The goal of this puzzle is to logically combine a set of fragments using valence and NMR information.
In this puzzle, three fragments are correlated through 2-3J coupling responses (represented by a green arrow) that were extracted from a 1H-13C HMBC data (spectrum not shown). The carbon atoms with the 13C chemical shifts displayed in blue indicate the presence of an adjacent heteroatom. Based on these criteria, what ‘complete’ fragment(s) supports the data and is there anything missing?
In order to accommodate these restrictions, a logical fit is to consider a trivalent atom, e.g. nitrogen.