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Topic: Synthesis Help  (Read 2093 times)

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Offline nickpapa

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Synthesis Help
« on: December 16, 2015, 11:46:06 AM »
I am treating 5-chloro-1H-pyrrolo[2.3-b]pyridine-3-carbaldehyde with nitromethane and ammonium acetate, refluxing overnight. I concentrated the mixture, and when attempting to extract, the mixture just formed an emulsion and wouldn't dissolve in anything. I partitioned it in water and ethyl acetate, noting. I then tried DCM, diethyl ether, THF...and still nothing. Any suggestions? I am currently rotovapping off all the solvents and water to see if methanol has any solubility.

Offline kriggy

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Re: Synthesis Help
« Reply #1 on: December 16, 2015, 01:19:55 PM »
From top of my head:
1) you can wait to see if the suspension goes away (might take a lot of time)
2) you can add NaCl into the aq. phase to improve the layer separation
3) you can use hairdryer to carefuly heat the separation funnel near the stopcock (takes some time to separate)
4) you can filter it through sintered glass
5) try to sonificate the mixture for a bit

What worked for me are 1/2/3 the others are that I heard of or worked for my friends.


Offline nickpapa

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Re: Synthesis Help
« Reply #2 on: December 16, 2015, 01:58:27 PM »
@kriggy I let everything sit last night and nothing. I added NaCl to the aqueous layer and still nothing. I also stirred and heated to mixture and still nothing. I will try filtering off the solid and see what happens then.

Offline kriggy

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Re: Synthesis Help
« Reply #3 on: December 17, 2015, 02:24:45 AM »
YOu can also evaporate the mixture to dryness and then add water + ethyl acetate or whatever you will be extracting with

Offline Enthalpy

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Re: Synthesis Help
« Reply #4 on: December 17, 2015, 07:59:09 AM »
Centrifuge?

Offline eskil

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Re: Synthesis Help
« Reply #5 on: December 23, 2015, 09:48:34 AM »
Did you follow a published procedure to make the nitrostyrene? In that case what's the ref? You can use methanol as solvent and alkylamine as a catalyst, see: J. Org. Chem. 18, 1-3 (1953)


Best,
eskil

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