Synthesis of tritium-labeled plant hormones

Solid-phase catalytic hydrogenation, isotope exchange with tritium-enriched water, catalytic heterogeneous isotope exchange with gaseous tritium, and hydrogenolysis were studied as routes to tritium-labeled plant hormones. Th e investigation objects were representatives of the main plant hormones: au xins, cytokinins (kinetin, benzyladenine, zeatin, zeatin riboside), gibbere llins (A(1) and A(3)), and fusicoccin-H. Depending on the synthesis procedu re, the resulting labeled products had the molar activity from 5 to 155 Ci mmol(-1). General approaches to synthesis of tritium-labeled plant hormones were formulated on the basis of the results obtained.