[incolour]

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! 

[rosy]

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]

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]

Fair enough. Sorry, then. Glad that answered your question.


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

[glovesforfoxes]

He's starting up his own pharma business, and starting with aspirin. Sounds like a reasonable beginning!

[incolour]

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