| 摘要 |
The present invention provides a process for the preparation of a compound of formula (I) wherein R1 is C1-C4 haloalkyl; R2 is optionally substituted alkyl, optionally substituted aryl or optionally substituted heteroaryl; and R3 is methyl or ethyl; comprising reacting a compound of formula (IV) wherein R1, R2 and R3 are as defined for the compound of formula I; with an alkylating agent in the presence of an amide. |
