| 摘要 |
The present invention relates to a process for preparing a compound of formula (I), wherein R is C1-C10 alkyl, phenyl or substituted phenyl, comprising treating a compound of formula (II), with bis(tributyltin) oxide in an organic solvent selected from the group consisting of o-xylene, m-xylene, p-xylene and mixed xylenes; and subsequently treating the reaction mixture with a compound of formula (III), wherein X is halogen and R is defined as above. |
