| 摘要 |
<p>The present invention relates to a process for the preparation of compounds of formula I
wherein R 1 is C 6 -C 7 alkyl or a group A 1
wherein R 2 , R 3 and R 4 are each independently of the others hydrogen or C 1 -C 4 alkyl;
wherein a compound of formula II
wherein R 1 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.</p> |
