4-Methylaminorex (4-MAX)

4-Methylaminorex is a stimulant drug of the 2-amino-5-aryloxazoline class. 4-Methylaminorex exists as four stereoisomers - (±)-cis and (±)-trans. The (±)-cis isomers are the form used recreationally. The (±)-cis isomers [racemate (1:1-mixture) of the (4R,5S)-isomer and the enantiomeric (4S,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.