Fungal metabolism of 4-methylprimaquine.

4-Methylprimaquine (4-MPQ), an 8-aminoquinoline antimalarial drug, was subjected to microbial metabolism studies in an effort to isolate, identify, and predict the probable mammalian metabolite(s). Preliminary screening with a number of strains of Aspergillus indicated that several species were capable of metabolizing 4-MPQ to one major metabolite based on thin-layer chromatographic analysis. Preparative scale conversion of 4-MPQ using whole-cell suspensions of Aspergillus ochraceus afforded one major metabolite (4-MPQ-I). Based on spectroscopic and chemical evidence, the structure of the metabolite is proposed as 6-methoxy-8-(3-carboxyl-l-methylpropylamino)-lepidine.