CHEM 242 Organic Chemistry Lab II
Lab Exercise #6
Proton NMR: Spectra Interpretation II
PART I
INSTRUCTIONS:
Label each type of proton in the structure with a letter and place the same letter over the
corresponding peak on the NMR spectrum (see example below). Some NMR spectra show
a peak hovering above the baseline. This is a magnified view of one of the actual peaks, to
allow you to see splitting more clearly.
Example:
The 1H NMR spectrum of phenol is shown below. Assign the various resonances to the
hydrogen nuclei responsible for them.
b
c
NMR data for phenol(CDCl3).
Answer:
1
1.
NMR data for 1-chlorobutane (CDCl3).
2.
NMR data for 4-methyl-2-pentanol (CDCl3).
2
3.
NMR data for trans-4-methyl-2-pentene (CDCl3)
4.
NMR data for cis-4-methyl-2-pentene (CDCl3)
3
5.
NMR data for ethyl p-aminobenzoate (CDCl3)
4
Part II
Instructions:
Use the spectra (A-F) below to determine their structure. Assign the various resonances to
the hydrogen nuclei responsible for them.
A.
C5H12O
B.
C8H9NO
5
C.
C4H9Br
D.
C4H6O
6
E.
300 MHz ¹H NMR
In C DC l 3
1 .2
C6H12OS
1 .1
300 MHz ¹H NMR
1 .0
In C DC l 3
1 .2
0 .9
1 .1
1 .0
0 .8
0 .9
0 .8 0 .7
0 .7
0 .6
0 .6
0 .5
0 .5
0 .4
0 .3 0 .4
0 .2
0 .1 0 .3
0 .0
0 .2
-0.1
2 .2 5 2 .0 0 1 .7 5 1 .5 0 1 .2 5 1 .0 0 0 .7 5 0 .5 0 0 .2 5 -0.0 0
© Si g ma -Al d ri c h C o .
ALL R IGHTS R ESER VED
0 .1
0 .0
-0 .1
1 5 .0 1 2 .5 1 0 .0 7 .5 5 .0 2 .5 0 .0 -2 .5 -5 .0
© Si g ma -A l d ri c h C o .
A LL R IG HTS R ESER V ED
7
F.
300 MHz ¹H NMR
In C DC l 3
1 .2
1 .1
C8H5NO 300 MHz ¹H NMR
In C DC l 3
1.2
1.1
1 .0
0 .9
1.0
0 .8
0.9
0.8 0 .7
0.7
0 .6
0.6
0.5 0 .5
0.4
0 .4
0.3
0.2 0 .3
0.1
0 .2
0.0
-0.1 0 .1
9.00 8.75 8.50 8.25 8.00 7.75 7.50 7.25 7.00
© Si gma -Al dri c h C o.
ALL R IGHTS R ESER VED
0 .0
-0.1
10 9 8 7 6 5 4 3 2 1 0
© Si g ma -A l d ri c h C o .
A LL R IG HTS R ESER V ED
8
Following are the NMR spectra of three isomeric esters with the formula C7H14O2, all derived from propanoic acid.
Provide a structure for each and assign the various resonances to the hydrogen nuclei responsible for them.
