscopy. This compound was called subchrysine and identified as (1R,3S,4E,6R,7S)-3-acetoxy-1-hydroxygernmacra-4,10(14), 11(13)-trien-12,6-olide. Pronounced temperature dependence of the1H and13C NMR spectra of subchrysine was observed. The results of conformational analysis of subchrysine by quantum-chemical (PM3) and molecular mechanics (MMX) methods are also presented.

A new sesquiterpene lactone having the structure 3β-acetoxy-1β-hydroxy-6β, 7α(H)-germacra-4,10(14), 11(13)-trien-6, 12-olide has been isolated fromArtemisia subchrysolepis Filat. and has been called subchrysin. Its stereochemistry has been established by x-ray structural analysis.

The sesquiterpene lactone argolide has been converted into its 1(10)-epoxide. The structure of the latter has been investigated by NMR, x-ray structural analysis, and molecular mechanics.

A new germacranolide, ajanolide A, was isolated from aerial parts ofAjania fruticulosa by means of extraction with CHCl3 and adsorption chromatography. This compound was identified as (1(10)E,3S,4Z,6R,7S,11R)-3-acetoxygermacra-1(10),4-dien-12,6-olide ((1S,7S,10R,13R)-7-acetoxy-4,8,13-trimethyl-11-oxabicyclo[8.3.0]trideca-4(E),8(Z)-dien-12-one) by X-ray diffraction analysis. 2D1H−1H (COSY) and13C−1H (COSY) NMR spectroscopy was used for assigning the1H and13C NMR signals in the spectra of ajanolide A.

A tetrabromo derivative of arglabin was synthesized stereoselectively. The molecular structure of the new compound was established using PMR and 13C NMR spectra and an x-ray structure analysis. Its antifungal activity was demonstrated.

A new bisazulene, the structure of which was established using x-ray structure analysis and PMR and 13C NMR spectra, was isolated from essential oil of Ajania fruticulosa obtained by steam distillation.

The germacranolide 11,13-dihydroridentin, for which the previously unknown S-configuration of the asymmetric center on C-11 was established, was isolated for the first time from Artemisia pontica L.

Dehydroisoleucomisin (anhydroaustricin) was converted in good yield to guai-1(10),3,5,7(11), 8-pentaen-2-on-12,8-olide by the action of anhydrous HCl in dry DMF. The chemical structure of the product was established using spectral data. The probable formation scheme of this lactone was proposed to include a series of prototopic transformations and ionic dehydrogenation of intermediates.

3,23-Dioxo-7,24-lanostadien-26-oic acids, components of a natural mixture of triterpenoids from Siberian fir needles, undergo fragmentation of the side-chain as well as condensation with piruvic acid formed in the reaction in boiling alcoholic alkali and give the 2-ethylidene derivative of the fragmentation product; the structure of the latter was established by NMR spectra and supported by X-ray analysis of its photoisomerization product.

(3aR*,6aR*)-3,3,5,5-Tetramethyl-3a,6a-dinitro-3a,6a-dihydro-3H-cyclopentano[c]pyrazol-2-oxide was formed by reaction of cycloartemisiaketone oxime [4,4-dimethyl-2-(1-methylethylidene)cyclopentanone oxime] with AcOH and NaNO2 in CHCl3 solution. The structure was solved by x-ray structure analysis.

The reaction of the oxime of verbenone, a bicyelie ketone, with sulfuric acid in acetonitrile gives a lactamsultone, which is readily separated and whose structure was demonstrated by x-ray diffraction structural analysis.

The reactions of the natural flavonoids tectochrysin and pinostrobin with chlorine in methanol afforded for the first time their 6,8-dichloro derivatives. Under the reaction conditions, dichloropinostrobin was transformed further into a tetrachloromethoxy derivative. The molecular structure of the latter was established by X-ray diffraction analysis.

A new trichlorometoxy derivative of achillin was isolated from the mixture of chlorination products of achillin in MeOH. The structure of this product was established by X-ray diffraction analysis. This confirmed the previously proposed stereochemistry for the molecules of other two products of this reaction.

Oxidation of (+)-sabinol, (1S,3R,5S)-1-isopropyl-4-methylidenebicyclo[3.1.0]hexan-3-ol, by active MnO2 afforded not the expected sabinone but only its [4+2]-cyclodimer. The molecular structure of the latter was established by X-ray diffraction analysis. The 1H and 13C NMR spectra of this cyclodimer were interpreted using 2D NMR spectroscopy.

The presence of bioregulators of animal organisms — dolichols — has been established in the needles, needle-free shoots, and bark of the Siberian stone pine. The qualitative and quantitative compositions of the mixtures of the isoprenologues and polyprenols have been established by the HPLC method. In addition, known diterpene alcohols ((E,E,E)-geranylgeraniol and labd-8(17),13E-dien-15-ol) esterified with higher fatty acids have been identified in the bark.

A mixture of gibberellin A3 derivatives with 1(10)-ene-2β,3β-diol and 1(10)-ene-2α,3β-diol (2:5) groups, readily obtained from gibberellin A3, has been used for a new and simple synthesis of gibberellin A8 and its esters. The hydrolysis of GA3 and the iodolactonization of a mixture of the 2-epimers was carried out in aqueous solution in a single flask, as also was a synthesis of GA56 from GA3 by a method that we have modified. The mixture of 1β-iodides of GA8 and GA56 was separated by chromatography on SiO2 in the form of methyl or p-bromophenacyl esters which were then deiodinated and the methyl or p-bromphenacyl ester of GA8 was isolated. Free GA8 was obtained by the dephenylation of the latter ester. By two-dimensional NMR spectroscopy we succeeded in assigning all the signals in the13C and1H NMR spectra of the methyl esters of GA8 and GA56. In an attempt to obtain GA5 methyl ester by the action of trimethylchlorosilane/sodium iodide on the 2α,3β-diol system in GA56 methyl ester, the 8,13-epimer of the latter was formed, the structure of its molecule being established from the results of X-ray structural analysis.

It has been established that during the cyclization of 5β-acetoxyisocembrol under the action of HCOOH + D2O the D atom enters position 7α of the product molecules exclusively, which is in harmony with the proposed cyclization scheme. Using model compounds, an alternative scheme for the formation of one of the products has been disproved.

The structures and the stereochemistries of all the main products of the carbocyclization of 5β-acetoxyisocembrol on its interaction with aqueous formic acid in chloroform have been established. This reaction takes place more selectively than the cyclization of cembrene under the same conditions and is distinguished by the complete predominance in its last stage of the 1,5-hydride shift from C-15 to C-4 over the splitting out of a proton from the C(4)-methyl group.

Under the action of N-bromosuccinimide in aqueous acetone, cembrene has given a low yield of a cyclization product, the structure and stereochemistry of the molecule of which have been established by x-ray structural analysis. In contrast to the cyclization of cembrene under the action of formic acid, in the reaction under consideration a 1,5-hydride shift in the last stage dominates substantially over the splitting out of a proton from the methyl group at C-4.

1α,2α-Epoxygibberellin A3 has been obtained for the first time in almost quantitative yield by the dehydroiodination of the known 1β-iodogibberellin A56, and the structure of its molecule has been established by the XSA method. An interpretation of all the signals in its1H and13C spectra has been made from the results of two-dimensional NMR. In the amylase biotest, 1α,2α-epoxgibberellin A3 exhibited an activity amounting to one third of the activity of gibberellin A3 at concentrations of 10−7 to 10−9 M.

When heated in benzene with paraformaldehyde and boric acid, 1,1"-methylenebis(2-naphthol) easily decomposes to 1,2-naphthoquinone 1-methide, which dimerizes into a spirodimer. The by-product of the reaction is 14I-dibenzo[a,j]xanthene.