Preparation of a tritiated ginkgolide

Ginkgolide B, a constituent of the tree Ginkgo biloba, was radiolabeled with the β-emitter tritium ([3H]) in two steps from ginkgolide C. First, a triflate precursor was prepared utilizing the selective reactivity of 7-OH in ginkgolide C; the triflate was then reduced with sodium borotritide to yield tritiated ginkgolide B ([3H]GB) in good yield and high specific activity. The tritiated ginkgolide will be an important tool for studying neuromodulatory properties of ginkgolides.