(-)-Mandelic acid → Mandelic Acid

Participants

Reaction Steps

47 of D-(-)-mandelic acid, dissolved in 650 ml of methanol, are added dropwise, whilst stirring, to a solution of 55 g of 2-amino-1,2,3,4-tetrahydro-6-methoxy-naphthalene in 650 ml of methanol. The reaction solution so obtained is left to stand for 3 hours at room temperature, the precipitated crystals filtered off, washed with ether and dried. The (-)-mandelic acid salt thus obtained, is recrystallised from hot methanol and the procedure repeated until, at any given time a test showed that the optical rotation of the amine set free from the mandelic acid salt by extraction with IN sodium carbonate solution/methylene chloride is constant. The (+)-antipode of the title compound thus obtained is converted to the hydrochloride and recrystallised from methanol. M.P. 262°-264°. [α]D20 =+77.6° (C=1 in methanol). [Hydrochloride salt form].

Provenance & Evidence