Preaustinoid A: a meroterpene produced by Penicillium sp.

Abstract

The title meroterpene preaustinoid A (systematic name: methyl 15-hydroxy-2,6,6,10,13,15-hexamethyl-17-methylene-7,14,16-trioxotetracyclo[11.3.1.0(2,11).0(5,10)] heptadecane-1-carboxylate), C(26)H(36)O(6), features a fused four-ring arrangement. Three rings are in different distorted chair conformations and the other is in a distorted boat conformation. The absolute configuration was established based on [alpha(D)] = -4.97 degrees (c = 1.10 g l(-1), CH(2)Cl(2)). In the crystal, the molecules are connected into supramolecular chains via O-H center dot center dot center dot O hydrogen bonds.