1H and 13C NMR spectral assignments of naphthalenyl chalcone derivatives

Full text of DOI:10.1002/mrc.4458

Letter - spectral assignment
Received: 14 March 2016
Revised: 2 May 2016
Accepted: 7 May 2016
Published online in Wiley Online Library
(wileyonlinelibrary.com) DOI 10.1002/mrc.4458
1
13
H and C NMR spectral assignments of
naphthalenyl chalcone derivatives
Dongsoo Koh,a† Yearam Jung,b† Beom Soo Kim,b Seunghyun Ahnb**
and Yoongho Limb*
Keywords: phenylnaphthalenylpropenone; chalcone; NMR; 1H NMR; 13C NMR; HR/MS
the synthesis of derivatives 25–30 by reacting methoxy-
substituted-2-hydroxyacetophenone (I) with 2-naphthylaldehyde
Introduction
Cellular homeostasis of reduction and oxidation is maintained by
the elimination and generation of reactive oxygen species
(ROS).[1] In cancer cells, the amount of ROS produced by glycolysis
is higher than that of normal cells. As a result, ROS generation is
more lethal to cancer cells than normal cells. This phenomenon
has been applied to the development of chemotherapeutic agents.
Compounds generating ROS can be potent anticancer drugs and
selectively kill cancer cells.[2,3] ROS consist of hydroxy radicals,
hydrogen peroxide, and superoxide.[4] Many ROS-generating natu-
ral compounds are known, including curcumin, piperlongumine,
chalcone, and cinnamaldehyde[2,5–7] (Fig. 1A). All these compounds
contain a Michael acceptor moieties, which are known to generate
ROS.[8] The ability to generate ROS depends upon the aromatic
rings or substituents attached to the α,β-unsaturated carbonyl
group, as shown in inset of Fig. 1A.[9] We designed compounds con-
taining α,β-unsaturated carbonyl groups with a 2-hydroxyphenyl
substituent attached to the ketone carbon and a naphthalenyl
group attached to the beta carbon (Fig. 1B) and synthesized 30
naphthalenyl chalcone derivatives. Their complete 1H and 13C
Nuclear magnetic resonance (NMR) data and high-resolution mass
spectrometric (HRMS) data are reported here as references for iden-
tifying newly synthesized derivatives or those isolated from natural
sources in the future.
(III). These syntheses are summarized in Scheme 1.
NMR spectra
The synthesized naphthalenyl chalcone derivatives were dissolved
in deuterated dimethyl sulfoxide (DMSO-d6). NMR samples were
prepared inside 2.5mm NMR tubes with approximately 100 mM
concentration. All NMR data were collected on an Avance 400
spectrometer system (9.4T; Bruker, Karlsruhe, Germany) at room
temperature, and chemical shifts were referenced to
tetramethylsilane (at 0 ppm). 1H NMR experiments were performed
with the following parameters: relaxation delay, 1 s; 90° pulse,
11.8 μs; spectral width, 5500Hz; number of data points, 32 k; and
digital resolution, 0.34 Hz/point. The same parameters for 13C
NMR and distortionless enhancement by polarization transfer ex-
periments were 3 s, 15.0μs, 21,000 Hz, 64K, and 0.64Hz/point, re-
spectively. Two-dimensional experiments, including correlation
spectroscopy (COSY), nuclear Overhauser exchange spectroscopy
(NOESY), heteronuclear multiple quantum correlation (HMQC),
and heteronuclear multiple bond correlation (HMBC), were
acquired with data points of 2 k × 256 (t2 × t1). The long-range cou-
pling time for HMBC was 70 ms, and the mixing time for NOESY was
1.5 s. The processing and analysis of NMR data were undertaken as
previously reported.[10]
Experimental
General experimental procedures
To confirm the structures of the naphthalenyl chalcone derivatives,
high-resolution electron impact ionization mass spectrometry was
Syntheses
The general synthetic procedure is described later, using the prepa-
ration of compound 11 as an example of derivatives 1–24. To a
solution of 4,6-dimethoxy-2-hydroxyacetophenone (I, 10 mmol,
1.96 g) in ethanol (50 mL) was added an equimolar amount of
2-methoxy-1-naphthaldehyde (II, 10 mmol, 1.86 g), and the temper-
ature was adjusted to 0–4 °C in an ice-bath. To the cooled reaction
mixture was added 50% (w/v) aqueous KOH solution (10 mL). The
reaction mixture was stirred at room temperature for 24 h and mon-
itored using thin-layer chromatography. At reaction completion, ice
water was added to the mixture, before acidifying with 6 N HCl
(pH = 3–4). The precipitate was filtered and washed with water and
ethanol. The crude solid was purified by recrystallization from etha-
nol to afford the pure chalcone compound (11, m.p. 121–123 °C,
51% yield). The general method described earlier was applied to
*
Correspondence to: Yoongho Lim, Division of Bioscience and Biotechnology,
Konkuk University, Hwayang-Dong 1, Kwangjin-Ku, Seoul 143-701, Korea.
E-mail: yoongho@konkuk.ac.kr
** Correspondence to: Seunghyun Ahn, Bio/Molecular Informatics Center,
Konkuk University, Hwayang-Dong 1, Kwangjin-Ku, Seoul 143-701, Korea.
E-mail: mistahn321@naver.com
†
D. Koh and Y. Jung contributed equally to this work.
a Department of Applied Chemistry, Dongduk Women’s University, Seoul 136-714,
Korea
b Division of Bioscience and Biotechnology, BMIC, Konkuk University, Seoul 143-701,
Korea
Magn. Reson. Chem. 2016
Copyright © 2016 John Wiley & Sons, Ltd.

D. Koh et al.
6.94 and 7.15 ppm in the COSY spectrum. These protons should
belong to the phenyl ring. Because the proton peak at 7.15 ppm
showed a doublet of doublet whose coupling constants were 9.0
and 3.1 Hz in the 1H-NMR spectrum, it was assigned H-4. The proton
peak at 7.35 ppm was determined to be H-6 because it was
long-range coupled to the ketone carbon. The remained proton
peak at 6.94ppm was H-3. The carbon peak at 155.1ppm showing
two long-ranged couplings with H-4 and H-6 should be C-2. H-3
showed two long-ranged couplings with two carbon peaks at
121.7 and 151.7 ppm. More deshielded 13C peak was assigned C-5
because of the methoxy group and more shielded 13C peak was
determined to be C-1. Because C-5 showed a long-ranged coupling
with the methoxy proton at 3.74ppm, this proton was assigned
5-OMe. The carbon peak at 115.9 ppm showing a long-ranged
coupling with H-α was assigned C-1’. Of two 13C peaks at 132.2
and 157.9 ppm showing long-ranged couplings with H-β, more
deshielded 13C peak was assigned C-2’ because of the methoxy
group, and another was determined to be C-9’. C-2’ was confirmed
by the long-ranged coupling with the methoxy proton at 4.02 ppm.
At the same time, 2’-OMe was determined because the carbon peak
at 56.4ppm was attached directly to the methoxy proton at
4.02 ppm in the HMQC spectrum. Among the remained carbons
of nephthalenyl group, the 13C peak at 128.5 ppm was a singlet car-
bon, so that it should be C-10’. Of six protons attached directly to
the remained carbons mentioned earlier, two protons at 7.52 and
8.04 ppm were correlated in COSY, and they showed same coupling
Figure 1. Structures of (A) curcumin, piperlongumine, chalcone, and
cinnamaldehyde, and (B) (E)-1-(2-hydroxyphenyl)-3-naphthalenylprop-2-
en-1-one.
1
constants (9.7Hz) in the H-NMR spectrum. As a result, they were
performed on a JMS700 spectrometer (JEOL, Tokyo, Japan) at the
Korea Basic Science Institute, Daegu, Korea.[11]
assigned H-3’ and/or H-4’. Because they showed long-ranged cou-
plings with C-1’ and C-2’, respectively, they were determined to
be H-3’ and H-4’, respectively. The 13C peak at 128.8 ppm showing
a long-ranged coupling with H-4’ was assigned C-5’. The proton
peak at 8.19 ppm showing two long-ranged couplings with C-10’
and C-1’ should be H-8’. Because C-5’ was long-range coupled to
the 1H peak at 7.57 ppm, it was assigned H-7’. Because the 1H peak
at 7.41 ppm was long-range coupled to C-10’ (128.5ppm) and C-8’
(122.8 ppm), it was assigned H-6’. Becuase six protons of the
naphthalenyl group were correlated in the COSY spectrum, the ear-
lier assignments were confirmed. Only one proton peak at
10.75ppm was determined to be 2-OH. Important correlations
obtained from the COSY and HMBC spectra of derivative 8 are
shown in Fig. 2. The NMR data of other derivatives (1–7 and
9–24) containing naphthalen-1-yl groups were assigned in a similar
Results and Discussion
All naphthalenyl chalcone derivatives are listed in Table 1. Twenty-
four derivatives (1–24) contain naphthalen-1-yl groups, while six
derivatives (25–30) have naphthalen-2-yl group. The procedures
for assigning derivative 8 (containing naphthalen-1-yl), and deriva-
tive 29 (containing naphthalen-2-yl) are given later as examples.
The most deshielded 13C peak, at 193.0 ppm of derivative 8, was
the ketone carbon, which had a long-range coupling with three
protons at 8.01, 8.35, and 7.35 ppm in the HMBC spectrum. Two
protons with peaks at 8.01 and 8.35 ppm were directly attached
to the two carbons at 127.2 and 136.8 ppm, respectively, in the
HMQC spectrum, and assigned as H-α/C-α and H-β/C-β, respec-
tively, because their coupling constants (15.7Hz) showed a cou-
pling relationship between vicinal protons at the trans position.
The proton peak at 7.35 ppm was correlated with other protons at
1
fashion to derivative 8. Complete assignments of the H and 13C
NMR data for derivatives containing naphthalen-1-yl groups
(1–24) are listed in Tables 2 and 3, respectively.
Likewise, the NMR data of derivative 29 were assigned as follows:
the most deshielded 13C peak, at 192.2 ppm, was the ketone
Scheme 1. Procedure for the preparation of naphthalenyl chalcones 1–30.
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Magn. Reson. Chem. 2016

NMR spectral assignments of naphthalenyl chalcones
Table 1. Structures, names, and high-resolution mass spectrometric data of naphthalenyl chalcones 1–30
Derivative
R1
R2
R3
R4
R5
R6
Mass
Name
(calcd./found)
1
2
3
4
5
6
7
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
OCH3
H
H
H
274.0994/274.0992
304.1099/304.1103
304.1099/304.1101
334.1205/334.1201
334.1205/334.1201
304.1099/304.1101
304.1099/304.1096
(E)-1-(2-hydroxyphenyl)-3-
(naphthalen-1-yl)prop-2-en-1-one
(E)-1-(2-hydroxy-5-methoxyphenyl)-
3-(naphthalen-1-yl)prop-2-en-1-one
(E)-1-(2-hydroxy-6-methoxyphenyl)-
3-(naphthalen-1-yl)prop-2-en-1-one
(E)-1-(2-hydroxy-4,5-dimethoxyphenyl)-
3-(naphthalen-1-yl)prop-2-en-1-one
(E)-1-(2-hydroxy-4,6-dimethoxyphenyl)-
3-(naphthalen-1-yl)prop-2-en-1-one
(E)-1-(2-hydroxy-4-methoxyphenyl)-3-
(naphthalen-1-yl)prop-2-en-1-one
(E)-1-(2-hydroxyphenyl)-3-(2-
methoxynaphthalen-1-yl)prop-2-en-
1-one
OCH3
H
OCH3
OCH3
OCH3
H
OCH3
H
OCH3
H
H
OCH3
OCH3
OCH3
OCH3
OCH3
OCH3
H
H
H
8
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
OCH3
H
H
334.1205/334.1204
334.1205/334.1207
364.1311/364.1313
364.1311/364.1312
334.1205/334.1205
304.1099/304.1101
334.1205/334.1202
334.1205/334.1201
364.1311/364.1310
364.1311/364.1314
334.1205/334.1206
(E)-1-(2-hydroxy-5-methoxyphenyl)-3-
(2-methoxynaphthalen-1-yl)prop-2-
en-1-one
9
H
OCH3
H
(E)-1-(2-hydroxy-6-methoxyphenyl)-3-
(2-methoxynaphthalen-1-yl)prop-2-
en-1-one
10
11
12
13
14
15
16
17
18
OCH3
OCH3
OCH3
H
OCH3
H
(E)-1-(2-hydroxy-4,5-dimethoxyphenyl)-
3-(2-methoxynaphthalen-1-yl)prop-
2-en-1-one
OCH3
H
(E)-1-(2-hydroxy-4,6-dimethoxyphenyl)-
3-(2-methoxynaphthalen-1-yl)prop-
2-en-1-one
H
(E)-1-(2-hydroxy-4-methoxyphenyl)-3-
(2-methoxynaphthalen-1-yl)prop-
2-en-1-one
OCH3
OCH3
OCH3
OCH3
OCH3
OCH3
H
H
(E)-1-(2-hydroxyphenyl)-3-(4-
methoxynaphthalen-1-yl)prop-2-en-
1-one
H
H
OCH3
H
H
(E)-1-(2-hydroxy-5-methoxyphenyl)-3-
(4-methoxynaphthalen-1-yl)prop-2-
en-1-one
H
H
OCH3
H
(E)-1-(2-hydroxy-6-methoxyphenyl)-3-
(4-methoxynaphthalen-1-yl)prop-2-
en-1-one
H
OCH3
OCH3
OCH3
OCH3
H
(E)-1-(2-hydroxy-4,5-dimethoxyphenyl)-
3-(4-methoxynaphthalen-1-yl)prop-
2-en-1-one
H
OCH3
H
(E)-1-(2-hydroxy-4,6-dimethoxyphenyl)-
3-(4-methoxynaphthalen-1-yl)prop-
2-en-1-one
H
H
(E)-1-(2-hydroxy-4-methoxyphenyl)-3-
(4-methoxynaphthalen-1-yl)prop-
2-en-1-one
19
20
OCH3
OCH3
OCH3
OCH3
H
H
H
H
H
H
H
334.3652/334.1205
364.1311/364.1309
(E)-3-(2,3-dimethoxynaphthalen-1-yl)-
1-(2-hydroxyphenyl)prop-2-en-1-one
OCH3
(Continues)
Magn. Reson. Chem. 2016
Copyright © 2016 John Wiley & Sons, Ltd.
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D. Koh et al.
Table 1. (Continued)
Derivative
R1
R2
R3
R4
R5
R6
Mass
Name
(calcd./found)
(E)-3-(2,3-dimethoxynaphthalen-1-yl)-
1-(2-hydroxy-5-methoxyphenyl)prop-
2-en-1-one
21
22
23
24
OCH3
OCH3
OCH3
OCH3
OCH3
OCH3
OCH3
OCH3
H
H
H
H
H
H
OCH3
H
OCH3
H
364.1311/364.1310
394.1416/394.1415
394.1416/394.1414
364.1311/364.1312
(E)-3-(2,3-dimethoxynaphthalen-1-yl)-
1-(2-hydroxy-6-methoxyphenyl)prop-
2-en-1-one
OCH3
OCH3
OCH3
(E)-3-(2,3-dimethoxynaphthalen-1-yl)-
1-(2-hydroxy-4,5-
dimethoxyphenyl)prop-2-en-1-one
(E)-3-(2,3-dimethoxynaphthalen-1-yl)-
1-(2-hydroxy-4,6-
OCH3
H
dimethoxyphenyl)prop-2-en-1-one
(E)-3-(2,3-dimethoxynaphthalen-1-yl)-
1-(2-hydroxy-4-
H
methoxyphenyl)prop-2-en-1-one
Derivative
R1
R2
R3
Mass (calcd./found)
Name
25
26
27
28
29
30
H
H
H
H
274.0994/274.0991
304.1099/304.1101
304.1099/304.1098
334.1205/334.1202
334.1205/334.1205
304.1099/304.1096
(E)-1-(2-hydroxyphenyl)-3-(naphthalen-2-yl)prop-2-en-1-one
H
OCH3
H
(E)-1-(2-hydroxy-5-methoxyphenyl)-3-(naphthalen-2-yl)prop-2-en-1-one
(E)-1-(2-hydroxy-6-methoxyphenyl)-3-(naphthalen-2-yl)prop-2-en-1-one
(E)-1-(2-hydroxy-4,5-dimethoxyphenyl)-3-(naphthalen-2-yl)prop-2-en-1-one
(E)-1-(2-hydroxy-4,6-dimethoxyphenyl)-3-(naphthalen-2-yl)prop-2-en-1-one
(E)-1-(2-hydroxy-4-methoxyphenyl)-3-(naphthalen-2-yl)prop-2-en-1-one
H
OCH3
H
OCH3
OCH3
OCH3
OCH3
H
OCH3
H
H
carbon. As mentioned earlier, H-α (7.78 ppm) and H-β (7.84 ppm)
were determined based on the long-range couplings with the
ketone carbon peak in the HMBC spectrum and coupling constants
(15.7Hz) in the 1H-NMR spectrum. The 1H peak at 13.39 ppm should
be hydroxyl proton, 2-OH. Because it had long-range couplings
with three carbon peaks at 93.9, 106.4, and 165.5 ppm, they had
possible assignments of C-1, C-2, and/or C-3 (Fig. 3). Of these carbon
peaks, most deshielded peak at 165.5 ppm was assigned C-2
because it was attached to oxygen directly. The 13C peak at 93.9
was attached directly to the 1H peak at 6.12 ppm in HMQC, so that
it was determined to be C-3. As a result, the remained carbon peak
was C-1. Because the 1H peak at 6.14 ppm showed a cross peak with
H-3 (6.12 ppm) in the COSY spectrum and its coupling constant was
the same as H-3 (2.3Hz), it was assigned H-5. Two methoxy carbons
at 55.7 and 56.2 ppm and two methoxy protons at 3.82 and
3.89 ppm were observed at the 13C-NMR and 1H-NMR spectra,
respectively. To distinguish the two methoxy proton peaks, a
NOESY experiment was carried out, which revealed a cross peak
between 3.89 ppm and 7.84 ppm (H-β) (Fig. 4). Only the 6-OMe
protons were able to have an nOe correlation with H-β, thus, the
peak at 3.89 ppm was determined to be 6-OMe. The remained
proton peak at 3.82 ppm should be 4-OMe. Because two methoxy
protons at 3.82 and 3.89 ppm showed long-range couplings with
two carbons at 165.6 and 161.9ppm, respectively, these carbons
were assigned C-4 and C-6, respectively. The 13C peak at
132.4ppm showing long-range couplings with H-α was assigned
C-2’. Two carbon peaks at 123.8 and 130.4 ppm were long-range
coupled to H-β. Therefore, they could be assigned C-1’ and/or
C-3’. Two protons at 7.85 and 8.17 ppm were directly attached to
the above carbons, respectively in HMQC. Among nine carbons of
Figure 2. Important correlations obtained from the correlation
spectroscopy (COSY) and heteronuclear multiple bond correlation (HMBC)
spectra of derivative 8.
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Copyright © 2016 John Wiley & Sons, Ltd.
Magn. Reson. Chem. 2016

NMR spectral assignments of naphthalenyl chalcones
Magn. Reson. Chem. 2016
Copyright © 2016 John Wiley & Sons, Ltd.
wileyonlinelibrary.com/journal/mrc

D. Koh et al.
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Copyright © 2016 John Wiley & Sons, Ltd.
Magn. Reson. Chem. 2016

NMR spectral assignments of naphthalenyl chalcones
Magn. Reson. Chem. 2016
Copyright © 2016 John Wiley & Sons, Ltd.
wileyonlinelibrary.com/journal/mrc

D. Koh et al.
Table 3. 13C NMR chemical shifts of naphthalenyl chalcones 1–30
Position
1
2
3
4
5
6
7
8
9
10
C¼O
193.0
131.1
126.0
125.7
131.0
128.8
126.3
127.3
122.9
131.2
133.4
121.0
161.7
117.7
136.3
119.2
130.9
124.4
140.4
—
192.8
131.1
126.1
125.7
131.1
128.8
126.3
127.3
122.9
131.2
133.4
121.0
155.8
118.7
123.9
151.8
113.3
124.8
140.4
—
194.1
130.8
125.8
125.5
130.7
128.8
126.3
127.2
122.5
131.1
133.3
115.4
157.5
109.1
132.3
102.4
158.3
130.7
139.8
—
191.2
131.2
126.1
125.6
131.0
128.8
126.3
127.2
122.9
131.2
133.3
111.8
160.8
100.6
157.1
142.0
112.0
124.0
139.8
—
192.1
131.0
125.8
125.5
130.5
128.8
126.3
127.2
123.1
131.4
133.4
106.3
165.8
93.9
191.6
131.1
126.0
125.7
131.0
128.8
126.3
127.3
122.9
131.2
133.4
113.9
165.7
101.0
166.1
107.5
132.8
123.7
139.8
—
193.7
115.7
157.6
113.5
132.7
128.9
124.0
128.0
122.7
132.3
128.6
121.4
161.3
117.7
135.9
119.3
130.4
126.3
137.1
56.5
193.0
115.9
157.9
113.5
132.5
128.8
123.9
127.9
122.8
132.2
128.5
121.7
155.1
118.7
123.2
151.7
112.7
127.2
136.8
56.4
194.6
115.6
157.0
113.5
132.6
128.9
123.9
127.8
122.3
132.5
128.6
115.2
158.0
109.2
132.2
102.4
158.5
132.0
136.6
56.4
191.7
116.2
157.1
113.4
132.2
128.8
123.9
127.8
122.9
132.3
128.8
111.2
160.3
100.7
156.7
141.8
111.9
126.3
136.5
56.1
1’
2’
3’
4’
5’
6’
7’
8’
9’
10’
1
2
3
4
165.8
91.2
5
6
162.0
130.1
138.4
—
α
β
2’-OMe
4-OMe
5-OMe
6-OMe
—
—
—
56.0
55.7
55.8
—
—
—
56.0
—
55.9
—
56.6
—
—
—
55.5
—
56.4
—
—
55.8
—
56.3
—
—
—
55.9
—
NMR, Nuclear magnetic resonance.
(Continues)
Table 3. Continued
Position
11
12
13
14
15
16
17
18
19
20
C¼O
192.6
116.2
157.1
113.4
132.1
128.8
123.8
127.7
122.8
132.1
128.7
106.3
165.7
94.0
192.1
115.8
157.4
113.4
132.3
128.8
123.9
127.9
122.7
132.2
128.6
114.1
165.5
101.0
165.8
107.5
132.6
125.4
136.6
56.5
193.3
123.1
127.7
104.8
157.6
122.3
125.8
128.0
122.7
123.3
124.8
121.1
161.9
117.7
136.1
119.1
130.8
120.8
140.7
—
192.8
123.6
127.8
104.7
157.5
122.3
125.7
127.9
122.7
132.3
124.8
121.5
156.0
118.6
123.1
151.7
113.3
120.8
140.6
—
194.0
123.1
126.9
104.8
157.0
122.3
125.7
127.8
122.3
131.9
124.8
115.6
157.4
109.1
132.1
102.3
158.3
128.2
140.0
—
191.2
123.2
127.6
104.6
157.3
122.2
125.7
127.9
122.7
132.3
124.7
111.7
160.8
100.6
156.8
141.8
112.1
121.0
139.8
—
192.0
123.9
127.4
104.8
157.0
122.2
125.8
127.9
122.9
132.1
124.8
106.3
165.5
93.9
191.7
123.2
127.6
104.7
157.4
122.2
125.7
127.9
122.7
132.3
124.8
113.9
165.7
101.0
165.9
107.4
132.6
120.6
139.9
—
192.8
123.6
148.8
151.4
110.0
128.7
125.6
125.1
123.6
127.4
131.2
121.7
161.1
117.7
136.0
119.4
130.6
126.7
136.9
60.5
192.6
123.8
148.7
151.5
109.8
127.4
125.6
125.0
123.4
126.7
131.2
121.9
154.9
118.8
123.7
151.8
112.8
129.4
136.7
60.5
1’
2’
3’
4’
5’
6’
7’
8’
9’
10’
1
2
3
4
166.1
91.2
165.8
91.1
5
6
162.0
131.6
135.3
56.4
161.9
127.0
138.7
—
α
β
2’-OMe
3’-OMe
4’-OMe
4-OMe
5-OMe
6-OMe
—
—
—
—
—
—
—
—
55.8
—
55.8
—
—
—
56.1
56.0
55.9
55.9
55.9
56.0
55.7
55.7
—
—
—
56.0
55.7
55.7
—
—
—
—
—
55.9
—
56.5
—
—
—
55.6
56.2
—
—
—
55.8
—
56.2
—
—
—
(Continues)
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Copyright © 2016 John Wiley & Sons, Ltd.
Magn. Reson. Chem. 2016

NMR spectral assignments of naphthalenyl chalcones
Table 3. Continued
Position
21
22
23
24
25
26
27
28
29
30
C¼O
194.3
123.5
148.4
151.8
109.7
127.5
125.6
124.9
123.2
126.4
131.2
115.1
157.9
109.2
132.6
102.3
158.5
134.2
136.7
60.4
191.2
124.1
148.4
151.5
109.7
127.4
125.6
125.0
123.8
126.7
131.1
111.3
160.3
100.7
156.8
141.9
112.0
128.5
136.5
60.5
192.3
123.9
148.6
151.5
109.7
127.5
125.6
124.9
123.5
126.6
131.3
106.2
165.7
94.0
191.3
123.7
148.7
151.5
109.9
127.4
125.6
125.1
123.7
126.7
131.1
114.2
165.4
101.1
166.4
107.6
132.4
127.6
136.8
60.5
193.6
131.2
132.1
124.5
128.5
127.7
127.6
126.8
128.6
132.9
134.1
120.8
161.9
117.7
136.3
119.2
130.9
122.1
144.8
—
193.1
131.2
132.2
124.5
128.5
127.7
127.6
126.8
128.6
132.9
134.1
120.8
156.0
118.7
123.8
151.8
113.6
122.4
144.8
—
194.4
130.4
132.0
123.9
128.6
128.6
127.7
126.8
128.7
132.9
133.8
115.7
157.0
109.0
131.8
102.3
158.1
128.5
143.8
—
191.4
131.1
132.3
124.6
128.4
127.7
127.5
126.8
128.6
132.9
134.0
111.8
160.9
100.6
157.1
141.9
112.3
121.6
144.1
—
192.2
130.4
132.4
123.8
128.5
127.7
127.4
126.8
128.6
133.0
133.8
106.4
165.5
93.9
191.8
131.0
132.2
124.5
128.5
127.7
127.5
126.8
128.6
132.9
134.0
113.9
165.8
100.9
166.0
107.5
132.7
121.5
144.1
—
1’
2’
3’
4’
5’
6’
7’
8’
9’
10’
1
2
3
4
165.9
91.3
165.6
91.1
5
6
162.1
133.3
135.1
60.5
161.9
127.8
142.4
—
α
β
2’-OMe
3’-OMe
4-OMe
5-OMe
6-OMe
55.7
55.8
55.8
55.8
—
—
—
—
—
—
—
—
—
—
—
—
—
56.0
55.7
55.8
—
—
—
—
—
56.0
—
56.8
—
—
—
—
—
—
—
55.8
—
56.2
—
naphthalenyl group except C-2’ determined above, two carbons at
133.0 and 133.8ppm were singlet carbons. Because both two pro-
tons at 7.85 and 8.17 ppm attached to two carbon peaks at 123.8
and 130.4 ppm showed long-range couplings with the carbon peak
at 133.8ppm, this carbon should be C-10’. As a result, the remained
carbon peak at 133.0 ppm was C-9’. The correlations of three pro-
tons at 8.17 (1.6Hz), 7.85 (1.6, 8.6 Hz), and 7.94 (8.6Hz) ppm were
observed the COSY spectrum, and their coupling constants were
1
determined by the H-NMR spectrum. Also, their corresponding
carbons were determined to be 130.4, 123.8, and 128.5 ppm, re-
spectively by the HMQC spectrum. Becuase the proton peak at
1
7.85 ppm showed a doublet of doublet in the H-NMR spectrum,
it was assigned H-3’. Therefore, the proton peak at 8.17 ppm show-
ing the long-ranged coupling with C-10’ was determined to be H-1’.
Among three protons at 8.17, 7.85, and 7.94 ppm, the remained
proton at 7.94 ppm was H-4’. The 13C peak at 127.7 ppm showing
a long-ranged coupling with H-4’ was assigned C-5’. Likewise, the
13C peak at 128.6 ppm showing a long-ranged coupling with H-1’
was assigned C-8’. Because two proton peaks at 7.53 and
7.55 ppm showed long-ranged couplings with the carbon peaks
at C-5’ and C-8’, respectively, they were determined to be H-7’
and H-6’, respectively. Important correlations obtained from the
COSY and HMBC spectra of derivative 29 are shown in Fig. S1.
The complete assignments of 1H and 13C NMR data for derivative
25–28 and 30 are listed in Tables 2 and 3, respectively. To confirm
the results obtained from the NMR data, HRMS was carried out. The
calculated molecular masses and data from the HRMS experiments
are listed in Table 1. Additionally, all NMR data obtained here
were compared with the NMR data of previously reported
2’-hydroxychalcones, naphthalenyl-phenyl-pyrazolines and 2’-hy-
droxy-methoxychalcones.[12–14] All data provided here will aid the
future identification of new naphthalenyl chalcone derivatives. All
Figure 3. Partial heteronuclear multiple bond correlation spectrum of
derivative 29 showing long-range couplings between 2-OH (13.39 ppm)
and C-2 (165.5 ppm), and C-1 (106.4 ppm), and C-3 (93.9 ppm). Whole
heteronuclear multiple bond correlation spectrum is provided as Fig. S2.
Magn. Reson. Chem. 2016
Copyright © 2016 John Wiley & Sons, Ltd.
wileyonlinelibrary.com/journal/mrc

D. Koh et al.
Development Administration), and Basic Science Research Program
through the National Research Foundation of Korea (NRF-
2013R1A1A2005214).
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Figure 4. Partial nuclear Overhauser exchange spectroscopy spectrum of
derivative 29 showing an nOe cross peak between H-β (7.84 ppm) and 6-
OMe (3.89 ppm). Whole nuclear Overhauser exchange spectroscopy
spectrum is provided as Fig. S3.
1H and 13C NMR spectra, and HRMS spectra are provided in the sup-
plementary material.
Supporting information
Additional supporting information may be found in the online ver-
sion of this article at the publisher’s web site.
Acknowledgments
This work was supported by the Priority Research Centers Program
(NRF, 2009-0093824), Cooperative Research Program for Agricul-
ture Science & Technology Development (PJ01130302, Rural
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Copyright © 2016 John Wiley & Sons, Ltd.
Magn. Reson. Chem. 2016