<unk>  exists as four stereoisomers : (±)-cis and (±)-trans. The (±)-cis isomers are the form used recreationally. The (±)-cis isomers racemate (1:1-mixture) of the <unk> R,5S)-isomer and the enantiomeric <unk> S,5R)-isomer generally synthesized from dl-phenylpropanolamine in one step by cyclization with cyanogen bromide (sometimes prepared in situ by reacting sodium cyanide with bromine). Alternate synthesis routes generally involve more steps, such as replacing cyanogen bromide with sodium or potassium cyanate to form an intermediate and then reacting it with concentrated hydrochloric acid. A method reported in microgram replaced the need for a separate addition of hydrochloric acid by starting with the hydrochloride salt of the dl-phenylpropanolamine but side-products are noted. The (±)-trans isomers racemate (1:1-mixture) of the <unk> S,5S)-isomer and the enantiomeric <unk> R,5R)-isomer are synthesized in the same manner above but dl-norephedrine is used as the starting material instead. The cyanate reaction proceeds differently from the cyanogen bromide and transforms norephedrine into trans-4-methylaminorex instead, as noted in the DEA micrograph. The cyanogen bromide, by comparison, transformed norephedrine into the cis isomer and norpseudoephedrine into the trans isomers of the final product.
4-Methylaminorex
Methylenedioxypyrovalerone
D-DOPA
3-Chloropropanoic acid
Beta-Hydroxy beta-methylbutyric acid
3-Indolepropionic acid
L-DOPA
Vanillylmandelic acid