Patent ID: 7737301

Claim:
A process for the preparation of a compound of formula I wherein R 1 , R 2 and R 3 are each independently of the others hydrogen or C 1 -C 4 alkyl, which comprises a) reacting a compound of formula II wherein R 1 , R 2 and R 3 are as defined for formula I and X is bromine or chlorine, with a compound of formula III wherein R 4 is hydrogen or C 1 -C 4 alkyl, in the presence of a base and catalytic amounts of at least one palladium complex compound, to form a compound of formula IV wherein R 1 , R 2 and R 3 are as defined for formula I and R 4 is as defined for formula III; and b) converting that compound, using a reducing agent, into the compound of formula I.