The structures of A88696C (1), D (2) and F (3), isolated from Streptom
yces sclerotialus, are described on the basis of spectroscopic analysi
s. 1 and 3 are spirotetronic acid-containing macrolides, and 2 is the
beta-dicarbonyl tautomer with a spiroepoxide at the alpha-site of the
lactone ring.