Teuvincenone

The eo-clerodane diterpenoids were isolated from the aerial parts of Teucrium species, however, from the roots rearranged abietane diterpenes were obtained. The first study with the roots of T. polium subsp. vincentinum was carried out by the Spanish-Italian group [71]. In this study four new compounds teuvincenones A, B, C and D (122-125) have been isolated. Two of them, teuvincenones C (124) and D (125) possess a novel hydrocarbon skeleton which contains a cyclopropane ring constituted by C-3, C-4 and C-18 carbons of the 17(15-16)-a6eo-abietane framework. 

The structures of these compounds were established by spectral data. UV spectra of compounds 122-125 revealed of a phenolic system conjugated with a diosphenol moiety by the addition of base, AICI3 and AICI3-HCI which showed characteristic band shifts of this cross-conjugated chromophore. These results were identical with those reported for coleon U (126), lanugons R (127) and S (128) [72]. The spectral data of compounds 122-125 were given in Tables 19 and 20. The X-ray analyses of teuvincenones A (122) and C (124) confirmed their structures. 

The same group observed in a similar compound teuvincenone E (129) isolated from the roots of T. fruticans [73]. 

The structure of (129) has been established by spectral data as well as by comparison with closely related compounds such as (16S)- and (16R)-plectrinone A (130,131). The UV spectrum showed characteristic band shifts of a cross conjugated chromophore by an a,P,Y,8-diunsaturated ketone moieties at 430 (sh), 370 (sh), 298, 254(sh) nm. The same group was found and studied on teuvincenones F and G (132,133) together with compound 129 from different collection of T. fruticans and on four... 

In a more recent study with the whole plant of T. divaricatum subsp. villosum [75] we have isolated one known diterpenoid teuvincenone B [71] and three new rearranged abietane diterpenoids villosins A (136) B... 

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