H-NMR CORRELATIONS
Explanations (highest to lowest ppm)
1. Hj is part of an aldehyde, typically 8-10 ppm and would be a singlet
2. Hd is not coupled by any other hydrogens and is aromatic (typically 6-8 ppm)
3. Hs is very similar to Hd given that Hs is not coupled by other hydrogens and is aromatic, however, the additional conjugation causes the shift of Hs to be slightly upfield
4 Hc and Hu are aromatic hydrogens that are coupled by other aromatic hydrogens leading to a complex splitting pattern.
5. He and Ht are also aromatic hydrogens that are coupled by other aromatic hydrogens and have a complex splitting pattern, but are further upfield than Hc and Hu because He and Ht are further away from the electronegative oxygen.
6. Hl and Hk are deshielded as they are adjacent to a nitrogen molecule and are coupled by two sets of different hydrogens leading to a doublet of doublets. Although Hl and Hk couple eachother, the coupling constant is probably so small that it has no impact on the peaks.
7. Ha, Hb, Hw, Hv are all on a carbon attached to two electronegative oxygen atoms, creating a lot of deshielding. Again, although the two sets of hydrogens probably couple each other, the coupling constants are so small that the peak appears as a singlet.
8. Hg and Hh are slightly more deshielded than a typical sp3 carbon as a result of the nearby carbonyl groups. Also, these hydrogens are coupled by two very similar hydrogens resulting in a triplet.
9. Hq and Hr are attached to sp2 carbons (3-4 ppm). They both have very similar chemical shifts but are being coupled by different hydrogens, creating a multiplet.
10. Hf and Hi are similar to Hg and Hh, but now further away from the carbonyl groups leading to less deshielding. Also, There is an additional coupling partner leading to a multiplet.
11. Hm, Hn, Ho, and Hp are all on sp3 carbons, have similar chemical shifts and are coupling with one another to give a big, honkin’ multiplet at a low ppm.