STIMULANTS A compound of the formula: <IMG> in which the enantiomeric form is d,1 or 1- when R5 is hydrogen and d,1 or 1-threo when R5 is other than hydrogen; R1 and R2 are, independently, hydrogen, alkyl of 1 to 6 carbon atoms, alkoxy of 1 to 6 carbon atoms, halo, perfluoroalkyl of 1 to 3 carbon atoms, nitro, alkanoyl of 2 to 4 carbon atoms or alkoxycarbonyl of 2 to 4 carbon atoms; R3 is hydrogen, halo, nitro or alkanoyl of 2 to 4 carbon atoms; R5 and R6 are, independently, hydrogen or methyl; or a non-toxic acid addition salt thereof, are central nervous system stimulants.
STIMULANTS