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Topic: Vilesmeier - Haack Formylation  (Read 3216 times)

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Offline darkdevil

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Vilesmeier - Haack Formylation
« on: September 22, 2014, 05:21:20 AM »
Dear,

I am doing the formylation of this compounds using Vilesmeier Reagent (DMF + POCl3)
However, when doing NMR analysis I found the that aldehyde group was attached on the nitrogen atom instead of the aromatic ring.


I saw wikipedia demonstrated a similar reaction with Indole, and the reaction occurs at the ring. The only difference is that I used DMF as solvent while they used toluene. Does the solvent effect really that matter?


Thanks!


Offline discodermolide

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Re: Vilesmeier - Haack Formylation
« Reply #1 on: September 22, 2014, 06:18:46 AM »
The solvent won't make much difference, usually you need traces of DMF. It's not surprising that it N-formylated, where did you expect to react?
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Offline darkdevil

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Re: Vilesmeier - Haack Formylation
« Reply #2 on: September 22, 2014, 07:19:09 AM »
I expect it to react at the aromatic ring

Offline discodermolide

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Re: Vilesmeier - Haack Formylation
« Reply #3 on: September 22, 2014, 09:05:25 AM »
Perhaps you should try protecting the NH groups. Even then I am not convinced that it formylate the aromatic ring(s).
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