Structure Identification of Novel Compounds Using Simple IR, ¹H, and ¹³C NMR Spectroscopy and Computational Tools

A simple method is suggested to identify the structure of novel compounds with basic IR, ¹H, and ¹³C nuclear magnetic resonance (NMR) spectroscopy and computational tools. With the molecular formula obtained from high‐resolution mass spectrometry, all possible isomers are calculated. The absence or presence of particular functional groups which were inferred from IR, ¹H, and ¹³C NMR and DEPT spectra are used to sort all the possible isomers using SMARTS code and RDKit. Then, the final structure(s) are identified by comparing the correlation between Quantum mechanically calculated ¹³C NMR chemical shielding constants and experimental ¹³C chemical shifts of molecules in consideration. We have applied this protocol to five natural compounds, the number of heavy atoms ranging from 11 to 15, and correctly identified the structures of all test cases. The limitations and further consideration are discussed.