The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 01, 2011
Filed:
Jan. 05, 2007
Alexei Kalinin, Springfield, MO (US);
Guofang Qiu, Springfield, MO (US);
Thomas J. Marren, Springfield, MO (US);
James E. Aldred, Jr., Springfield, MO (US);
Yu Ji, Springfield, MO (US);
Alexei Kalinin, Springfield, MO (US);
Guofang Qiu, Springfield, MO (US);
Thomas J. Marren, Springfield, MO (US);
James E. Aldred, Jr., Springfield, MO (US);
Yu Ji, Springfield, MO (US);
Archimica, Inc., Springfield, MO (US);
Abstract
A process for preparing the d-threo isomer of methylphenidate hydrochloride which includes (i) resolving a racemic mixture of racemic threo-methylphenidate hydrochloride with a less than stoichiometric amount of tertiary amine base to obtain a methylphenidate-chiral acid salt, (ii) basifying the methylphenidate-chiral acid salt to obtain methylphenidate free base, and (iii) converting the methylphenidate free base into d-threo-methylphenidate hydrochloride.