Hello
From phenylisopropyl(methyl)amine freebase;
Extract the freebase amine with toluene. Prepare a solution of dextrorotary tartaric acid(1), 50g in 300ml dH2O, stir to dissolve. Extract the amine by adding in 25ml portions with vigorous shaking the acid soln. to the Toluene containing the free amine. The aqueous layer will gain a purple/red color, is separated, and placed in a separate beaker. Repeat this until no appreciable color change to the aqueous layer takes place. Pour all the aqueous extracts in an evaporating dish and let stand undisturbed for several hours until the l-amine d-tartarate crystals precipitate out of solution. Decant the mother liquor and wash the crystals with 2x25ml dH2O, adding the wash to the mother liquor. Basify the mother liquor which contains the desired d-amine d-tartarate salt. Extract w/ toluene, dry the solvent, gas w/HCl, filter the precipitate and recrystalize.
That was the easiest thing after trying a lot. As well as the most effective, for me