Problem Set 1 - NMR Spectra Two Isomers of C4H8O2 2

Problem Set 1 - NMR Spectra Two Isomers of C4H8O2 2

Problem Set 1 - NMR Spectra
Reich
Chem 345
Two Isomers of C4H8O2
Problem R-16A: C4H8O2
300 MHz 1H NMR Spectrum in CDCl3
Source: Aldrich Spectral Viewer/Reich
IHD = 1
3
O
30
O
20
10
0
Hz
CH2 CH3
X
CH3
Observed protons are circled
protons causing splitting are underlined
3
2
O
CH2 CH3
quartet
4.2
10
9
8
4.1
7
6
Problem R-16B: C4H8O2
300 MHz 1H NMR Spectrum in CDCl3
Source: Aldrich Spectral Viewer/Reich
2.05 2.00
5
ppm
4
3
1.30 1.25
2
1
0
IHD = 1
3
O
CH2 CH3
O
3
O
CH3
X
30
20
10
0
CH2 CH3
Hz
1.20 1.15 1.10
2
2.4
3.70 3.65
10
9
8
7
2.3
6
5
ppm
4
3
2
1
Two Isomers of C4H8O2
Problem R-16C: C4H8O2
300 MHz 1H NMR Spectrum in CDCl3
Source: Aldrich Spectral Viewer/Reich
IHD = 1
CH2 CH2 CH3
CH2 CH3
O
H
O
30
20
10
0
Hz
O
3.00
H
1.8
1.7
1.6
2.06
2.11
8.1
8.0
CH2 CH2
O
1.00 0.95
1.01
4.15 4.10
10
9
8
7
Problem R-16D: C4H8O2
100 MHz 1H NMR Spectrum
Source: Reich
6
5
ppm
4
3
2
1
0
IHD = 1
1.17
O
1.00
OH
CH2 CH3
CH2 CH2 CH3
CH2 CH2
0.94
0.32
OH
12
2.4
11
1.7
2.3
10
9
8
1.0
1.6
7
6
ppm
5
4
3
2
1
0
Problem R-18L C4H9Br
300 MHz 1H NMR spectrum in CDCl3
Source: Aldrich Spectra Viewer/Reich
Br
30
20
10
Hz
0
CH2 CH3
IHD = 0
CH2 CH2 CH2
CH2 CH2 CH3
sextet
pentet
1.95 1.90 1.85 1.80 1.75 1.70 1.65 1.60 1.55 1.50 1.45 1.40 1.35
X
CH2 CH3
1.00 0.95 0.90
2.20
1.42
1.00
3.45 3.40 3.35
7
6
5
4
100
ppm
80
3
2
60
40
1
CDCl3
Problem R-18L: C4H9Br
75 MHz 13C NMR spectrum
Solv: CDCl3
Source: ASV/Reich
0
13.2
8
21.3
9
34.8
33.6
10
200
180
160
140
120
20
0
US
Problem R-7N C8H10O
300 MHz 1H NMR spectrum in CDCl3
Source: Aldrich Spectra Viewer 33-09
IHD = 4
CH2 CH3
O
7.3
7.2
7.1
7.0
6.9
6.8
O CH2 CH3
3
R
5
2
6
5
120.6
129.5
Problem R-7N: C8H10O
75 MHz 13C NMR spectrum
Solv: CDCl3
Source: ASV/Reich
4
3
2
1
0
ppm
Infrared Spectrum:
210 200 190 180 170 160 150 140 130 120 110 100
ppm
90
80
70
60
14.9
7
3.9
63.3
8
4.0
114.6
9
1.4
50
40
30
20
10
0
Problem R-7R: C5H9BrO2
300 MHz 1H NMR spectrum in CDCl3
Source: Aldrich Spectra Viewer 33-09
X
IHD = 1
X
CH2 CH2
30
3.6
3.5
3.4
20
10
3.3
0
Hz
3.2
3.1
O
Br
CH2 CH3
CH2 CH2
3.0
2
O
3
2
2
1.00
2.9
1.05
1.43
1.00
1.3
O
CH2 CH3
4.2
10
9
Infrared Spectrum:
8
7
6
5
ppm
4
3
2
1
0
100
60
40
20
1600
1400
1200
1000
800
600
400
200
14.2
25.9
cm-1
CDCl3
Problem R-7R: C5H9BrO2
75 MHz 13C NMR spectrum
Solv: CDCl3
Source: ASV/Reich
1800
37.8
Change of scale
at 2000 cm-1
61.0
4000 3800 3600 3400 3200 3000 2800 2600 2400 2200 2000
170.4
Percent Transmittance
80
210 200 190 180 170 160 150 140 130 120 110 100
ppm
90
80
70
60
50
40
30
20
10
0
Problem R-7P C9H10O
300 MHz 1H NMR spectrum in CDCl3
Source: Aldrich Spectra Viewer 33-09
US
IHD = 5
R = electron withdrawing group
R
30
20
10
0
Hz
CH2 CH3
3
8.0
7.9
7.8
7.7
7.6
7.5
7.4
2.32
O
2
5
X
1.54
CH2 CH3
1.00
6
Problem R-7P C9H10O
75 MHz 13C NMR spectrum
Solv: CDCl3
Source: ASV/Reich
5
ppm
1.25 1.20
4
3
2
1
0
31.8
7
3.0
132.8
128.5
127.9
8
136.9
9
200.6
10
Infrared Spectrum:
3.0
8.2
3.1
1
4
4
CDCl3
O
1
210 200 190 180 170 160 150 140 130 120 110 100
ppm
90
80
70
60
50
40
30
20
10
0
Problem R-7M: C11H14O
300 MHz 1H NMR
Solv: CDCl3
Source: A. Fiedler/Reich
IHD = 5
30
20
10
0
Hz
O
nonet
Ph
CH2
CH (CH3)2
R = electron withdrawing group
CH (CH3)2
R
X
CH2
CH
6.14
7.95 7.90
ppm
7.60
7.55
7.50 7.45
ppm
7.40
7.35
2.40
2.35
2.30
ppm
2.25
2.20
2.98
2.00
2.03
1.01
2.85
8
7
6
5
1.00
ppm
2.80
ppm
4
ppm
3
2
1
0
210 200 190 180 170 160 150 140 130 120 110 100
ppm
90
80
70
60
50
25.1
22.8
47.4
132.7
128.5
128.0
137.3
199.9
Problem R-7M C11H14O
75 MHz 13C NMR spectrum
Solv: CDCl3
Source: ASV/Reich
40
30
20
10
0
Problem R-7K C5H9ClO2
250 MHz 1H NMR spectrum in CDCl3
Source: Adam Fiedler/Reich
IHD = 1
30
20
10
0
Hz
O
O
Cl
O
3.26
O
3.13
Cl
CH2 CH3
Correct structure
This is a reasonable alternative
structure - also fits the 1H NMR
data
X
X = O, Cl
CH CH3
2.16
CH2 CH3
CH CH3
X
4.45
8
4.40
1.00
4.35
4.30
ppm
7
4.25
4.20
4.15
6
1.35
1.70 1.65
ppm
5
4
ppm
3
2
1.30
ppm
1.25
1
0
Infrared Spectrum:
100
60
40
20
1800
1600
1200
1000
800
600
400
200
14.0
CDCl3
21.5
62.0
Problem R-7K: C5H9ClO2
75 MHz 13C NMR spectrum
Solv: CDCl3
Source: ASV/Reich
1400
cm-1
Change of scale
at 2000 cm-1
52.6
4000 3800 3600 3400 3200 3000 2800 2600 2400 2200 2000
170.1
Percent Transmittance
80
220
210
200
190
180
170
160
150
140
130
120
110
ppm
100
90
80
70
60
50
40
30
20
10
0
Problem R-7O C5H8
300 MHz 1H NMR spectrum in CDCl3
Source: Aldrich Spectra Viewer 33-09
40
20
0
CH2 CH3
Hz
triplet of doublets (td)
H
H
CH2 CH2
CH2
CH2 CH2 CH3
1
3
2
2
2.2
H
2.1
2.0
1.9
1.8
1.7
1.6
1.5
1.4
1.3
1.2
1.1
1.0
0.9
IHD = 2
There is a long-range coupling
(over 4 bonds) between the
alkyne proton and the CH2 group
10
9
8
7
6
5
ppm
4
3
Problem R-7O: C5H8
75 MHz 13C NMR spectrum
Solv: CDCl3
Source: ASV/Reich
H
2
1
0
C
H
C
210 200 190 180 170 160 150 140 130 120 110 100
ppm
90
80
70
60
50
40
30
20
10
0
Problem R-18C C10H12O
300 MHz 1H NMR spectrum in CDCl3
Source: Aldrich Spectra Viewer/Reich
IHD = 5
CH2 CH3
CH2 CH3
quartet
O
30
Ph
20
10
0
Hz
2.50 2.45 2.40
2.51
CH2
3
R
5
1.05 1.00 0.95
2
1.02
7.35 7.30 7.25 7.20 7.15
5
4
3
100
80
2
1
0
7.8
6
35.1
7
49.8
8
134.4
129.3
128.6
126.8
9
1.00
3.70 3.65 3.60
208.8
10
1.52
2
Problem R-18C: C10H12O
75 MHz 13C NMR spectrum CDCl3
Source: ASV/Reich
R
CDCl3
O
220
200
180
160
140
120
ppm
60
40
20
0
Reich
Chem 345
Problem R-18R: C5H10O2
300 MHz 1H NMR Spectrum in CDCl3
Source: Aldrich Spectral Viewer/Reich
CH2 CH3
CH2 CH2 CH3
IHD = 1
O
O
30
Propyl acetate
20
10
0
Hz
O
1.70 1.65 1.60
CH2 CH2
CH3
1.57
1.49
1.09
1.00
3
2
9
8
Problem R-18S: C5H10O2
300 MHz 1H NMR Spectrum in CDCl3
Source: Aldrich Spectral Viewer/Reich
7
6
5
ppm
3
2.05 2.00
4.05 4.00
10
4
3
2
IHD = 1
1
0
CH2 CH2 CH3
CH2 CH3
O CH3
O
CH2 CH2
O
methyl butyrate
30
20
10
0
Hz
1.7
1.00
8
7
6
5
ppm
2
4
3
0.96
0.95 0.90
2
3
2.35 2.30 2.25
3.70 3.65
9
1.6
0.66
0.64
3
10
1.00 0.95 0.90
2
2
1
0