273180219
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Dimethylmalonyl dichloride synthesis
I have searched the board, but it seems that the praparation of this substance has not been discussed extensively yet.
today I tried out generally following the affiliated reference(marked with red lines) that published nearly two decades ago at JACS.
The most different is that I purified my product only with rotary evaporation instead of distillization.At first, I got the clear and colorless
solution(Figure 1),which have been determined dimethylmalonyl dichloride with MS and H NMR.
However, when I wanted to synthesize it again, it resulted bad with the product of mixture contained yellow oil and white solid(Figure 2).
I even don't kwon what the solid is.
Does anybody have experience with the synthesis of dimethylmalonyl dichloride ?
What is the composition of my solid?
Are there any advanced methods to synthesize this substance?
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Ozone
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Did you use oxalyl chloride in DMF/DCM?
See pp. 4543: http://evans.rc.fas.harvard.edu/pdf/evans228.pdf
O3
-Anyone who never made a mistake never tried anything new.
--Albert Einstein
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273180219
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Thanks for your reply. I did use oxalyl chloride in DMF to acylate dimethylmalonic acid to the substance mentioned above.
I wander if it's neccesarry to purify the solution by distillation, could the one-step ratory evaporation afford clear and pure products (Have you
ever had a try? ). I did try to distill my liqiud before, but little products was collected.
Did you get pure products by distillation? How did you set up the experimental facilities? Would you mind offer me a photo, and tell me some details
of the purification procedure?
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DraconicAcid
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I don't have a lot of experience with this material, but any time I see solid stuff forming in an acyl chloride, I automatically suspect that some
water has gotten in there and you have the acid.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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273180219
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Quote: Originally posted by DraconicAcid  | | I don't have a lot of experience with this material, but any time I see solid stuff forming in an acyl chloride, I automatically suspect that some
water has gotten in there and you have the acid. |
Once you get the solid, how to remove it ? I tried filtration before, but there were still some solid.
Maybe I misunderstand the meaning of this sentence "The
solution was concentrated in vacuo to give a yellow liquid with denser orange oil droplets", rotary evaporation is carried out all the time.
Do you kwon how to concentrate in vacuo ?
Thanks for your reply!
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Ozone
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I'm guessing you either have some water in there (wet DMF, maybe) or the DMF has a good amount of dimethylamine in it. Does the solvent smell like
DMA?
Did it fizz a lot when the oxalyl chloride was added?
Either way, you'll have a product you don't want in there...acid and/or amide.
In either case, I'd dry DMF before use in a reaction like this.
O3
-Anyone who never made a mistake never tried anything new.
--Albert Einstein
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273180219
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In the reaction, DMF was used as a catalyst in the amount of 0.5-1.0ml. Tha solvent used was CH2Cl2.There were a lot of fog escaped from the flask
instead of fizzing.
At the beginning of evaporation, no solid was formed. However, when it turned to oil, solid came out with a lot of water-like fog. So when you
suggested that acid may be formed as the existence of undesired water, I strongly believe that some water dropped in the liqiud when evaporation
happened.
Do you dry DMF with 4A molecular sieve? Or other ways?
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Ozone
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4A sieves:
http://chemwiki.ucdavis.edu/Reference/Lab_Techniques/Distill...
http://www.lookchem.com/Chempedia/Chemical-Technology/Labora...
O3
-Anyone who never made a mistake never tried anything new.
--Albert Einstein
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273180219
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Thks, I will try that.
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273180219
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Today, amazing things happened to evaporation of what I synthesized. I still got the white solid, however, I found it disppeared as I put it aside
and cooled itself before. Finally, evaporation was carried out again, and nothing decreased.
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