amrhamed2
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p-Anisidine-2-sulfonic acid
I would like to ask about the control of temperature in this reaction .....why it was heated for 60 minutes at 60 and then heated for 10 hr at 170
Second,is there any easier path to get this compound
third,where to get the reference mentioned 
fourth, if i want to get the amide of the sulfonic acid ,should i protect the amino group or not
[Edited on 1-3-2008 by amrhamed2]
[Edited on 1-3-2008 by amrhamed2]
amr h mahmoud
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Nicodem
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It is very hard to say what and why was done just from that SciFinder output. It is very strange that p-anisidine survives such extreme
conditions without suffering demethylation, oxidation or whatever else undesired destiny. The amino group is protonated in aqueous sulfuric acid so it
is deactivating to the two ortho positions in relation to the amino (protonated amino, actually). Therefore the first position to be
sulfonated is expected to be the ortho positions in relation to the methoxy group (that would be the kinetic product). However, sulfonation
is reversible as long as >60% sulfuric acid is used so I would tend to believe that the heating to 170°C is done in order to obtain the
thermodynamic product. 2-Amino-5-methoxybenzenesulfonic acid is supposed to be the thermodynamic product because the ipso electrophilic
substitution at the sulfonic group position with H<sup>+</sup> (the mechanism which makes the sulfonation a reversible process) is
inhibited since the intermediate arenium ion is more destabilized in comparison to the arenium ion formed by an identical attack on
5-amino-2-methoxybenzenesulfonic acid (the supposed kinetic product).
I hope you read the abstract as well? Often you can get some more useful data from the abstract, even a rough experimental outline, though admittedly
mostly just for the very old papers where they did not put so much ideological and fashion crap in the abstracts and introduction chapters as done
these days.
The "30 min, 60°C" info is probably a consequence of the authors mentioning that the mixture self heated upon the mixing of reactants (heat from
acid&base reacting). It would not be surprising that the person who abstracted the article shortened such data like that.
If that method works, then I highly doubt there exists or could exist any simpler method.
As far as obtaining that paper, I can only think about emailing some Chinese friend or colleague to send a photocopy or a scan to you. Alternatively
you can try your luck posting a request on one of the Chinese chemical forums.
How do you plan to make the sulfonamide from this compound?
[Edited on 2/3/2008 by Nicodem]
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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amrhamed2
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none of my colleagues believe that it will work .......though I am more interested in obtaining the compound (Aldrich 25 grams for 122 dollars)....Is
there any suggestion for any simple route to get such a compound ...I did literature search but I found only exhaustive multi step methods of cost
more than the compound price.....
I thought about the classic way nitration ...reduction...diaznoium salt water pathway ....what is possibility of undesired outcome
[Edited on 2-3-2008 by amrhamed2]
amr h mahmoud
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Nicodem
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At the moment I can only come out with this alternative:
Prepare 2-amino-4-methoxy-acetanilide (references can be found here).
Diazotize it and prepare the 2-acetamido-5-methoxybenzenesulfonyl chloride with the Sendmeyer reaction using SO2/CuCl (see one of the references in
your other sulfamide thread where that sulfonyl chloride is done this way). Make the amide with ammonia and find some way to selectively hydrolyze the
acetamido group. Honestly I don't believe this would work, but I don't have anything better to propose (you should check SciFinder if
2-aminoacetanilides work normally in Sendmeyer reactions; I have some doubts).
The only other way that might or might not work, depending on the regioselectivity, is to chlorosulfonate p-methoxyacetanilide with
chlorosulfonic acid. You might be lucky and get the right isomer – the regioselctivity data for nitration seems to indicate you might have just one
such luck.
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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amrhamed2
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here is the answer .........found in a patent
amr h mahmoud
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amrhamed2
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I will try another method .......if anyone has comments on it ,plz tell me
I will use acetylation of p-anisidine as a way for regioselectivity to the o-position of amino and use chlorosulfonic acid to add sulfonylchloride at
that position .Then ammonia will be used to convert it into sulfonamide
This method was used in a paper for regioselelective nitration at the same position
Abstract of the paper
p-MeOC6H4NH2 (123 g.) in 300 ml. AcOH and 217 ml. H2O, cooled to 0-5°, treated with 103 ml. Ac2O, heated on a steam bath until
soln. results, cooled to 45°, and treated with 100 ml. HNO3 (d. 1.42), gives 75-9% of 2,4-O2N(MeO)C6H3NHAc; hydrolysis with
Claisen's alkali (15 min. on the steam bath) gives 95-7% of 2,4-O2N(MeO)C6H3NH2, m. 122.5-3°.
http://www.orgsyn.org/orgsyn/default.asp?dbname=orgsyn&d...
amr h mahmoud
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Nicodem
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If you would have read my previous reply you would have noticed that I already commented on that potential route two posts above:
| Quote: | Originally posted by Nicodem
The only other way that might or might not work, depending on the regioselectivity, is to chlorosulfonate p-methoxyacetanilide with
chlorosulfonic acid. You might be lucky and get the right isomer – the regioselctivity data for nitration seems to indicate you might have just one
such luck. |
...and I still think it is a long shot. Try it and report back how it worked. I'm quite curious about it.
PS: Your link above only leads to a table of contents of Org. synth. preparations. I assume the one you are referring to is: http://www.orgsyn.org/orgsyn/orgsyn/prepcontent.asp?print=1&...
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