Version A
1) Evaluate the partial mechanisms below and decide whether the products drawn could
result from the curved arrows provided. “Yes” = products follow from arrows. (3 points)
Yes / No
Yes / No
Yes / No
2) Supply the missing curved arrows for the following mechanism. Note that this is NOT a
transformation you have seen before. You’ll have to determine the electron flow based on
which atoms and electrons have moved during the reaction. (2 points)
3) Draw the structure of the following compounds: (4 points)
ortho-bromotoluene 3-nitrofuran
4) Classify the following structures as either aromatic (A), anti-aromatic (AA) or non-
aromatic (NA). Assume that all atoms lie in the same plane. (5 points)
AA A NA AA A
-1-
, Version A
5) Which structure would be expected to have the greatest max? (1 point)
6) Draw an example of a molecule containing a conjugated system spread over 5 atoms. The
system should include two pi bonds, a nitrogen atom and a positive charge. (2 points)
7) The compound shown has four signals in its 1H NMR spectrum, including an
exchangeable signal at 5.34 ppm. Complete the table below, indicating the number of
hydrogens represented by each signal and the expected splitting patterns. (8 points)
Chemical shift (ppm) Integration (# hydrogens) Splitting pattern (s, d, t, etc.)
9.72 1 Triplet
5.34 1 Singlet
3.86 2 Triplet
2.59 2 Doublet of triplets
8) Identify the most shielded and deshielded signals in the molecule below. (2 points)
9) Indicate whether the following statements are TRUE or FALSE. (2 points)
NMR spectroscopy uses a strong magnetic field and radio waves
TRUE / FALSE
to study the chemical environment of spin-active nuclei.
Every hydrogen in a molecule has a unique resonance frequency
TRUE / FALSE
which is determined by its chemical environment.
-2-
1) Evaluate the partial mechanisms below and decide whether the products drawn could
result from the curved arrows provided. “Yes” = products follow from arrows. (3 points)
Yes / No
Yes / No
Yes / No
2) Supply the missing curved arrows for the following mechanism. Note that this is NOT a
transformation you have seen before. You’ll have to determine the electron flow based on
which atoms and electrons have moved during the reaction. (2 points)
3) Draw the structure of the following compounds: (4 points)
ortho-bromotoluene 3-nitrofuran
4) Classify the following structures as either aromatic (A), anti-aromatic (AA) or non-
aromatic (NA). Assume that all atoms lie in the same plane. (5 points)
AA A NA AA A
-1-
, Version A
5) Which structure would be expected to have the greatest max? (1 point)
6) Draw an example of a molecule containing a conjugated system spread over 5 atoms. The
system should include two pi bonds, a nitrogen atom and a positive charge. (2 points)
7) The compound shown has four signals in its 1H NMR spectrum, including an
exchangeable signal at 5.34 ppm. Complete the table below, indicating the number of
hydrogens represented by each signal and the expected splitting patterns. (8 points)
Chemical shift (ppm) Integration (# hydrogens) Splitting pattern (s, d, t, etc.)
9.72 1 Triplet
5.34 1 Singlet
3.86 2 Triplet
2.59 2 Doublet of triplets
8) Identify the most shielded and deshielded signals in the molecule below. (2 points)
9) Indicate whether the following statements are TRUE or FALSE. (2 points)
NMR spectroscopy uses a strong magnetic field and radio waves
TRUE / FALSE
to study the chemical environment of spin-active nuclei.
Every hydrogen in a molecule has a unique resonance frequency
TRUE / FALSE
which is determined by its chemical environment.
-2-
