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Author: Subject: p-aminoacetophenone
tomas
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[*] posted on 26-10-2009 at 17:23
p-aminoacetophenone


My first post, actually, I am not a Chemist, but tyring to understand some procedures, hope someone can help.

I have found few literature in this regard, maybe I haven't looked into the right direction... starting with acetanilide it is possible to obtain p-aminoacetophenone using a Fries rearrengement, correct? What I found was that using AlCl3 as catalyst and under 90°c the reaction will take place, obtaining the desired product.

1 Which solvent could be used? Ethanol?
2 How much catalyst is needed in proportion to the acetanilide?
(i.e. 10gr of acetanilide with xgr of catalyst)
3 The reaction is done under reflux or sealed vessel?
4 Wich impurities can be found after reaction? o-aminoacetophenone?

Last question: if you were in need of the p-aminoacetophenone which procedure would you use in order to obtain it ( yes, I know, buying could be an option:) )?

Thanks in advance

[Edited on 27-10-2009 by tomas]
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kclo4
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[*] posted on 26-10-2009 at 18:37


Not sure, haven't looked into this but I am just going to point out that the AlCl3 probably needs to be anhydrous -- This is a lot harder to make then it sounds. IIRC AlCl3 reacts with ethanol to form aluminum ethoxide and HCl - though I could be wrong, so double check that but that is another thing to possibly be concerned about if you try to use ethanol as the solvent.
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not_important
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[*] posted on 27-10-2009 at 07:31


If done using AlCl3 or similar Lewis acids, the solvent must not react with the catalyst - thus water, alcohols, and primary and secondary amines are out. Similarly alkyl halides, esters, and similar compounds that can undergo Friedel-Crafts reaction with the substrate won't work.

For the phenol-based Fries rearrangement, typically at least 1.5 moles of catalyst is used per mole of substrate. Commonly the rearranged product has and o,p ratio between 1:2 and 2:1, with combined yields of those in the 40% to 80% range; the de-acetylated base compound is a frequent byproduct. Nitrobenzene and chlorobenzene have been used as solvents, as has carbon disulfide.

The photo-rearrangement is another route, and zeolites have been used as catalysts as has P4O10.

Also see the attached file



Attachment: IJCB 46B(4) 713-715.pdf (25kB)
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Nicodem
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[*] posted on 27-10-2009 at 07:52


Tomas, this might be your first post, but don't you find it absurd that you ask a question about a reaction of which you don't even provide the reference? How is anybody to give you any good answers pertaining to your specific case? All we can do is give you general answers. So please provide the reference and/or cite the procedure of which you talk.
Opening threads without providing references is only tolerated in the Beginnings section!
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tomas
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[*] posted on 27-10-2009 at 18:00


First of all, thanks for your answers and the attachment... now I understand the reason for such solvents and some of the conditions of the experiment.

Sorry if it was rude to post without a source... I read hereabout the posibility.

In the above reference it is mentioned that zeolites
Quote:

have proven to be unsuitable, since they are deactivated, but strong acids, such as sulfonic acids, provide a reasonable alternative.


Well, it seems like this theme should be study deeply before giving any further step.

Tomas

... did I said thank you very much for the attachment? :D

[Edited on 28-10-2009 by tomas]
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