Identification of nekoflavin as 7 alpha-hydroxyriboflavin

Nekoflavin, which was found in cat's choroids [Matsui, K. (1965) J. Biochem. 57, 201-206], was identified as 7 alpha-hydroxyriboflavin by comparing the physicochemical properties of nekoflavin acetate with those of chemically synthesized 7 alpha-hydroxyriboflavin pentaacetate. 7 alpha-Hydroxyriboflavin was synthesized from 4-chloro-2-methylbenzonitrile through 7-cyano-7-demethylriboflavin and 7 alpha-aminoriboflavin, which are also new flavins.