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Author: Subject: Addition of hydroxylamine across double bonds
Boffis
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[*] posted on 30-8-2019 at 05:43
Addition of hydroxylamine across double bonds


I am trying to prepare the reagent for tungsten described in this paper:

Attachment: Tungsten with Anti-1,5-di(p-methoxyphenyl-1-hydroxylamino-3-oximno-4- pentene JAnalChem Yoe & Jones 1944 p45-48.pdf (632kB)
This file has been downloaded 277 times

Tungsten reagent.jpg - 6kB

As you can see from the paper, they have not published the preparation but on examination of the structure it looks like it is the oxime of di(4-methoxybenzal)-acetone with an extra hydroxylamine group added across one of the double bonds. I can imagine all sorts of complex routes to this compound but my gut feeling is that it simply results from the treatment of a dibenzalacetone type compound with excess hydroxylamine.

Has anyone ever come across such a reaction before or have any ideas about this possible reaction and the conditions which might favor it? Alternatively can anyone see an alternative route that looks realistic?
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Pumukli
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[*] posted on 30-8-2019 at 11:52


Maybe the reaction is as simple as you speculate and goes automatically if hydroxylamine is in 2-fold molar excess to the enone.

I tried looking up the authors of the article, but nothing came up about this type of compound in general. I think it was just too valuable in those days to publish the synthesis, they may kept it as a trade secret for themselves and tried to make some money from it.

Maybe a reaxys search on a simpler analog would be useful!
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Cactuar
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[*] posted on 30-8-2019 at 12:49


Maybe one approach would be to condense 1 eq acetone with 1 eq anisaldehyde and then take the condensated product and condense that with 1 eq anisaldehyde under milder conditions to get the beta-hydroxyketone. This could then by acylated. The acylated product would then react with an excess of hydroxylamine which would form the product through both Sn2 of the acetoxy and condensation of the ketone.
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Boffis
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[*] posted on 31-8-2019 at 04:05


Thanks guys. I will probably tackle waffles for a search but I will need to think about the nature of the search.

@ Cactaur, I like your idea and I can see some interesting possibilities for the second condensation. For example if the condensation occurs under basic conditions could I use hydroxylamine as the base?
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Cactuar
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[*] posted on 31-8-2019 at 14:41


That could be possible. Nitro-aldol condensations occur easily with amine bases. Maybe you could even do an acid condensation using hydroxylamine hydrochloride, see attachment.



possibleroute.jpg - 29kB
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unionised
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[*] posted on 1-9-2019 at 09:10


I'd try this
https://en.wikipedia.org/wiki/Curcumin

Does anyone have access to this?
https://www.longdom.org/proceedings/transition-metal-complex...

According to the abstract "We provide a summarized synthesis and structural determination of Curcumin Oxime, Curcumin Th."

However, I have bad news; this might happen
https://pubs.rsc.org/en/content/articlelanding/1970/j3/j3970...


[Edited on 1-9-19 by unionised]
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Pumukli
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[*] posted on 3-9-2019 at 11:44


Accidental find:

Harries, C.: Ann. [330] 185 (1903)

and

Trozzolo, A. M., and Lieber, E.: Anal. Chem. [22] 764 (1950)

The former reportedly speak about the addition of hydroxylamine to double bonds, the later is about the reaction with benzalacetophenone in alkaline medium. (A series of reaction products.)

Maybe worth checking.
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Boffis
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[*] posted on 4-9-2019 at 08:48


@Pumukli, many thanks for the tip-off on these papers! I have read the Harries paper and it is exactly what I was looking for. I will have to read and digest the relevant section again but this seem to comfirm my initial suspicions of a simple hydroxylamine addition across the double bond in preference to oxime formation under the right conditons. I'll have a go with this reaction in the near future.

I haven't looked at the second paper yet (it took me most of the day to get through the first as its 95 pages long!!) but I am about to start.

I have some work to finish off on my nitro-chlorophenol sulphonic acid project before I move on to this one.
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