Complete assignments of 1H and 13C NMR data for 21 naphthalenyl-phenyl-pyrazoline derivatives

Article abstract of DOI:10.1002/mrc.3981

To find potent new chemotherapy drugs, we designed and synthesized a series of naphthochalcones bearing naphthalenyl-phenyl-pyrazoline moieties. The complete ¹H and ¹³C NMR data for these compounds are reported here and can be used t

Full text of DOI:10.1002/mrc.3981

MRC Letters
Received: 2 May 2013
Revised: 28 May 2013
Accepted: 29 May 2013
Published online in Wiley Online Library
(wileyonlinelibrary.com) DOI 10.1002/mrc.3981
1
13
Complete assignments of H and C NMR
data for 21 naphthalenyl-phenyl-pyrazoline
derivatives
Doseok Hwang,a Hyuk Yoon,a Seunghyun Ahn,b Dong-Wook Kim,c
Dong-Ho Bae,a Dongsoo Kohb and Yoongho Lima*
To find potent new chemotherapy drugs, we designed and synthesized a series of naphthochalcones bearing naphthalenyl-
phenyl-pyrazoline moieties. The complete 1H and 13C NMR data for these compounds are reported here and can be
used to identify further new naphthochalcones bearing the desired pyrazoline moieties. Copyright © 2013 John Wiley
& Sons, Ltd.
Supporting information may be found in the online version of this article.
1
Keywords: NMR; H NMR; 13C NMR; 2D NMR; flavonoid; naphthochalcone; pyrazoline
phenyl-pyrazolines synthesized in this study. These NMR data can
help us to identify newly isolated or synthesized naphthochalcones
Introduction
Chalcones are secondary plant metabolites that belong to the
flavonoids and have a C6-C3-C6 skeleton (Fig. 1A). Unlike most
flavonoids consisting of A-, C-, and B-rings, chalcones have an
α,β-unsaturated carbonyl group instead of a closed C-ring, as
shown in Fig. 1B. They are made by chalcone synthase in the
biosynthetic pathway of plants or synthesized via the aldol con-
densation of acetophenone and benzaldehyde. Chalcones have
antibacterial and antimalarial properties, activate nuclear factor
erythroid 2 p45-related factor 2 and a basic-leucine zipper
transcription factor in cytoplasm, and inhibit the activity of
nuclear factor kappa-light-chain-enhancer in activated B cells
(NF-κB).[1–4] Given these diverse biological activities, various
chalcones have been isolated from natural sources and
synthesized. Several chalcones inhibit NF-κB on HCT116 human
colorectal cancer cells via tumor necrosis factor alpha (TNFα).[5]
The effects of 2',4'-dihydroxy-6'-methoxy-3',5'-dimethylchalcone
on cell proliferation, cell cycle distribution, and programmed cell
death in cultures of human colorectal carcinoma HCT116 have
been described.[6] The cytotoxic effects of 2',5'-dihydroxychalcone
on HCT116 have also been evaluated.[7] Because compounds
containing pyrazoline moieties show anti-colon cancer activity,[8]
we tried to replace the α,β-unsaturated carbonyl group of chalcone
with a pyrazoline, as shown in Fig. 1C. Another class of
flavonoids, naphthoflavones (benzoflavones), has an additional
benzene ring attached to the A-ring of flavone (Fig. 1D).
Recently, 7,8-benzoflavone was identified as a potent inhibitor
of the breast cancer resistance protein,[9,10] and the effects of
5,6-benzoflavone on chemically-induced mammary carcinogenesis
have been reported.[11] Therefore, we designed naphthochalcones
bearing pyrazoline moieties to enhance these effects (Fig. 1E). In
this research, 21 naphthalenyl-phenyl-pyrazoline derivatives were
synthesized, of which, only three have been reported
previously.[12–14] Here, we report the complete 1H and 13C nuclear
magnetic resonance (NMR) data for the 21 naphthalenyl-
bearing pyrazoline moieties.
Experimental
Synthesis
Naphthalenyl-phenyl-pyrazoline derivatives 1–21 were synthesized as
shown in Scheme 1. Claisen–Schmidt condensation of 2'-hydroxy-1'-
acetonaphthone (I) with methoxy- substituted benzaldehydes (II)
under basic conditions afforded (E)-1-(2-hydroxynaphthalen-1-yl)-3-
(methoxyphenyl)prop-2-en-1-ones (benzochalcones) (III), as
we reported previously.[15] Benzochalcones (III), treated with
p-chlorophenyl hydrazine (IV) in refluxing ethanol, produced
novel 1,3,5-trisubstituted pyrazoline derivatives (1–4) with good
yields. When the benzochalcones (III) were reacted with hydrazine
(V), new 3,5-disubstituted pyrazoline derivatives (5–8) were
obtained. Claisen–Schmidt condensation of 1'-hydroxy-2'-
acetonaphthone with methoxy-substituted benzaldehydes (II)
gave the corresponding (E)-1-(1-hydroxynaphthalen-2-yl)-3-
(methoxyphenyl)prop-2-en-1-ones (VI), which were treated with
hydrazine to produce the desired, new 3,5-disubstituted pyrazoline
*
Correspondence to: Yoongho Lim, Division of Bioscience and Biotechnology,
Konkuk University, Hwayang-Dong 1, Kwangjin-Gu, Seoul, Korea 143-701.
E-mail: yoongho@konkuk.ac.kr
a Division of Bioscience and Biotechnology, BMIC, Konkuk University, Seoul
143-701, Korea
b Department of Applied Chemistry, Dongduk Women's University, Seoul
136-714, Korea
c
National Institute of Animal Science, Rural Development Administration,
Suwon 441-706, Korea
Magn. Reson. Chem. (2013)
Copyright © 2013 John Wiley & Sons, Ltd.

D. Hwang et al.
(A)
Mass spectra
B
O
To confirm the structures of the 21 synthesized naphthalenyl-
phenyl-pyrazoline derivatives, high-resolution electron impact
mass spectra (HREIMS) were obtained and analyzed in the Korea
Basic Science Institute at Daegu, using a JMS700 spectrometer
(JEOL, Tokyo, Japan).
2
C
A
O
O
(B)
(C)
(D)
B
A
1'
1
α
β
Results and Discussion
The structures and nomenclature of naphthalenyl-phenyl-pyrazolines
1–21 are shown in Fig. 2. Naphthalenyl-phenyl-pyrazoline derivatives
1–4 have a 1-[1-(4-chlorophenyl)-5-(methoxyphenyl)-pyrazolin-3-yl]
naphthalen-2-ol moiety, 5–8 are 1-[5-(methoxyphenyl)-pyrazolin-3-yl]
naphthalen-2-ols, 9–17 are 2-[5-(methoxyphenyl)-pyrazolin-3-
N
NH
O
O
yl]naphthalen-1-ols, and 18–21 have
a 2-[5-(naphthalen-1-yl)-
pyrazolin-3-yl]phenol moiety. All of the naphthalenyl-phenyl-pyrazoline
derivatives, except 1, 5, and 12,[12–14] are new compounds.
The procedures used to assign the NMR data of the compound
with the most complex structure (2) are explained in detail here.
Of the 27 carbons of compound 2, 25 13C peaks were observed in
the 13C NMR spectrum. Two signals at 113.9 and 128.7 ppm were
assigned C-2"/C-6" and C-3"/C-5", respectively, because they had
double the intensity of the neighboring signals. Based on the
interpretation of the HMBC spectrum, C-1" and C-4" were
determined. Because the 13C peak at 46.0 ppm was a triplet in
the DEPT spectrum, it was assigned to C-py-4 of the pyrazoline
group. C-py-3 and C-py-5 were determined easily based on the
(E)
N
NH
Figure 1. The structures of (A) flavonoid, (B) chalcone, (C) 3,5-diphenyl-
4,5-dihydro-pyrazoline, (D) 7,8-benzoflavone, and (E) naphthochalcone
bearing pyrazoline moieties.
1
connectivities of the COSY and HMBC spectra. The H and 13C
derivatives (9–17). The same procedures were used to synthesize
additional pyrazolines (18–21) but starting from benzochalcones,
(E)-1-(2-hydroxy-methoxyphenyl)-3-(naphthalen-1-yl)prop-2-en-1-one
(VII). The reaction mechanism for the formation of pyrazolines from
chalcones is well established[16,17]: primary amines of arylhydrazine
initially form an imine with the carbonyl part of chalcones, followed
by the attachment of another nitrogen to the carbon-carbon
double bond for pyrazoline ring formation, eventually giving only
one regioisomer.
peaks of 2-hydroxynaphthalene were assigned by comparisons
with reported NMR data.[15,18] The C-1 of the dimethoxyphenyl
group showed long-range coupling with H-py-4 of the pyrazoline
group in HMBC. In addition, two long-range couplings of C-1
were observed with two protons at 6.63 and 6.48 ppm. Whereas
the former was a doublet peak, the latter was a doublet of a
doublet; thus, they were assigned to H-3 and H-5, respectively.
The two carbon peaks at 98.9 and 105.0 ppm were C-3 and C-5,
respectively, based on the direct correlations between the proton
1
and carbon in HMQC. The H peak at 7.05 ppm should be H-6.
Because the 13C peak at 157.2 ppm was long range coupled to
H-py-5 in HMBC, it was identified as C-2. Therefore, the 13C peak
at 159.9 ppm was assigned to C-4. Two methoxy protons at 3.87
and 3.73 ppm showed long-range coupling with two 13C peaks
at 157.2 and 159.9 ppm, respectively, so these two protons were
assigned 2-OCH3 and 4-OCH3, respectively. The proton signal of the 2'-
hydroxyl group contained in naphthalene was found at 10.23 ppm.
The important connections obtained from the COSY and HMBC
experiments are shown in Fig. S1. As a result, derivative 2 was
determined to be 1-[1-(4-chlorophenyl)-5-(2,4-dimethoxyphenyl)-
pyrazolin-3-yl]naphthalen-2-ol. This result was confirmed by the
HREIMS data, as its observed molecular mass was 458.1395 and
calculated mass was 458.1397. The complete assignments of the
1H and 13C NMR data of 2 are listed in Tables 1 and 2, respectively.
NMR spectra
All of the synthetic naphthalenyl-phenyl-pyrazoline derivatives,
except for 1, 3, 4, 19, and 20, were dissolved in DMSO-d6, and
the remaining five derivatives were dissolved in CHCl3-d. The H
1
and 13C chemical shifts of the deuterated solvent were
referenced to tetramethylsilane (TMS). The NMR samples were
prepared at approximately 50 mM and transferred to 2.5-mm
NMR tubes. The NMR experiments were carried out using a
Bruker Avance 400 spectrometer system (9.4 T; Bruker, Karlsruhe,
Germany) at 298 K. For one-dimensional (1D) 1H NMR spectra, the
relaxation delay, 90° pulse, spectral width, and digital resolution
were 1 s, 11.8 μs, 5555 Hz, and 0.17 Hz/point, respectively. For
the 13C NMR and distortionless enhancement by polarization
transfer (DEPT) experiments, the same parameters were 3 s,
15.0 μs, 20,964 Hz, and 0.32 Hz/point, respectively. For two-
dimensional (2D) correlation spectra (COSY, HMQC, and
HMBC) all data were acquired with 2 K × 256 data points
(t2 × t1). The delay for the long-range coupling of HMBC
was 70 ms. The zero-filling of 2 K and the sine-squared bell
window function were applied before Fourier transformation
using XWin-NMR (Bruker).[18] All NMR data were analyzed
using Sparky.[19]
1
Similarly, the H and 13C NMR data of the other 20 naphthalenyl-
phenyl-pyrazoline derivatives were acquired and are listed in
Tables 1 and 2, respectively.
The H-py-5s of the pyrazoline rings in 18–21 were the most
deshielded among the compounds tested here and were
connected to naphthalene directly. The second deshielded
chemical shifts of H-py-5s were observed in 1–4, in which two
phenyl groups were neighbors. Likewise, the H-py-1s of 18–21
were the most deshielded, and the naphthalene was linked in the
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Copyright © 2013 John Wiley & Sons, Ltd.
Magn. Reson. Chem. (2013)

1H and 13C NMR data for 21 naphthalenyl-phenyl-pyrazoline derivatives
Scheme 1. The synthetic methods used to prepare naphthalenyl-phenyl-pyrazoline derivatives 1–21.
Figure 2. The structures, nomenclature, and mass analysis data of naphthalenyl-phenyl-pyrazolines 1–21.
α-position. Whereas the C-py-3s of the pyrazoline ring in 9–17 were
deshielded more than in the other compounds, the C-py-4s of 9–17
were shielded more than others. The C-py-5s of 5–8 were also more
deshielded than in the other compounds. More polysubstituted
naphthalenyl-phenyl-pyrazoline derivatives synthesized in the
future can be identified based on the NMR data reported here.
Magn. Reson. Chem. (2013)
Copyright © 2013 John Wiley & Sons, Ltd.
wileyonlinelibrary.com/journal/mrc

D. Hwang et al.
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Copyright © 2013 John Wiley & Sons, Ltd.
Magn. Reson. Chem. (2013)

1H and 13C NMR data for 21 naphthalenyl-phenyl-pyrazoline derivatives
Magn. Reson. Chem. (2013)
Copyright © 2013 John Wiley & Sons, Ltd.
wileyonlinelibrary.com/journal/mrc

D. Hwang et al.
Table 2. The 13C NMR chemical shifts of naphthalenyl-phenyl-pyrazoline derivatives 1–21
Position
1
2
3
4
5
6
7
8
9
10
11
C-py*-3
150.5
48.8
148.2
46.0
150.7
47.6
151.3
47.4
149.1
44.9
63.0
134.7
127.9
113.7
158.4
113.7
127.9
112.4
154.5
118.3
129.9
128.1
122.7
125.4
124.2
132.5
128.0
—
148.9
44.3
57.5
136.3
146.2
152.2
111.7
123.9
118.6
112.4
154.4
118.3
129.8
128.1
122.7
126.4
124.2
132.5
128.0
—
149.2
43.3
57.4
122.6
157.6
98.3
159.7
104.3
127.0
112.5
154.5
118.3
130.0
128.1
122.7
126.4
124.2
132.4
128.0
—
148.9
44.7
63.3
145.6
104.5
160.5
98.9
160.5
104.5
112.4
154.5
118.3
129.9
128.1
122.7
126.4
124.2
132.5
128.0
—
153.1
40.5
56.4
135.8
146.3
152.3
112.0
124.0
118.6
153.2
110.0
124.7
118.5
127.5
127.0
125.4
122.3
123.9
133.7
—
153.2
39.5
56.4
129.8
156.6
110.8
128.4
120.3
126.3
153.1
110.1
124.7
118.5
127.5
127.0
125.4
122.3
123.9
133.7
—
153.3
41.0
62.1
143.8
112.3
159.3
112.8
129.6
118.9
153.2
110.0
124.7
118.5
127.5
127.1
125.5
122.3
123.9
133.7
—
C-py*-4
C-py*-5
63.8
57.1
58.8
58.4
1
132.7
127.2
114.7
159.4
114.7
127.2
109.1
157.4
119.2
131.9
129.4
123.1
126.8
123.2
131.9
129.0
142.6
114.8
129.1
125.0
129.1
114.8
—
121.1
157.2
98.9
125.9
150.8
142.4
153.6
107.5
121.2
109.3
157.2
119.2
131.7
129.3
123.1
126.8
123.3
132.0
129.0
142.5
114.4
129.1
124.6
129.1
114.4
60.9
119.7
150.6
97.6
2
3
4
159.9
105.0
127.1
112.0
154.3
118.2
130.4
128.2
122.9
126.9
124.1
132.6
128.0
143.6
113.9
128.7
121.6
128.7
113.9
55.7
149.5
143.6
110.5
109.5
157.3
119.3
131.9
129.5
123.2
126.9
123.4
132.1
129.1
142.9
114.7
129.2
124.9
129.2
114.7
56.4
5
6
1'
2'
3'
4'
5'
6'
7'
8'
9'
10'
1''
2''
—
—
—
—
—
—
—
3''
—
—
—
—
—
—
—
4''
—
—
—
—
—
—
—
5''
—
—
—
—
—
—
—
6''
—
—
—
—
—
—
—
2-OCH3
3-OCH3
4-OCH3
5-OCH3
—
60.2
55.6
—
55.4
—
—
60.3
55.7
—
55.5
—
—
—
—
61.0
—
—
55.1
—
55.0
—
55.3
55.2
56.0
56.3
55.0
—
55.2
—
—
—
—
—
56.7
—
55.1
—
—
—
Position
12
13
14
15
16
17
18
19
20
21
C-py*-3
153.3
41.0
153.3
39.5
56.2
122
153.4
41.0
153.3
40.4
153.5
39.8
153.4
38.2
152.3
40.7
151.1
44.8
152.9
41.2
151.7
44.8
58.4
138.4
123.2
125.5
127.5
128.7
125.7
126.2
123.5
130.5
133.5
100.0
160.1
93.9
161.1
90.5
158.9
—
C-py*-4
C-py*-5
61.7
62.2
56.5
56.2
50.5
58.8
58.6
58.5
1
134.0
127.9
113.8
158.6
113.8
127.9
—
144.6
104.7
160.5
99.0
127.8
151.1
152.7
141.7
107.8
121.3
—
121.0
151.1
98.5
110.4
159.2
91.3
138.0
123.1
125.5
127.6
128.6
125.7
126.2
123.5
130.5
133.5
116.8
156.7
115.7
129.7
119.1
127.7
—
138.3
123.1
125.5
127.5
128.7
125.7
126.3
123.5
130.5
133.5
106.5
158.6
102.2
130.0
109.2
157.9
—
138.2
123.1
125.5
127.5
128.7
125.7
126.2
123.6
130.5
133.5
107.9
152.1
100.4
150.5
141.7
111.3
—
2
157.6
98.5
159.8
104.4
127
3
4
148.8
142.5
111.7
—
160.3
91.3
5
160.5
104.7
—
6
159.2
—
7
—
8
—
—
—
—
—
—
9
—
—
—
—
—
—
10
—
—
—
—
—
—
1'
153.2
110.0
124.7
118.5
127.5
127.0
125.5
122.3
123.9
133.7
—
153.1
110.1
124.7
118.4
127.4
127.0
125.4
122.3
123.9
133.6
55.5
153.2
110.0
124.7
118.5
127.5
127.1
125.5
122.3
123.9
133.7
—
153.2
110.1
124.7
118.4
127.5
127.0
125.4
122.3
123.9
133.7
60.9
153.2
110.1
124.7
118.4
127.5
127.0
125.4
122.3
123.9
133.7
56.3
153.0
110.3
124.7
118.2
127.4
126.7
125.3
122.3
123.9
133.4
55.8
2'
3'
4'
5'
6'
7'
8'
—
—
—
—
9'
—
—
—
—
10'
—
—
—
—
2-OCH3
—
—
—
—
(Continues)
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Copyright © 2013 John Wiley & Sons, Ltd.
Magn. Reson. Chem. (2013)

1H and 13C NMR data for 21 naphthalenyl-phenyl-pyrazoline derivatives
Table 2. (Continued)
Position
12
13
14
15
16
17
18
19
20
21
3-OCH3
4-OCH3
5-OCH3
6-OCH3
4'-OCH3
5'-OCH3
6'-OCH3
—
55.1
—
—
55.2
—
55.1
—
55.8
60.3
—
—
55.8
56.3
—
—
55.2
—
—
—
—
—
—
—
—
—
—
—
—
—
—
55.1
—
—
—
—
—
—
—
55.8
—
—
—
—
—
—
—
—
—
—
55.5
56.3
—
55.2
—
—
—
—
—
—
—
—
—
—
—
—
—
—
55.7
55.6
* py denotes pyrazoline.
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Acknowledgements
[8] D. Havrylyuk, B. Zimenkovsky, O. Vasylenko, L. Zaprutko, A. Gzella,
This work was supported by the Priority Research Centers
Program (NRF, 2012-0006686), Agenda program (RDA, PJ006853),
and the next generation Biogreen21 program (RDA, PJ009532).
D. Hwang and H. Yoon contributed equally to this work.
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Magn. Reson. Chem. (2013)
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