Patent ID: 8609903

Claim:
A process for preparing an aldehyde of the formula (I) wherein one, two or all three radicals from the group of R 1 , R 3 and R 5 are hydroxyl, and that radical or those radicals from the group of R 1 , R 3 and R 5 which are not hydroxyl are each independently hydrogen, C 1 -C 8 -alkyl or C 6 -C 14 -aryl, and R 2 and R 4 are each independently hydrogen, C 1 -C 8 -alkyl, C 1 -C 8 -alkoxy or C 6 -C 14 -aryl, which comprises converting an aldehyde of the formula (II) in which one, two or all three radicals from the group of R′ 1 , R′ 3 and R′ 5 are C 1 -C 8 -alkoxy, and that radical or those radicals from the group of R′ 1 , R′ 3 and R′ 5 which are not C 1 -C 8 -alkoxy are each independently hydrogen, C 1 -C 8 -alkyl or C 6 -C 14 -aryl, and R 2 and R 4 are each as defined for formula (I), at elevated temperature and elevated pressure in the presence of (C 1 -C 4 -alkyl) 2 -amine, and then isolating the reaction product of the formula (I).