Problem 6

From the m/z value of the molecular ion of unknown compound 6 (m/z 318), quite a few molecular formulas can be deduced using the rule of thirteen (e.g., C₂₄H₃₀, C₂₃H₂₆O, C₂₂H₂₂O₂, C₂₂H₂₆N₂, C₂₀H₁₄O₂S, etc.). In this case,¹H NMR and¹³C NMR are quite simple for a molecule whose mass is 318 mass units, so the symmetry of the molecule is obviously high. The protons of the compound are a multiple of 11 and the number of non-equivalent carbons is 9. Besides, the chemical shifts suggest that there are heteroatoms in the molecule. So, we can start working out which molecular formula fits the data or, we can just start “putting the pieces together” and think about what is missed later.