| abstract |
The invention according to Scheme 2, [1] In the presence of an excess of an oxidizing agent, an acid, and optionally a catalyst selected from vanadium pentoxide and ammonium heptamolybdate, a bromide-containing source is reacted with a phenyl derivative (Formula 1) in a two-phase (liquid) system to give 4- Forming a bromo derivative (compound of formula 2) and 2,4-dibromo derivative (compound of formula 3), and a 2-bromo derivative (compound of formula 4) as an intermediate product, and [2] reacting the 2-bromo derivative in step [2] to give a 2,4-dibromo derivative (Formula 3) A method for preparing a mixture of a 4-bromophenyl derivative (compound of Formula 2) and a 2,4-dibromophenyl derivative (compound of Formula 3) is disclosed. <Scheme 2> In which R 1 is hydroxy, C 1 -C 5 alkoxy or —NR 2 R 3 ; R 2 and R 3 are independently of each other hydrogen or C 1 -C 5 alkyl) |