3′-Demethoxy-3′-hydroxystaurosporine, a Novel Staurosporine Analogue Produced by a Blocked Mutant

3'-Demethoxy-3'-hydroxystaurosporine, 1 (CGP 58,546), a novel staurosporine analogue, was isolated from a mutant of Streptomyces longisporoflavus R19 blocked in the last step of the biosynthetic pathway. CGP 58,546 was less potent than staurosporine, but it showed a more selective inhibition pattern against various subtypes of protein kinase C.