Organic Chemistry Laboratory I - Chem 341

Quiz 8a

1. Define or give an example to explain the following NMR term: integration curve. (2 pts)

Integration curve or integral number is defined as the area under the peak, which is a measure of the relative number of protons in the molecule. The signals for diethyl ether would have a ratio of 3:2 for the methyl protons relative to the methylene protons.

2. Circle the structure most consistent with the following ¹H NMR spectrum. (2 pts)

3. How many different types of protons are present in the following compound? (2 pts)

Five

4. Consider the compound below and answer the following questions:

(a) What would the splitting pattern for the protons on carbon a look like? (e.g. singlet, doublet, triplet, etc.) (2 pts)

Triplet because it has two adjacent protons, so n = 2 and n+1 = 3.

(b) Specify where the protons on carbon d would show up on the ¹H NMR spectrum, i.e. what ppm? (2 pts)

Proton d is aromatic so it will show up from about 6.8 to 8 ppm. Since d is close to bromine it will probably be closer to 7.5 ppm. 2 pts for 7.5 ± 1 ppm. Since d and f are homotopic, they will each be split into a doublet by c and e, respectively.