Method for the preparation of 6-hydroxy-2,5,7,8-tetraalkyl-2-(4-aminophenoxymethyl) chromans
AssigneesLonza Ltd., Sankyo Company, Limited
InventorJosef Heveling
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Abstract
A novel process for the preparation of aminochromans of the general formula: ##STR1## wherein R is a C.sub.1 -C.sub.4 alkyl group. In the process, a nitrochromanone of the general formula: ##STR2## is hydrogenated with hydrogen in the presence of a hydrogenation catalyst. The resultant aminochromanone (III) is reduced using zirconium oxide/isopropanol to the aminochromene (IV). The latter is finally hydrogenated with hydrogen in the presence of a hydrogenation catalyst to give the final product. The aminochromans are useful intermediates for the preparation of hypolipidaemic pharmaceuticals.
Claims20
A process for the preparation of 6-hydroxy-2,5,7,8-tetraalkyl-2-(4-aminophenoxymethyl)chroman of the formula:
- ##STR10## wherein R is a C.sub.1 -C.sub.4 -alkyl group, characterized in that, in a first step, a 6-hydroxy-2,5,7,8-tetraalkyl-2-(4-nitrophenoxymethyl) chroman-4-one of the formula:
- ##STR11## wherein R has the above-stated meaning, is hydrogenated with hydrogen in the presence of a hydrogenation catalyst to give a 6-hydroxy-2,5,7,8-tetraalkyl-2-(4-aminophenoxymethyl)chroman-4-one of the formula:
- ##STR12## wherein R has the above-stated meaning, in a second step, said aminochromanone of formula III is reduced under pressure in the presence of a catalyst system of amorphous zirconium oxide/isopropanol to give a 6-hydroxy-2,5,7,8-tetraalkyl-2-(4-aminophenoxymethyl)chrom-3-ene of the formula:
- ##STR13## wherein R has the above-stated meaning, and in a third step, the aminochromene of formula IV is finally converted into the final product using hydrogen in the presence of a hydrogenation catalyst.
Dependencies are inferred from the claim text.