CHEM 331 Problem Set #1: Inter-molecular Forces and Vapour ...
Chem 3013-01 Problem Set 6 Due March 9 in Classchalker.ens.utulsa.edu/chem/Teaching_files/Problem...
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Chem 3013-01 Problem Set 6 Due March 9 in Class Complete the 8 problems below on separate paper. Clearly indicate the exercise number and ensure all writing and illustrations are legible. For problems that use spectroscopic data, you may write your solution on the spectra itself. Please write your name on all pages and submit a stapled copy of your solutions. 1. Indicate the number of magnetically distinct protons in the following molecules (i.e. how many peaks do you expect in the 1 H NMR?). For each peak, predict the splitting pattern due to spin coupling (don’t forget long range coupling, where applicable). Example: 2. The indicated protons have a chemical shift of -0.6 ppm. Explain why the proton appears so far upfield and support your explanation with a clear perspective drawing of the chemical structure. CH 3 H H H H CH 3 p-Xylene has two peaks in the 1H NMR δ = 2.30 (6H, s) δ = 7.05 (4H, s) OH N H O OH O O O Cl OH Cl HO Cl Cl OH Br CH 2 δ = -0.6 ppm
Transcript of Chem 3013-01 Problem Set 6 Due March 9 in Classchalker.ens.utulsa.edu/chem/Teaching_files/Problem...
Chem 3013-01 Problem Set 6 Due March 9 in Class
Complete the 8 problems below on separate paper. Clearly indicate the exercise number and ensure all writing and illustrations are legible. For problems that use spectroscopic data, you may write your solution on the spectra itself. Please write your name on all pages and submit a stapled copy of your solutions.
1. Indicate the number of magnetically distinct protons in the following molecules (i.e. how many peaks do you expect in the 1H NMR?). For each peak, predict the splitting pattern due to spin coupling (don’t forget long range coupling, where applicable). Example:
2. The indicated protons have a chemical shift of -0.6 ppm. Explain why the proton appears
so far upfield and support your explanation with a clear perspective drawing of the chemical structure.
CH3
HH
H HCH3
p-Xylene has two peaks in the 1H NMR
δ = 2.30 (6H, s)δ = 7.05 (4H, s)
OH NH
O
OHO
O
O
ClOH
Cl
HO
ClClOH
Br
CH2 δ = -0.6 ppm
3. A compound with the molecular formula C6H10O2 has the following IR, 1H, and 13C spectra. Propose a structure for the compound that is consistent with this data. Justify your proposal with reference to appropriate absorption bands, chemical shifts, and spin coupling.
IR (neat):
1H (90 MHz, CDCl3): 1.30 (3H, t, J = 7.1), 1.94 (3H, t, J = 1.3), 4.21 (2H, q, J = 7.1), 5.54 (1H, m), 6.10 (1H, m)
13C (25 MHz, CDCl3): 14.3, 18.3, 60.7, 125.1, 136.7, 167.5
4. A compound with the molecular formula C3H5NO has the following IR, 1H, and 13C spectra. Propose a structure for the compound that is consistent with this data. Justify your proposal with reference to appropriate absorption bands, chemical shifts, and spin coupling.
IR (neat):
1H (90 MHz, CDCl3): 2.61 (2H, t, J = 6.1 Hz), 3.44 (1H, s), 3.85 (2H, t, J = 6.1 Hz)
13C (25 MHz, CDCl3): 21.4, 57.4, 118.9
5. A compound with the molecular formula C10H14O2 has the following IR, 1H, and 13C spectra. Propose a structure for the compound that is consistent with this data. Justify your proposal with reference to appropriate absorption bands, chemical shifts, and spin coupling. IR (KBr disc):
1H (90 MHz, CDCl3): 1.37 (3H, t, J = 7.0), 3.96 (2H, q, J = 7.0), 6.81 (4H, s)
13C (25 MHz, CDCl3): 15.0, 64.0, 115.4, 153.1
6. A compound with the molecular formula C4H6O has the following IR, 1H, and 13C spectra. Propose a structure for the compound that is consistent with this data. Justify your proposal with reference to appropriate absorption bands, chemical shifts, and spin coupling. IR (neat):
1H (90 MHz, CDCl3): 2.03 (3H, dd, J = 1.5, 6.8), 6.15 (1H, dd, J = 7.8, 15.5), 6.88 (1H, m), 9.50 (1H, d, 7.8)
13C (25 MHz, CDCl3): 18.6, 134.6, 154.3, 194.0
7. 1H, 13C, COSY, and HSQC spectra are provided for the following compound (see attached).
Fully assign all peaks the 1H and 13C spectra with this information, clearly indicating your assignments on the spectra provided.
8. 1H, 13C, DEPT-135, COSY, and HSQC spectra are provided for the following compound (see attached).
Assign peaks the 1H and 13C spectra as fully as possible, clearly indicating your assignments on the spectra provided. Specify the stereochemistry at carbon 1 based on this information (see numbering above).
H2N
N3
OH
O
O
N3NHAcAcO
AcOOAc
123
4 5
6
1 H N
MR
(400
MH
z, D
2O):!1
.99
(2H
, m),
3.44
(2H
, m),
3.69
(1H
, dd,
J =
5.6
, 7.2
). (P
eak
at 4
.68
is D
OH
from
the
solv
ent)
H 2
N
N 3
OH
O
13C
NM
R (1
00 M
Hz,
D2O
)
H 2
N
N 3
OH
O
CO
SY
H 2N
N 3
OH
O
HS
QC
H 2N
N 3
OH
O
1 H N
MR
(400
MH
z, C
DC
l 3): 1
.96,
2.0
1, 2
.02,
2.0
8 (3
H e
ach,
s),
3.82
(1H
, ddd
, J =
9.9
, 4.9
, 2.3
), 3.
92 (1
H, q
, J
= 9.
4), 4
.15
(1H
, dd,
J =
12.
3, 2
.3),
4.25
(1H
, dd,
J =
12.
3, 4
.9),
4.80
(1H
, d, J
= 9
.4),
5.08
(1H
, t, J
= 9
.9),
5.27
(1H
, t, J
= 9
.9),
6.24
(1
H, d
, J =
9.4
).
(Pea
k at
7.2
7 is
CH
Cl 3
from
sol
vent
)
O
N 3NH
AcAcO
AcO
OAc
13C
NM
R (1
00 M
Hz,
CD
Cl 3)
: 20.
57, 2
0.62
, 20.
7, 2
3.18
, 54.
0, 6
1.9,
68.
2, 7
2.1,
73.
8, 8
8.3,
169
.3, 1
70.6
7,
170.
72, 1
70.9
. (T
riple
t at 7
7.0
is C
DC
l 3 pe
ak)
O
N 3NH
AcAcO
AcO
OAc
DE
PT-
135
O
N 3NH
AcAcO
AcO
OAc
CO
SY
O
N 3NH
AcAcO
AcO
OAc
HS
QC
O
N 3NH
AcAcO
AcO
OAc
