Methods for preparing levorphanol and related compounds, and compositions thereof
AssigneeAMPAC Fine Chemicals LLC
InventorsWilliam Dubay, Alex Nichols, Wei Chen, Alec Brozell, Ajay Ryerson
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Abstract
A method for producing substantially pure levorphanol and related compounds, when compared to the conventional process, is provided. In particular, a method for producing substantially pure levorphanol tartrate dihydrate is described. Also described are compositions comprising levorphanol and related compounds, particularly compositions comprising levorphanol tartrate dihydrate, levomethorphan, and norlevorphanol in which the levomethorphan and norlevorphanol are present in the composition in reduced levels.
Claims4
A method of preparing a composition comprising levorphanol tartrate dihydrate in an amount of 99.80% or greater and norlevorphanol in an amount of 0.20% or less, the method comprising:
- (i) reacting levorphanol tartrate with a base to obtain a mixture;
- (ii) reacting the mixture with ethyl formate to obtain a second mixture;
- (iii) reacting the second mixture with L-(+)-tartaric acid to obtain a third mixture comprising levorphanol tartrate;
- and
- (iv) crystallizing the levorphanol tartrate from the third mixture in an aqueous-organic solvent mixture to obtain the composition.
Dependencies are inferred from the claim text.