Metabolism of cathinone to (-)-norephedrine and (-)-norpseudoephedrine.

S-(-)-Cathinone (S-(-)-alpha-aminopropiophenone) is the major active principle of khat leaves (Catha edulis), which are widely used in East Africa and the Arab peninsula as an amphetamine-like stimulant. After oral administration of synthesized cathinone (isomers, racemate), 22-52% was recovered in 24 h urine samples mainly as aminoalcohol metabolites. With GC/MS, HPLC and CD, the main metabolite of S-(-)-cathinone was identified as R/S-(-)-norephedrine and the main metabolite of R-(+)-cathinone as R/R-(-)-norpseudoephedrine. Both aminoalcohols are formed by a stereospecific keto reduction.