Secondary Metabolites from the Cnidarian Cavernularia sp.: Structures of the New Briaranes Cavernulin A and B.

Abstract

Terpenes Terpenes U 0200 Secondary Metabolites from the Cnidarian Cavernularia sp.: Structures of the New Briaranes Cavernulin A and B. -(PATRA*, A.; MAJUMDAR, A.; MANDAL, K. K.; GHOSH, A.; BANERJEE, D.; HALDAR, B. P.; J. Indian Chem. Soc. 78 (2001) 10-12, 619-626; Dep. Chem., Univ. Coll. Sci., Calcutta 700 009, India; Eng.) -M. Kowall

Briarenols Q–T: Briaranes from A Cultured Octocoral Briareum stechei (Kükenthal, 1908)

“…The latter structural feature was confirmed by the presence of signals at δ C 202.6 (C-12), 154.6 (CH-14), and 124.1 (CH-13) in the 13 C NMR spectrum ( Table 1 ), and the presence of a mutually coupled pair of doublet signals in the 1 H NMR spectrum at δ H 5.85 (H-13) and 6.39 (H-14) ( J = 10.2 Hz) corresponding to the α- and β-olefinic protons, respectively ( Table 2 ). The spectroscopic data of 4 were similar to those of a known diterpene, cavernulin B ( 7 ) ( Figure 1 ), isolated from a sea pen, Cavernularia sp., collected from the Eastern Coast of Bay of Bengal near Digna, India [ 13 ], except that the signals corresponding to the 12-hydroxy group in 7 disappeared and were replaced by a ketone group in 4 , as assessed by comparing the related spectroscopic data of 4 with those of 7 . The locations of functional groups were confirmed by 2D NMR correlations ( Figure 5 ), and hence the structure of briarenol T was assigned as 4 , and the configurations of the stereogenic carbons were elucidated as 1 S ,2 S ,7 S ,8 R ,9 S ,10 S ,11 R , and 17 R ( Figure 4 ) ( Supplementary Materials, Figures S32–S41 ).…”

Marine natural products

“…366 Briarane skeleton terpenoids, cavernulin A 566 and B 567 were isolated from a Cavernularia sp. 367 A metabolite containing an aromadendrane-type skeleton, 3-acetoxyspathulenol 568, was isolated from the soft coral Parerythropodium fulvum. 368 Paesslerins A 569 and B 570, the first examples of metabolites containing the 2,8,8,10-tetramethyltricyclo[4.3.2.0 2,5 ]undecane (paesslerane) skeleton, were isolated from a South Georgia Island collection of the pink soft coral Alcyonium paessleri.…”

Briaexcavatolides S−V, Four New Briaranes from a Formosan Gorgonian Briareum excavatum

“…In addition, over 300 briarane-type diterpenoids have been isolated from various marine organisms, and some of these metabolites were proven to possess interesting biological activities (e.g., cytotoxicity, antiinflammatory, antiviral, insecticidal, antifouling, immunomodulatory effect, antibacterial, and biotoxin) . Recently, several new briaranes have been discovered by different research groups. − Our continuing study on the chemical constituents of the Formosan gorgonian coral Briareum excavatum also has further yielded four new briaranes, briaexcavatolides S−V ( 1 − 4 ). The structures of these four minor components were elucidated by spectroscopic methods, including extensive 2D NMR spectral data analyses.…”