Six new triterpenoids (1-6) and the previously known penasterone, acetylpenasterol, and ergosta-4,24(28)-dien-3-one were isolated from a Penares sp. sponge collected from Vietnamese waters. Structures of the obtained compounds were established by extensive 1D and 2D NMR spectroscopy and mass spectrometry. Configurations of the triterpene epoxy lactones (1-4) were determined on the basis of NOESY and CD data and calculation of spin coupling constants and confirmed by X-ray crystallographic analysis of compound 2. The isolated triterpenoid 6 was cytotoxic against human leukemia HL-60 cells (IC₅₀ = 9.7 μM).

Five new (1, 2, 4-6) and one known (3) diterpenoid were isolated from the keratose sponge Spongia (Heterofibria) sp. Structures of these compounds and their absolute configurations were proposed on the basis of X-ray analysis of 1, its CD spectrum, and NMR and MS spectroscopic studies of 1-6. One of the new diterpenoids was shown to be 2(R),3(S),4(S)-3,18-methylene-2-acetoxyspongia-13(16),14-diene (6), possessing a novel carbon skeleton system.

The molecular and crystal structures of chlorine-, bromine and nitro-substituted chromium(III) acetylacetonate are determined. Connecting the substituent to the central atom does not change bond lengths and valence angles in metal chelate rings. Studied chromium complexes are characterized by greater intermolecular interactions compared with analogous metal acetylacetonates. In some cases, intermolecular interactions increase the bend of chelate rings along the O···O line. Substituents do not interact with chromium ions of neighboring molecules, because metal is blocked by three ligands.