Neoclerodane Diterpenoids from Teucrium massiliense

A reinvestigation of the diterpene metabolites of Teucrium massiliense L. allowed the isolation of four new neoclerodane derivatives, teumassilenins A-D, together with all the diterpenoids previously reported as constituents of this plant. The structures of the new compounds (1-4) were established by chemical and spectroscopic means. A plausible biogenetic relationship between several of these substances is briefly discussed, and some unpublished physical and spectroscopic data of the previously known diterpenoid teumassin (5) are now reported.

The C-12 and C-20 configurations of some neo-clerodane diterpenoids isolated from Teucrium species

Abstract A convenient and conclusive method for determining the C-12 stereochemistry of neo-clerodan-20,12-olide derivatives, even when only one epimer is available, is by 1H NMR NOE measurements. The C-12 configuration of 26 neo-clerodane diterpenoids isolated from Teucrium species has been re-examined by using this type of experiment. The results indicated that all the previous assignments were correct, except for teupyreinin, where the previously assigned C-12(S) configuration must be amended to C-12(R). This was confirmed by chemical transformations and additional 1H and 13C NMR studies. Furthermore, the NOE experiments allowed the assignment of a C-20(S) configuration for teuflavin, th…

Isomotiol, a new triterpene from strychnos potatorum

Isomotiol (fern-8-en-3β-ol) was isolated from the leaves of Strychnos potatorum; it was not known previously as a natural product, but it has been obtained by acidic isomerization of compounds with a fern-7-ene or a fern-9(11)-ene skeleton. From the leaves and the bark mixtures of sitosterol, stigmasterol and campesterol were also isolated.

Triterpenes from amaracus dictamnus

Abstract From the aerial parts of Amaracus dictamnus several triterpenes were isolated: oleanolic and ursolic acids, uvaol, the rare 21α-hydroxyoleanolic acid and a new 21α-hydroxyursolic acid.

A minor diterpene from Amaracus akhdarensis

Abstract A new isopimarane diterpenoid, isoakhdartriol, was isolated in very small amount from the aerial part of Amaracus akhdarensis. Its structure, isopimar-15-en-3β,8β,19-triol, was established by spectroscopic means.

New furanoid diterpenes from l'her.

Kauranoid dieterpenes in Espeletia grandiflora

Abstract The resin of Espeletia grandiflora contains (-)-kaur-16-en-19-ol, (-)-kaur-16-en-19-al (not previously isolated from natural sources), (-)-kaur-16-ene and (-)-kaur-16-en-19-oic acid.