To a gently stirred mixture of 33.55g (0.25mol P2P), and 30.3g (0.25mol) (R)-(+)-a-Methylbenzylamine, in anhydrous EtOH (125mL) under N2 was added 10mL glacial acetic acid. Next, 7.5g Pd/C 10% was added carefully. The gaseous layer was exchanged with 4-5 bar H2 by applying the vacuum ventilation procedure for three times, and then the mixture was hydrogenated at 4-5 bar H2 under vigorous stirring for 10-16 hours. After completion of conversion the mixture was filtered through a celite pad inorder to remove any of the catalyst, and the filter pad was rinsed with additional EtOH (2x 20mL). The filtrate was neutralized (pH 3-5) by the careful addition of concentrated aq. HCl and then the volatiles were removed in vacuo at 40C to obtain the crude product in its hydrochloric form as a yellowish oil. The residue was dissolved in 400mL water and washed with DCM (3x 100mL). The aqueous layer was adjusted to pH 10-12 using cold NaOH aqueous 25% and the liberated base was extracted with DCM (4x 100mL) maintaining 15-20C. The combined extracts are dried over MgSO4, filtered, and concentrated at 40c in vacuo. The residue is subjected to vacuum distillation. 31.63g d-MA freebase was dissolved in 375mL Et2O containing 0.5% iPrOH under N2. The mechanically stirred solution was kept below 20C by using a cooling bath and was carefully neutralized to pH 4.5 by gassing. The white suspension is filtered off and the filter cake was rinsed with Et2O (2x 150mL), Et2O/iPrOH 9:1 (2x 100mL), and again with Et2O (2x 100mL), and the white solid dried under high vacuum for 2 days at 40C. Yield 85%.
