Studies on the Metabolic Products of Macrosporium porri Elliott

Part III. Structure of Macrosporin (Group II)

Abstract

Macrosporin (I), C₁₆H₁₂O₅ was ethylated with diazoethane to monoethylether (IV), which was oxidized to 4-methyl-5-ethoxy phthalic acid (V). Oxidation of monoethylether (IX) gave 3, 5-dimethoxy phthalic anhydride (XI). From these results and I.R. absorption spectra of macrosporin and its derivatives, the structure of macrosporin is established to be 3, 5-dihydroxy-7-methoxy-2-methyl anthraquinone.