The shrub ma huang contains two biologically active stereoisomers - ephedrine and pseudoephedrine with two stereogenic centers as shown in the given structure. Ephedrine is one component of a once popular combination drug used by bodybuilders to increase energy and alertness, while pseudoephedrine is a nasal decongestant. Draw the structure of naturally occurring (-)-ephedrine, which has the 1R,2S configuration. Click the "draw structure" button to launch the drawing utility. OH H T 2 N 1 OH edit structure ... isolated from ma huang