Sesquiterpene Aldehydes Research Articles

Total Synthesis of the Marine Sesquiterpene Quinones Hyatellaquinone and Spongiaquinone

AbstractThe synthesis of the marine sesquiterpene quinone (+)‐hyatellaquinone (1) was achieved starting from the sesquiterpene aldehyde (+)‐albicanal ((+)‐3) (Schemes 3 and 4). Coupling of (+)‐albicanal with 2,3,5,6‐tetramethoxyphenyllithium led to the aryl‐sesquiterpene system, which was modified to the target molecule. Furthermore, the first total synthesis of the marine compound spongiaquinone (2) was carried out starting from ((−)‐albicanal (−)‐3) in a reaction sequence encompassing a stereoselective CC bond hydrogenation and a one‐pot AcOH elimination/demethylation reaction (Schemes 7 and 10). The occurrence of 1,2‐ and 1,4‐benzoquinone forms of 1 and 2 depends on the pH of the solvent system.

Leaf and peel volatile compounds of an interspecific citrus somatic hybrid [Citrus aurantifolia (Christm.) Swing. + Citrus paradisi Macfayden

AbstractThe volatile compounds from leaves and peels of an interspecific citrus somatic hybrid, Citrus aurantifolia (Christm.) Swing. + Citrus paradisi Macfayden, obtained by fusion of protoplasts from lime, Citrus aurantifolia (cv. Mexican Lime) and grapefruit, Citrus paradisi (cv. Star Ruby), were extracted by pentane : ether (1 : 1) from liquid nitrogen ball‐milled leaves and flavedo and examined by GC–MS in comparison to those of its parents. The hybrid quantitatively retained the ability of the lime parent to synthesize in its leaves the major monoterpene aldehydes (neral, geranial) the monoterpene alcohols (nerol, geraniol), and their acetates, and also the capacity of the grapefruit parent to produce a sesquiterpene aldehyde (β‐sinensal) in its leaves and nootkatone in its peel. Conversely, synthesis of most sesquiterpene hydrocarbons and long chain aliphatic aldehydes, which are present in the lime parent leaves and peel, was strongly inhibited in the hybrid, as in the grapefruit parent. In comparison to its parents, the hybrid overproduced citronellal in its leaves and α‐sinensal and β‐sinensal in its peel. Based on these results, the future prospects for a better understanding of the inheritance mechanisms with regards to aroma biosynthesis in citrus leaves and peels are discussed. Copyright © 2002 John Wiley & Sons, Ltd.

Molecular cloning and functional identification of (+)-delta-cadinene-8-hydroxylase, a cytochrome P450 mono-oxygenase (CYP706B1) of cotton sesquiterpene biosynthesis.

In cotton, gossypol and related sesquiterpene aldehydes are present in the glands of aerial tissues and in epidermal cells of roots. A cytochrome P450 was found to be expressed in aerial tissues of glanded cotton cultivars, but not or at an extremely low level in the aerial tissues of a glandless cultivar. Its cDNA was then isolated from Gossypium arboreum L. After expression in Saccharomyces cerevisiae, the P450 was found to catalyse the hydroxylation of (+)-delta-cadinene, forming 8-hydroxy-(+)-delta-cadinene. This P450 mono-oxygenase has been classified as CYP706B1, and is the first member of the CYP706 family for which a function has been determined. Sesquiterpene aldehydes and CYP706B1 transcripts were detected in roots of both the glanded and glandless cultivars and in aerial tissues of the glanded cultivar. In suspension cultured cells of G. arboreum, elicitors prepared from the phytopathogenic fungus Verticillium dahliae caused a dramatic induction of CYP706B1 expression. The expression pattern of CYP706B1 and the position at which it hydroxylates (+)-delta-cadinene suggest that it catalyses an early step in gossypol biosynthesis. Southern blotting revealed a single copy of CYP706B1 in the genome of G. arboreum. CYP706B1 holds good potential for manipulation of gossypol levels in cottonseed via genetic engineering.

Isolation of a (+)- δ-cadinene synthase gene CAD1-A and analysis of its expression pattern in seedlings ofGossypium arboreum L.

The cotton sesquiterpene cyclase, (+)-delta-cadinene synthase, is encoded by a gene family, which can be divided into two subfamilies:CAD1-A and CAD1-C. The geneCAD1-A was isolated fromG. arboreum. In situ hybridization performed on seven-day-old cotton seedlings localized transcripts of both the CAD1 -A and CAD1 -C mainly in lateral root primordium and apical ground meristem, vascular tissues of emerging lateral roots, and also in procambium and some subepidermal cells of the hypocotyl. The CAD1 -A promoter showed a similar tissue-specificity in transgenic tobacco plants. Histochemistry showed occurrence of sesquiterpene aldehydes in outer cells of the lateral root tips, as well as in pigment glands. The CAD1 gene expression in G.arboreum seedlings and the spatial pattern of sesquiterpene biosynthesis constitute a chemical defense machinery in cotton seedlings.

Expression pattern of (+)-delta-cadinene synthase genes and biosynthesis of sesquiterpene aldehydes in plants of Gossypium arboreum L.

The cotton (+)-delta-cadinene synthase, a sesquiterpene cyclase, is encoded by a complex gene family which, based on homology, can be divided into two subfamilies: cad1-A and cad1-C. Southern blots revealed several members of the cad1-C subfamily, and a single member of the cad1-A subfamily, in the diploid Gossypium arboreum genome. One of the cad1-C genes, cad1-C3, was isolated from this species. According to reverse transcriptase-polymerase chain reaction, transcripts of both cad1-C and cad1-A genes appeared in roots from the second day post germination and in 1-d-old cotyledons, whereas the transcription levels were too low to be detected in the hypocotyls. Initially, sesquiterpene cyclase activities were found to be high in the seedlings, then dropped in aerial organs but increased in roots during development. Sesquiterpene aldehyde contents followed the same pattern. In fully developed plants, the transcripts of cad1-C were detected in stems, leaves and pericarps, as well as in the sepals and petals 3 d before anthesis, but not at the day of anthesis. In contrast, cad1-A transcripts were not detected in any of these aerial organs. The sesquiterpene aldehyde contents increased in petals but decreased in sepals after anthesis. Treatment of G. arboreum stems with a Verticillium dahliae elicitor-preparation activated cad1-A transcription, but a significant level of cad1-C transcripts was detected both before and after elicitation. In G. hirsutum cv. GL-5, a glandless cultivar, the cad1-C gene was activated by the same fungal elicitor, followed by the synthesis of the sesquiterpene cyclase, and accumulation of sesquiterpene aldehydes. The cad1 gene expression during development and in response to elicitation, as well as the spatial and temporal pattern of sesquiterpene biosynthesis, constitute a chemical defense machinery in cotton plants.

Synthesis of (10R)-(E)-acora-3,7(11)-dien-12-al, a new fragrant sesquiterpene aldehyde

The synthesis of (10R)-(E)-acora-3,7(11)-dien-12-al (1) is described starting from the enantiomerically pure (+)-pulegenic acid (4) via the Diels-Alder adducts 8a,b. The odour of the new sesquiterpene aldehyde was typically aldehydic, fruity and leathery. Copyright © 2000 John Wiley & Sons, Ltd.

Expression pattern of genes encoding farnesyl diphosphate synthase and sesquiterpene cyclase in cotton suspension-cultured cells treated with fungal elicitors.

Cotton plants accumulate sesquiterpene aldehydes in pigment glands. The two enzymes farnesyl diphosphate synthase (FPS) and (+)-delta-cadinene synthase (CAD), a sesquiterpene cyclase, are involved in the biosynthesis of these secondary metabolites. A full-length cDNA (garfps) encoding FPS was isolated from Gossypium arboreum and identified by in vitro enzymatic assay of the garfps protein heterologously expressed in Escherichia coli. Treatment of G. arboreum suspension-cultured cells with an elicitor preparation obtained from the phytopathogenic fungus Verticillium dahliae dramatically induced transcription of both FPS and CAD, paralleling the accumulation of the sesquiterpene aldehydes in these cells. For G. australe, a wild species from Australia, the V. dahliae elicitor preparation also caused an induction of FPS but only a low rate of induction of CAD, apparently because of a constitutive expression of the sesquiterpene cyclase gene in suspension-cultured cells. Two transcripts and proteins of FPS were detected in the elicited G. australe cells; the smaller FPS seemed to be de novo synthesized after elicitation. Furthermore, G. australe-cultured cells accumulated the cadinene, instead of sesquiterpene aldehydes, indicating that the biosynthetic pathway leading to sesquiterpene aldehydes was absent or blocked after FPP cyclization.

Constituents of the essential oil ofPulicaria gnaphalodes (Vent.) Boiss. from Iran

The essential oil of Pulicaria gnaphalodes (Vent.) Boiss. from Iran was investigated by GC, GC–MS and NMR spectroscopy. Typical for this oil are pinane [chrysanthenone (23), cis-chrysanthenol (34)], cadinane [cadina-1(10),4-dien-8α-ol (114)] and bisabolane derivatives [nuciferol (118), γ-curcumen-12-ol (119)]. New, naturally occurring compounds are (Z)-3-methylnon-3-en-2-one (43), the so-called helifolen-12-als 94, 95, 98, 99, tricyclic sesquiterpene aldehydes with a helifolane (syn. allo-cedrane or khusiane) skeleton, and the italicen-12-ols 108 and 110. These aldehydes and alcohols are presumably formed by [4+2] resp. [2+2] cycloaddition of the corresponding γ-curcumene derivatives. Copyright © 1999 John Wiley & Sons, Ltd.

Eudesmane-Type Sesquiterpenoids from Japanese Liverwort Frullania tamarisci subsp. obscura.

The diethyl ether extract of the Japanese liverwort Frullania tamarisci subsp. obscura yielded a new sesquiterpene aldehyde in addition to a new dimeric sesquiterpenoid with a eudesmane-type carbon skeleton. Their structures were established by extensive 2D NMR techniques and chemical evidence. They were shown to be 4α, 6α-dihydroxy-11(13)-eudesmen-12-al and its dimer with 4-epi-arbusculin A at the C-4 ether linkage.

Cyclosantalal and epicyclosantalal—new sesquiterpene aldehydes from east Indian sandalwood oil

AbstractTwo new minor components of East Indian sandalwood oil have been isolated by chromatography. Structure elucidation using spectroscopical methods resulted in formulae 1 and 2. The relative configurations of the epimeric sesquiterpene aldehydes 1, 2 were determined by two‐dimensional NMR‐analysis (HETCOR‐, INADEQUATE‐, and NOE‐experiments) of the corresponding acids, cyclosantalic acid (3) and epicyclosantalic acid (4). The proposed structures of the aldehydes were confirmed by oxidative degradation reactions. Both aldehydes could be oxidized under normal conditions resulting in the known products acetyldihydroalbene (7) and albene (12) but also some new products such as the acids 3,4 and the formates 8,9. Trace amounts of those oxidation products could also be detected as constituents of sandalwood oil. A possible biogenetic pathway leading from p‐santalane derivatives to the cyclosantalals is briefly discussed.

Revision of the structure of an aristolane sesquiterpene aldehyde isolated from the root of Plectranthus hereroensis and Aristolochia debilis

From the acetone extract of the root of Plectranthus hereroensis an aristolane sesquiterpene aldehyde has been isolated. This substance was identical to a compound previously isolated from the root of Aristolochia debilis to which the structure of 1(10)-aristolen-12-al was attributed. Now, extensive NMR spectroscopic studies have established that the structure of this substance must be amended to 1(10)-aristolen-13-al. This sesquiterpene showed moderate antimicrobial activity.

Synthesis and the absolute configuration of the sesquiterpene aldehyde tridensenal from the Taiwanese liverwort Bazzania tridens

The absolute configuration of the sesquiterpene aldehyde tridensenal isolated from the Taiwanese liverwort Bazzania tridens has been determined by a total synthesis of the optically active compound as well as its diastereoisomer to have S,R configuration starting from (–)- and (+)-menth-1-ene and (+)-pulegone, respectively.

Automated HPLC‐HRGC: A powerful method for essential oil analysis. Part III. Aliphatic and terpene aldehydes of orange oil

AbstractThe application of a new method, computer‐controlled on‐line HPLC‐HRGC, to the analysis of the components of sweet orange oil has enabled the determination of aldehydes without interferences. HPLC was used to separate the oil aldehydes into three fractions, aliphatic aldehydes, sesquiterpene aldehydes, and monoterpene aldehydes. These fractions were transferred automatically to the GC, where the individual aldehydes were separated into well resolved chromatographic peaks.

Fragrant sesquiterpenes from agarwood

Two new sesquiterpene aldehydes, (−)-selina-3,11-dien-14-al and (+)-selina-4,11-dien-14-al, methyl ester derivatives of three new sesquiterpene carboxylic acids, (−)-methyl selina-3,11-dien-14-oate, (+)-methyl selina-4.11-dien-14-oate, and (+)-methyl 9-hydroxyselina-4,11-dien-14-oate, and a new nor-sesquiterpene ketone, (+)-1,5-epoxy-nor-ketoguaiene, have been isolated from Aquilaria agallocha (agarwood). Their structures have been established on the bases of detailed spectroscopic analyses and synthesis. The occurrences of dehydrojinkoh-eremol and neopetasane in agarwood were also confirmed by comparison of their mass spectral data and R inn , on capillary GC with those of synthesized samples. The odoriferous properties of some natural and synthesized sesquiterpenes are also described.

Contents of poison apparatus and their relation to trail-following in the antDaceton armigerum

The poison gland, which is the source of the trail pheromone inDaceton armigerum, contains a mixture of dimethylpyrazine, trimethylpyrazine and 3-ethyl-2,5-dimethylpyrazine in approximately equal proportions, similar to that of the antManica rubida. The cross-activity in trail-following tests with several other species can thus be explained. The Dufour gland ofD. armigerum contains a mixture of 26 identified hydrocarbons, chiefly 9-tricosene, tricosane, and 9-pentacosene. It also contains very small amounts of two sesquiterpene aldehydes, tetramorine-2 and tetramorine-3, already known in other myrmicine Dufour glands. No volatile substances were detected in the pygidial gland.

The isolation of new sesquiterpene aldehydes from injured fruit bodies of Lactarius scrobiculatus

The enzymatic conversion products of stearoylvelutinal in injured fruit bodies of Lactarius scrobiculatus have been investigated. Two sesquiterpene aldehydes not previously reported as natural products were isolated in addition to known sesquiterpenes. The structures were determined by spectroscopy combined with molecular mechanics calculations, and chemical transformation into known compounds.

Tridensenal, A Sesquiterpene of Novel Skeleton from the Taiwanese Liverwort Bazzania Tridens

AbstractThe sesquiterpene aldehyde, tridensenal, of previously unknown skeleton was isolated from the Taiwanese liverwort Bazzania tridens. The structure of tridensenal was elucidated on the basis of spectral data and proved by synthesis of the diastereomeric mixture.

ChemInform Abstract: The Coformation of Sesquiterpene Aldehydes and Lactones in Injured Fruit Bodies of Lactarius necator and L. circellatus. The Isolation of epi‐Piperalol.

AbstractThe pungency of the fruit bodies is caused by the enzymatic formation of unsaturated dialdehydes, e.g. velleral, when they are injured.

Assays of the biological activities of guaiane sesquiterpenoids isolated from the fruit bodies of edible lactarius species

Three sesquiterpenoids that are found in the edible mushrooms Lactarius deliciosus, L. deterrimus and L. sanguifluus, have been assayed for biological activity. The compounds tested were a stearic acid ester of a sesquiterpene (I) and a sesquiterpene aldehyde (lactaroviolin, II) and alcohol (deterrol, III). The assays used were for mutagenic activity in the Ames Salmonella assay, for antimicrobial activity against bacterial fungi and algae, for cytotoxicity against Ehrlich ascitic tumour cells and L 1210 cells, and for phytotoxic activity against Lepidium sativum and Seteria italica. All three compounds showed weak mutagenic activity in the Ames assay. Two compounds (II and III) were found to have moderate cytotoxic activity and one (III) exhibited weak antibacterial activity. No compound revealed phytotoxic, algicidal or antifungal activity.

The Co-formation of Sesquiterpene Aldehydes and Lactones in Injured Fruit Bodies of Lactarius necator and L. circellatus. The Isolation of epi-Piperalol.

The sesquiterpenoid contents of intact and of injured fruit bodies of the pungent species Lactarius necator and L. circellatus (mushrooms) have been investigated. The fruit bodies originally contain fatty acid esters of the sesquiterpene velutinal as the only sesquiterpenoids. When the fruit bodies are injured, by grinding, the esters are enzymatically converted into sesquiterpene furans, mono- and di-aldehydes, and lactones