Structure of the Antibacterial Compound, Aspergillic Acid

Abstract

REDUCTION of aspergillic acid, C₁₂H₂₀O₂N₂, an antibiotic isolated from culture filtrates of Aspergillus flavus¹, gives in high yield a neutral reaction product, deoxyaspergillic acid, C₁₂H₂₀ON₂, to which the structure 2-hydroxy-3 : 6-disec.-butylpyrazine has been ascribed². We have previously described syntheses of 2-hydroxy-3 : 6-disec.-butylpyrazine⁸, and although We were unable to resolve the racemic compound, a comparison of its properties with those of deoxyaspergillic acid led us to conclude that the latter is a hydroxypyrazine derivative. Substantial differences in the intensity of light absorption in the ultra-violet, however, suggested that the two compounds differ more profoundly than in stereochemical orientation. Moreover, deoxyaspergillic acid has been racemized by treatment with alkali, and the racemate is distinct from 2-hydroxy-3 : 6-disec.-butylpyrazine, which is itself unaffected by similar treatment with alkali.