Ent-pimarane and ent-abietane diterpenes from Euphorbia fidjiana

Diterpenoids and Triterpenoids from Euphorbia retusa

“…Considering the constituents isolated so far from Euphorbia species, compound 1 was presumed to be an ent-abietane diterpene. 13,14,24 The assigned orientations of H-5, H-9, and Me-20 confirmed this to be a compound belonging to the ent series. [20][21][22][23][24][25][26] The orientation of the OH group attached to C-8 was determined from the NOESY spectrum recorded in DMSO-d 6 .…”

“…The IR spectrum had no OH band, but showed a band at 1618 cm -1 (double bond). The 1 H and 13 C NMR signals of 2 were similar to those of 1 (Tables 2 and 3). The only differences were the lack of signal at δ 76.1 (for C-8 in 1) and the appearance in the J-modulated 13 C spectrum of two signals attributed to olefinic carbons of a tetrasubstituted double bond at δ 134.6 and 160.5.…”

NMR studies of darutoside, a rare ENT-pimarane glucoside

“…Darutoside (2) and darutigenol (1) have been found exclusively in the Asteraceae plants, S. orientalis [1][2][3]6] and S. pubescens [5], and in Palafoxia arida [16]. There are only a few reports on the occurrence of ent-pimar-8(14)-enes in nature, as 2-, 3-, 15-, 16-and 18-alcohols [5,11,12,15,17,18]. Seven hydroxy-ent-pimar-8(14)-ene 16-O--glucosides have been reported from Relhania calycina subsp.…”

Diterpenes and Diterpene Glucosides from Phlogacanthus curviflorus

“…4), leading to the structure of 6-epiharpagoside 1 ) (7) for curvifloruside F. Besides the seven new compounds, eleven known compounds were isolated from the plant. Comparison of the physicochemical and NMR properties with the reported data allowed for their structures to be identified as phlogacantholide C (8) [9], phlogacantholide C diacetate (9) [9], phlogacanthoside B (10) [9], jolkinolide E (11) [10], caprarioside (12) [13], harpagoside (13) [14], and acetylmartynoside A (18) [16]. Among them, the sesquiterpene and iridoid glycosides were isolated for the first time from the genus of Phlogacanthus.…”