New diterpenes from Sideritis candicans

The three new diterpenes candol-A (ent-16-kauren-7α-ol, I), candol-B (ent-16-kauren-18-ol, III) and epicandicandiol 7β-monoacetate (ent-7α-acetoxy-16-kauren-18-ol, V) as well as epicandicandiol (VII) have been isolated from Sideritis candicans.     

Epoxy-isosidol: A new diterpenoid from Sideritis biflora

The new diterpenoid ent-3β-acetoxy-7α,18-dihydroxy-15β,16-epoxykaurane has been isolated from Sideritis biflora. Twelve previously known ent-kaurane derivatives have also been obtained from the same source.     

Four new diterpenes from Sideritis serrata

Four new diterpenes have been isolated from Sideritis serata: lagascol (4, ent-8,5-friedopimar-5-ene-15S,16-diol), tobarrol (8, ent-15-beyerene-12α,17-diol), benuol (12, ent-15-beyerene-7α,17-diol) and serradiol (18, ent-16R-atis-13-ene-16,17-diol). The previously known diterpenes lagascatriol (1, ent-8,5-friedopimar-5-ene-11β,15S,16-triol), jativatriol (2, ent-15-beyerene-1β,12α,17-triol), conchitriol (3, ent-15-beyerene-7α,12α,17-triol) and sideritol (17, ent-16R-atis-13-ene-1β,16,17-triol) have also been obtained from the same source.     

New diterpenes from Sideritis canariensis

Two new diterpenes ribenol [3α-hydroxy-(?)-13-epimanoyl oxide] (I)and 7β-acetoxy-18-hydroxytrachylobane (IX) as well as the known (?)-13-epimanoyl oxide (IV) have been isolated from Sideritis canariensis Ait.     

New labdane diterpenoids from Sideritis chamaedryfolia

From the aerial parts of Sideritis chamaedryfolia six previously known ent-kaurene diterpenoids have been isolated. In addition, seven new labdane derivatives have also been obtained from the same source. The structures of these new natural diterpenoids have been established by chemical spectroscopic means and by correlation with known products.     

Diterpenoids from Sideritis foetens

From the aerial parts of Sideritis foetens, the previously known ent-13(16),14-labdadiene-6α,8α,18-triol (andalusol) has been isolated. In addition, two new natural andalusol monoacetates and the novel ent-6α-acetoxy-13(16),14-labdadiene-3β,8α-diol have also been obtained from the same source. The structures of these new diterpenoids have been established by chemical and spectroscopic means.     

Two flavone glycosides from Sideritis leucantha

8-Hydroxyluteolin occurs in Sideritis leucantha as the 7-(2″-allosylglucoside) and the 8-glucoside of its 6,7-dimethyl ether has also been characterized from the same plant.     

Diterpenoids from Sideritis arborescens subsp. Paulii

Several ent-labda-13(16),14-dienes, ent-13-epi-manoyl oxides and the new natural products ent-6α,8α-dihydroxylabda-13(16),14-diene, ent-18-hydroxy-15(16)peroxylabd-13-ene,ent-16,18-dihydroxymanoyl oxide, ent-13-epi-16,18-dihydroxymanoyl oxide and ent-6α16,18-trihydroxymanoyl oxide have been isolated from Sideritis arborescens subsp. paulii. The structures of these compounds have been established by spectroscopic means and chemical correlations.     

New labdane diterpenes from Araucaria cooki

Eight new and seven known labdane diterpenes were identified in the oleoresin of Araucaria cooki.     

Ucriol,an epoxy-diterpene from Sideritis syriaca

The isolation of a new epoxy-diterpene from the inflorescence of Sideritis syriaca (S. sicula Ucria) is described. Its structure and stereochemistry were established by spectroscopy and partial synthesis.     

Hypolaetin 8-glucoside from Sideritis leucantha

A new naturally occurring hypolaetin 8-β-D-glucoside has been isolated and identified from Sideritis leucantha. The natural compound suffered nuclear methylation during derivatization.     

Neutral diterpenes from Araucaria bidwilli

Five ent-labdane diterpenes were isolated from the neutral fraction of the resin of Araucaria bidwilli. Three of them, previously unknown, were     

Teucrins H1-H4, novel clerodane-type diterpenes from Teucrium hyrcanicum

The structure and stereochemistry of teucrins H1, H2, H3 and H4, four novel diterpenes from Teucrium hyrcanicum have been established by detailed studies of the PMR and ¹³C NMR spectra, CD results and chemical transformations. Teucrin H4, a minor constituent is shown to possess a unique stereochemistry hitherto not reported for related diterpenoids.     

New diterpenes from Chamaecyparis pisifera

Three new diterpenes, pisiferin, 15-hydroxyferruginol, and O-methyl pisiferic acid have been isolated and the presence of 12-hydroxyabieta-8,11,13-trien-20-al has been confirmed in studies of the leaves of Chamaecyparis pisifera. The structure of pisiferin, a phenolic diterpene with a new carbon skeleton, has been determined by chemical degradation. The presence of diterpenes of the ferruginol type in the leaves of four varieties of C. pisifera has been examined.     

Sesquiterpenes from two subspecies of Sideritis varoi

Two subspecies of Sideritis varoi afforded, in addition to previously reported diterpenes, the following series of new eudesmane and eudesmene acetates: 1β-hydroxy-6β-acetoxy-eudesm-4(15)-ene; 1β,4β-dihydroxy-6β-acetoxy-eudesmane; 1β-hydroxy-6β-acetoxy-eudesm-3-ene; 1β-hydroxy-6β-acetoxy-eudesm-4-ene. The structures of these compounds were elucidated by chemical and spectroscopic means.     

Labdane diterpenes from an acacia species

Two new diterpenes, (13E)-labd-13-ene-3β,8α,15-triol and (13E)-3β,8α-dihydroxylabd-13-en-15-oic acid have been isolated from an unclassified Acacia sp. Chemical and spectroscopic evidence for their structure is presented. The known labdanes, sclareol, 13-epi-sclareol and (13E)-labd-13-ene-8α,15-diol were also isolated.     

Three diterpenes from Conyza podocephala

The investigation of Conyza podocephala afforded, in addition to known compounds, two clerodane derivatives and a dihydroxyfarnesyl methylfuran. Furthermore two new resorcinol derivatives were isolated. The structures were elucidated by spectroscopic methods and by chemical transformations. The chemotaxonomic situation within the genus is discussed briefly.     

Neo-clerodane diterpenes from Teucrium fruticans

In addition to three out of the four previously reported neo-clerodanes already found in Teucrium fruticans (fruticolone, isofruticolone and 8 beta-hydroxyfruticolone), and 6-acetylteucjaponin B (isolated from T. scordium and T. grisebachii), four new neo-clerodanes, namely 7 beta-hydroxyfruticolone, 11-hydroxyfruticolone, deacetylfruticolone and 6-acetyl-10-hydroxyteucjaponin B were also isolated. The structures were unambiguously elucidated based on extensive NMR spectral studies (one- and two-dimensional experiments). Semi-prep-HPLC proved to be a convenient purification procedure, occasionally being followed by TLC. The new compounds were assayed against Spodoptera littoralis and two of them were shown to have potent antifeedant activity.