Process for preparing the d-threo isomer of methylphenidate hydr

Details Process for preparing the d-threo isomer of methylphenidate hydr Process for preparing the d-threo isomer of methylphenidate hydr

1998-12-03

2000-12-19

Kight, John

Organic compounds -- part of the class 532-570 series

Organic compounds

Heterocyclic carbon compounds containing a hetero ring...

C07D21132

Patent

active

061629197

ABSTRACT:
A process for preparing the d-threo isomer of methylphenidate hydrochloride comprising converting d,l-threo methylphenidate hydrochloride to the free base form in a first step, resolving the free base prepared in the first step with (R)-(-)-1,1'-binaphthyl-2,2'-diyl hydrogen phosphate to obtain the phosphate salt enriched with the d-threo isomer of methylphenidate in a second step, basifying the phosphate salt to obtain the free base form of the d-threo isomer of methylphenidate in a third step, converting the free base to the hydrochloride salt form of the d-threo isomer of methylphenidate in high optical purity in a fourth step, and recrystallizing the hydrochloride salt form to obtain the desired d-threo isomer in a higher optical purity. An alternative embodiment relates to the preparation of the d-threo isomer of methylphenidate hydrochloride utilizing the hydrochloride salt form of the racemic mixture of threo-methylphenidate directly.

REFERENCES:
patent: 2957880 (1960-10-01), Rometsch
patent: 5733756 (1998-03-01), Zeitlin et al.
Journ. of Pharmacol. & Experimental Therapeutics, Patrick et al., vol. 241, pp. 152-158 (1987).
J.Med.Chem.,Thai, et al., vol. 41, pp. 591-601 (1998).
Tetrahedron: Asymmetry, vol. 9, pp. 2133-2136 (1998).
Journal of Chromatrography vol. 328, pp. 378-386 (1985).

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