Biosynthesis of ditigloyl esters of DI- and tri-hydroxytropanes in Datura

3α-Tigloyloxytropane-¹⁴CO] N-¹⁴Me], ratio 1·6:1 and valtropine-¹⁴CO] N-¹⁴Me], ratio 1·75:1 were separately fed via cotton wicks to 4-month-old Datura innoxia plants. After 8 days the root alkaloids 3α-tigloyloxytropane, 3α,6β-ditigloyloxytropane and 3α,6β-ditigloyloxytropan-7β-ol were isolated and the distribution of radioactivity in the acid and alkamine moieties was determined by hydrolysis. The precursor ratios were not maintained in the isolated ditigloyl esters, a result which does not support our hypothesis that the ditigloyl esters are formed by the progressive hydroxylation of 3α-tigloyloxytropane.