The Impact of Long‐Range 1H‐15N Heteronuclear Shift Correlation Data on Computer‐Assisted Structure Elucidation: Posaconazole

Considerable work has been invested in the area of computer‐assisted structure elucidation (CASE) methods. As NMR techniques have been developed that provide more effective atom‐to‐atom connectivity information, it has become theoretically possible to do de novo structure elucidation based on 2D NMR datasets recorded for an unknown molecule. However, as annular (ring) nitrogen atoms become more prevalent in complex chemical structures, the ability to rely solely on ¹H and ¹³C homo‐ and hetero‐nuclear direct and long‐range connectivity information to solve a structure correspondingly diminishes. Hence, we now wish to report the results of an investigation into the application of CASE methods with and without long‐range ¹H‐¹⁵N data using posaconazole as a model compound, which has eight annular nitrogens in its structure. With the inclusion of ¹H‐¹⁵N data long‐range data, the structure could be successfully determined in a few hours. Excluding the ¹H‐¹⁵N data caused the program to generate millions of candidate structures, none of which fit the data well enough to be stored.