Disclosed is a process for the preparation of a mixture of 4-bromophenyl derivatives (compound of formula (2)) and 2,4-dibromophenyl derivatives (compound of formula (3)) comprising the steps of [1] reacting in a two-phase (liquid-liquid) system a bromide containing source with a phenyl derivative (formula (1)) in the presence of an excess of an oxidizing agent, an acid, and optionally a catalyst selected from vanadium pentoxide and ammonium heptamolybdate forming 4-bromo- (compound of formula (2)) and 2,4-dibromo derivatives (compound of formula (3)) and as intermediate product the 2-bromo derivative (compound of formula (4)) which reacts in step [2] to the 2,4-dibromo derivative (formula (3)) according to the following reaction scheme 2 wherein R1 is hydroxy; C1-C5alkoxy; or -NR2R3; and R2 and R3 independently from each other are hydrogen; or C1-C5alkyl.
本发明揭示了一种制备4-
溴苯基衍
生物(化合物式(2))和2,4-二
溴苯基衍
生物(化合物式(3))混合物的方法,包括以下步骤:[1]在存在过量氧化剂、酸和可选的催化剂(从
钒酸五
钠和七
钼酸
铵中选择)的两相(液-液)体系中,将含
溴源与苯基衍
生物(式(1))反应,形成4-
溴(化合物式(2))和2,4-二
溴衍
生物(化合物式(3))以及中间产物2-
溴衍
生物(化合物式(4)),该中间产物在步骤[2]中进一步反应为2,4-二
溴衍
生物(式(3)),反应方程式如下:其中R1为羟基、C1-C5烷氧基或-NR2R3;R2和R3独立地为氢或C1-C5烷基。