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Author: Subject: Nitration of Propenylbenzenes
T=HC2
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[*] posted on 30-1-2006 at 21:19
Nitration of Propenylbenzenes


To a solution of sodium nitrite (13.24 g, 192 mmol) and ethylene glycol (8.93g, 144 mmol) in 20 mL of water, a solution of asarone (10g, 48 mmol) in 150 mL of ethyl acetate was added followed by addition of iodine (18.28g, 72 mmol) at 0°C. The reaction mixture was stirred at room temp for 48 hrs under nitrogen and then was poured into a seperatory funnel together with ethyl acetate and partitioned. The ethyl acetate solution was successively washed with water, aqueous 10% thiosulfate and aqueous saturated NaCl. After drying over anhydrous magnesium sulfate, the ethyl acetate solution was evaporated to obtain the crude product as dense dark yellow crystals, containing some unreacted asarone. The product was recrystallized from alcohol to afford 2,4,5-trimethoxyphenyl-2-nitropropene (2-nitroasarone) in 75%+ yield.



I'm trying to confirm the validity of the above procedure. One glaring error (typo?) is 18.2gm equaling 72mmol of iodine. 72mmol is 9.1gm correct? Or is it necessary to use such a large excess of I2 for some reason? I'm very interested in this procedure. Hopefully some more experienced chemists here have tried this and could share their experience etc before I dive in.
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The_Davster
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[*] posted on 30-1-2006 at 22:01


72mmol is indeed 18.2g. It is I2, not I...



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T=HC2
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[*] posted on 31-1-2006 at 12:48


Oh yeah, duh..lol. On another forum a member suggested to me that I use 100 ml of ethyl acetate in the partitioning step. Is that correct?
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Drunkguy
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[*] posted on 31-1-2006 at 17:14


This procedure looks extremely interesting if other people can get it to work. You can see why some people might be quite skeptical of a procedure that appears this effortless though, but if it does work, then this procedure would have to be heralded as some type of latent breakthrough to crack pot theoreticians skilled in the art.



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[*] posted on 1-2-2006 at 11:42


Quote:
This procedure looks extremely interesting if other people can get it to work.


This procedure is taken from a published paper so it is assumed to work unless someone proves otherwise. It seams though it was not tried on asarone in the original paper but it does work on various syrenes: styrene, 1-phenylcyclohexene and 1,2-Dihydronaphtalene.
See: http://www.erowid.org/archive/rhodium/chemistry/nitryliodide...
http://designer-drugs.com/pte/12.162.180.114/dcd/chemistry/n...




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T=HC2
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[*] posted on 3-2-2006 at 12:31


I will try this with asarone soon. If the target compound was PiHKAL #158 only B-asarone would be useful huh?
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stoichiometric_steve
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[*] posted on 27-10-2008 at 02:44


Many sources cite that asarone and its 2-substituted derivatives are unstable under acidic conditions, and since in this procedure HI is released, this would be the case...



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Foss_Jeane
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[*] posted on 27-10-2008 at 12:46


Quote:
Originally posted by T=HC2
To a solution of sodium nitrite (13.24 g, 192 mmol) and ethylene glycol (8.93g, 144 mmol) in 20 mL of water, a solution of asarone (10g, 48 mmol) in 150 mL of ethyl acetate was added followed by addition of iodine (18.28g, 72 mmol) at 0°C.


Don't do it! The original paper mentions styrenes, and asarone ain't no styrene. Yeah, it's close, but sometimes that makes all the difference in the world. Lots of reactions fail completely because of an extra methyl group, or having something in the wrong place on the benzene ring. Since you already have the asarone and NaNO2, why not just use the pseudonitrosite method which has been well known and tried a great many times over the last 110 years? Surely the H2SO4 and ether required is a helluvalot easier to come by than ethylene glycol and I2. Asarone is especially amenable to this particular method.
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stoichiometric_steve
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[*] posted on 27-10-2008 at 12:59


Quote:
Originally posted by Foss_Jeane Asarone is especially amenable to this particular method.


I don't think so. It has been noted at the former "Hive" that Asarone isn't particularly easy to handle in the Pseudonitrosite nitration reaction.




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Foss_Jeane
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[*] posted on 27-10-2008 at 13:39


According to This thread, it seems to work just fine.

I'm assuming that this "Hive" thingy is an amatuer site like this one, which means lots of improvisations and compromises, both in the nature of reagents used and technical skill. I would expect that there'd be a lot of variation due to that.

It'd still be my preference if I was going to do anything like that.
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stoichiometric_steve
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[*] posted on 27-10-2008 at 15:27


Quote:
Originally posted by Foss_Jeane
According to This thread, it seems to work just fine.


Have you ever done it yourself? Otherwise, the assumption that the procedure discussed here doesnt work as described is pretty weak...

[Edited on 28-10-2008 by stoichiometric_steve]




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Foss_Jeane
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[*] posted on 27-10-2008 at 15:47


Quote:
Originally posted by stoichiometric_steveHave you ever done it yourself? Otherwise, the assumption that the procedure discussed here is pretty weak...


Let's just say that I have a very good reason to believe it works just fine with good quality ether, NaNO2 and sulphuric acid and shielding the reaction with helium.
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stoichiometric_steve
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[*] posted on 27-10-2008 at 15:58


Quote:
Originally posted by Foss_Jeane Let's just say that I have a very good reason to believe it works just fine


How lame is this?




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[*] posted on 28-10-2008 at 03:25


Quote:
Originally posted by Foss_Jeane
Quote:
Originally posted by stoichiometric_steveHave you ever done it yourself? Otherwise, the assumption that the procedure discussed here is pretty weak...


Let's just say that I have a very good reason to believe it works just fine with good quality ether, NaNO2 and sulphuric acid and shielding the reaction with helium.

For anyone attempting any of these procedures I would suggest you read the original paper,you can't assume the propenylbenzenes are interchangable in these reactions,
Bruckner noted differences between isoafrole , anethole and asarone in his work in the 1930's.
By way of example and something I am familiar with it is essential to recrystallise the anethole psuedonitrosite from acetone(monomerises in other solvents)before proceeding further otherwise you just end up with pleasent smelling crap that won't crystallise.
Asarone in particular is noted as engaging in some atypical behaviour across a range of reactions,particularly in acid conditions as noted by steve.
@Foss_Jeane did you note marked differences using an inert atmosphere? You've got a NOx overpressue anyway don't you?

[Edited on 28-10-2008 by starman]

[Edited on 28-10-2008 by starman]
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Foss_Jeane
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[*] posted on 29-10-2008 at 20:56


Quote:
Originally posted by starman@Foss_Jeane did you note marked differences using an inert atmosphere? You've got a NOx overpressue anyway don't you?


I never tried it without an inert atmosphere. As you are aware, NO likes to oxidize to NO2 when exposed to atmosphereic O2. That's a good thing if you're trying to make nitrates and/or nitric acid by burning atmospheric nitrogen, but not here. Helium is cheap, available, and so why not use it? (Argon for TIG welding is another possibility.)
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[*] posted on 6-12-2012 at 15:42


The pseudonitrosite rxn DOES work with asarone, no question, provided distilled ether is used. Its yields, however, are considerably lower than with other propenylbenzenes like iso-safrole which undergoes pseudonitration in near quantitative yields.

Don't think an inert atmosphere is required, otherwise quantitative yields with iso-safrole would not be possible without. Besides, eventually the N02 will displace whatever O2 remains in the headroom of the flask. Its obvious when this happens as the red fumes in the flask disappear. Good idea to vent the flask out of doors.


[Edited on 6-12-2012 by antibody]
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[*] posted on 23-1-2013 at 08:04


If I have nitric acid and steel wool, can I avoid the H2SO4 in the reaction? If I'm using the N2O3 gassing procedure?



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[*] posted on 21-3-2013 at 21:03


the inert gas blanket isnt strictly necessary, as you're going to be generating (or at least should be) the n02 in excess anyway. the important parameters are : do this in an ice bath, use clean ether (starting fluid will work.as it is a mix of dimethylether and hydrocarbons -but also has god knows what, antiknock additives,maybe some hideous manganese tricarbonyl which is probably best avoided!) and of course the big one: clean asarone -this is where things get gooey-most attempts arent utilising distilled asarone, and what you end up with is a ball of goop sitting between the aqeous/organic mix. cleaning up that relatively small amount of goop with alcohol and bicarb in needed, as its added, if things are going your way, you see really really tiny bubbles of nitrous oxide...and eventually a superfine layer of yellow particles. People claim this method is tricky and so on, I agree.I realise that iodine is another precious commodity that you may or may not have,but given the crappy nature of the pseudonitrosite route maybe its worth a look at.....The method of oxidising asarone (or just calamus oil !!) by suspending it in a 90 celsius solution of sodium bicarb with fast stirring then adding hot semi conc. permanganate drip wise, then whilst still hot fast vacuum filter out the mno2,let the yellow filtrate cool...and...voila! sexy light yellow crystals of 2,4,5 trimethoxy Benzaldehyde. its on the hive ,Zorohustra wrote it up...damn fine chap he is.....
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