| 摘要 |
<p>Isomerisation of bromohalogenobenzene of formula (I) comprises contacting (I) with an alkaline base and a cpd. (II) which complexes the cation of the alkaline base (where X1 and X2 are each Cl or F, n and m are 0-3 and n + m=2 or 3). (I) is pref. 2,4- or 2,3-dichlorobromobenzene, or 3,5-difluoro-bromobenzene. The base is an alkaline amide. The process gives the required prod. selectively under mild temp. conditions and allows easy recovery of the prod. while avoiding the use of harmful solvents.</p> |
