A neo-clerodane diterpenoid from Scutellaria seleriana

Some Biogenetic-Type Transformations of Neoclerodane Diterpenoids from Scutellaria Species

“…The structures of 2 and 3 were in agreement with their 1 H and 13 C NMR spectra (see Table ) and other spectroscopic data (see Experimental Section). In particular, the stereochemistry at the C-13 stereogenic center was firmly supported by NOE experiments, because 2 showed NOE enhancements in the signals of the H A -16 (δ 4.10, 2% enhancement) and H B -16 (δ 4.20, 4%) protons when the Me-17 protons (δ 1.21) were irradiated, whereas in 3 irradiation at δ 1.27 (Me-17) caused NOE enhancements in both protons of the C-14 methylene group (δ 2.56 and 2.70, 1% and 3% NOE enhancement, respectively). ,,− …”

“…Several neoclerodanes found in Scutellaria species possess in their structures a cis -fused 8β,13-tetrahydropyran ring system and a 13-spiro-15,16-γ-lactone − ,,− involving the C-8, C-9, and C-11−C-16 carbons of the neoclerodane framework (Scheme 1, compounds such as A ). From a biogenetic point of view, the tetrahydropyran moiety of these substances ( A ) may arise from 8β-hydroxyneoclerod-13-en-15,16-olide derivatives (Scheme 1, compounds of type B , also found in Scutellaria species 2-4,12 ) by an intramolecular hetero-Michael addition.…”

“…Species of the genus Scutellaria (family Labiatae) are the source of the most potent neoclerodane insect antifeedants known so far, 6,7 and efforts toward the total synthesis of such compounds have been made recently. 8,9 Several neoclerodanes found in Scutellaria species possess in their structures a cis-fused 8β,13-tetrahydropyran ring system and a 13-spiro-15,16-γ-lactone [2][3][4]7,[10][11][12][13][14][15][16] involving the C-8, C-9, and C-11-C-16 carbons of the neoclerodane framework (Scheme 1, compounds such as A). From a biogenetic point of view, the tetrahydropyran moiety of these substances (A) may arise from 8β-hydroxyneoclerod-13-en-15,16-olide derivatives (Scheme 1, compounds of type B, also found in Scutellaria species [2][3][4]12 ) by an intramolecular hetero-Michael addition.…”

Hastifolins A–G, antifeedant neo-clerodane diterpenoids from Scutellaria hastifolia

“…javalambrensis (de la Muñoz et al, 1997), S. orientalis subsp. sintenisii (Ezer et al, 1998), Scutellaria guatemalensis (Esquivel et al, 2000), Scutellaria seleriana (Esquivel et al, 1998), Scutellaria caerulea (Esquivel et al, 2001), Scutellaria barbata (Dai et al, 2006a(Dai et al, ,b, 2007b, only one of the two possible epimers has so far been isolated.…”

Diterpenoids (1998)

“…22) from S. repens, 31 and scuteselerin 23 from S. seleriana. 32 Some biogenetically patterned transformations of the clerodane diterpenoids of Scutellaria species have been reported. 33 Clerodane insect antifeedants have also been obtained from Ajuga species.…”