New Isomalabaricane-Derived Metabolites from a <i>Stelletta</i> sp. Marine Sponge
Sophia A. Kolesnikova,
Ekaterina G. Lyakhova,
Anastasia B. Kozhushnaya,
Anatoly I. Kalinovsky,
Dmitrii V. Berdyshev,
Roman S. Popov,
Valentin A. Stonik
Affiliations
Sophia A. Kolesnikova
G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch of Russian Academy of Sciences, Pr. 100-let Vladivostoku 159, 690022 Vladivostok, Russia
Ekaterina G. Lyakhova
G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch of Russian Academy of Sciences, Pr. 100-let Vladivostoku 159, 690022 Vladivostok, Russia
Anastasia B. Kozhushnaya
School of Natural Sciences, Far Eastern Federal University, Sukhanova Str. 8, 690000 Vladivostok, Russia
Anatoly I. Kalinovsky
G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch of Russian Academy of Sciences, Pr. 100-let Vladivostoku 159, 690022 Vladivostok, Russia
Dmitrii V. Berdyshev
G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch of Russian Academy of Sciences, Pr. 100-let Vladivostoku 159, 690022 Vladivostok, Russia
Roman S. Popov
G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch of Russian Academy of Sciences, Pr. 100-let Vladivostoku 159, 690022 Vladivostok, Russia
Valentin A. Stonik
G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch of Russian Academy of Sciences, Pr. 100-let Vladivostoku 159, 690022 Vladivostok, Russia
In continuation of our studies on a Vietnamese collection of a Stelletta sp., sponge we have isolated two new isomalabaricane triterpenoids, stellettins Q and R (1 and 2), and four new isomalabaricane-derived nor-terpenoids, stellettins S-V 3–6, along with previously known globostelletin N. Among them, compound 3 contains an acetylenic fragment, unprecedented in the isomalabaricane family and extremely rare in other marine sponge terpenoids. The structures and absolute configurations of all new compounds were established by extensive NMR, MS, and ECD analyses together with quantum-chemical modeling. Additionally, according to obtained new data we report the correction in stereochemistry of two asymmetric centers in the structures of two known isomalabaricanes, 15R,23S for globostelletin M and 15S,23R for globostelletin N.
