Describe the ¹H NMR spectrum you would expect for each of the following compounds, indicating the relative positions of the signals:

f.

Describe the ¹H NMR spectrum you would expect for each of the following compounds, indicating the relative positions of the signals:

g. CH₃CH₂OCH₂CH₃

Describe the ¹H NMR spectrum you would expect for each of the following compounds, indicating the relative positions of the signals:

i.

Describe the ¹H NMR spectrum you would expect for each of the following compounds, indicating the relative positions of the signals:

k.

Describe the ¹H NMR spectrum you would expect for each of the following compounds, indicating the relative positions of the signals:

n.

Propose structures that are consistent with the following spectra. (Integral ratios are given from left to right across the spectrum.)

b. The ¹H NMR spectrum of a compound with molecular formula C₆H₁₀O₂ has two singlets with integral ratios of 2 : 3.

Why is there no coupling between the a and c protons or between the b and c protons in the cis and trans alkenes shown in Figure 14.20?

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Draw a splitting diagram for H_b, where

a. J_ba = 12 Hz and J_bc = 6 Hz.

For the following compounds, which pairs of hydrogens (H_a and H_b) are enantiotopic hydrogens?

1.

For the following compounds, which pairs of hydrogens (H_a and H_b) are enantiotopic hydrogens?

Which pairs are diastereotopic hydrogens?

How would the ¹H NMR spectra for the four compounds with molecular formula C₃H₆Br₂ differ?

Explain why the chemical shift of the OH proton of a carboxylic acid is at a higher frequency than the chemical shift of an OH proton of an alcohol.

Propose a mechanism for proton exchange of an alcohol in aqueous base.

Answer the following questions for each compound:

a. How many signals are in its ¹³C NMR spectrum?

b. Which signal is at the lowest frequency?

9. CH₂=CHBr

Answer the following questions for each compound:

a. How many signals are in its ¹³C NMR spectrum?

b. Which signal is at the lowest frequency?

8.

Answer the following questions for each compound:

a. How many signals are in its ¹³C NMR spectrum? b. Which signal is at the lowest frequency?

7.

Describe the proton-coupled ¹³C NMR spectra for compound 5 in Problem 41, indicating the relative positions of the signals.

5.

Describe the proton-coupled ¹³C NMR spectra for compound 3 in Problem 41, indicating the relative positions of the signals.

3.

Describe the proton-coupled ¹³C NMR spectra for compound 1 in Problem 41, indicating the relative positions of the signals.

1. CH₃CH₂CH₂Br

How can 1,2-, 1,3-, and 1,4-dinitrobenzene be distinguished by

a. ¹H NMR spectroscopy?

How can 1,2-, 1,3-, and 1,4-dinitrobenzene be distinguished by

b. ¹³C NMR spectroscopy?

Identify each compound below from its molecular formula and its ¹³C NMR spectrum.

a. C₁₁H₂₂O

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Identify pairs of coupled protons in the compound whose COSY spectrum is shown below.

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What does cross peak X in Figure 14.34 tell you?

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How many signals are produced by each of the following compounds in its

a. ¹H NMR spectrum?

4.

5.

6.

How many signals are produced by each of the following compounds in its

b. ¹³C NMR spectrum?

1.

How many signals are produced by each of the following compounds in its

b. ¹³C NMR spectrum?

2.

Label each set of chemically equivalent protons, using a for the set that will be at the lowest frequency in the ¹H NMR spectrum, b for the next lowest, and so on. Indicate the multiplicity of each signal.

a.

Label each set of chemically equivalent protons, using a for the set that will be at the lowest frequency in the ¹H NMR spectrum, b for the next lowest, and so on. Indicate the multiplicity of each signal.

c.