Canescones A–E: aromatic polyketide dimers with PTP1B inhibitory activity from Penicillium canescens

Abstract

Three pairs of enantiomers (±)-canescones A–C (1–3), along with a pair of stereoisomers canescones D (4) and E (5), aromatic polyketide dimers bearing unprecedented 5/6/6/6/5 heterocyclic chemical architectures with a rare pentacyclic dihydrobenzo[1,4]dioxine core, were isolated from the fungus Penicillium canescens. Structure elucidation unambiguously suggests that 1 and 2 feature a new cyclopentanone ring A rather than a pyrrolidinone or furanone ring present in 3–5. All compounds were assayed for PTP1B inhibitory activity, and their hypothetical biosynthetic pathways were proposed.