An efficient process of racemization of alpha-ethyl-2-oxo-1-pyrrolidineacetic acid: A levetiracetam intermediate

(S)-alpha-ethyl-2-oxo-1-pyrrolidineacetic acid (3), an advance intermediate to assemble Levetiracetam, is prepared by resolution of alpha-ethyl-2-oxo-1-pyrrolidineacetic acid (2) with (R)-(+)-α-methyl benzyl amine in benzene. Although this process is efficient, there is need to develop an alternative, cost effective and eco friendly process for resolution of compound 2 using ecofriendly solvent in place of Benzene and also there is need to recycle the unwanted (R)-alpha-ethyl-2-oxo-1-pyrrolidineacetic acid and uncrystallized S-acid from the mother liquor which is yet unknown. The purpose of this study is twofold, first being to replace benzene and second the pollution issue to discard generated large amount of undesired isomer during resolution and reduce the cost of 1. We have developed a novel resolving system in which compound 2 is resolved using eco friendly solvent like toluene pet ether mixture or THF in place of Benzene and racemization process of 4 in which 4 was treated with potassium hydroxide in refluxing methanol and water followed by acidification using hydrochloric acid to give (2), the latter intermediate has already been converted into 1.

Author(s): Neelakandan K., Anil B. Chavan, B. Prabhakaran and Manikandan. H

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