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Author: Subject: Is it possible to make this?
tshirtdr1
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[*] posted on 19-7-2017 at 11:55
Is it possible to make this?


I have been trying to synthesize the following molecule for the past couple of days, but today I considered that it might not be possible. I am performing this synthesis simply to characterize the sulfur-carbon linkages spectroscopically for future reference. I can't find any references in the literature for this molecule. I am in an academic lab with relatively good equipment (but not the best).

It looks complex, but if you observe the parts, it is just DTT (Dithiothreitol) and maleic anhydride. (Both are solids.)

I tried two techniques:

1. Using maleic acid and DTT in pH10 buffer to deprotonate the DTT and perform a conjugate addition at the double bond. After the reaction, I tried to remove the buffer with nitrogen gas, but the solubility of the observed product was high so I heated it. Product decomposed upon heating. Verified decomposition by NMR.

2. Using Maleic anhydride with DTT in dry diethyl ether over sodium carbonate. Interestingly, with the sodium carbonate, I observed a pink product briefly (which quickly decomposed) upon decanting the ether from it. Didn't bother with NMR. Got an oily yellow liquid.

I did not try this in an inert atmosphere, but plan to repeat in that perhaps tomorrow. I am thinking I may get side products with the alcohol groups and the anhydride (or acid). Any opinions? My graduate program was computational, so I am pretty much self-taught at synthesis. I may be missing something really stupid and obvious.

Thanks.



DTT_diMaleicAcidproduct.png - 7kB
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subskune
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[*] posted on 20-7-2017 at 01:00


It seems that you want to add a thiol to a double bond. If it was an alcohol you would add sulfuric acid as catalyst in waterfree solvent.
http://www.kshitij-iitjee.com/Addition-of-Water-and-Addition...

Maybe this works for thiols as well. You might need to protect the alcohol groups first.

Beside from this there are a lot of other mechanisms. On wiki you might get an overview
https://en.wikipedia.org/wiki/Thiol-ene_reaction

Check this for details:
http://www.organic-chemistry.org/synthesis/C1S/sulfides.shtm




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Eddygp
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[*] posted on 20-7-2017 at 03:26


Conjugate addition should be easy, because RSH are soft nucleophiles. The ROH will need protection, or maybe the yield won't be too negatively affected.




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CuReUS
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[*] posted on 20-7-2017 at 06:12


http://pubs.acs.org/doi/abs/10.1021/ja01068a022 - Have you seen this ? Its literally the first thing google came up with:P
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tshirtdr1
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[*] posted on 20-7-2017 at 08:21


CuReUS, Thanks. I am not a current ACS member, and don't have access to the journal. I may try to get it through the library if I don't work it out. Thanks.

Thanks all for your input.
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boilingstone2
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[*] posted on 20-7-2017 at 08:28


It would be a shame if someone downloaded the paper and uploaded it here

Attachment: The Mechanism of the Base-Catalyzed Addition of Thiols to Maleic Anhydride.pdf (480kB)
This file has been downloaded 325 times

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tshirtdr1
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[*] posted on 20-7-2017 at 18:23


Thanks!
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