Trifluoroacetic
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condensation reaction with cinnamaldehyde
Ok folks I have a question. Cinnamaldehyde will condense with acetone in the presence of NaOH to form Dicinnamalacetone. I happened to notice that
DMSO has a structure similar to acetone so I was wondering if it would undergo a condensation reaction with cinnamaldehyde.
So I mixed cinnamaldehyde and DMSO in a 2:l ratio and added aqueous NaOH. The sloution turned light yellow and heated up. A reaction appeared to
happen. The solution was turbid from un-reacted cinnamaldehyde. So I did the reaction with even less cinnamaldehyde. I placed to drops in a larger
ammount of DMSO then I added the NaOH. This time the solution turned blood red and heated up. I repeated the experiment and ommited the Cinnamaldehyde
to see if the NaOH was reacting with the DMSO. Nothing happened.
So my question is the cinnamaldehyde condensing with itself or with the DMSO?
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DJF90
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Did you try a control experiment using just the cinnamaldehyde and the NaOH..?
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Trifluoroacetic
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no but I will. I'll solvate it in some ethanol.
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Trifluoroacetic
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I added a few drops of cinnamaldehyde to isoproponol then added NaoH solution. Slight yellowing occurred
but nothing else happened.
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Trifluoroacetic
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something strange appears to be taking place with the DMSO/cinnamaldehyede/NaOH reaction. IF very little DMSO is used almost nothing happens but if a
substatntially large ammount is used the reaction takes place and the solution turnsdark
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DJF90
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I was thinking perhaps you got a Canizzaro reaction occuring.
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Trifluoroacetic
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HMM I detect an almond oder in the solution when just enough DMSO is added to turn it dark yellow. If the solution turns dark red the Almond oder is
weaker.
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Trifluoroacetic
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I think you might be right. I wonder if this
coul be useful for anything?
The solution smells good! Perhaps it will taste good too?
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DJF90
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Well I'm not sure I'd want to taste it. Something you could do is check the pH (dissolve a small amount of reaction mix in water first). The odour
could be either the acid, the alcohol, or the ester (perhaps admixed with the odour of cinnamaldehyde itself). I cant think of any other reasonable
explanation at the moment in time.
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Trifluoroacetic
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Hmm? I took the Isopropanol mixture and added potassium metabisulfite to it and as expected it crystalized due to the formation of a bisulfite adduct.
Then I added the bisulfite to the DMSO solution and no adduct formed. This is strange. A dark precipitate is now forming in the DMSO solution that
didn't have any metabisulfite added to it.
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ThatchemistKid
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Would cinnamaldehyde not under go 1,4 addition with nucleophiles? I am not sure if it would occur over a cannizzaro though?
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Trifluoroacetic
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The yellow solution is quite basic as it turned my universal indicator slip dark blue. Perhaps I have a bunch of worthless condensation products. I'll
put this in a mini distilling flask and se what comes off tomorrow.
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