Novel Methods for Preparation of (+)-1-ethyl-4-[2-(4-morpholinyl)ethyl)-3,3-diphenyl-2-pyrrolidinone
The present invention includes a method of preparing a composition comprising (+)-doxapram or a salt thereof, wherein the composition is essentially free of (?)-doxapram or a salt thereof.
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Paragraph 0084
(2013/05/09)
4-(BETA-SUBSTITUTED ETHYL)-3,3-DIPHENYL-2-PYRROLIDINONES. A NEW SERIES