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Author: Subject: On the reaction of chlorogrignard reagent with o-chlorobenzonitrile
zhouxiaogui
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smile.gif posted on 24-2-2022 at 22:54
On the reaction of chlorogrignard reagent with o-chlorobenzonitrile


Why do I use chlorocyclopentane to make Grignard reagent and o-chlorobenzonitrile to make ketone with low purity. I added the solution of o-chlorobenzonitrile and toluene dropwise at 80 ℃, heated it at 100 ℃ for 6 hours, and then added hydrochloric acid dropwise at room temperature for hydrolysis. The purity of ketone is not high enough. I want to ask you whether the dropping temperature of my o-chlorobenzonitrile solution is wrong? Do you need a higher temperature drop or a lower temperature drop? thank you
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njl
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[*] posted on 25-2-2022 at 08:30


This website has a good reference. Look there and you'll find what you're doing wrong.



Reflux condenser?? I barely know her!
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clearly_not_atara
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[*] posted on 25-2-2022 at 10:43


Since you're preparing the Grignard reagent from chlorocyclopentane, I suspect the preparation may not be working well enough. You can titrate the Grignard solution in order to make sure there is actually enough C5H9MgCl before you start the coupling reaction.

Unfortunately, 100% theoretical yield is probably not achievable in this reaction, because of the unavoidable transmetalation side reaction with the aryl chloride moiety. But a good enough yield is still possible.




[Edited on 04-20-1969 by clearly_not_atara]
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zhouxiaogui
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[*] posted on 25-2-2022 at 19:45


Quote: Originally posted by clearly_not_atara  
Since you're preparing the Grignard reagent from chlorocyclopentane, I suspect the preparation may not be working well enough. You can titrate the Grignard solution in order to make sure there is actually enough C5H9MgCl before you start the coupling reaction.

Unfortunately, 100% theoretical yield is probably not achievable in this reaction, because of the unavoidable transmetalation side reaction with the aryl chloride moiety. But a good enough yield is still possible.


I forgot to say that I added 2% mol of cuprous bromide before dropping o-chlorobenzonitrile
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zhouxiaogui
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[*] posted on 25-2-2022 at 19:48


Quote: Originally posted by njl  
This website has a good reference. Look there and you'll find what you're doing wrong.


thank you
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