“…Louis, Missouri, U.S.A. Authentic samples of the following phorbol 12, 13-diesters obtained in this laboratory in previous investigations on croton oil (7,8,9,14) were: 12-O-tiglylphorbol-13-acetate (1), 12-0tiglylphorbol-13-isobutyrate (2), 12-O-(2-methyl)-butyrylphorbol-13isobutyrate (3), 12-O-tiglylphorbol-13-(2-methyl)-butyrate (4), 12-0decanoylphorbol-13-acetate (5), 12-O-dodecanoylphorbol-13-acetate (6), 12-O-tetradecanoylphorbol-13-acetate (7), 12-0-hexadecanoylphorbol-13-acetate (8), 12-O-acetylphorbol-13-decanoate (9), and 12-O-(2-methyl)-butyrylphorbol-13-decanoate (13). Compounds 5-8 and 9 and 13 represent Hecker's croton oil fractors A1-A4 and B2 and B7, respectively.…”