Hello
Can anyone explain why don't protons numbered "7" in 3,4-diaminoanisol give any HMBC crosspeaks? I'm not even sure which ones are "7"
1) 3.98 in the spectrum
2) 3.44 and 3.98 in spectrum and the integrals are bigger because of impurities
3) 4.50 (same as "8") but the integral is just smaller
Spectra:
1H
HMBC(green) HSQC (red)