5-[4-(Benzyloxy)-3-methoxyphenyl]penta-2,4-dienoic acid → 5-(4-Hydroxy-3-methoxyphenyl)pentanoic acid

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Reaction Steps

The raw product obtained in Example 21 was dissolved in 500 ml of N,N-dimethylformamide and 22 g of 10% palladium on charcoal catalyst was added. The mixture was hydrogenated at 60° C. and normal pressure until the theoretical amount (3 mole) of hydrogen was consumed. After filtering the solvent was evaporated in vacuo to a great extent and the residue was dissolved in 1 l of dichloromethane and washed with 2 l of water. The product was extracted with 1.5 l of saturated NaHCO3 -solution. After acidification of the aqueous phase with hydrochloric acid the product was extracted with 1 l of dichloromethane. The solvent was distilled off in vacuo and the semisolid residue (180 g) was used to the next step.

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