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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: redballoons on January 14, 2013, 09:57:41 PM

Title: Compound Synthesis from Succinic Anhydride
Post by: redballoons on January 14, 2013, 09:57:41 PM
Starting with succinic anhydride, give the reagents and/or conditions necessary to produce...

NH4+-OOCCH2CH2CONH2



First I would added H2O/H+ to the succinic anhydride to open the ring and give...

HOOCCH2CH2COOH


Then I would add NH3...

This is where I'm getting confused because I have two mechanisms in my notes for adding NH3 to a carboxylic acid.

1.) R-COOH + NH3  :rarrow: R-COO-NH4+ (used during imide formation)

2.) R-COOH + HNR2  :rarrow: R-CONR2 (used during amide formation)


Which one is right?
And how can I get CONH2 at one end but COO-NH4 at the other?

Title: Re: Compound Synthesis from Succinic Anhydride
Post by: redballoons on January 14, 2013, 10:32:27 PM
Ok so I have done some more research and I would still add H2O/H+ to get...

HOOCCH2CH2COOH

Then I would add SOCl2 :rarrow: R-COCl

Then I would add NH3  :rarrow: R-COO-NH4+ + HCl

Then I could heat it  :rarrow: R-CONH2 + H2O

But is there a way to protect one end so that it doesn't go from R-COO-NH4+ to R-CONH2 when heated?


Or am I making this way more difficult then it really is?
Would adding 2NH3 to succinic anhydride  result in the desired product? It would have a similar reaction to the addition of concentrated ammonia solution added to ethanoic anhydride.
Title: Re: Compound Synthesis from Succinic Anhydride
Post by: ashmus on January 15, 2013, 12:38:32 AM
Going back, are you certain the following reaction will equate to the carboxylate ammonium salt? Go through the mechanism. What is the nucleophile and what is the electrophile?

RCOCl + NH3  :rarrow: R-COO-NH4+

You were making it a bit more complicated, but it seems you now managed to make your compound in one step.  :)
Title: Re: Compound Synthesis from Succinic Anhydride
Post by: discodermolide on January 15, 2013, 12:43:35 AM
Why not just use concentrated ammonia?
Title: Re: Compound Synthesis from Succinic Anhydride
Post by: orgopete on January 15, 2013, 12:56:11 AM
Hint, I think the answer could be the reaction of two equivalents of ammonia with succinct anhydride. Can you determine why this might succeed?