Preparation of 1-(4-hydroxy-phenyl)-butan-3-one and novel intermediates
AssigneeBASF SE
InventorsWerner Hoffmann, Dieter Degner
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Abstract
A simple process for preparing 1-(4-hydroxy-phenyl)-butan-3-one, a sought-after natural aromatic, in a pure form and in good yield from easily accessible starting materials, wherein a 4-tert-alkoxy-benzaldehyde is condensed, under alkaline conditions, to give a novel 1-(4-tert.-alkoxy-phenyl)-but-1-en-3-one, the latter is hydrogenated, during or after this condensation, to give a novel 1-(4-tert.-alkoxy-phenyl)-butan-3-one, and isobutene or 2-methyl-but-1(2)-ene is eliminated from this compound in the presence of a catalytic amount of an acid. The novel intermediates have the general formula ##STR1## where R is H or CH.sub.3 and the broken line may or may not be an additional carbon-carbon bond.
Claims10
1-(4-tert.-Alkoxy-phenyl)-butan-3-one and -but-1-en-3-one derivatives of the general formula III ##STR6## where R is H or CH.sub.3 and the broken line may or may not be an additional bond between the carbon atoms which it links.
A process for the preparation of 1-(4-hydroxyphenyl)-butan-3-one, comprising:
- (a) preparing a compound of the formula:
- ##STR7## wherein R is H or CH.sub.3 by condensing acetone under alkaline conditions with a compound of the formula:
- ##STR8## (b) hydrogenating compound IIIa after or while it is formed thereby yielding a compound of the formula:
- ##STR9## (c) eliminating isobutene or 2-methyl-but-1(2)-ene from compound IIIb at a temperature of 40.degree. to 150.degree. C. in the presence of an acid.
Dependencies are inferred from the claim text.