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Karlo Vizec

SOCl2 addition

Chris Harper  Follow
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No, the amine is not attacked first. I think you need to review SOCl2 chemistry: https://www.masterorganicchemistry.com/2011/12/03/reagent-friday-thionyl-chloride-socl2/

Okay, thanks!

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David  Follow
The thionyl chloride converts the carboxylic acid to an acid chloride. Can you attempt to draw the mechanism knowing that?

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Chuck Smallman  Follow
I think the aniline is not really THAT reactive (I had some problems making amides without additional base). I mean there is highly deactivating group on the ring (not in conjugation though) and methyl grop ortho to amine proceting some steric hinderance. Also, methanol is in high excess.

Also, its possible that the reaction procees via formation of methylchloride from methanol and then alkylation of the carboxylic acid?

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Bubba Bear Huntington  Follow
No, the amine is not attacked first. I think you need to review SOCl2 chemistry: https://www.masterorganicchemistry.com/2011/12/03/reagent-friday-thionyl-chloride-socl2/

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Andy Carnduff  Follow
I gotta say, it is a little weird to expect a acyl chloride and aniline to exist together. I guess the amine is protonated quite quickly but even so... I would have expected some amount of oligomer if you don't move fast.

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Allan Nicholas  Follow
So, the sulfur atom is attacked?

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Albert Donnay  Follow
Quote from:
The thionyl chloride converts the carboxylic acid to an acid chloride. Can you attempt to draw the mechanism knowing that?

I don't really understand the process after all. Is NH2 attacked?

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David Beckham  Follow
wouldn't the aniline be protonated all along by the carboxylic acid?

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Connor Becz  Follow
I agree anilines aren't all that nucleophilic (certainly nowhere near as nucleophilic as alkyl amines). However, they are almost certainly more nucleophilic than carboxylic acids, which raises the question why does the SOCl2 react with the carboxylic acid not the aniline? Or does it react reversibly with the aniline? Maybe it's just early in the morning and I'm being dumb.

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Donald Werve  Follow
Just a plain amine, yes. But the Wikipedia page of anthranilic acid suggests they are present in both forms in the absence of another acid or base.

Aniline is too weak a base to fully deprotonate a carboxylic acid at 1eq.

Edit: here's the paper wiki is referring to https://royalsocietypublishing.org/doi/10.1098/rspa.1968.0003

DOI:10.1098/rspa.1968.0003

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David Cislo  Follow
Usually a huge excess of thionyl chloride is used in chlorination reactions. I typically use it as the solvent along with a catalytic drop of DMF.

So yeah, probably some gets consumed making the ammonium chloride salt, but there's plenty left to make acid chloride.

Kirggy, under acidic conditions that methyl chloride reaction doesn't sound very good. It's a very ordinary way to make esters to make the acid chloride, not really isolate it, then dump in a bunch of your desired alcohol.

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