The enantioselective metabolism of 4-isopropenyltoluene in rabbits.

4-Isopropenyltoluene (8) was administered orally to rabbits and the following four optically active metabolites, 2-(p-tolyl)propanoic acid (10), p-(1-carboxyethyl)benzoic acid (11), 2-hydroxy-2-(p-tolyl)propanoic acid (12), and 2-(p-tolyl)-1,2-propanediol (13) were isolated from urine in addition to an optically inactive metabolite, 4-isopropenylbenzoic acid (9). The enantiomeric ratios of the metabolites 10 and 11 were respectively R/S = 33:67 and 39:61 (S predominance), whereas those of the metabolites 12 and 13 possessing a tertiary hydroxyl group were R/S = 77:23 and 84:16 respectively (R predominance). The presumed metabolic pathways of 8 in rabbits leading to these metabolites are discussed.