Preparation of Radioactive Gibberellins A20, A5and A8

Abstract
Radioactive gibberellin [Gibberella fujikuroi and higher plants] A20 (GA20, I) was prepared by hydrogenation of GA5 methyl ester-16,17-epoxide with tritium gas followed by removal of epoxide oxygen and hydrolysis. Radioactive GA5 was obtained by hydrogenation of GA3 methyl ester monomesylate with tritium gas followed by hydrolysis and radioactive GA8 was obtained by oxidation of radioactive GA5 with osmium tetroxide.