N-hydroxypyridones, phenylhydrazones, and a quinazolinone from Isaria farinosa

Abstract

New N-hydroxypyridones, militarinones E (1) and F (2), phenylhydrazones, farylhydrazones A (3) and B (4), a quinazolinone, 2-(4-hydroxybenzyl)quinazolin-4(3H)-one (5), and the known militarinones A (6) and B (7) were isolated from cultures of the Cordyceps-colonizing fungus Isaria farinosa. The structures of 1-5 were elucidated by spectroscopic methods, and 3 was confirmed by X-ray crystallography. The absolute configuration of the C-4' secondary alcohol in 1 was deduced via the circular dichroism data of the in situ formed [Rh(2)(OCOCF(3))(4)] complex. Compounds 1 and 6 showed significant cytotoxicity against A549 cells, whereas 7 was active against Staphylococcus aureus, Streptococcus pneumoniae, and Candida albicans.