Reported here is the first polyarsenic compound ever found in nature. Denominated arsenicin A, it was isolated along a bioassay-guided fractionation of the organic extract of the poecilosclerid sponge Echinochalina bargibanti collected from the north-eastern coast of New Caledonia. In defining an adamantine-type polyarsenic structure for this compound, deceptively simple NMR spectra were complemented by extensive mass spectral analysis. However, it was only the synthesis of a model compound that provided the basis to discriminate structure 4 from other spectrally compatible structures for arsenicin A; to this end, a comparative ab initio simulation of IR spectra for the natural and the synthetic compounds was decisive. Arsenicin A is endowed with potent bactericidal and fungicidal activities on human pathogenic strains. All this may revive pharmacological interest in arsenic compounds while prompting us to rethink the arsenic cycle in nature.

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Five new amino acid derivatives were isolated from the New Caledonian sponge Jaspis carteri, together with known bengamides A and B. The structures of the new compounds were determined by interpretation of their spectral data and by comparison with spectral data of known bengamides. Compounds 4−7 are simply the tridecanoate and pentadecanoate analogues of the original bengamides A and B, whereas compound 8 is a caprolactam formamide derivative of bengamide B.

The structure of title compound (I) is assigned by NMR and mass spectroscopy and supported by a comparative ab initio simulation of IR spectra for the natural compound and synthetic analogues. -(MANCINI*, I.; GUELLA, G.; FROSTIN, M.; HNAWIA, E.; LAURENT, D.; DEBITUS, C.; PIETRA, F.; Chem. Eur. J. 12 (2006) 35, 8989-8994; Lab. Chim. Bioorg., Univ. Trento, I-38050 Povo-Trento, Italy; Eng.) -Nuesgen 14-214