Isolation of the bromo analogue of caldariomycin from Caldariomyces fumago.

When bromide ion was substituted for chloride in the growth medium of Caldariomyces fumago, a new substance was produced. It was isolated by solvent extraction and purified by alumina chromatography. Examination of the physicochemical properties of the substance led to its identification as the bromo analogue of the normal metabolite, caldariomycin. Thus, biological substitution of bromine for chlorine has been demonstrated in the metabolic formation of a purely aliphatic secondary mold metabolite.