Methanol → Dexmethylphenidate

Participants

Reaction Steps

Resolve dl-threo-methylphenidate by the procedure described in the Example of PCT/GB97/00185 (International Publication No. WO 97/27176): Ditoluoyl-D-tartaric acid (5.033 g, 12.4 mmol) was suspended in a solution of 2% methanol in acetone (10 ml), and a solution of threo-methylphenidate (2.9 g, 12.4 mmol) in the same solvent (10 ml) was added. The solution was gently warmed to reflux whereupon all the reagents dissolved. The solution was immediately cooled and crystals began to form. The solution was allowed to stand at 4° C. for 17 hours and was then filtered. The crystals were washed with acetone (3×15 ml) and dried in vacuc to yield the ditoluoyl-D-tartrate salt of d-threo-methylphenidate (3.516 g, 44.3% by weight; corresponding to 97%. ee d-threo methylphenidate, as determined by chiral HPLC after salt cracking). The mother liquors were dried in vacuo to yield the ditoluoyl-D-tartrate salt of l-threo-methylphenidate as a solid, dry form (4.508 g, 50.5% yield, 88% ee).

Provenance & Evidence