Hydrochloric Acid → (1R*,2S*)-2-(1-Methylhydrazino)-1-phenyl-1-propanol Hydrochloride

To a solution of 1-oxa-2-azaspiro[2.5]octane (0.60 g, 5.3 mmol) in ether (20 ml) a solution of (1R*,2S*)-2-methylamino-1-phenyl-1-propanol (0.86 g, 5.3 mmol) in ether (5 ml) was added. The reaction mixture was stirred at room temperature for 30 minutes then evaporated to dryness. 5% Hydrochloric acid (30 ml) was added to the residue and the mixture was stirred at ambient temperature for 1 h. The mixture was washed with Et2O (2×30 ml), made alkaline with Na2CO3 under ice-cooling and extracted with EtOAc (3×50 ml). The combined EtOAc extracts were dried and evaporated to give a solide residue which was dissolved in methanol (5 ml) and converted to the crystalline hydrochloride salt by using 22% ethanolic hydrogen chloride (2 ml) and diethyl ether. Crystals were filtered off and recrystallized from methanol/diethyl ether.