[Steve8765]

I need some help with what went on during this lab and interpreting the results. Here is the reaction:



I believe that the anionic product X is Is this correct?

We are also asked for the structure of the solid intermediate that is produced during the initial stage of the reaction. I am not sure what that is?

Also, from the IR there are 2 N-H peaks, but on is seen at 3277 cm^-1 and one is seen at 3208 cm^-1. I am not sure which is which? Any ideas on this?

[Steve8765]

Ok, I think that I get the first parts. I still don't know how to assign each Nitrogen to its peak on the IR spectrum. I think that the N-H that is between the two carbonyl groups would have the lower IR peak, at 3208 cm^-1. I think this because you are able to draw 2 resonance structures of the conjugate base that makes the nitrogen more single bonded. Is this a correct way to think about this or is there a different way?

[sjb]

Seems a reasonable way to think about the problem, I can't see how else to determine them, short of complex things like deuterated urea undergoing the reaction and / or things like NOESY NMR experiments (possibly with methylurea or similar).

The main thing is, I think you have a rationale that makes sense.

S