[asdfTT123]

Hey guys, question in regards to proton NMR.

I ran a two proton NMR samples today - an aromatic ethyl ester (5-Azidonicotinic acid ethyl ester) and aromatic carboxylic acid (5-Azidonicotinic acid).  The ethyl ester was done in CDCl3 and carboxylic acid was in DMSO-d6.  I ran this because I wanted to see if I was able to successfully deprotect the ethyl ester group to obtain my desired product - 5-Azidonicotinic acid.

Both samples are supposed to have three aromatic hydrogens with different chemical shifts, however I noticed that one of the hydrogens in my final compound was more downfield (the other two H's remained remained roughly the same).  Here's the data:

5-Azidonicotinic acid ethyl ester (in CDCl3) - 8.894, 8.409, 7.864
5-Azidonicotinic acid (in DMSO-d6) - 8.854, 8.605, 7.931

All other peaks check out (ethyl ester compound shows the methylene and methyl H's of the ethyl ester; carboxylic acid shows no such methylene/methyl H's).

Notice I'm concerned about the above bolded protons.  Is this any cause for concern (i.e. I'm afraid something could have changed the azido group into something else).  Or could this be an effect of the carboxylic acid?

Many thanks

[asdfTT123]

Also, here are the NMR spectra for the two compounds - I wrote on them with the peak assignments.

[Babcock_Hall]

You have also changed solvents, which might have an effect.

[willug]

Is it a known compound? You could compare your data to the literature if so. Otherwise FTIR will tell you if your azide is still there (about 2100 cm-1), or mass spec. Although, I can't see what you think might have happened to it.

You could also try the next step (I guess your clicking it to something) and if it works, then you know you had your compound.