[janapix]

I'm just having some issues with this spectrum.
I've attached the work I've done on it so far... could you help me assign the rest of the peaks?
spectrum: http://i317.photobucket.com/albums/mm395/MunsterMunster/University%20stuff/knorrhnmrspechelp.png

ps: This is for my Knorr synthesis lab - I've also had an issue with the final cyclization step... so just in case anyone would like to save me further hours of pain, I've attached that too =D

mechanism:
http://i317.photobucket.com/albums/mm395/MunsterMunster/University%20stuff/finalknorr.png

[Dan]

This is a little bit tricky to see straight away because you've got some overlapping peaks.

A: NH - I agree
B: chloroform (from the NMR solvent).

That leaves C, D and E.

You've called E a quartet, and assigned this as the methyl groups 8 and 11. This signal is for Me groups 8 and 11, but it is not a quartet, it is two separate signals. Me 8 and 11 are chemically inequivalent, and so will give two separate signals. Each of them couples to an adjacent CH₂, so we would expect to see two separate 1:2:1 triplets for methyl groups 8 and 11. Now, in this case these two signals are very close together and overlap slightly.

I will try to explain, you have two triplets: 1:2:1  1:2:1
But they overlap like this: 1:2:1
                                      1:2:1
             So it looks like a 1:3:3:1  quartet, but in reality is not.

The overlapping is nothing other than bad luck.

Hint: Consider this kind of situation when looking at signal C

What splitting patterns would you expect from the H at positions 7, 10, 12 and 13?

Hint: For signal D, you have measured a coupling constant of 21 Hz, which implies you think it's a doublet. 21 Hz is too high for a H-H coupling constant (0-15 is the usual range)...

[discodermolide]

Try running the spectrum again in C6D6 you will get an aromatic induced shift which, with a bit of luck, will separate your signals for you.

[janapix]

Absolutely thrilled to wake up to an answer that helped me assign all my peaks =)
Thanks very much Dan!

As for running a new spectrum, I'm still looking forward to running an NMR at all (sigh, undergrad degree...)