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Deoxyfunicone, rapicone and their 5,6-epoxy-derivatives are γ-pyrone compounds with cytostatic and antiproliferative properties. Here we describe a synthesis of these compounds by carbonylative Stille coupling between kojic acid derivatives and functionalized iodo aryl compounds. The main advantages of this patent pending synthetic strategy lie in the simplicity and clean conversion of products, and in the possibility to obtain a high number of analogs by minor changes of the synthetic synthons.

Chemical investigation of the culture broth of the fungus Eutypella scoparia ICB-OBX, isolated from the marine pulmonate mollusc Onchidium sp., led to the finding of novel compounds 1 and 2 , structurally related to angiotensin II binding inhibitors cytosporins, along with unrelated known nitrogen metabolites (compounds 3 – 5 ). The structure and the relative stereochemistry of the novel metabolites were assigned mainly by a detailed analysis of two-dimensional NMR techniques whereas the absolute stereochemistry was proposed by modified Mosher's method. Compound 2 contains an unusual cyclic carbonate functionality that is rare among natural products.

Described in this paper is the biosynthesis of defensive drimanes in dorid nudibranchs. Two geographically distinct populations of molluscs belonging to the genus Dendrodoris have been studied. The de novo synthesis of 7-deacetoxyolepupuane (2) has been demonstrated by radiolabelled precursors in both species. The results of the studies are consistent with the pivotal role of 2 in the formation of the other drimanes both in the mantle and in the egg masses of the molluscs. The new drimane 6-β-acetoxypolygodial (7) is reported from the skin extract of the pacific Dendrodoris arborescens. Its structure elucidation was accomplished by NMR spectroscopy.

Two new cembranes (2 and 3) have been isolated from the extract of the Antarctic sponge Lissodendoryx flabellata. Their structural elucidation has been performed by spectroscopic techniques, whereas the absolute configuration of the secondary carbinolic center was inferred by Mosher's method. The absolute stereochemistry of the second asymmetric carbon, as well as the solution conformation of 2, has been determined by a computational approach based on conformational search, restrained molecular dynamics and semi-empirical calculations. The main product 2 showed cytotoxic and anti-proliferative activity against mammalian tumor cells.