Conformational stability of avarol-type molecules. Crystal structure of 3′-methylaminoavarone, a metabolite from Dysidea avara

Cinerols, Nitrogenous Meroterpenoids from the Marine Sponge Dysidea cinerea

Eleven new nitrogenous meroterpenoids, cinerols A-K (1-11), were isolated from the marine sponge Dysidea cinerea collected in the South China Sea, and their structures were determined by detailed spectroscopic analysis. Cinerols A (1) and B (2) feature a rare 5H-pyrrolo[1,2a]benzimidazole moiety, while cinerols C-G (3-7) are examples of rare meroterpene benzoxazoles. The cinerols are noncytotoxic to human melanoma A375 cells at the concentration of 32 μM; however, selected cinerols exhibit moderate inhibitory activity against one or more of protein-tyrosine phosphatase 1B, ATP-citrate lyase, and SH2 domain-containing phosphatase-1 with IC₅₀ values of 2.8-27 μM.

(−)-Kolavenic acid

In the two, almost identical, mol­ecules in the asymmetric unit of the title compound [systematic name: (E)-3-methyl-5-(1,2,4a,5-tetra­methyl-1,2,3,4,4a,7,8,8a-octa­hydro­naphthalen-1-yl)pent-2-enoic acid], C₂₀H₃₂O₂, the rings are trans fused. The cyclo­hexane ring has a chair conformation and the cyclo­hexene ring a distorted half-boat conformation. The two independent mol­ecules are connected into a dimer via O—H⋯O hydrogen bonds. The dimers are associated into supra­molecular chains along c via C—H⋯O contacts.