All-in-one NMR spectroscopy of small organic molecules: complete chemical shift assignment from a single NMR experiment

A new class of NOAH NMR experiments (NOAH-AST and NOAH-AST(PS)), with the abbreviations, A: 1,1-ADEQUATE, S: sensitivity improved version of multiplicity-edited (ME)-HSQC, T: TOCSY, and T(PS): pure shift TOCSY, are reported to obtain complete chemical shift assignments of small organic molecules from a single NMR experiment. While NOAH-AST provides (13)C–(13)C, (1)H–(13)C, and (1)H–(1)H connectivities for molecules with well resolved chemical shifts, NOAH-AST(PS) experiments discern (1)H–(1)H connectivities even in complex organic molecules such as steroids at ultra-high resolution. These methods are very flexible and allow to record data through non-uniform-sampling, which reduces the experimental time to a great extent. In order to make these methods friendly to non-NMR experts (especially organic chemists and natural product scientists), python scripts have been developed and they help researchers in using these methods.