Abstract:
The class of compounds known as the pyranonaphthoquinone antibiotics are isolated from various strains of bacteria and fungi, the majority being microbial in origin.1 The basic skeleton of these antibiotics is the naphtho[2,3-c]pyran-5,10-dione ring system (Fig. 1), with some members of the family containing an additional γ-lactone ring fused to the dihydropyran moiety as the basic subunit. This substituted benzoisochromane skeleton represents a biosynthetic product common to all members of this class and is built up from acetate/malonate units via a polyketide pathway