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

Abstract

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 ¹³C–¹³C, ¹H–¹³C, and ¹H–¹H connectivities for molecules with well resolved chemical shifts, NOAH-AST_PS experiments discern ¹H–¹H 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.