| 摘要 |
The present invention relates to a process for the preparation of compounds of formula (I) wherein R1 is C6-C7 alkyl or a group (A1) wherein R2, R3 and R4 are each independently of the others hydrogen or C1-C4 alkyl; wherein a compound of formula (II) wherein R1 is as defined for formula (I) and X is bromine or chlorine, is reacted with urea in the presence of a base and a catalytic amount of at least one palladium complex compound, wherein the palladium complex compound comprises at least one ferrocenyl-biphosphine ligand.
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