Diterpene Hydrocarbons Research Articles

Studies in terpenoids. Part 43: Synthesis of (±)-2,6-dimethyl-10-(p-tolyl) undeca-2,6 (E)-diene, the diterpene ofSalvia dorisiana

(±)-2, 6-Dimethyl-10-(p-tolyl) undeca-2,6(E)-diene (1a), a diterpene hydrocarbon from the essential oil ofSalvia dorisiana has been synthesised by two methods. One pot reaction ofp-tolylmagnesium bromide with geranylacetone (5) and hydrogenolysis of the resulting benzylic alcohol (1b) without isolation furnished the natural product (1a). In the other method citrylidene-p-methylacetophenone (6a) was used as the starting material. The trienone (6a) was reduced to the corresponding alcohol (6b) which was hydrogenated to (6c) and oxidised to the dienone (6d). Reaction of the dienone (6d) with methylmagnesium jdoide, followed by dehydration of the carbinol and reduction with lithium in liquid ammonia furnished the diterpene (1a).

Cubitene: an irregular twelve-membered-ring diterpene from a termite soldier

Cubitene was isolated from the hexane extract of C. umbratus soldier heads by chromatography over Florisil followed by preparative GLC. High resolution mass spectroscopy indicated the formula of cubitene to be C/sub 20/H/sub 32/. Mass spectra of catalytically hydrogenated cubitene products showed peaks at m/rho 279, consistent with their formulation as substituted cycloalkanes of the composition C/sub 20/H/sub 40/. Cubitene is therefore a monocyclic hydrocarbon with four centers of unsaturation. the /sup 1/H NMR spectral data revealed the presence of two 1,1-disubstituted double bonds, and two additional olefinic protons. Four methyl groups attached to double bonds are also observed. The /sup 13/C NMR spectrum indicated the presence of two tribsubstituted double bonds. Fortunately, cubitene could be obtained in crystalline form (mp 34.5-35/sup 0/C) from cold methanol, allowing a single-crystal x-ray diffraction analysis. It crystallized in the monoclinic crystal class. Lattice parameters were: a = 15.963 (5), b = 6.799 (2), c = 17.038 (5) A; theta = 96.99 (2)/sup 0/. Evidence shows cubitene to be 1,5-dimethyl-8,10-bis(isopropenyl)cyclododeca-1,5-diene, a structure in which one isoprene unit is irregularly joined to three others. It appears to be the first example of a diterpene hydrocarbon based on a twelve-membered carbocyclic ring. Its biosynthesis poses interestingmore » problems. Two possible biosynthetic routes are suggested. An even more basic question remains....whether termite soldiers synthesize cubitene at all, or whether they simply sequester it (or a closely related precursor) from their food.« less

Chemosystematic studies in the genus Abies. III. Leaf and twig oil analysis of amabilis fir

The volatile oil of the leaves, and also the twigs, of amabilis fir consists mainly of (−)-β-phellandrene, (+)-car-3-ene, (−)-β-pinene, (−)-α-pinene, myrcene, (−)-limonene, terpinolene, β-sesquiphellandrene, and β-bisabolene. Smaller relative amounts of santene, tricyclene, camphene, sabinene, α-phellandrene, cis- and trans-ocimene, γ-terpinene, linalool, terpinen-4-ol, α-terpineol, bornyl acetate, methyl thymol, thymol, α-cubebene, α-copaene, caryophyllene, humulene, and cadinene–muurolene isomers and their corresponding alcohols were also identified. The presence of three minor diterpene hydrocarbons and manool was indicated by gas chromatography – mass spectrometry.The quantitative variation within trees, between trees, and among northern, central, and southern populations was determined. The high tree-to-tree variability obscures any significant (P = 0.05) geographic trend that may exist. Several qualitative and many significant quantitative differences exist between the leaf oil compositions of amabilis, grand, alpine, and balsam firs andpossibly also noble, white, and California red firs, and these can serve well in chemosystematic studies.

Cyclization of Polyenes XVIII. Selective Synthesis of Cembrene

Abstract Cembrene(1) is a typical macrocyclic diterpene hydrocarbon having four double bonds in the ring. One is cis and the others are trans, respectively. Due to its skeletal as well as stereoisomerical points of view, cembrene is an attractive target for synthetic organic cherist. Dauben and his coworkers2 have recently carried out the first total synthesis by multi-step reactions.

Chemical studies of marine invertebrates. XXV1. Flexibilene, an unprecedented fifteen‐membered ring diterpene hydrocarbon from the soft coral Sinularia flexibilis (Coelenterata, Octocorallia, Alcyonacea)

AbstractFlexibilene is a novel monocyclic diterpene hydrocarbon isolated from the soft coral Sinularia flexibilis. Spectroscopic analyses established its structure as 1,1',5,9,13‐pentamethyl‐Δ2,5,9,13‐cyclopentadecatetraene (II). Flexibilene is the first 15‐membered ring diterpene to be found in nature.

Neutrals in southern pine tall oil

AbstractBlack‐liquor soap skimmings from commercial pulping of southern pine wood contained 4.8% neutrals by wt. The neutrals were quantitatively analyzed and more than 80 compounds found. All of the compounds that comprised 0.1% or more of the neutrals were identified; these included 0.3% α‐terpineol, 2.5% diterpene hydrocarbons, 8.1% resin alcohols, 10.0% resin aldehydes, 0.5% resin acid methyl esters, 1.2% norditerpene alcohols, 16.8% labdane diterpenes, 2.1% other diterpenes, 32.4% steroids, 0.6% triterpenes, 0.7% polyprenols, 6.1% wax alcohols, 5.7% stilbenes, 4.4% lubricating oil, and 8.6% minor (<0.1%) constituents. Sitosterol, campesterol, stigmastanol, pinosylvin dimethyl ether, lignoceryl and ceryl alcohols, agathadiol, isoagatholal, communol, abietal, and diterpenes with the pimarane or isopimarane skeleton were the major components.

Casbene: An anti-fungal diterpene produced in cell-free extracts of Ricinus communis seedlings

The capacity of cell-free extracts of 2·5-day-old castor bean seedlings for synthesis of casbene from mevalonic acid were compared for seedings which had been germinated under sterile conditions and seedlings which were intentionally exposed to fungal cultures. Extracts from seedlings exposed to cultures of Rhizopus stolonifer, Aspergillus niger or Fusarium moniliforme produced much higher levels of casbene than extracts from sterile controls; the initial rates of casbene synthesis were 20–40 times higher in the extracts of seedlings that had been exposed to fungus. Although some variation in the capacity for synthesis of other diterpene hydrocarbons from mevalonic acid was seen in the two types of extracts, no consistent or striking stimulation in the synthesis of any of these was noted under these conditions of exposure of the seedlings to fungi. The potato-dectrose agar used as a fungal growth medium did not itself evoke the increase in casbene synthesis. Intact mycelia and cell-free extracts of mycelia of Rhizopus stolonifer gave no indication of diterpene biosynthesis from mevalonic acid. Purified casbene at concentrations of 10 μg ml −1 or greater retarded the development of A. niger on potato-dextrose medium. Casbene was also found to inhibit the endogenous and gibberellic acid-stimulated growth of leaf sheaths of the dwarf-5 mutant of Zea mays and of the growth of the K-12 strain of Escherichia coli on glucose-minerals medium. It is suggested that casbene may serve the castor bean plant as a phytoalexin.

Terpenoids from oleoresin of Pinus taiwanensis

The neutral fraction of the oleoresin from Pinus taiwanensis contained 89%. of monoterpene hydrocarbons (α-pinene, camphene, β-pinene, myrcene, limonene, β-phellandrene, p-cymene), 8.6% of sesquiterpene hydrocarbons (longicyclene, longifolene and caryophyllene) and 2.4% of oxygenated compounds (bornyl acetate, 4-terpineol, myrtenal, trans-pinocarveol, trans-verbenol, verbenone, myrtenol, caryophyllene oxide, 13-epimanoyl oxide, longiborneol and methyl dehydroabietate). Two diterpene hydrocarbons [pimara-8(14),15-diene, dehydroabietane], three norterpenoids [nopinone, longicamphenylone and 18-norpimara-8(14),15-dien-4-ol] and 13 n-alkanes (C 22C 34) were also identified. The norterpenoids appear to be formed by autoxidation of hydrocarbons during the isolation process and the results of autoxidation of β-pinene and longifolene supported this view. The main constituent of the acidic part of the oleoresin was abietic acid (90%).

Composition of neutral oils from rosin

AbstractThe neutral fractions from gum, wood and tall oil rosins were isolated and examined by gas chromatography. The major components found were diterpene aldehydes and alcohols. Smaller quantities of diterpene hydrocarbons and monoterpenes were identified. The differences in the composition and concentrations of the neutral fractions appear to explain some of the differences in physical characteristics of the three types of rosin.

Dehydroabietane from the oleoresin of Pinus pallasiana

The known diterpene hydrocarbon dehydroabietane has been isolated from a natural source — the oleoresin of the Crimean pine — for the first time.

The volatile oil of the leaves of chamaecyparis nootkatensis

Analysis of the volatile leaf oil of the Alaska (yellow) cedar showed (−)-α-pinene, (+)-3-carene, and (+)-limonene to be the main constituents. In addition, nine monoterpene hydrocarbons, seven oxygenated monoterpenes, six sesquiterpene hydrocarbons, nerolidol, cedrol, bisabolol, α-cadinol, nine diterpene hydrocarbons (including one new one), manoyl-, 13- and 8-epimanoyl- and 8,13-diepimanoyl oxides, phyllocladol, six n-alkanes, three alkanals and nine C 5-branched chain or aromatic esters of isovaleric, 3-methyl-2-, and 3-methyl-3-butenoic acids were identified. The structures of the esters were confirmed by synthesis. Many of the sesquiterpene and diterpene hydrocarbons, cedrol and phyllocladol are typical constitutuents of the order Cupressales, but the new oxides and esters, the n-alkanes, alkanals, and possibly 1-methyl-4-isopropenyl- and 1-methyl-(α-hydroxyisopropyl)-benzene appear to be characteristic of this cedar species. The quantitative composition of the leaf oil from different trees varied little when the leaves were collected in winter, although some variation from one population to another may exist. Large losses of the low boiling components may ensue if the foliage is transported in an unsealed container.

Neocembrene — A new diterpene hydrocarbon from Picea obovata and Pinus koraensis

From the hydrocarbon fractions of the oleoresins ofPicea obovata Ledb andPinus koraensis Sieb. Zucc. a new monocyclic diterpene hydrocarbon — neocembrene — has been isolated, and a structure has been proposed for it.

The diterpenes from the leaves of Cryptomeria japonica

Cryptomeria japonica trees can be sub-divided into four chemically distinct varieties on the basis of the diterpene hydrocarbon content of their leaves. Seven other species from the Taxodiaceae have been analysed for diterpenes.

Biosynthesis of cyclic diterpenes in extracts from seedlings of Ricinus communis. II. Conversion of geranylgeranyl pyrophosphate into diterpene hydrocarbons and partial purification of the cyclization enzymes

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTBiosynthesis of cyclic diterpenes in extracts from seedlings of Ricinus communis. II. Conversion of geranylgeranyl pyrophosphate into diterpene hydrocarbons and partial purification of the cyclization enzymesDavid Rodney Robinson and Charles A. WestCite this: Biochemistry 1970, 9, 1, 80–89Publication Date (Print):January 6, 1970Publication History Published online1 May 2002Published inissue 6 January 1970https://doi.org/10.1021/bi00803a011RIGHTS & PERMISSIONSArticle Views246Altmetric-Citations81LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-Alerts Get e-Alerts

Biosynthesis of cyclic diterpenes in extracts from seedlings of Ricinus communis. I. Identification of diterpene hydrocarbons formed from mevalonate

Biosynthesis of cyclic diterpenes in extracts from seedlings of Ricinus communis. I. Identification of diterpene hydrocarbons formed from mevalonate

The enzymic preparation of 14C-kaurene

Endosperm from immature seeds of Cucurbita pepo L. converts 2-(14)C-DL-mevalonate to (14)C-(-)-kaurene with a yield of nearly 40% of the active isomer. Kaurene is the main product and the only diterpene hydrocarbon which is formed from mevalonate in the system and is therefore easily obtained radiochemically pure. The product was identified by thin-layer chromatography and recrystallization with authentic (-)-kaurene to constant specific radioactivity.

Quantitative analysis of mixtures of diterpene hydrocarbons by gas chromatography-mass spectrometry

The use of combined gas chromatography-mass spectrometry in the quantitative analysis of hydrocarbon mixtures containing components inseparable by gas chromatography is described.

The Aroma of Hops III. The Occurrence of Diterpenes in Hop Oil

AbstractTwo diterpene hydrocarbons have been isolated from hop oil. One is camphorene, the other is a hitherto unknown camphorene isomer. These terpene hydrocarbons, now called para and meta camphorene were not signalled before in hop oil.

Composition of the neutral fraction of the resin ofPinus sibirica R. Mayr.

1. The high-boiling neutral fraction of the resin of the Siberian cedar contains abietinal, a diterpene diol C20H34O2, and the diterpene alcohol cembrol C20H34O2 which has a 14-membered ring and three double bonds; the dehydration of cembrol gives the diterpene hydrocarbon cembrene C20H32; the probable structure of cembrol is 14-isopropyl-3, 7, 11-trimethylcyclotetradeca-1, 3, 6-trien-11-ol. 2. Besides the diterpene alcohols and abietinal, the high-boiling oxygen containing fraction of the cedar resin contains D-δ-cadinol C15H26O and a lactone C17H26O3.

The taxonomic distribution of some diterpene hydrocarbons

A survey of twenty-eight species of the Podocarpaceae and of nine related gymnosperms for diterpene hydrocarbons has been carried out by gas-liquid chromatography. The results have been used to clarify previously reported occurrences of diterpenes and to assess their taxonomic value.