The molecular formula for an unknown compound is C9H8O4.
The 1H, 13C, DEPT135, HMQC and HMBC spectra are supplied separately for the unknown compound. NMR spectra were acquired on a
500 MHz Bruker instrument using deuterated methanol (MeOD) as the NMR solvent.
Use the data to determine the structure of the unknown compound. You can then fill in the required information in the tables provided, to give full
justification for your answer. Each proton and carbon must be clearly labelled using an alphabetical system and should clearly correspond to any
inferences you list in the tables provided.

Part A: Draw your labelled molecular structure here: (6 marks)

Part B: Interpretation of 1H NMR data (10 marks)
i) Chemical
shift (δ)
ii) Integration
and splitting
pattern.
(e.g., 2H,
triplet)
iii) Coupling
constants
(J-values in Hz
taken from data)
iv) Inference using an alphabetical system to label each proton on your proposed structure. Exchangeable
protons do not need to be assigned. Provide reasons why the 1H peaks correspond to the labelled hydrogens
on your proposed structure.

Part C: Using the same alphabetical system to label each carbon on your proposed structure, fill in the table below to interpret each 13C
signal. Use the 2D spectra provided, your knowledge of chemical shift and how electron withdrawing and donating groups can affect the
chemical shift of 13C signals for this exercise. (18 marks)
i)Chemical shift
(δ)
ii) Inference using an alphabetical system to label each carbon on your proposed structure. Provide reasons (using the 2D data), why
this 13C peak corresponds to the labelled carbon on your proposed structure.