ChemistryGhost - 3-6-2023 at 04:27
Hello! I was wondering if it was possible to chloromethylate thiophene to 2-chloromethylthiophene and if zinc chloride was still necessary. I don't
want it dicloromethylate the thiophene, just mono chloromethylation to 2-(chloromethyl)thiophene.
nimgoldman - 3-6-2023 at 12:08
Indeed it is possible, just quick search took me to this patent:
It references an older patent that uses simple chloromethylation which gives significant amount of the bis-chloromethyl impurity.
You can look up both patents, it surely notes whether they've used a catalyst or not.
The article "CHLOROMETHYLATION OF AROMATIC COMPOUNDS" from Reynolds, Fuson and McKeever discusses results on various substrates (I am not sure about
thiophene specifically, but there is resulsts part regarding thioethers).