New cembradiene diterpenoids from an undescribed Caribbean gorgonian of the genus Eunicea

New Diterpenoids from Soft Coral Sarcophyton ehrenbergi

“…The crucial NOE correlations between H-2/H-3, H-2/Me-16, H-2/Me-18, H-2/H-15, H-3/H-7 ( δ H 4.05), and H-3/H-14a ( δ H 2.64) indicated that the geometries of the two olefins at C-1/C-2 and C-3/C-4 were assigned as both E . The coupling constant between H-2 and H-3 ( J 2,3 = 8.4 Hz) [ 23 ] further suggested the s-trans geometry of the conjugated double bonds. Furthermore, the crucial NOE correlations between H-7/H-9a ( δ H 2.13), H-11/H-9a, H-11/H-10a ( δ H 1.74), H-11/H-13a ( δ H 1.97), Me-19/H-6b ( δ H 1.84), Me-19/H-10b ( δ H 1.78), Me-20/H-14b, Me-20/H-10b, and H-3/H-14a ( δ H 2.64) demonstrated the 7 R *, 8 S *, 11 S *, and 12 R * configurations as depicted in Figure 5 .…”

Isolation and structure elucidation of natural products of three soft corals and a sponge from the coast of Madagascar

“…The isolation of (+)-(7S,8S)-epoxy-7,8-dihydrocembrene C [(+)-1] has been reported before by Deng and coworkers from the soft coral S. molle with a specific optical rotation of [α] 25 D = +99.0 (c 1.9, acetone) 24 . 25 Subsequently, the same compound has been obtained from an unidentified species of a Caribbean gorgonian of the genus Eunicea 26 and from the soft coral S. trocheliophorum. 27 The absolute stereochemistry of (−)-1 was assigned as (7R,8R) via enantioselective total synthesis in 2000 by Li et al 28 They reported a specific optical rotation of [α] 20 D = −25.2 (c 0.21, CHCl 3 ) which is in good agreement with the value of the natural product originally isolated by Bowden.…”

Cembrane Diterpenes Chemistry and Biological Properties

“…52, 58-63, 627-631, 640-644 [24,29,179,184] Eunicea pinta 333-340 [104] Eunicea knighti 163-165 [63] Eunicea mammosa 161, 162, 203, 321-332 [62,[100][101][102][103] Eunicea succinea 158-160, 202, 311-320, 620 [61,98,99] Eunicea tourniforti 36-39 [19] Leptogorgia sp. 482-487, 519 [147,148] Leptogorgia alba 473, 474 [138] Leptogorgia laxa 155, 156 [59] Leptogorgia setacea 475, 476 [142] Lophogorgia peruana 157, 462-471, 526 [60,[137][138][139][140]143] Pseudopterogorgia sp.…”

“…From the soft coral Sarcophyton sp., studies have led to the identification of two new cembranes, epoxysartone B (24), and sartone E (25) [15]. Naturally occurring cembranes (26)(27)(28)(29) have been isolated from Sarcophyton sp. These compounds have not previously been found to occur in nature but had been obtained as intermediates in a synthetic modification.…”

“…(53)(54)(55) [25], Sinularia ovispiculata (56) [26], Cladiella kashmani (57) [27], Alcyonium flaccidum (56) [28]. Five new cembradiene diterpenoids (58)(59)(60)(61)(62)(63) have been isolated from an undescribed Caribbean gorgonian of the genus Eunicea [29]. Flabellatenes A (64), and B (65) have been isolated from the extract of the Antarctic sponge Lissodendoryx flabellata.…”