Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
2006-02-21
2006-02-21
Chang, Celia (Department: 1625)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
C546S237000
Reexamination Certificate
active
07002016
ABSTRACT:
The present invention provides a process for the preparation of threo-methylphenidate hydrochloride. According to a preferred embodiment, the process comprises the following steps:(a) contacting 1-(phenylglyoxylyl)piperidine arenesulfonylhydrazone of the formulawherein Ar denotes an aryl group, where the aryl group may be substituted by a C1–C6alkyl, halo or nitro group;with an inorganic base in the presence of a water immiscible organic solvent and a phase transfer catalyst to obtain (R*,R*)-enriched 7-phenyl-1-azabicyclo [4.2.0]octan-8-one of the formula:(b) reacting the (R*,R*)-enriched 7-phenyl-1-azabicyclo[4.2.0]octan-8-one prepared in step (a) with a solution of hydrogen chloride in methanol to obtain threo-enriched methylphenidate hydrochloride;(c) crystallizing the threo-enriched methylphenidate hydrochloride prepared in step (b) to give the desired threo-methylphenidate hydrochloride. Preferably, the threo-methylphenidate hydrochloride produced by the process of the present invention contains no more than 1% of the erythro-isomer.
REFERENCES:
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Gutman Arie
Nisnevich Gennady
Shalimov Anton
Sotrihin Maxim
Zaltsman Igor
Chang Celia
Davis William J.
Imre Balogh
ISP Investments Inc.
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