Oxidative ring fission of the naphthoquinones lapachol and dichloroallyl lawsone by Penicillium notatum.

The naphthoquinones lapachol and dichloroallyl lawsone readily undergo oxidative ring fission when incubated with several fungi and streptomycetes. Penicillium notatum was employed to produce the ring fission product of dichloroallyl lawsone which was isolated and characterized by spectral analyses and chemical synthesis. The mechanism of oxidative ring fission of lapachol was studied by growing P. notatum cultures in an 18O2 atmosphere. Mass spectral analysis of the isolated and labeled metabolite indicates that ring fission occurs via a monooxygenase pathway most probably involving an epoxide intermediate.