Synthesis of tetrahydroisoquinoline derivatives and evaluation of their anti-breast cancer activity

Article abstract of DOI:10.1134/S1070363216060311

Four novel tetrahydroisoquinoline derivatives 1–4 were synthesized and characterized by IR, ¹H NMR, HRMS, and single crystal X-ray crystallography. Anticancer effect of the products were studied on five human breast cancer cell lines including

Full text of DOI:10.1134/S1070363216060311

ISSN 1070-3632, Russian Journal of General Chemistry, 2016, Vol. 86, No. 6, pp. 1430–1433. © Pleiades Publishing, Ltd., 2016.
Synthesis of Tetrahydroisoquinoline Derivatives
and Evaluation of Their Anti-Breast Cancer Activity1
X. P. Zhanga, F. J. Yub, X. W. Dinga, X. M. Hea, and D. H. Zoua*
a Department of Breast Tumor Surgery, Zhejiang Cancer Hospital, Hangzhou, Zhejiang, 310022 China
*e-mail: zoude_hong66@163.com
b Department of Medical Record Management, Zhejiang Cancer Hospital, Hangzhou, Zhejiang, 310022 China
Received March 29, 2016
1
Abstract—Four novel tetrahydroisoquinoline derivatives 1–4 were synthesized and characterized by IR, H
NMR, HRMS, and single crystal X-ray crystallography. Anticancer effect of the products were studied on five
human breast cancer cell lines including MDA-MB-231, MDA-MB-468, SK-BR-3, MCF7, HCC70 T4-2.
Compounds 3 and 4 demonstrated higher activity than 1 and 2.
Keywords: tetrahydroisoquinoline, crystals, breast cancer
DOI: 10.1134/S1070363216060311
Tetrahydroisoquinoline derivatives possess diverse
biological properties including antitumor, antifungal, anti-
microbial, anti-inflammatory, and insecticidal [1, 2].
We report herein the synthesis of four novel tetrahyd-
roisoquinoline derivatives and their preliminary in
vitro antitumor evaluation data.
room temperature. The precipitates were filtered off,
washed with ice-cooled water and ethanol, and dried
under vacuum.
6-Amino-2-methyl-8-phenyl-2,3,8,8a-tetrahydro-
1H-isoquinoline-5,7,7-tricarbonitrile (1). mp 195–
196°C. IR spectrum, ν, cm–1 : 3077, 2946, 2778, 1654,
1
EXPERIMENTAL
1457, 1081. H NMR spectrum, δ, ppm: 7.53–7.56 t
(3H), 7.42–7.44 t (1H), 7.10–7.16 m (2H), 5.67 s (1H),
4.37 s (1H), 3.88–3.90 d (1H), 3.78 s (3H), 3.43–3.45
m (2H), 2.64–2.67 m (1H), 2.41–2.45 m (1H), 1.04–
1.07 t (3H). HRMS (ESI+): m/z: 338.1388. Calculated
for C19H17N5: 338.1376 [M + Na]+.
IR spectra (400–4000 cm–1) were recorded on a
Brucker Equinox-55 spectrophotometer as KBr discs.
1H NMR spectra of solutions in DMSO-d6 were
measured on a Varian Inova-400 spectrometer (at
400 MHz). Mass spectra were measured on a
micrOTOF-Q II mass spectrometer. Melting points
were determined by a XT-4 micro melting apparatus.
6-Amino-8-(4-methoxyphenyl)-2-methyl-2,3,8,8a-
tetrahydro-1H-isoquinoline-5,7,7-tricarbonitrile
(2). mp 142–143°C. IR spectrum, ν, cm–1: 3310, 1065,
1
Five human breast cancer cell lines (MDA-MB-
231, MDA-MB-468, SK-BR-3, MCF7, HCC70 T4-2)
were purchased from Institute of Basic Medical
Sciences (IBMS) of Chinese Academy of Medical
Sciences (CAMS) (Beijing, China).
2657, 1655, 1460, 1378, 1270, 889. H NMR spec-
trum, δ, ppm: 7.53–7.56 t (3H), 7.42–7.44 t (1H), 7.10–
7.16 m (2H), 5.67 s (1H), 4.37 s (1H), 3.88–3.90 d
(1H), 3.78 s (3H), 3.43–3.45 m (2H), 2.11 s (3H), 1.04–
1.07 t (3H). HRMS (ESI+): m/z: 368.1433. Calculated
for C20H19N5O: 368.1482 [M + Na]+.
Synthesis and characterization of compounds 1–4.
Compounds 1–4 (Fig. 1) were synthesized according
to the earlier reported procedure [3]. A mixture of N-
methyl-4-piperidone (10 mmol), aromatic aldehyde
(10 mmol) and malononitrile (10 mmol) in ethanol
(100 mL) was refluxed for 2–3 h and then cooled to
6-Amino-8-(4-chlorophenyl)-2-methyl-2,3,8,8a-
tetrahydro-1H-isoquinoline-5,7,7-tricarbonitrile
(3). mp 175–176°C. IR spectrum, ν, cm–1: 3320, 2796,
1
1711, 1650, 1366, 1205, 979. H NMR spectrum, δ,
ppm: 7.67–7.75 q (2H), 7.55–7.59 t (3H), 7.39–7.40 d
(1H), 5.66 s (1H), 4.36–4.37 t (1H), 3.72–3.74 d (1H),
3.43–3.45 q (2H), 2.63–2.66 d (1H), 2.38–2.41 q (1H),
1 The text was submitted by the authors in English.
1430

SYNTHESIS OF TETRAHYDROISOQUINOLINE DERIVATIVES
1431
O
Cl
NO2
CN
CN
CN
CN
N
N
N
N
CN
NH2
CN
NH2
CN
NH2
CN
NH2
CN
CN
CN
CN
1
2
3
4
Fig. 1. Chemical structures of compounds 1–4.
1.04–1.07 t (3H). HRMS (ESI+): m/z: 372.0967.
Calculated for C19H16ClN5: 372.0986 [M + Na]+.
m/z: 383.1545. Calculated for C19H16N6O2: 383.1227
[M + Na]+.
6-Amino-8-(4-nitrophenyl)-2-methyl-2,3,8,8a-
tetrahydro-1H-isoquinoline-5,7,7-tricarbonitrile
(4). mp 189–190°C. IR spectrum, ν , cm–1 : 3028,
2788, 1644, 1440, 1310, 1200, 1055, 954. 1H NMR spec
-trum, δ, ppm: 7.86–7.93 m (3H), 7.67–7.69 d (1H),
7.58 s (2H), 5.68–5.69 d (1H), 4.36–4.38 t (1H), 3.88–
3.90 d (1H), 3.43–3.45 m (2H), 2.64–2.67 m (1H),
2.37–2.39 q (1H), 1.04–1.07 t (3H). HRMS (ESI+):
Crystal structure. Suitable single crystals of com-
pound 1 were obtained by evaporation of the chloro-
form solution. 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. The structure (Table 1) was
elucidated by using the program SHELXL-97 [4] and
Fourier difference techniques, and refined by full-
Table 1. Crystal data of compound 1
Value
Formula
Parameter
C20H21N5O
347.42
Value
Parameter
1986.9 (11)
4
V, Å3
Molecular weight
Temperature, K
Crystal system
Space group
a, Å
Z
293 (2)
Dcalc, g/cm3
1.161
Monoclinic
P21/c
μ(MoKα), mm–1
θ range, deg
0.075
2.48 to 25.00
9627
11.789 (5)
11.593 (4)
17.470 (3)
90
Reflections collected
Number of unique data (Rint)
Number of data with I ≥ 2σ(I)
R1
b, Å
3480 (0.1107)
1530
c, Å
α, deg
0.0942
β, deg
123.68 (2)
90
ωR2 (all data)
0.2510
γ, deg
CCDC
1471074
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 86 No. 6 2016

1432
ZHANG et al.
Table 2. In vitro antitumor activity of compounds 1–4 and ifosfamide
IC50, μMa
Compounds
MDA-MB-231
7.67
MDA-MB-468
8.89
SK-BR-3
7.56
MCF7
8.44
7.68
1.65
1.78
3.67
HCC70 T4-2
7.12
1
2
3
4
8.67
9.10
8.27
6.89
2.10
2.10
1.98
2.78
2.35
1.89
2.78
3.66
Ifosfamideb
1.15
3.57
4.34
2.33
a Concentration which produces 50% inhibition of proliferation after 72 h of incubation. b Compared drug.
matrix least-squares method on F2. All hydrogen atoms
were added theoretically.
CO2/95% air atmosphere in a humidified incubator.
The culture cells were fixed with 10% cold TCA and
stained with 0.4% SRB dissolved in 1% acetic acid.
After solubilizing the bound stain with 10 mM of
unbuffered Trisma base solution (pH = 10.5) using
gyratory shaker, the absorbance at 520 nm was measured
spectrophotometrically in a microplate reader. Cytotoxic
activity was evaluated by measuring the concentration
of a compound, which was required to inhibit the
protein synthesis by 50% (IC50) and compared with
that of ifosfamide.
Anticancer activity. Five human breast cancer cell
lines (MDA-MB-231, MDA-MB-468, SK-BR-3, MCF7,
HCC70 T4-2) were used for cytotoxicity tests in vitro
using the SRB (sulforhodamine B) assay. Those were
maintained as stocks in RPMI 1640 (Gibco) supple-
mented with 10% fetal bovine serum (Gibco). Cell
cultures were passaged once or twice weekly by using
trypsin-EDTA to detach the cells from their culture
flasks. The rapidly growing cells were harvested,
counted, and incubated at the appropriate concentra-
tion [(1–2) × 104 cells/well] in 96-well plates. After
incubation for 24 h, the compounds dissolved in
culture medium were applied to the culture wells in
triplicate and incubated for 48 h at 37°C under 5%
RESULTS AND DISCUSSION
1
Molecular structure. H NMR spectrum, IR and
MS data for the products were in good agreement with
1
the title compounds. In the H NMR spectra of com-
pounds 1–4, single peaks at 4.37–5.66 ppm were
characteristic of the CH group.
The crystal structure of compound 1 is presented in
Fig. 2. The six-membered carbon ring is nearly planar
(maximum deviation = 0.2324 Å) and the adjacent six-
membered ring containing nitrogen atom adopts a
flattened chair conformation [dihedral angle (C10–C5–
C6–N3) = 5.239°]. The six-membered carbon ring is
almost perpendicular to the benzene ring [dihedral
angle = 87.123°] and is almost coplanar with the mean
plane of six-membered ring containing nitrogen atom
(dihedral angle = 9.122°).
Anticancer activity. The in vitro cytotoxicity of
compounds 1–4 was evaluated in five human breast
cancer cell lines (MDA-MB-231, MDA-MB-468, SK-
BR-3, MCF7, HCC70 T4-2) by the SRB (sulforhod-
Fig. 2. Molecular structure of compound 1.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 86 No. 6 2016

SYNTHESIS OF TETRAHYDROISOQUINOLINE DERIVATIVES
1433
amine B) method (Table 2). Compounds 3 and 4
demonstrated highest anticancer activity, even superior
to ifosfamide for some cell lines.
withdrawing groups in the phenyl ring in the structure
of compound 1.
REFERENCES
The electron-withdrawing groups (Cl and NO2)
introduced in the phenyl ring enhanced antitumor
activity of compounds 3 and 4.
1. Xu, X., Hong, Y.K., Park, J., Lee, W., and Lane, A.M.,
Electro. Mater. Lett., 2015, vol. 11, p. 1021. DOI:
10.1007/s13391-015-5163-1.
2. Xu, X., Hong, Y.K., Park, J., Lee, W., and Lane, A.M.,
J. Solid. State. Chem., 2015, vol. 231, p. 108.
DOI: 10.1016/j.jssc.2015.08.019.
3. Khan, A.T., Lal, M., Ali, S., and Khan, Md.M.,
Tetrahedron Lett., 2011, vol. 52, p. 5327. DOI: 10.1016/
j.tetlet.2011.08.019.
4. Sheldrick, G.M., SHELXL-97, Program for Solution
Crystal Structure and Refinement; University of
Göttingen: Göttingen, Germany, 1997.
CONCLUSIONS
We have synthesized four novel tetrahydroisoquinoline
derivatives and characterized those by IR, H NMR
spectrum, HRMS, and single crystal X-ray crystallo-
graphy. Compounds 3 and 4 exhibited higher
antitumor activity with IC50 values ranging from
1.65 to 2.78 μM, possibly due to the electron-
1
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 86 No. 6 2016