The relative and absolute configuration of PF1140

A potentially general approach for elucidating the absolute configuration of N-hydroxypyridone antibiotics has been developed. One member of this family of antibiotics, PF1140, was efficiently purified from a crude fungal extract following allylation of its N-hydroxyl group. Removal of the resultant allyl group permitted regeneration of the N-hydroxyl group as well as conversion into the corresponding pyridone derivative. The stereochemistry of PF1140 including the absolute configuration was established by X-ray crystallographic analysis of the S-2-methoxy-2-(1-naphthyl)propionic ester derivative.