| abstract |
Provided is a process for preparing a compound shown as formula (I), comprising a step of contacting a compound shown as formula (II) or a salt thereof with a brominating agent, wherein R 1 is OR 2 or NR 3 R 4 ; R 2 is C1-C6 alkyl or phenyl; each R 3 , R 4 is independently H, C1-C6 alkyl or cycloalkyl, wherein C1-C6 alkyl, cycloalkyl, or phenyl is optionally further substituted by F, Cl, Br, CH 3 or CF 3 . A process for preparing a compound shown as formula (II), a process for preparing a compound shown as formula (V), a process for preparing a compound shown as formula (III), and an intermediate compound as shown as formula (IIa) or formula (Ib) are also provided. |