New Highly Oxidized Formamidobisabolene‐Derived Sesquiterpenes from a Hainan Sponge Axinyssa variabilis

Abstract

Two new highly oxidized formamidobisabolene sesquiterpenes (1 and 2), together with seven known related analogues (3 -9), were isolated from a Hainan sponge Axinyssa variabilis. Their structures were determined by extensive 1D-and 2D-NMR and MS spectra analyses, and by comparison of their spectroscopic data with those of the related model compounds. The plausible biosynthetic relationship between compounds 1 -9 has also been described.

Cytotoxic Nitrogenous Terpenoids from Two South China Sea Nudibranchs Phyllidiella pustulosa, Phyllidia coelestis, and Their Sponge-Prey Acanthella cavernosa

“…The abovementioned usual workup of the Et 2 O-soluble portion of the acetone extract of the animals of P. coelestis yielded six pure compounds: 6 , 8 – 11 , and 14 (Figure 1). The known compounds were identified as one eudesmane-type sesquiterpenoid: 6 [39,40], four bisabolane-type sesquiterpenoids: 8 [1], theonellin formamide ( 9 ) [33], theonellin isothiocyanate ( 10 ) [33], and 7-isocyano-7,8-dihydro- α -bisabolene ( 11 ) [42], and one mixture of pupukeanane-type sesquiterpenoids: 14 [6] by direct comparison of its NMR data and specific rotation with those reported in the literature.…”

“…In our previous chemical investigation on South China Sea (Hainan) nudibranchs and sponges, nitrogenous terpenoids were isolated and structurally characterized [1,17,18,32,33,34]. In the course of our continuing project on searching for chemically fascinating and biologically active secondary metabolites from Hainan marine molluscs, as well as the chemical ecology study between nudibranchs and their sponge-preys, we made different collections of two nudibranchs, Phyllidiella pustulosa and Phyllidia coelestis , as well as their sponge-prey Acanthella cavernosa , from the same location (Xidao Island, Hainan Province, China), with the aim of accumulating their nitrogenous metabolites for further study of their bioactivities, as well as studying the dietary relationship between P. pustulos , P. coelestis , and their sponge-prey A. cavernosa .…”

Marine natural products

“…[446][447][448] Only two meroditerpenoids 931 and 932 were reported in 2016, 449 while sesquiterpenoids, their formamides, isocyanides, thiocyanates, isothiocyanates and dimers 933-947 (ref. [450][451][452] were reported from Axinyssa, Dysidea and Halichondria sponges; 944 is a known synthetic compound. 453 A novel taurinated norditerpene geodiataurine 948 was reported from a sample of Geodia macandrewii dredged in both Nordland and Trøndelag, Norway.…”

Antifungal mono- and dimeric nitrogenous bisabolene derivatives from a sponge in the order Bubarida from Futuna Islands

“…9 The apparent “doubling” of many signals in the 1 H and 13 C NMR spectra (Tables 1 and 2) was indicative of rotational isomers around the amide bond ( cis and trans rotamers also called endo and exo in this case), a phenomenon already observed for formamide substituted terpenoids. 10,11 Due to chemical exchange correlation, the negative nOe correlations between the formyl signals at δ H 7.87 (s, H-16, endo ) and 8.24 (s, H-16, exo ) confirmed the presence of the two rotamers present in a 3 : 1 ratio in favour of the endo . The relative configuration around the cyclohexane ring was assigned through interpretation of coupling constant values and NOESY data.…”