Baccharis structure

Clerodanes.—In a study of South African Macowania species, a cis-clerodane acid (28) and labdanolic acid were obtained from M. glandulosa. Deoxymarrubialac-tone (29) has been isolated from Chaiturus marrubiastrum. Linarienone (30) is another ds-fused clerodane which has been obtained from the roots of Linaria japonica (Scrophulariaceae) and correlated with linaridial. The bacchotricuneatins A (31) and B (32) are two new diterpenoid lactones which were isolated from Baccharis tricuneata (Astereae) and whose structures were determined by a combination of spectra and X-ray analysis. 

Quijano, L. et al.. The molecular structure of maniladiol from Baccharis salicina. Phytochemistry, 49, 2065, 1998. 

Baccharis Oxide.—The interesting structure (79) has been proposed for baccharis oxide, from Baccharis halimifolia. In biogenetic terms baccharis oxide is readily derivable from the cation (80), which leads to ebelin lactone (81) and shionone (82). On treatment with boron trifluoride dihydro-baccharis oxide rearranged to (83). 

Fig. (25). Structure of labda-7,13 -dien-2 3-15-diol isolated from Baccharis grisebachii...

The roridin family constitutes another subclass of the trichothecane macrolides. Two examples of this group are roridin E (148) and baccharin Bj (150). The latter is isolated from the plant Baccharis megapotamica and is a potent antileukemic agent. Structurally, this class of compounds is quite similar to the verrucarins discussed above, with the exception of the replacement of the hydroxypentanoic acid-muconic ester linkage by an ether bond and some additional carbon substitution. 

Li et al. [26] also reported the isolation and structure elucidation of a new clerodane diterpenoid from Baccharis myrsinites (Lam) Pers., a species endemic to the Dominican Republic, while the aerial parts of Baccharis santelicis Phi., an endemic species from Chile, afforded several known furoclerodanes [27], From another endemic species from Chile, B. incarum, a newweo-clerodane diterpenoid named bincatriol, Fig. (6) was isolated [28],... 

Fig. (10). Structure of a new labdane aldehyde isolated from Baccharis scoparia...

Fig. (47). Structure of 3-acetoxyflavanones isolated from Baccharis varians...

Fig. (49). Structure of coumaric acid derivatives isolated from Argentinian Baccharis spp.

Fig. (50). Structure of prenylated coumaric acids isolated from Baccharis boliviensis...

Fig. (52). Structure of new p-hydroxyacetophenones isolated from Baccharis latifolia and Baccharis calvescens...

Fig. (53). Structure of a propiophenone derivative isolated from Baccharis magellam ica...

Fig. (54). Structure of prenyl derivatives isolated from Baccharis salicifolia...

Fig. (62). Structure of an antimicrobial diterpene lactone isolated from Baccharis genistelloides...

Fig. (64). Structure of protozoocidal eo-clerodane diterpenoids isolated from Baccharis spp.

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