Novel Pyran and Polyhydroquinoline Derivatives: Inhibiting Human Osteosarcoma Activity

Article abstract of DOI:10.1134/S1070363218060336

A series of pyran 1–6 and polyhydroquinoline derivatives 7–9 are synthesized targeting anticancer agents for clinical trials. Their structures are characterized by IR, ¹H NMR, and HRMS spectra, and single crystal X-ray crystallography. Their anticancer activity against four human osteosarcoma cells (Saos-2, MG-63, 143B, and U2-OS) is evaluated in vitro using the MTT assay. The compounds 7–9 demonstrate high anticancer activity against the four cancer cells.

Full text of DOI:10.1134/S1070363218060336

ISSN 1070-3632, Russian Journal of General Chemistry, 2018, Vol. 88, No. 6, pp. 1247–1251. © Pleiades Publishing, Ltd., 2018.
Novel Pyran and Polyhydroquinoline Derivatives:
Inhibiting Human Osteosarcoma Activity1
X.-X. Fana, P. Shena, and X.-H. Zhoua*
a Department of Orthopaedics, Huzhou Central Hospital, Huzhou, Zhejiang, 313003 China
*e-mail: xinhua_zhou666@yeah.net
Received April 9, 2018
Abstract—A series of pyran 1–6 and polyhydroquinoline derivatives 7–9 are synthesized targeting anticancer
1
agents for clinical trials. Their structures are characterized by IR, H NMR, and HRMS spectra, and single
crystal X-ray crystallography. Their anticancer activity against four human osteosarcoma cells (Saos-2, MG-63,
143B, and U2-OS) is evaluated in vitro using the MTT assay. The compounds 7–9 demonstrate high anticancer
activity against the four cancer cells.
Keywords: pyran, polyhydroquinoline, X-ray, cancer cell
DOI: 10.1134/S1070363218060336
INTRODUCTION
methyl-3,5-cyclohexanedione (10 mmol) with an
aromatic aldehyde (10 mmol), malononitrile (ethyl
cyanoacetate) (10 mmol), and 4-(dimethylamino)
pyridine (DMAP) (1 mmol) in ethanol (100 mL) was
refluxed for 2–3 h and then cooled down to room
temperature. After filtering off the precipitate, the cor-
responding product was sequentially washed with ice-
cold water and ethanol and then dried under vacuum.
Antitumor chemotherapy is a very active field of
research, and a huge amount of information on the
topic is generated annually [1–4].
Pyran and polyhydroquinoline derivatives are
important classes of heterocyclic structures found in
many synthetic and natural products, and have
received considerable attention due to their remarkable
biological activities, such as antibacterial, antifungal,
anticonvulsant, anti-inflammatory, antimicrobial,
herbicidal, and antitumor properties [5–7]. Based on
the above, and in continuation of our interest in syn-
thesis of pyran and polyhydroquinoline derivatives with
anticancer activity, in the current study we targeted
synthesis of new series of pyran 1–6 and polyhydro-
quinoline derivatives 7–9 (Fig. 1) and screening their
in vitro anticancer activity by the MTT assay.
2-Amino-3-cyano-7,7-dimethyl-4-(4-methylphenyl)-
5-oxo-4H-5,6,7,8-tetrahydrobenzo[b]pyran (1). mp
204–205°C. IR spectrum, ν, cm–1: 3433, 2523, 1713,
1
1533, 971. H NMR spectrum, δ, ppm: 0.946 s (3H),
1.033 s (3H), 2.065–2.106 d (1H), 2.222–2.262 t (3H),
2.495–2.504 t (3H), 4.120 s (1H), 6.949 s (2H), 7.004–
7.024 d (2H), 7.070–7.090 d (2H). HRMS (ESI+): m/z:
calculated for C19H20N2O2: 331.1422 [M + Na]+;
found: 331.1434.
2-Amino-3-cyano-7,7-dimethyl-4-(4-methylsulfanyl-
phenyl)-5-oxo-4H-5,6,7,8-tetrahydrobenzo[b]pyran
(2). mp 199–200°C. IR spectrum, ν, cm–1: 3302, 2721,
EXPERIMENTAL
1
1729, 1642, 970. H NMR spectrum, δ, ppm: 0.950 s
IR spectra for KBr pellets were recorded on a
1
(3H), 1.035 s (3H), 2.085 s (2H), 2.113 s (1H), 2.228–
2.268 d (1H), 2.442 s (3H), 4.134 s (1H), 6.998 s (2H),
7.067–7.088 d (2H), 7.172–7.188 d (2H). HRMS
(ESI+): m/z: calculated for C19H20N2O2S: 340.1245
[M + Na]+; found: 340.1233.
Brucker Equinox-55 spectrophotometer. H NMR
spectra were measured on a Varian Inova-400 spectro-
meter in DMSO-d6. Mass spectra were measured on a
micrOTOF-Q II mass spectrometer. Melting points
were determined on a XT-4 micro melting apparatus.
2-Amino-3-cyano-7,7-dimethyl-4-(2,6-dichloro-
phenyl)-5-oxo-4H-5,6,7,8-tetrahydrobenzo[b]pyran
(3). mp 200–201°C. IR spectrum, ν, cm–1: 3432, 2721,
Compounds 1–6 were synthesized according to a
reported earlier procedure [8]. A mixture of 1,1-di-
1
1 The text was submitted by the authors in English.
1722, 1632, 945. H NMR spectrum, δ, ppm: 0.999 s
1247

1248
FAN et al.
NH2
CN
O
Cl
Cl
NC
CN
O
CH3
1
SCH3
2
3
R
NH2
O
COOEt
O
Cl
NC
COOEt
CHO
NO2
O
O
OC2H5
6
Cl
4
5
NH2
O
O
O
COOCH3
CH3
CN
OCH3
N
H
7
8
9
Fig. 1. Synthetic approaches to compounds 1–9.
(3H), 1.046 s (3H), 2.048–2.088 d (1H), 2.233–2.273 d
(1H), 2.353–2.397 d (1H), 2.503–2.550 m (1H), 5.212
s (1H), 7.107 s (2H), 7.230–7.270 t (1H), 7.341–7.364
q (1H), 7.446–7.469 q (1H). HRMS (ESI+): m/z: cal-
culated for C18H16Cl2N2O2: 385.0487 [M + Na]+;
found: 385.0417.
d (1H), 7.695 s (2H), 7.961–8.006 m (2H). HRMS
(ESI+): m/z: calculated for C20H22N2O6: 409.1376 [M +
Na]+; found: 409.1323.
Ethyl 2-amino-7,7-dimethyl-4-(4-ethoxyphenyl)-
5-oxo-5,6,7,8-tetrahydro-4H-chromene-3-carboxylate
(6). mp 211–212°C. IR spectrum, ν, cm–1: 3121, 2741,
1
Ethyl 2-amino-7,7-dimethyl-4-(2,4-dichlorophenyl)-
5-oxo-5,6,7,8-tetrahydro-4H-chromene-3-carboxylate
(4). mp 210–211°C. IR spectrum, ν, cm–1: 3431, 2731,
1732, 1642, 971. H NMR spectrum, δ, ppm: 1.29–
1.32 t (6H), 1.35–1.37 t (6H), 4.14–4.18 q (4H), 4.29–
4.32 q (4H), 7.12–7.15 m (4H), 8.06–8.09 m (4H),
8.30 s (2H). HRMS (ESI+): m/z: calculated for
C22H27NO5: 408.1787 [M + Na]+; found: 408.1798.
1
1729, 1532, 965. H NMR spectrum, δ, ppm: 1.112–
1.136 t (3H), 2.033–2.060 d (1H), 2.110–2.131 d (6H),
2.233–2.260 d (1H), 2.452–2.555 m (2H), 3.931–3.960
m (2H), 4.426 s (1H), 6.813–6.828 q (1H), 6.896 s
(1H), 6.932–6.945 d (1H), 7.486 s (2H). HRMS
(ESI+): m/z: calculated for C20H21Cl2NO4: 432.0745
[M + Na]+; found: 432.0765.
Compounds 7–9 were synthesized according to an
earlier reported procedure [9]. A mixture of methyl
3-amino-crotonate (10 mmol) with an aromatic
aldehyde (10 mmol) and 1,1-dimethyl-3,5-cyclo-
hexanedione (10 mmol) in ethanol (100 mL) was
refluxed for 2–3 h and then cooled down to room
temperature. After filtering off the corresponding
precipitate, it was sequentially washed with ice-cold
water and ethanol and then dried under vacuum.
Ethyl 2-amino-7,7-dimethyl-4-(3-nitrophenyl)-5-
oxo-5,6,7,8-tetrahydro-4H-chromene-3-carboxylate
(5). mp 207–208°C. IR (KBr spectrum, ν, cm–1: 3431,
1
2743, 1733, 1634, 940. H NMR spectrum, δ, ppm:
0.901 s (3H), 1.049–1.084 q (6H), 2.064–2.091 d (1H),
2.271–2.298 d (1H), 2.499–2.604 m (2H), 3.921–3.956
m (2H), 4.611 s (1H), 7.528–7.554 t (1H), 7.598–7.611
Methyl 2,7,7-trimethyl-4-(2-cyanophenyl)-5-oxo-
1,4,5,6,7,8-hexahydroquinoline-3-carboxylate (7).
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 88 No. 6 2018

NOVEL PYRAN AND POLYHYDROQUINOLINE DERIVATIVES
Table 1. Crystal data and structure refinements for compounds 1, 4, and 7
1249
Parameter
1
4
7
Formula
C19H20N2O2
308.37
C20H21Cl2NO4
410.28
C21H22N2O3
350.41
Mr
Crystal system
Space group
a, Å
Monoclinic
P21/n
Monoclinic
P21/c
Monoclinic
P21/c
9.4627 (8)
16.8902 (13)
10.834 (1)
90
11.468 (4)
8.888 (5)
20.485 (6)
90
10.920 (3)
15.070 (2)
14.147 (2)
90
b, Å
c, Å
α, deg
β, deg
γ, deg
V, Å3
111.796 (3)
90
105.14 (2)
90
126.58 (9)
90
1607.8 (2)
4
2015.6 (13)
4
1869.5 (6)
4
Z
D
calc, g/cm3
1.274
0.083
1.352
0.347
1.245
0.084
μ(MoKα), mm–1
θ range, deg
2.36 to 24.99
9973
1.84 to 25.00
9590
2.25 to 24.99
9127
Reflections collected
Number unique data (Rint)]
Number data with I ≥ 2σ(I)
R1
2762 [0.0147]
2542
3535 [0.0382]
2378
3289 [0.2396]
810
0.0461
0.0478
0.0814
ωR2(all data)
0.1373
0.1223
0.2467
CCDC
1819951
1819952
1819953
mp 217–218°C. IR spectrum, ν, cm–1: 3341, 2532,
HRMS (ESI+): m/z: calculated for C22H27NO3: 376.1889
[M + Na]+; found: 376.1877.
1
1722, 1612, 971. H NMR spectrum, δ, ppm: 0.828 s
(3H), 1.012 s (3H), 1.890–1.930 d (1H), 2.148–2.188 d
(1H), 2.265–2.307 t (4H), 2.434–2.476 d (1H), 3.485 s
(3H), 5.077 s (1H), 7.236–7.276 m (1H), 7.331–7.350
d (1H), 7.527–7.610 m (2H), 9.233 s (1H). HRMS
(ESI+): m/z: calculated for C21H22N2O3: 373.1528 [M +
Na]+; found: 373.1565.
Crystal structures determination. Suitable single
crystals of compounds 1, 4, and 7 were obtained by
evaporation of their chloroform solutions. Diffraction
data were collected on a Bruker Smart Apex CCD area
detector using a graphite monochromated MoKα
radiation (λ = 0.71073 Å) at room temperature
(Table 1). The structure was solved by using the program
SHELXL-97 [10] and Fourier difference techniques,
and refined by full-matrix least-squares method on F2.
All hydrogen atoms were added theoretically.
Methyl 2,7,7-trimethyl-4-(2-methoxyphenyl)-5-
oxo-1,4,5,6,7,8-hexahydroquinoline-3-carboxylate
(8). mp 221–222°C. IR spectrum, ν, cm–1: 3411, 2631,
1
1735, 1622, 960. H NMR spectrum, δ, ppm: 0.856 s
(3H), 1.006 s (3H), 1.885–1.926 d (1H), 2.110–2.278
m (5H), 2.390–2.432 d (1H), 3.484 s (3H), 3.706 s
(3H), 5.057 s (1H), 6.743–6.780 t (1H), 6.834–6.854 d
(1H), 7.029–7.083 m (2H), 8.990 s (1H). HRMS
(ESI+): m/z: calculated for C21H25NO4: 378.1681 [M +
Na]+; found: 378.1677.
Antitumor activity. Four human osteosarcoma cells
(Saos-2, MG-63, 143B, and U2-OS) were grown in a
RPMI 1460 medium supplemented with 10% fetal calf
serum, 100 μg/mL penicillin and 100 μg/mL
streptomycin. They were incubated at 37°C in a
humidified incubator (5% CO2). Cells at the
exponential growth were diluted to 5×104 cells/mL
with RPMI1460, and then seeded in 96-well cell
culture, volume of 100 μL per cell, and incubated for
24 h at 37°C in 5% CO2. After incubation of cells, the
medium was removed from each cell. The IC50 values
were determined by plotting the percentage viability
versus concentration on a logarithmic graph. Each
Methyl 2,7,7-trimethyl-4-(3,4-dimethylphenyl)-
5-oxo-1,4,5,6,7,8-hexahydroquinoline-3-carboxylate
(9). mp 213–214°C. IR spectrum, ν, cm–1: 3211, 2561,
1
1719, 1652, 970. H NMR spectrum, δ, ppm: 0.853 s
(3H), 1.001 s (3H), 1.957–1.984 d (1H), 2.099–2.167 q
(7H), 2.267–2.291 d (4H), 2.390–2.418 d (1H), 3.520 s
(3H), 4.784 s (1H), 6.827–6.924 m (3H), 9.026 s (1H).
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 88 No. 6 2018

1250
FAN et al.
(a)
(b)
Fig. 2. Molecular structures of compounds (a) 1 and (b) 7.
(a)
(b)
(c)
Fig. 3. Crystal packing structures of compounds (a) 1 (along the c axis), (b) 4 (along the a axis), and (c) 7 (along the a axis).
experiment was repeated not less than three times for
deducing the mean values.
P21/n. All three compounds exhibit 2-D supra-
molecular structure. The detailed information on
hydrogen bonds of compounds 1, 4 and 7 is listed in
Table 2. In the structural unit of compound 1, the
dihedral angle between the six-membered ring
containing one O atoms (C9, C10, C11, O1, C5, and C6)
and the adjacent six-membered carbon ring C13–C18 is
70.62°. In the structure of 1, the bond lengths of C–O,
C–C and C–N are in the ranges of 1.226(6)–1.376(0),
1.336(4)–1.534(4), and 1.148(8)–1.343(7) Å,
respectively. These fall in their normal scopes and are
comparable with the previously reported compounds.
RESULTS AND DISCUSSION
Molecular structure. The crystal structures of
three compounds 1, 4, and 7 (Fig. 2) were determined
by X-ray single-crystal structural analysis. Owing to
similarity of their crystal structures, here we present
the structure of compound 1. According to the
accumulated data compound 1 belongs to the
monoclinic crystal system with the space group of
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 88 No. 6 2018

NOVEL PYRAN AND POLYHYDROQUINOLINE DERIVATIVES
Table 2. Hydrogen-bond geometry for compounds 1, 4, and 7
1251
Compound no.
D–H···A, Å
D–H, Å H···A, Å D···A, Å D–H···A, deg
Symmetry code
1
N1–H1A···O2
N1–H1B···N2
C1–4H14A···O2
0.8600
0.8600
0.9300
0.8600
0.8600
0.8600
0.9800
2.0800
2.6200
2.4800
2.7600
2.0800
2.1500
2.6700
2.9136
3.1676
3.2381
3.4424
2.6893
2.9037
3.1926
164.00
123.00
138.00
137.00
127.00
145.00
114.00
–1/2 + x, 1/2 – y, 1/2 + z
1/2 + x, 1/2 – y, 1/2 + z
4
7
N1–H1D···Cl1
N1–H1D···O2
N1–H1E···O3
C14–H14A···Cl1
x, 1 + y, z
x, 1 + y, z
N2–H2A···O3
C5–H5A···O2
0.8600
1.9700
2.8236
170.00
x, 1/2 – y, –1/2 + z
0.9600
2.1200
2.8582
133.00
Table 3. Growth inhibitory effects of compounds 1–9 and
CONCLUSIONS
vinorebine on Saos-2, MG-63, 143B, and U2-OS cancer cells
Based on biological activity of the synthesized com-
pounds, polyhydroquinoline derivatives 7–9 exhibit more
efficient inhibition of the cancer cells lines than pyran
derivatives 1–6. Therefore, compounds 7–9 can be consi-
dered as potential anticancer drugs, yet requiring further
tests for determining their in vivo anticancer activity.
IC50, μM
Compound
Saos-2 MG-63 143B
U2-OS
>100
>100
>100
>100
>100
>100
45
1
>100
>100
>100
>100
>100
>100
30
>100
>100
>100
>100
>100
>100
25
>100
>100
>100
>100
>100
>100
40
2
3
REFERENCES
4
1. Du, X., Shi, Z., Peng, Z., Zhao, C., Zhang, Y., Wang, Z.,
Li, X., Liu, G., and Li, X., J. Cell Physiol., 2017,
vol. 232, p. 3296. doi 10.1002/jcp.25773
5
6
2. Song, Y., Li, N., Gu, J., Fu, S., Peng, Z., Zhao, C.,
Zhang, Y., Li, X., Wang, Z., Li, X., and Liu, G., J. Dairy
Sci., 2016, vol. 99, p. 9184. doi 10.3168/jds.2016-11219
3. Sun, X., Yuan, X., Chen, L., Wang, T., Wang, Z., Sun, G.,
Li, X., Li, X., and Liu, G., Cell Physiol. Biochem.,
2017, vol. 42, p. 1109. doi 10.1159/000478765
7
8
30
35
35
40
9
35
30
30
30
Vinorebine
35
30
40
35
4. Du, X., Zhu, Y., Peng, Z., Cui, Y., Zhang, Q., Shi, Z.,
Guan, Y., Sha, X., Shen, T., Yang, Y., Li, X., Wang, Z.,
Li, X., and Liu, G., J. Dairy Sci., 2018, vol. 101, p. 1.
doi 10.3168/jds.2017-13234
The compounds contain multiple hydrogen bonds (1:
N–H···O, C–H···O and N–H···N; 4: N–H···Cl, C–
H···Cl, N–H···O; 7: C–H···O and N–H···O) in their
packing structures (Fig. 3). By means of these
interactions via H-bonds, they all display 2-D supra-
molecular structures.
5. Li, J., Lv, C.W., Li, X.J., Qu, D., Hou, Z., Jia, M.,
Luo, X.X., Li, X., and Li, M.K., Molecules, 2015,
vol. 20, p. 17469. doi 10.3390/molecules200917469
6. Khan, K.M., Iqbal, S., Lodhi, M.A., Maharvi, G.M., Zia-
Ullah, Choudhary, M.I., Atta-ur-Rahman, and Perveen, S.,
Bioorg. Med. Chem., 2004, vol. 12, p. 1963. doi
10.1016/j.bmc.2004.01.010
Antitumor activity. The synthesized compounds
1–9 were evaluated against Saos-2, MG-63, 143B, and
U2-OS human osteosarcoma cells by the MTT assay
(Table 3). Compounds 1–6 were inactive against all of
these cell lines (IC50 > 100 μM). Upon incubation of
the tumor cells in the presence of compounds 7–9 for
72 h, the IC50 values determined for the compounds
ranged from 25 to 45 μM. In some cases the values
were lower than those of vinorebine. The accumulated
data indicated that compounds 7–9 exhibited anti-
cancer activity against all of these cell lines.
7. Khan, A.T., Lal, M., Ali, S., and Khan, Md.M.,
Tetrahedron Lett., 2011, vol. 52, p. 5327. doi 10.1016/
j.ejmech.2018.04.005
8. Li, J., Sui, Y.P., Xin, J.J., et al., Bioorg. Med. Chem.
Lett., 2015, vol. 25, p. 5520. doi 10.1016/
j.bmcl.2015.10.063
9. Li, J., Xue, X.-Y., Li, X., et al., Arch. Pharm. Res.,
2016, vol. 39, p. 1349. doi 10.1007/s12272-015-0614-7
10. Sheldrick, G.M., SHELXL-97, Program for Solution
Crystal Structure and Refinement, Göttingen: University
of Göttingen, Germany 1997.
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