Patent ID: 7321039

Claim:
A process for preparing compound of formula (IV) wherein R denotes a group selected from C 1 -C 4 -alkyl, C 2 -C 6 -alkenyl and C 1 -C 4 -alkylene-phenyl, each of which may be subtituted by hydroxy or C 1 -C 4 -alkoxy, and R″ denotes a group selected from C 1 -C 4 -alkyl and C 1 -C 4 -alkylene-phenyl comprising reacting a compound of formula (II) wherein R denotes a group selected from C 1 -C 4 -alkyl, C 2 -C 6 -alkenyl and C 1 -C 4 -alkylcne-phenyl, each of which may be substituted by hydrixy or C 1 -C 4 -alkoxy, optionally in the form of an acid addition salt thereof or a hydrate thereof, in a suitable solvent with a formamide-acetal of formula (III) wherein R′ denotes C 1 -C 4 -alkyl and R″ denotes a group selected from C 1 -C 4 -alkyl and C 1 -C 4 -alkyle-phenyl.