Neo-clerodane diterpenoids from Scutellaria alpina subsp. javalambrensis

Neoclerodane Diterpenoids from Scutellaria polyodon

“…12 The observed differences between the 1 Hand 13 C-NMR spectra of 3 and 12 were consistent with the presence in the former of a 2-methylbutanoyloxy substituent at the C-6R position 11 [δ H 2.31, 1H, sext (H-2′), 1.68 and 1.46, 1H each, both ddq (H A -3′ and H B -3′), 0.90, 3H, t (Me-4′), and 1.12, 3H, d (Me-5′); δ C 175.1 s (C-1′), 41.4 d (C-2′), 26.4 t (C-3′), 11.4 q (C-4′), and 16.5 q (C-5′)] instead of the isobutyrate ester of the latter 12 [δ H 2.49, 1H, sept (H-2′), and 1.15 and 1.18, 3H each, both d (Me-3′ and Me-4′); δ C 174.1 s (C-1′), 34.1 d (C-2′), 20.2 q (C-3′), and 21.0 q (C-4′)]. In particular, the location of the acetate group at the C-11 position is in agreement with the chemical shifts and coupling con-stants shown by the C-11 and C-12 protons of 3 (see Table 1), which were identical with those reported [12][13][14][15] for other neoclerodanes having an 11S-acetoxyl substituent and an R,β-unsaturated 15,16-γ-lactone moiety, previously isolated from Scutellaria plants.…”

Neoclerodane Diterpenoids from Scutellaria pontica

“…8 The UV spectrum of 7 [λ max nm (log ) 227 (4.47) and 273 (3.27)] corroborated the existence of unsaturated chromophores in this diterpenoid. The 1 H-and 13 C-NMR spectra of 7 (see Table 3) displayed signals for a β-substituted R,βunsaturated γ-lactone involving the C-13-C-16 carbons 8,18 [δ H 6.10, 1H, t, J ) 1.9 Hz (H-14), 4.84 and 4.91, 1H each, both dd, J gem ) 18.1 Hz, J allylic ) 1.9 Hz (2H-16); δ C 172.9 s (C-13), 116.1 d (C-14), 173.3 s (C-15), and 70.6 t (C-16)], as well as for a 8β-hydroxyl group [δ H 1.11, 3H, s (Me-17), 1.56, 3H, s (Me-20), and 1.60, 1H, s (8β-OH); δ C 77.0 s (C-8), 40.2 s (C-9), 19.8 q (C-17), and 21.4 q (C-20)], and two benzoyloxy groups (see Table 3) attached to the C-6R and C-7β equatorial positions [δ H 6.02 and 5.84, 1H each, both d, J ) 10.0 Hz (axial H-6β and H-7R protons, respectively); δ C 74.7 d (C-6) and 75.4 d (C-7)]. These functionalities were identical with those found in scutalpins K and L, two 6R,7βdibenzoyloxy-8β-hydroxyneoclerod-13-en-15,16-olide derivatives isolated from Scutellaria alpina.…”

“…From a chemotaxonomic point of view, it is of interest to note that scupontins A-F (1-6, respectively) are the first neoclerodanes isolated from Scutellaria species possessing (S)-3-hydroxybutyric ester groups, 2,3,[6][7][8][9][10][11]18,22,23 and their arrangement in these diterpenoids is a very unusual structural feature in natural products, although (R)-poly(3-hydroxybutanoate) of microbial origin is a well-known and useful compound. 24…”

“…19 D -25.2°(c 0.424, CHCl 3 ); IR (KBr) ν max 1790 (γ-lactone), 1740, 1250 (esters), 2980, 1450, 1370, 1180, 1100, 1060, 1020, 990, 970, 930, 880 cm -1 ; 1 H NMR (300 MHz), see Table1;13 C NMR (75.4 MHz), see Table2; positive FABMS m/z (rel int) 681 [MH] + (30), 635(18), 484(18), 311(25), 237(20), 157 (38), 69 (100); anal. C 60.09%, H 7.14%, calcd for C 34 H 48 O 14 , C 59.97%, H 7.11%.…”

Natural and hemisynthetic neoclerodane diterpenoids from Scutellaria and their antifeedant activityElectronic supplementary information (ESI) available: natural neoclerodanes from Scutellaria. See http://www.rsc.org/suppdata/np/b1/b111150g/

“…The only differences between scuterepenin A 1 (30) and scuterepenins A 2 (31) and B (32) were the presence of a cis-cinnamoyl group instead of the trans-cinnamoyl one in the former, and an additional α-hydroxy group on carbon C-2 in the second compound. Scuterepenin C 1 (28) and C 2 (29), with a 4,18-epoxide, had the trans or cis-cinnamoyl group at carbon C-6 instead of carbon C-7. Scuterepenin D 1 (33), D 2 (34) and E (35), lacking the oxygen function at carbon C-13, possessed carbon C-18 as an aldehyde.…”