Three New Cadinene Derivatives from Xenia Puerto‐Galerae

Abstract

Chromatographic investigation of an acetone extract of the octocoral Xenia puerto‐galerae afforded three new cadinene sesquiterpenes; 8‐epi‐xenitorin A (1), 10‐epi‐xenitorin C (2), and 7‐isopropenyl‐4,10‐dimethyl‐2,3,4,5‐tetrahydronaphthalene (3), in addition to four known cadinene analogs (4, 11–13) and six xenicanes (5–10). The structures were elucidated through spectroscopic analysis, especially 2D NMR. A biogenetic pathway of 1–3 and analogs was proposed.

Terpenoid Content of the Antarctic Soft Coral Alcyonium antarcticum

“…The remaining signals integrating for twelve protons were attributed to four methylenes and four methines. The 1 H-1 H COSY experiment showed the presence in the molecule of a single spin system, H-1/H 2 -9 sequence (Table1), which was consistent with the decaline framework of a cadinene carbon skeleton[9][10][11][12][13]. Diagnostic HMBC correlations observed between COCH 3 and H-2; C-10 and H-1, H 2 -9, and H 2 -15; C-7 and both H 2 -13 and H 3 -14, allowed the connection of the substituents, as depicted in formula 1.…”

“…cadinane: δ C-11 23.05 [10]) or the axial methyl (i.e. xenitorin A: δ C-11 18.3 [11]; 8-epi-xenitorin A: δ C-11 18.1 [12]). Diagnostic NOE effects were observed between H 3 -11, H-6 and H-2 thus inferring the axial orientation for all of them (Fig.…”

Marine natural products

“…628 In addition to a number of known sesquiterpenes and diterpenes, the cadinene sesquiterpenes 8-epi-xenitorin A 624, 10-epi-xenitorin C 625 and 626 were isolated from Xenia puerto-galerae (Green Is., Taiwan). 646 The bicyclic sesquiterpenes paralemnolins D-I 627-632 were reported from extracts of Paralemnalia thyrsoides (Green Is., Taiwan). 647 The absolute configuration (5S) of 627 was determined while the configurations of the C-1 and C-12 methyl groups were based upon the known configurations of related natural products.…”

Natural sesquiterpenoids

“…Five cadinane derivatives 185-189 have been identified as components of Tarenna madagascariensis. 145 Another three new sesquiterpenes, 8-epi-xenitorin A 190, 8-epi-xenitorin C 191 and the cadinane 192, have been found in an acetone extract of the octocoral Xenia puerto-galerae, 146 whilst the known sesquiterpene xenitorin A has been isolated from another species of this genus, Xenia umbellata. 147 The anti-estrogenic activity of mansonone I 193, a new sesquiterpenoid from the heartwood of Mansonia gagei, has been investigated.…”