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Niklas
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So I just rewatched Sam‘s Lugduname video (https://youtu.be/YdGalCuJ96Q?si=G7DkvF4hivI_6Eki), where he made the ortho isomer of piperonal as an intermediate, and to make it he used the
rather interesting approach of catalyzing the methylenedioxy-synthesis with copper(II)-oxide, I presume to achieve an Ullmann-condensation kind of
mechanism.
Literature claims 90%, and while it is using dibromomethane, I now wonder how well this procedure could be applied to protocatechulic aldehyde using
DCM, as it‘s definitely a lot more accessible than any of the quaternary ammonium catalysts I‘m personally trying to employ.
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underground
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Quote: Originally posted by Niklas ![](images/xpblue/lastpost.gif) | So I just rewatched Sam‘s Lugduname video (https://youtu.be/YdGalCuJ96Q?si=G7DkvF4hivI_6Eki), where he made the ortho isomer of piperonal as an intermediate, and to make it he used the
rather interesting approach of catalyzing the methylenedioxy-synthesis with copper(II)-oxide, I presume to achieve an Ullmann-condensation kind of
mechanism.
Literature claims 90%, and while it is using dibromomethane, I now wonder how well this procedure could be applied to protocatechulic aldehyde using
DCM, as it‘s definitely a lot more accessible than any of the quaternary ammonium catalysts I‘m personally trying to employ.
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What is also interesting is that he is also using Glacial AA and 48% HBr for the cleavage reaction in inert atmosphere with 48% yields. No pyridine,
no ALCL3. Just distill some HBr from a Br salt + drain cleaner and you are ready.
[Edited on 20-1-2025 by underground]
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Niklas
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Quote: Originally posted by underground ![](images/xpblue/lastpost.gif) |
What is also interesting is that he is also using Glacial AA and 48% HBr for the cleavage reaction in inert atmosphere with 48% yields.
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Indeed, definitely wouldn’t have expected much more than maybe 20% with that approach.
I honestly can’t believe it would work this well for normal vanillin as well, like logically it should, but it can’t be that nobody tried that one
and we are still rather using stuff like the AlCl3 / Py demethylation..
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underground
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Quote: Originally posted by Niklas ![](images/xpblue/lastpost.gif) | Quote: Originally posted by underground ![](images/xpblue/lastpost.gif) |
What is also interesting is that he is also using Glacial AA and 48% HBr for the cleavage reaction in inert atmosphere with 48% yields.
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Indeed, definitely wouldn’t have expected much more than maybe 20% with that approach.
I honestly can’t believe it would work this well for normal vanillin as well, like logically it should, but it can’t be that nobody tried that one
and we are still rather using stuff like the AlCl3 / Py demethylation.. |
LoL i was editing but you was faster
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