Isp Investments Inc.

Satish C Nigam

Mark J Cooney

Jonathan Caudill

Krishnamurthy Nacharaju

Christophe Buron

Cletis Stiffler

Methods for the preparation of pharmaceutically acceptable organic or inorganic salts of 5-methylpyrazinecarboxylic acid-4-oxide esters including tris(hydroxymethyl)aminomethanol, N,N-dimethylethanolamine, N-methyl-D-glucamine, L-Lysine, L-arginine, Na, K, Ca and Mg. The esters of 5-methylpyrazinecarboxylic acid-4-oxide are oxidized in aqueous hydrogen peroxide at a pH of 2.5 to 7 in the presence of a catalyst selected from the group consisting of sodium tungstate, tungstic acid and ammonium heptamolybdate. The salts are formed by saponification of the esters followed by alcohol precipitation, or by reaction with a metal trimethylsilanoate, or by the reaction of organic bases with the saponified acids.

Pharmaceutically acceptable inorganic and organic salts of 5-methylpyrazine-2-carboxylic acid-4-oxide

Methods for the preparation of pharmaceutically acceptable salts of 5-methylpyrazine-carboxylic acid-4-oxide by using the oxidizing agent OXONE&#xae; for the N-oxidation of Cmethylpyrazinecarboxylic acid esters. The pharmaceutically acceptable salts are then formed by the saponification of the esters followed by alcohol precipitation.

Method for the preparation of 5-methylpyrazine-2-carboxylic acid-4-oxide and its salts

A method of producing gabapentin (1-amino-methyl)-1-cyclohexaneacetic acid) from its hydrochloric salt in an anhydrous medium, the method consisting of:

Process for the preparation of 1-(aminomethyl) cyclohexaneacetic acid

Method for preparing 1,2-dibromo-2,4-dicyanobutane by reacting 2-methyleneglutaronitrile with bromine in an alcoholic solvent at a temperature of about 25&deg; C. to 65&deg; C. and isolating the product in one unit operation without color or odor problems and in high yields.

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Hilliard, OH, United States of America

Satish C Nigam