title: First syntheses of the biologically active fungal metabolites pestalotiopsones A, B, C and F.
abstract: A synthetic approach accessing the pestalotiopsones, fungal chromones possessing a rare skeletal subtype, is reported for the first time. The synthesis of pestalotiopsone A (1) has been achieved in 7 linear steps (28%), from commercially available 3,5-dimethoxybenzoic acid and subsequently the first syntheses of pestalotiopsone B (2), C (3) and F (4) were performed utilising this chemistry. The key steps include a newly described homologation of a substituted benzoic acid to afford phenylacetate derivatives utilising Birch reductive alkylation conditions, a microwave mediated chromanone formation proceeding through an oxa-Michael cyclisation, and an IBX induced dehydrogenation to the desired chromone skeleton. The synthetic natural products were completely characterised for the first time, confirming their structures and their biological activities evaluated against a panel of bacterial pathogens.
authors.affiliation: Research School of Chemistry, The Australian National University, Canberra, ACT 0200, Australia.
authors.forename: Andrew Michael
authors.initials: AM
authors.lastname: Beekman
authors.forename: Edwin
authors.initials: E
authors.lastname: Castillo Martinez
authors.forename: Russell Allan
authors.initials: RA
authors.lastname: Barrow
mesh_terms: D000900:Anti-Bacterial Agents / Q000138:chemical synthesis* / Q000378:metabolism / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D015394:Molecular Structure; D020102:Mycobacterium smegmatis / Q000187:drug effects; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D013212:Staphylococcus epidermidis / Q000187:drug effects; D013329:Structure-Activity Relationship; D013098:Xylariales / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents