A process for the preparation of a 4-(4-flourophenyl)-6-alkyl-2-N-alkansulfonyl-N-alkylamino)pyrimidine-5-carboxylic acid ester of formula (Ib), in which R
1
, R
2
, R
3
and R
4
are identical or different and are each a C
1-6
-alkyl. A 2-[-1-amino-1-(4-flourophenyl)methylene]-4-alkyl-3-oxo-alkanoic acid ester of formula (IIIb), in which R
3
and R
4
have the above-mentioned meanings, is reacted with an N-cyano-N-alkylalkanesulfonamide, optionally isolated or prepares in situ, of formula (IVb), in which R
1
and R
2
have the above-mentioned meanings, to give the final product of formula (Ib).
一种制备式(Ib)的4-(4-
氟苯基)-6-烷基-2-N-烷磺酰基-N-烷基
氨基)
嘧啶-5-
羧酸酯的方法,其中R1、R2、R3和R4相同或不同,且均为C1-6烷基。式(IIIb)的2-[-1-
氨基-1-(4-
氟苯基)亚甲基]-4-烷基-3-氧代-酰基酸酯与式(IVb)的N-
氰基-N-烷基烷磺酰胺反应,其中R1和R2具有上述含义,可选地在现场分离或制备,以得到式(Ib)的最终产物。