The HMBC experiment is normally used to detect 1H-13C correlations, but it can also be used for 15N. An 15N HMBC experiment may provide structural information that cannot be obtained from a 13C HMBC, and it can also be used to determine the number of nitrogen atoms present in a compound. Recently I was asked, "How does the sensitivity of an 15N HMBC compare with that of a 13C HMBC?", so I decided to try and find out.
