# Assigning Peaks and Determining J Values for Mata-Disubstituted Benzene

I need to determine as many J values as I can for 3-methoxybenzaldehyde. The peaks overlap a lot, and I don't see the expected ddd or dt pattern that I would expect for the hydrogen on carbon 6. The HSQC I was given has the clearest peaks for the H NMR, so I attached that. Maybe someone with more NMR experience can help me tease apart the signals?

There's almost nothing you can do in this situation, unfortunately. Because of strong coupling and other issues, aromatic peaks often do not conform to the so-called $$n+1$$ rule, which makes it highly non-trivial to extract coupling constants. It is probably possible to "fit" coupling constants to the multiplet shape by simulating the spectrum for a given set of $$J$$'s and seeing which set best matches the observed spectrum.