Studies in the biochemistry of micro-organisms. 107. Metabolites of Penicillium viridicatum Westling: viridicatic acid (ethylcarlosic acid)

The mould Penicillium viridicatum Westling produces several crystalline metabolites. The mycelium has afforded viridicatin, CL5HI102N, which was first isolated and described by Cunning- ham & Freeman (1953). This product was later obtained from P. cyclopium Westling by Bracken, Pocker & Raistrick (1954), who determined the molecular structure as 2:3-dihydroxy-4-phenylquinoline or its ketotautomer. A product closely re- lated to viridicatin, namely cyclopenin, C17H.403N2, was also obtained from the mycelium of P. cyclopium, although not from the strains producing viridicatin. On mild acid hydrolysis, cyclopenin yields viridicatin, methylamine and carbon dioxide; on the basis of this reaction Bracken et al. (1954) suggested for cyclopenin two alternative structures.