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Author Topic: What is the aspirin synthesis mechanism?  (Read 17774 times)

incolour

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What is the aspirin synthesis mechanism?
« on: 25/11/2009 18:11:10 »
Hi,

I'm having an absolute nightmare trying to find this!

Essentially i'm looking for a proper curly arrow type mechanism for the synthesis of aspirin from salicylic acid (2-hydroxybenzoic acid) and ethanoic anhydride.

Like so;



Although in all honesty any acid anhydride + alcohol esterification reaction would do, just to see what's going on!

So yeah, does anyone have any ideas as to where i could find this? (or can describe it in words..)

Thanks!  :)
« Last Edit: 17/12/2009 11:37:58 by chris »

rosy

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Re: What is the aspirin synthesis mechanism?
« Reply #1 on: 25/11/2009 18:33:16 »
Yurs, well, it looks to me like you're trying to get us to do your assignment for you, so I'm not going to go off looking for pictures to make it even easier for you. You can try drawing this out, however...
Protonation of one of the anhydride carbonyls, attack on that carbonyl by the salicylic acid -OH, pushing e- density onto the protonated carbonyl.
The salicylic acid -OH deprotonates. The other carbonyl on the anhydride is protonated.
(One of) the -OH groups on the initially reacting carbonyl centre now pushes electron density in, to re-form the sp2 centre, the leaving group is now acetic acid and the carbonyl on the ester that's just formed deprotonates to give product.
If you draw that lot out and have a look at it, you could come back with any further questions.

incolour

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Re: What is the aspirin synthesis mechanism?
« Reply #2 on: 25/11/2009 22:06:55 »
Yurs, well, it looks to me like you're trying to get us to do your assignment for you, so I'm not going to go off looking for pictures to make it even easier for you. You can try drawing this out, however...


I'm not and it isn't, but ok.

And that's all I needed, thanks!

rosy

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Re: What is the aspirin synthesis mechanism?
« Reply #3 on: 25/11/2009 23:46:29 »
Fair enough. Sorry, then. Glad that answered your question.


Curiosity strikes... what *do* you want a mechanism for asprin synthesis for, then??

glovesforfoxes

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Re: What is the aspirin synthesis mechanism?
« Reply #4 on: 26/11/2009 00:18:22 »
He's starting up his own pharma business, and starting with aspirin. Sounds like a reasonable beginning!

incolour

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Re: What is the aspirin synthesis mechanism?
« Reply #5 on: 26/11/2009 18:13:46 »
That guy has it in one! Good call.

But nah really, it's just because I used to know it and had forgotten. It was bugging me that I couldn't remember it or work it out! Slightly obsessive/compulsive but there you go :D

 

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