| 摘要 |
<p>Undesired regioisomer 2-chloro-5-trifluoromethylaniline is formed along with intermediate 2-chloro-4-trifluoromethylaniline in the ammonolysis of 3, 4-dichlorobenzotrifluoride during synthesis of the agrochemical Fipronil. Since this regioisomer is formed in significant amount, overall yield is low. This problem is overcome by conversion of 2-chloro-5-trifluoromethylaniline or a mixture containing 2-chloro-5-trifluoromethylaniline and 2-chloro-4-trifluoromethylaniline to starting material (3,4-dichlorobenzotrifluoride) via diazo salt. The process disclosed provides improved conversion and yield of diazotization and nucleophilic displacement reaction. Other advantage of this reaction is that it is economic and environment friendly.</p> |
