THE OBLIGATORY ROLE OF PHENYLLACTATE IN THE BIOSYNTHESIS OF TROPIC ACID

Article abstract of DOI:10.1016/S0031-9422(00)95088-X

Phenyl<1-14C> lactic acid and phenyl<2-3H> lactic acid were synthesized by conventional routes and fed in admixture (3H:14C ratio 10:1) to Datura stramonium via the roots.Hyoscine (scopolamine) and hyoscyamine were isolated and found essentially the same 3H:14C ratios as the precursor (8.5 and 10.15, respectively).Hydrolysis of hyoscyamine showed that all the activity was present in the tropic acid moiety.The tropic acid was converted to atropic acid and then cleaved by means of osmium tetroxide and sodium metaperiodate to yield formaldehyde containing all the tritium and phenylglyoxylic acid containing all the 14C, a result which shows that the tritium at C-2 is an obligatory intermediate in the biosynthesis of tropic acid and that the rearrangement of the side-chain takes place at the phenyllactate and not the phenylpyruvate level. Key Word Index - Datura stramonium; Solanaceae; phenyllactic acid; tropane alkaloids; tropic acid biosynthesis.