Claudia Paul

Pacifigorgianes and tamariscene as constituents of Frullania tamarisci and Valeriana officinalis

The sesquiterpenoid constituents of the essential oils from the liverworts Frullania tamarisci, Frullania fragilifolia and of the angiosperm Valeriana officinalis were investigated. Tamariscene, a compound with a new sesquiterpene skeleton, valerena-4,7(11)-diene and five new pacifigorgiadienes, namely pacifigorgia-1,10-diene, pacifigorgia-1(6),10-diene, pacifigorgia-1(9),10-diene, pacifigorgia-2,10-diene, and pacifigorgia-2(10),11-diene were isolated and identified. Structure elucidation was carried out by NMR spectroscopy and chemical correlations to establish absolute configurations. Compounds present in both the essential oils of the Frullania species and Valeriana officinalis were enantiomeric to each other. A plausible biogenetic relationship between the pacifigorgiane, valerenane and tamariscane skeletons is postulated. Pacifigorgia-6,11-diene, not yet detected in nature, was generated by dehydration and rearrangement of natural (-)-tamariscol.

Volatile components from European liverworts Marsupella emarginata, M. aquatica and M. alpina

The hydrodistillation products of the liverworts Marsupella emarginata, M. aquatica and M. alpina were investigated by spectroscopic methods. A number of new compounds could be isolated by preparative gas chromatography (GC) and identified by spectroscopic techniques including GC-mass spectrometry, NMR and chemical correlations in conjunction with enantioselective GC. From M. emarginata, in addition to many known compounds, the sesquiterpene hydrocarbon (-)-7-epi-eremophila-1(10),8,11-triene (1) and the sesquiterpene derivatives (-)-4-epi-marsupellol (2), (-)-marsupellol acetate (18), (-)-4-epi-marsupellol acetate (4), (+)-5-hydroxymarsupellol acetate (5) and (-)-9-acetoxygymnomitr-8(12)-ene (24) could be identified. In M. aquatica the sesquiterpene hydrocarbons (-)-myltayl-8(12)-ene (7), ent-(+)-amorpha-4,11-diene (8), (-)-amorpha-4,7(11)-diene (9), the sesquiterpene alcohol (+)-9-hydroxyselina-4,11-diene (10) and (-)-2-acetoxyamorpha-4,7(11)-diene (11) were identified. In M. alpina (-)-trans-selina-4(15),11-dien-5-ol (12), (+)-8,9-epoxyselina-4,11-diene (13) and (+)-cis-selina-4(15),11-dien-5-ol (14) were found as new natural products.

epi-Cubebanes from Solidago canadensis.

GC-MS of the essential oil prepared by hydrodistillation of the green parts of a specimen of Solidago canadensis collected near Katowice, Poland, revealed two new sesquiterpene hydrocarbons. Their EI mass spectra resembled the mass spectrum of beta-ylangene (1) but the retention indices of the new compounds differed markedly from this known compound. After isolation of the new compounds by preparative GC their investigation by one- and two-dimensional NMR techniques resulted in the identification of 6-epi-alpha-cubebene (2) (minor constituent, 1.5%) and 6-epi-beta-cubebene (3) (major constituent, 20.5%).

Sesquiterpenoid constituents of the liverworts Lepidozia fauriana and Lepidozia vitrea.

The sesquiterpene constituents of the essential oils of the Taiwanese liverworts Lepidozia fauriana and L. vitrea were investigated. 11,12-Dihydrochiloscyphone and 7,10-anhydro-11,12-dihydrochiloscypholone were isolated from L. fauriana and spectroscopically characterised together with their hydrogenation products. From the same species three amorphane derivatives amorpha-4,9-dien-14-al, amorpha-4,9-dien-2-ol and 7,14-anhydroamorpha-4,9-diene, and from L. vitrea two oxygenated elemanes, namely 7-acetoxy-elema-1,3-dien-8-ol and elema-1,3-dien-7-ol, were isolated and identified. Structure elucidation was carried out by NMR spectroscopy and chemical correlations in conjunction with enantioselective gas chromatography were utilized to establish absolute configurations.

1,2:3,4-Diepoxy-p-menthane and 1,4-Epoxy-p-menth- 2-ene: Rare Monoterpenoids from the Essential Oil of Chenopodium ambrosioides L. var ambrosioides Leaves

Abstract The composition of the essential oil of leaves from Chenopodium ambrosioides L. var ambrosioides was analyzed by capillary GC and GC/MS. Ten compounds were identified accounting for 94.6% of the total oil. 1,2:3,4-Diepoxy-p-menthane and 1,4-epoxy-p-menth-2-ene were isolated from the oil; it was the first time that these compounds were identified from Chenopodium ambrosioides L. var ambrosioides. The major compounds in the hydrodistillate were α-terpinene (55.6%), p-cymene (16.7%) and 1,4-epoxy-p-menth-2-ene (17.7%).

Volatile constituents in the liverwort Tritomaria polita

The essential oil of the liverwort Tritomaria polita, collected in Otztal/Tyrol (Austria), was investigated by chromatographic and spectroscopic methods. Several new compounds were isolated by preparative gas chromatography (GC) and their structures investigated by mass spectrometry (MS) and NMR techniques. In addition to known constituents, the sesquiterpenoids (+)-eudesma-3,11-dien-8-one, (+)-eudesma-3,7(11)-dien-8-one, (+)-6,11-epoxy-eudesmane, (-)-6,7-seco-eudesm-7(11)-en-6-al, (+)-6beta-hydroxy-eudesm-11-ene, (-)-6alpha-hydroxy-eudesm-11-ene, (+)-6,11-epoxy-isodaucane could be identified as natural compounds for the first time.

Sesquiterpene constituents from the liverwort Bazzania japonica

The hydrodistillation products of the liverwort Bazzania japonica were separated by preparative gas chromatography (GC) and investigated by spectroscopic methods. Seven unknown compounds were isolated and identified by GC-MS and NMR. Four of them, the norsesquiterpene hydrocarbons 4-epi-11-nor-aristola-1(10),11-diene (1), 4-epi-11-nor-aristola-1,9,11-triene (2), 4-epi-11-nor-aristola-9,11-diene (3), and one oxygenated sesquiterpene, (-)-aristol-1(10)-en-12-ol (5) are new natural compounds, and one, (+)-himachala-2,4-diene (7), has for the first time been isolated from liverworts. The absolute configurations of 5 and 7 were derived by chemical correlation reactions and/or enantioselective GC using cyclodextrin phases. 1, 2 and 3 have identical absolute configuration.

Essential Oil of Lantana camara L. var. aculeata from Nigeria

Abstract Essential oils from the leaves and flowers of Lantana camara L. var. aculeata were analyzed by GC and GC/MS. Thirty-nine and 46 constituents were identified in the leaf and flower oils, respectively. Sabinene (19.6–21.5%), 1,8-cineole (12.6–14.8%), β-caryophyllene (12.7–13.4%) and α-humulene (5.8–6.3%) were the major components of both oils. Two rare sesquiterpenoids—humulene epoxide III and 8-hydroxybicyclogermacrene—were also isolated from the oils.

Total Synthesis of Tamariscene

Sesquiterpene hydrocarbons of the pacifigorgiane and of the novel tamariscane skeleton were detected by GC-MS in the essential oils of Aristolochia baetica collected at the Algarve. The same compounds were isolated from Frullania fragilifolia, Frullania tamarisci and Valeriana officinalis respectively, and submitted to NMR investigation. By NMR investigation only relative configurations can be determined, the absolute stereochemistry has to be identified by chemical correlation: closely related structures are transformed into the desired structure or, if these structures are unknown, total synthesis is needed. In the case of tamariscene, the first compound isolated with the tamariscane skeleton, total synthesis had to be undertaken to corroborate its postulated structure and to reveal its absolute configuration.