| 摘要 |
PROBLEM TO BE SOLVED: To industrially safely obtain 4-bromo-2-fluorobenzyl bromide at high selectivity and high yield without a regulated solvent or an operation such as photoradiation by brominating bromo-fluorotoluene with dibromo- dimethylhydantoin in the presence of a free radical-generating agent. SOLUTION: The objective compound is obtained by brominating 1 mol 4-bromo-2-flurotoluene(BFT) with (preferably 0.4-0.6 mol) 1,3-dibromo-5,5- dimethylhydantoin(DBH) in the presence of a free radical-generating agent at preferably 40-70 deg.C in a solvent (preferably methylene chloride or 1,2- dichloroethane). The free radical-generating agent is preferably azobis(4- methoxy-2,4-dimethylvaleronitrile) or the like, each having the half-life temperature of 30-80 deg.C and is preferably used in a quantity consumed of 0.005-0.5 weight times the DBH quantity. The reaction is preferably carried out in an organic solvent of 300-800 mL based on 1 mol BFT.
|
