Kalafungin, a New Broad Spectrum Antibiotic

Kalafungin is a new antibiotic extracted from the fermentation broth of Streptomyces tanashiensis strain Kala, and purified by chromatography on silica gel followed by crystallization. It is a weakly acidic, orange colored compound, pKa=10.0, with a molecular formula C16H12O6 and a molecular weight of 300. It is dextrorotatory in chloroform, [α]25D+159, and exhibits ultraviolet and visible absorption maxima at 212, 256, and 425 mμ in methanol. Kalafungin melts at 163-166°C and is readily soluble in ethyl acetate, chloroform, and acetone but only slightly soluble in water.