Resolution of d,1-menthol
AssigneeUop LLC
InventorDavid W. House
Life of this patent
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Abstract
1-Menthol can be readily obtained from racemic menthol by conversion of the latter to the diastereomeric esters of an optically active amino acid and chromatographing the diastereomers. The separation of the diastereomeric esters is relatively insensitive to the support or to the solvent used as eluant, and satisfactory separation occurs under a broad variety of conditions. 1-Menthol can be obtained by base catalyzed hydrolysis of the purified diastereomer with high optical purity.
Claims14
A method of preparing optically active menthol comprising contacting a solution containing the diastereomeric esters from racemic menthol and an optically active amino acid selected from the group consisting of naturally occurring amino acids, phenylglycine, 4-hydroxyphenylglycine, meta-tyrosine, 3,4-dihydroxyalanine, and 3,5-diiodothyronine with a chromatographic support, eluting said support with a solvent under chromatographic conditions, collecting at least one effluent fraction containing a purified diastereomer, treating the purified diastereomer to liberate optically active menthol, and recovering said optically active menthol.
The method of claim 7 where said hydrolysis is base catalyzed.
A method of obtaining a purified diastereomer from which l-menthol may be readily regenerated comprising contacting a solution containing the diastereomeric esters from racemic menthol and an optically active amino acid selected from the group consisting of naturally occurring amino acids, phenylglycine, 4-hydroxyphenylglycine, meta-tyrosine, 3,4-dihydroxyalanine, and 3,5-diiodothyronine, with a chromatographic support, eluting said support with a solvent under chromatographic conditions, and collecting at least one effluent fraction containing a purified diastereomer of l-menthol and said amino acid.
Dependencies are inferred from the claim text.