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Topic: 2,5-dihydroxybenzaldehyde oximes  (Read 5351 times)

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Offline angel-ist

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2,5-dihydroxybenzaldehyde oximes
« on: May 10, 2010, 10:45:10 AM »
Please help me ! I tried different method different solvent such as water, etoh, meoh, acetonitrile diferent base NaOH, CH3COONa, K2CO3..different condition heat,ice bath (with hydoxylaminHCl).When I had written project, ı selected this aldehyde becouse it has very biological important structure. Bu ı didnt synthesise it ???
I think hydrogen bond is important for this aldehyde
But I need this aldehyde oxime :'(

Offline Doc Oc

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Re: 2,5-dihydroxybenzaldehyde oximes
« Reply #1 on: May 10, 2010, 11:34:45 AM »
It sounds like you're trying to synthesize the oxime from benzaldehyde, is that correct?  If so then you need to get rid of water to drive the formation of your product.  Either do a Dean-Stark distillation or try refluxing over CaH2 or similar drying agent.

Offline angel-ist

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Re: 2,5-dihydroxybenzaldehyde oximes
« Reply #2 on: May 11, 2010, 09:32:07 AM »
Thank you. But, I tried different compound for absorbe the water. ZnCl2, MgSO4, Na2SO4. But I didnt try dean-stark staff . thank you

Offline angel-ist

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Re: 2,5-dihydroxybenzaldehyde oximes
« Reply #3 on: May 12, 2010, 03:53:51 PM »
I did it..
But it isn't workkkkk
I am very tired
I search lit. data I dont remember 100 maybe!!!!!
Please If you work aldoximes synthesise, will write me
Thanks

Offline sjb

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Re: 2,5-dihydroxybenzaldehyde oximes
« Reply #4 on: May 12, 2010, 05:13:13 PM »
Might you have to protect the hydroxyl groups? Is there any precedent in the literature?

Offline MissPhosgene

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Re: 2,5-dihydroxybenzaldehyde oximes
« Reply #5 on: May 12, 2010, 08:35:34 PM »
I had to work with 2,5-dihydroxybenzaldehyde for a few months. The idea was that I would do some stuff at the aldehyde, which is not well behaved at all... it ended up being really tricky.

Protect the alcohols. Remove water. You may have to take desperate measures... :P
Keep it in a dry, air-free environment if you can.

I had to beat the crap out of it.

Be creative.

Also... try purifying it first. The stuff I was buying wasn't good enough as it was from Aldrich or Alfa Aesar. Aldrich was better quality, but it still needed further purification.
Stereograms of the 32 crystallographic point groups: little bike wheels of cold, hard, pure rationality.

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