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donshwants
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[*] posted on 19-1-2006 at 08:08
2,5-dmb


2,5 dimethoxybenzaldehyde.
Does anyone know where to obtain this? Does anyone have any for sale/trade? I have purchased before, but it has been a while, last time I tried I was told it was no longer available. Does anyone know of any restrictions on it?

Thanks
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runlabrun
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[*] posted on 19-1-2006 at 17:51


being highly suspect for the use in the manufacture of Phikal #54 --> 2,5-DMA; 2,5-DIMETHOXYAMPHETAMINE it is no surprise the product has been removed or restricted in trade.

-rlr
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[*] posted on 4-2-2006 at 13:02


Since SWIY is asking for 2,5 DMBA they may already know this, so if you do, I apologize.

I certainly do not condone the production of any precursors for any controlled substances and am merely a researcher.

It is possible to make it from star anise oil. Microgram Journal 2004

And a quote from phenethyl_man from the now defunct the-hive.ws concerning a 4-bromo 2,5 DMBA for SWIY.

Quote:
A friend of mine told me this interesting story the other night.. Apparently he accidently broke his only condenser while disconnecting one of the hoses. Angered but not defeated he eyed the limited supply of chemicals at his disposal and here is what happenend:

In a round-bottomed flask equipped with magnetic stirring was added 250 mL of H2O, and 45 mL of 25% NaOH. 15 grams of hydroquinone was then added followed by 26mL of dimethyl sulfate. The flask was stirred at room temperature and after 15 minutes it was obviously no longer basic judging from the light color and flakes of hydroquinone floating around. At this point more 25% NaOH soln was added. In fact, he admits that too much base was added at this point which really hurt the yield in this reaction by slowing it down considerably. Anyhow, after another hour white crystals began to form out of the dark mixture and it took on the familiar smell of p-dimethoxybenzene. Stirring was continued for another 6 hrs, after which he became impatient and proceeded to vacuum filter the crystals on a buchner funnel and wash them with H2O. Yield: 11 grams (58%)

A solution of 10 g of potassium bromide in 250mL acetic acid was stirred on a ice/salt bath. When the solution was sufficiently cold, 5mL of 91% sulfuric acid was added slowly and the solution took on a light brown color. Over the course of the next 30 minutes, while maintaining the temperature at 5 degC, 8mL of 35% hydrogen peroxide was slowly added dropwise and subsequently the solution was allowed to stir for another 2 hrs. The soln was extracted w/2x75mL toluene and the extracts were washed w/50mL 5% NaOH, and then 50mL brine. The toluene was then removed in vacuo yielding a brown oil of presumably 1,4-dimethoxy-2-bromobenzene, which was used directly in the following reaction. Yield was not determined but appeared to him to be very good.

To an unknown amount of 1,4-dimethoxy-2-bromobenzene was added a soln. of 5 grams of glyoxylic acid monohydrate and 12 mL H2O. The solution was stirred vigorously on a ice/salt bath until a temperature of 5 degC was obtained and it was maintained at this temp throughout the subsequent reaction. Over the course of the next 30 minutes, 30mL 91% sulfuric acid was added dropwise; at this point the solution took on a dark black. The stirring was continued for the next 6 hours, the solution gradually taking on a light pink color with off-white crystals floating in the mixture. After completion of the reaction, the mixture was so viscous it could hardly be stirred. 100mL of cold water was then added, the mixture stirred for a short time longer and the crystals were vacuum filtered. The crystals were suspended in 100mL water and sufficent 25% aqueous NaOH was added until all of them dissolved into a dark brown solution. The solution was then extracted w/75mL toluene. The aqueous solution was once again cooled in an ice bath and ice-cold conc. HCl was added which cleared the solution and caused the crystals to precipitate back out and they were once again vacuum filtered and washed w/water. Yield: 20g of 4-bromo-2,5-dimethoxymandelic acid (86% from p-dimethoxybenzene)

To a solution of 40mL distilled water, and 20mL of 31.25% HCl was added a suspension of 20 grams of 4-bromo-2,5-dimethoxymandelic acid. The soln was cooled on an ice/salt bath to 5 degC and stirring was commenced. Into an addition funnel was added 4mL 70% nitric acid and 10mL water. The dilute HNO3 was added dropwise over about 15 minutes. The flask was removed from the ice bath and placed into a water bath maintained at 50 degC. It was heated and stirred at this temperature for about 1 hr. The flask was cooled to room temperature and an ice-cold solution of 60mL 25% NaOH was added which caused the unreacted acid to dissolve into the mixture. The remaining crystals were vacuum filtered and recrystallized from methanol. Yield 12.5g (74%).

Overall yield: 12.5g 4-bromo-2,5-dimethoxybenzaldehyde from 15g hydroquinone (37.5%)


One can probably even go as far back as bezene (HNO3/H2SO4) -> nitrobezene (electrochemically) -> hydroquinone. Although I would say the star anise oil method seems the most OTC.

Refs:

Production of nitrobenzene
Electrochemical reduction of nitrobenzene to hydroquinone
Star Anise oil as a precursor for 2X,5XBAs Microgram Journal 2004

I'm not a chemist, so please don't take what I say seriously. :D
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donshwants
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[*] posted on 5-2-2006 at 14:38
tnx seeman


Im glad to see someone posted something that wasnt completly useless, but as far as making it, I know of no reactions other than 14dimethoxy benzene->25dmb by either hcn or pocl3, (both equally difficult to buy or make) that doesnt use a methylating agent. Ive had difficulties with these reactions, and DMS is tough to get. Before some poser posts that crap on rhodium on how to make dms.. it doesnt work unless u have oleum, and making so3 is tough without a high temp furnace. Seems everyone here has read alot, but have no practical experience, just because it looks easy on paper doesnt mean its viable.
Thank s for the help anyways seeman, Ill be doing that one if i ever get ahold of dms
btw, anyone know of any sources of dms, tmp, or MeX they would be appreciated too, the #ofrxns ive ran in the past were halted by lack of a large volume of methylating agents.
To the one person here that might have actually done chemistry rather than just read about it and been a poser, then u know u need to experiment and find out what works, following info on the net is a good way to hurt yourself and waste chems.

[Edited on 5-2-2006 by donshwants]
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charles
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[*] posted on 12-2-2006 at 23:36


A lot of time ago i was able to find a stock of 2,5DMBA >95% at very cheap price (I think, but i do not know the exact price on the market now, it was like 1$ or 2$ /g) , it was bought to be used in massive experiments on synthetic aromatic essences by some private creative laboratory for perfumery.

2,5DMBA is a synthetic molecule which has similar parent in nature, like many of the essential oil components: asarone, safrole, eugenole, elemicin, vanillin, myristicin... have a similar structure on the aromatic ring where the only difference is the MeO- pattern.
MeO- groups on 2,5 position of an aromatic aldehyde or a correspondent allyl or vinil benzene are only in the 2,5DMBA which is synthetic so ther is no 2,5 substituited analog in nature, so it was intresting to be studied for new perfume components or aromatic agent.

However i don't know if this amount was still avalable and if it requires some sort of authorization to get some. are you intrested to get it?


[Edited on 13-2-2006 by charles]
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enima
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[*] posted on 15-2-2006 at 22:04


that method using mandelic acid does not work as advertised.

[Edited on 16-2-2006 by enima]
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JohnWW
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[*] posted on 18-2-2006 at 02:26


Quote:
Originally posted by seeman
Since SWIY is asking for 2,5 DMBA they may already know this, so if you do, I apologize.

I certainly do not condone the production of any precursors for any controlled substances and am merely a researcher.

It is possible to make it from star anise oil. Microgram Journal 2004
(cut)
I'm not a chemist, so please don't take what I say seriously. :D

That link is broken. Please re-upload, preferably to rapidshare.de.
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[*] posted on 18-2-2006 at 15:25
mandelic acid?


enima= What are you referencing with that comment? How do you know? Any other suggestions? Saying something like that without even quoting personal experience is more useless than saying nothing at all. If we should just all bow to your great knowledge and take what you say, then please let us know what does work. He took the time to share something that does work, with reference, no need to say it doesnt work without any proof.
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enima
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[*] posted on 25-2-2006 at 08:52


One would asssume that a comment would be made due to personal experience or otherwise. With both (1-bromo-2,5-dimethoxybenzene) and 2,5-dimethoxybenzene the synth (acid catalyzed) fails. This route works well for 1,3-methylenedioxybenzene (acid catalyzed) and 3-methoxy-4-hydroxybenzaldehyde (this is base catalyzed).
Halogenation of 1,4-dimethoxybenzene followed by bromomethylation was successful however this route is not very good for ones health. (This benzylbromide product can be oxidized to the aldehyde).

Alternatively, if you can obtain 3-bromopropene (alkylating agent), you could make 2-hydroxy-5-methoxyallylbenzene starting from 4-methoxyphenol and proceed with safe methylation using dimethyl carbonate at elevated temperatures (160C) and then proceed with isomerization, ozonolysis and finally a Zn/AcOH reduction of the ozonide to the aldehyde. The aldehyde purified by the bisulfite adduct or steam distillation.

If you would like refs please let me know, they are sitting on the laptop.

Another option would be using 2-hydroxybenzaldehyde, bromination followed by nuc. substitution w/ NaOMe to yield 2-hydroxy-5-methoxybenzaldehyde one can proceed with methylation of this product the achieve the desired end product. If this is done with 2-methoxybenzaldehdye (o-anisaldehyde) the yields for both the bromination and nuc. substitution are low. (again don't have exact info with me).


[Edited on 25-2-2006 by enima]

[Edited on 25-2-2006 by enima]
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[*] posted on 27-2-2006 at 00:24


Best idea I've seen for production of 2,5-dimethoxybenzaldehyde is a two step procedure from 1,4-dimethoxybenzene, which takes a total of, from memory, about an hour (reaction time only - purification, extractions etc. not included!). This scheme is, as far as I know, untested for this, but one I think should work. Also, working from memory, with references unavailable, so bear with me and I'll post the refs when I can.

Step one was to take 1,4-DMB and react it with NBS in acetonitrile to give 2,5-DiMeO-Br-Benene, in good yields. I think ammonium nitrate was used as a catalyst in this case. In any case, any suitable bromination would do the trick, I just liked this one.

This compound is then dissolved in dry DMF, placed in an ultrasound bath, and reacted with lithium metal. The lithium displaces the bromine to give the organometallic compound, which rapidly reacts with DMF to give the benzaldehyde. The ultrasound is required to give good yields in the one-pot reaction. Otherwise I'm sure you could just do the reaction in ether, and add DMF to it. The paper didnt try 2,5-DiMeO-Br-Benene from memory, but I dont see why it shouldn't work quite well.
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[*] posted on 27-2-2006 at 16:21


Quote:
Originally posted by enima
One would asssume that a comment would be made due to personal experience or otherwise. With both (1-bromo-2,5-dimethoxybenzene) and 2,5-dimethoxybenzene the synth (acid catalyzed) fails. This route works well for 1,3-methylenedioxybenzene (acid catalyzed) and 3-methoxy-4-hydroxybenzaldehyde (this is base catalyzed).
Halogenation of 1,4-dimethoxybenzene followed by bromomethylation was successful however this route is not very good for ones health. (This benzylbromide product can be oxidized to the aldehyde).

Alternatively, if you can obtain 3-bromopropene (alkylating agent), you could make 2-hydroxy-5-methoxyallylbenzene starting from 4-methoxyphenol and proceed with safe methylation using dimethyl carbonate at elevated temperatures (160C) and then proceed with isomerization, ozonolysis and finally a Zn/AcOH reduction of the ozonide to the aldehyde. The aldehyde purified by the bisulfite adduct or steam distillation.

If you would like refs please let me know, they are sitting on the laptop.

Another option would be using 2-hydroxybenzaldehyde, bromination followed by nuc. substitution w/ NaOMe to yield 2-hydroxy-5-methoxybenzaldehyde one can proceed with methylation of this product the achieve the desired end product. If this is done with 2-methoxybenzaldehdye (o-anisaldehyde) the yields for both the bromination and nuc. substitution are low. (again don't have exact info with me).


[Edited on 25-2-2006 by enima]

[Edited on 25-2-2006 by enima]



I am interested in the bromomethylation of 1,4 dmb, if you have the refs handy id like to look at them.
The claisen method w/ allyl bromide is clever, but seems like a bit more work than other methods such as pmeoPhenol>2oh5meoBA>2dmb, using a riemer tieman,
Also, I would think the 2ohBA bromination would yield alot of bromination ortho to the OH, which would fuck things up.
With the exception of a cylinder of MeBr , I am out of alkylating agents and MeBr requires special apparatus usually, so the bromomethylation is particularly intriguing.
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CherrieBaby
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[*] posted on 27-2-2006 at 16:56


I've seen about 3 different versions of that Microgram anise precursor article. One is from their web-site (HTML), one is from a 7-page PDF (extracted from the Jan-Dex 2004 Microgram, which I think came from their web-site) and the 3rd looks like a one page PDF version (from the Rhodium archive).

Anyway here are all 3 different versions of the Microgram article, plus something else I have which may be of interest.

Anise Oil As Precursor For Phenylethylamine Designer Drugs Of The 2C-X Family,
Microgram Journal, Volume 2, Numbers 1-4 (January - December 2004), pp 4-10.
Dieter Waumans, Noël Bruneel, Jan Tytgat

beta-2,5-Dihydroxyphenyl-DL-Alanine
Biochemical Preparations 3, 79-83 (1953)
H. B. Gillespie

Just as an experiment I have uploaded them to www.rapidshare.se to see if it works (although they say that ONLY JPEGs work there. So I am putting it here too.

http://www.rapidshare.se?1114648

Attachment: 2.5-dihydroxy-phenyl-something.zip (218kB)
This file has been downloaded 1199 times

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[*] posted on 27-2-2006 at 22:07


Ok, back in posession of the required refs. A few details I didnt get quite right, although the basic outline was pretty accurate.

The bromination gives a 94% yield on 1,4-dimethoxybenzene, in 10 minutes at 25*C, using 10% by weight of ammonium nitrate as a catalyst in acetonitrile. They purify by flash chromatography, but alternatives are probably viable (particularly if this was done on a larger scale).

The formylation step is actually done in THF, with sufficient DMF added for the reaction. After 5 minutes under ultrasound at 10*C, benzaldehyde was obtained from bromobenzene in 86% yield. Due to the coordinating effect of the methoxy group in our compound, I would expect the reaction to work even better.

Clearly, if this works, 2,5-dimethoxybenzaldehyde would be obtainable in good yields very rapidly (possibly a matter of an hour or two!).

The references below are at RapidShare (primarily because I cant figure out how to attach them :S)

http://rapidshare.de/files/14320898/Bromination_Li-Formylati...

Tanemura, K. et al., "Halogenation of Aromatic Compounds by N-Chloro, N-Bromo and N-Iodosuccinimide", Chemistry Letters, 32(10), 2003:932-933

Petrier, C. et al., "Ultrasounds in Organic Synthesis 3. A Simple, High Yield Modification of the Bouveault Reaction", Tetrahedron Letters, 23(33), 1982:3361-3364

[Edited on 28-2-2006 by ziqquratu]
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donshwants
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[*] posted on 28-2-2006 at 10:32


very nice, thnx, looks quick and easy, but am wondering how available lithium sand is.. wonder if Li turnings would work as well.
Excellent post
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ziqquratu
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[*] posted on 28-2-2006 at 14:25


If I recall, lithium sand is easily prepared by boiling lithium in hexane (or similar unreactive solvent) with strong stirring.
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charles
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[*] posted on 2-3-2006 at 00:20
why so difficult


hey boys, why to use those hard chemicals and watched precursor?

2,5 DMBA can be "easly" prepared starting by 4,MeO phenol.

4 methoxyphenol can be "formilated" very effectly using NOT standard conditions (reiman tieman formilation, strong NaOH water solution) but using a stronger base: magnesium methoxy.It deprotonates the OH of 4 methoxy phenol forming phenolate ion that is more active as nuclefil in the 2nd position, at the C near the C-OH.
magnesium methoxy solution can be prepared starting with anydrous mathanol, adding Mg dust **very very slowly** with **continus** stirring , Mg is an electropositive metal that reacts with protons of alcool reducing to H2 gas that bubble out of solution. reaction is exothermic so heat is generated and H2 (even in small quantity) is very very flammable, so it can be ignited and make an explosive mix with methanol fumes. so reaction must be carried in ice bath with a reflux and an extra neck to add solid Mg. when all the Mg is added, it will form an exact quantity of Mg++ (MeO-)2 in solution, and the rest of methanol used as solvent can be removed using azetrope distillation adding toluene, which carries out the excess methanol distilling an azeotrope methanol-toluene at 74° (if i remember but this temp must be checked) during the addiction of formaldheyde. obviusly a vigreaux is needed i think.

this reaction is extremly selective: formilation is only on orto position, the postion near OH: so we will have 2,5 dihidroxy-benzaldehyde.
the difference between this formilation and the standard reiman tieman formilation is the base: NaOh solution deprotonates the phenol less effective than methoxyde, because the reaction pruduct are water (from NaOH-) and phenolate ion so only a little part of phenolate is deprotonate, since the water formed CANNOT be easly removed at low temp and standard pressure, so the equilibrium phenolate - H2O is more in OH- than phenolate (less phenol turns in phenolate ion, phenolate is a stronger base than oxydril in water solution), in methanol the equilibrium can be carried at the best (max formation of phenolate) because the methanol formed when phenol is deprotonate and methoxyde is protonated is removed in continous, so all the 4MeO-phenol turns in phenolate ion.

the methylation of 2 OH aromatic groups can be made using metilenesoulfate in base, but is very difficult and DANGEROUS using this kind of hazard, and it is a liquid CARCINOGEN. it is so reactive that is extremly disidratant (metilene group is bonded with solfate, so it's almost free and terribly electrofilic).

a green and EASLY alternative is using iodometane (not so difficult to get) in DMSO at reflux with a base (i think). a PTC is required if i remember well, since the (di-)phenolate ions formed in polar base solution must meet the Iodomethane wich is quiete NONPOLAR so without a PTC it difficult finds the phenolate formed.

this route gives high yields in each steps, use not toxic or hard to use chems and each steps produces a intermediate that is easly ISOLATED and purificated.

starting with anise oil, so anethol, a strong toxic oxidant (Cr VI) must be used to transform the lateral alifatic insature chain in a OH group to perform the formilation, and i think this is difficult and not so simple to isolate the intermediate, using recrystalization and a **not easy** stream distillation.

anethol is obviusly OTC but 4meOphenol is almost like anethol to aquire and doesn't require a lot of hard steps.

hope this helps. if someone is intrested a I can post the entire procedure I red.
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[*] posted on 9-4-2006 at 17:35


Quote:
Originally posted by ziqquratu

This compound is then dissolved in dry DMF, placed in an ultrasound bath, and reacted with lithium metal. The lithium displaces the bromine to give the organometallic compound, which rapidly reacts with DMF to give the benzaldehyde. The ultrasound is required to give good yields in the one-pot reaction. Otherwise I'm sure you could just do the reaction in ether, and add DMF to it. The paper didnt try 2,5-DiMeO-Br-Benene from memory, but I dont see why it shouldn't work quite well.


That sounds like a really clever method. If you have the paper, please share it.

Of topic, has anyone used isopropylamine as nitrostyrene catalyst on 3,4,5-substitution pattern? I thought I'd get better results than with EDDA, but it is even crappier.


[Edited on 10-4-2006 by Sandmeyer]
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[*] posted on 10-4-2006 at 05:41


Quote:
Of topic, has anyone used isopropylamine as nitrostyrene catalyst on 3,4,5-substitution pattern? I thought I'd get better results than with EDDA, but it is even crappier.


From what I heard isopropylamine is preferable where methylamine gives lesser results as a Henry catalyst on some unconventional 3,4,5-substituted substrates.

Both should be used as the acetate salt. Add an aliquot of acetic acid after adding the amine works well for methylamine.
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[*] posted on 10-4-2006 at 06:05


Quote:
Originally posted by Vitus_Verdegast
Both should be used as the acetate salt. Add an aliquot of acetic acid after adding the amine works well for methylamine.


I use acetic as reaction solvent, do you know how many eq isopropylamie shall I used relative to aldehyde and how much nitromethane?
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[*] posted on 10-4-2006 at 12:29


For 25mmol of such a sweet substrate my guess would be that you could try maybe 100mg of isopropylamine monoacetate accompanied by 200-400uL of glacial acetic acid in 5 mL of NM. Heat it gently to 60°C. Hope it doesnt polymerise much. Post the result here...
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[*] posted on 15-4-2006 at 10:42


According to Trachsel's Psychedelische Chemie: 45 g 3,4,5-trimethoxybenzaldehyde in 30 mL CH3NO2, 1.4 ml HOAc, 1.4 ml BuNH2 > reflux for 70 min and recrystallize from MTBE. Yield: 73%

Acetic acid seems to do the trick and should be used in more than 1 eq relative to the amine catalyst. I have read they sometimes use it as (co)solvent for some substrates. Nitroalkenes are easily formed from the intermediary nitro-alcohol by dehydration (conjugation between aromatic system and the nitro-group). However, your nitroalkene is a good substrate for all the polymerization reactions you can dream of, especially with the nitro acting as a very powerfull EWG and the presence of an alkaline bath of nitronates.
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[*] posted on 15-4-2006 at 12:04


I always got the impression that using MeNO2 as solvent increases the amount of polymers. I have never tried using it as solvent, but will do, thanks!



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[*] posted on 16-4-2006 at 12:46


3,4-Dibenzyloxy-b-nitrostyrene

A solution of 3,4-dibenzyloxybenzaldehyde (10.0 g, 31.4 mmol), MeNO2 (10.2 mL, 188.8 mmol), and NH4OAc (9.7 g, 125.8 mmol) in AcOH (100 mL) was heated to reflux for 40 min. Most of the AcOH was removed under vacuum and the residue was dissolved in DCM (100 mL). The solution was washed with sat. K2CO3 solution until the aqueous layer was basic and then with water (100 mL). The organic layer was dried over Na2SO4/MgSO4 and the solvent was removed under reduced pressure to give the nitrostyrene (11.10 g, 98%) as a bright yellow solid.

Baldwin et al, Tetrahedron; 60; 16; 2004; 3695 - 3712.

As to workup, alternatively a lot of water can be added untill the nitrostyrene crash out.

[Edited on 16-4-2006 by Sandmeyer]




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