Synthesis and antitumour activity of novel colchicine C-10 derivatives

Article abstract of DOI:10.14233/ajchem.2014.16892

A series of new colchicine C-10 derivatives (2a-i, 3a-h) were synthesized by replacement of the 10-methoxy with NR₂ and SCH₃ in order to determine their cytotoxic activity. The compounds were synthesized in good yield and the structures of all newly synthesized compounds were established on the basis of their IR, ¹H NMR and elemental analysis. The synthesized compounds were tested in vitro antitumor activity against four human cancer cell lines by MTT assay. It was found that many of the derivatives displayed significant activity, particularly, compound 2a and 2b showed more potent cytotoxic activities than colchicine.

Full text of DOI:10.14233/ajchem.2014.16892

Asian Journal of Chemistry; Vol. 26, No. 21 (2014), 7475-7476
ASIAN JOURNAL OF CHEMISTRY
http://dx.doi.org/10.14233/ajchem.2014.16892
NOTE
Synthesis and Antitumour Activity of Novel Colchicine C-10 Derivatives
1,*
1
1
2
2
LI HONG SHEN , LE ZHANG , HAI XIAN WANG , XIN WANG and GAI JIAO ZHANG
1Handan Key Laboratory of Organic Small Molecule Materials, Handan College, Handan 056005, P.R. China
2Department of Chemistry, Handan College, Handan 056005, P.R. China
*Corresponding author: E-mail: latishen@sohu.com
Received: 19 December 2013;
Accepted: 20 February 2014;
Published online: 30 September 2014;
AJC-16166
A series of new colchicine C-10 derivatives (2a-i, 3a-h) were synthesized by replacement of the 10-methoxy with NR2 and SCH3 in order
to determine their cytotoxic activity. The compounds were synthesized in good yield and the structures of all newly synthesized compounds
1
were established on the basis of their IR, H NMR and elemental analysis. The synthesized compounds were tested in vitro antitumor
activity against four human cancer cell lines by MTT assay. It was found that many of the derivatives displayed significant activity,
particularly, compound 2a and 2b showed more potent cytotoxic activities than colchicine.
Keywords: Colchicine, Derivatives, Cytotoxic activity.
Colchicine (Col, 1), the major alkaloid extracted from the
seed of Colchicum autumnale Liliaceae and Gloriosa superba,
is a potent drug that interferes with microtubules both in vitro
and in vivo, thereby causing cells to accumulate in obvious
mitotic arrest during cell cycle1-3. Colchicine and many of its
derivatives are powerful mitotic poisons, antiinflammatories
and inhibitors of tumor growth4-6. Although colchicine is a
potent antimitotic agent, its medical uses in cancer chemo-
therapy are limited due to its high toxicity4. Structure-activity
relationship studies suggest that demethylation of 10-methoxy
to the 10-OH forms colchicine and destroys activity; however,
replacement of the 10-methoxy with NR2 or SCH3 (2, Scheme-I)
leads to increased potency7. Structure-activity studies indicate
that the C-10 substituent of colchicine is involved in its biolo-
gical activity. However, only a small variety of C-10 analogues
The synthetic route of these target compounds is outlined in
Scheme-I. Colchicine (1) was purchased fromTaiyuan Xingyuan
Biochemical Co. Ltd China, with an over 98 % purity.
The compound 2a was prepared from 1, according to the
literature13 in 90 % yield and then 2a was refluxed with 2 mol
L-1 HCl in CH3OH to give the compound 3a.
Colchicine (1) was treated with amines in the presence of
C2H5OH at room temperature to generate important interme-
diates 2b-2h in 90-95 % yields. Compounds 2b-2h were further
converted to the corresponding target compounds 3b-3h with
MeO
MeO
O
MeO
MeO
O
MeO
MeO
NHCCH3
NHCCH3
NH2
a
b
OMe
OMe
OMe
O
O
O
Col, 1
OMe
2a
R1
3a
R1
of colchicine have been synthesized8-10
.
c
O
NHCCH3
MeO
MeO
MeO
MeO
We reported previously some derivatives of N-methyl
colchiceinamide, which replacement of the 10-methoxy with
NHCH3, have proved that the derivatives of C-10 could really
improve colchicine's antitumor activity in vitro11,12. In view of
this, to search for antitumor drugs with high potency and
selectivity, we recently synthesized a series of new analogues
of colchicine which replacement of the 10-methoxy with NR2
or SCH3, hoping that these derivatives might be transported to
target site where they would release active compounds to
selectively kill tumor cells without affecting normal cells.
MeO
MeO
NH2
NH2
e
d
3h
OMe
OMe
OMe
O
O
O
2b-2h
R1
R1 = NHCH3;
R1 = NH(CH2)3CH3; R1
3b-3h
R1
R1 = NH(CH2)2CH3;
R1 =NHCH2CH2OH; R1 =NHCH2CH2Cl
3i
R1
a
f
R1=SCH3;
b
c
R1 = N(CH3)2;
d
e R1 = N(C2H5)2
g
=
;
h
i
N
Scheme-I:Reagents and conditions: (a) NaSCH3, H2O, r.t., 72 h, 65 %. (b)
2 mol L-1, HCl, MeOH, reflux, 24 h, 50 %. (c) Amines, r.t., 48 h,
90-95 %. (d) conc H2SO4, H2O, reflux, 5 h, 60-80 %. (e) SO2Cl2,
reflux, 5 h, 90 %

7476 Shen et al.
Asian J. Chem.
concentrated H2SO4 in water in good yields (60-85 %). Com-
pound 3h was refluxed with SO2Cl2 to give the compound 3i.
The resulting products were purified by column chromato-
graphy and their structures were shown in Scheme-I and the
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TABLE-1
CYTOTOXICITY DATA OF THE TARGET COMPOUNDS
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IC50 (µM)/cell line
Compound
A2780
0.095
0.098
0.120
0.195
0.207
0.226
0.245
0.230
0.102
0.168
0.258
0.224
0.285
0.207
0.326
0.335
0.232
0.094
A549
0. 080
0.088
0.115
0.198
0.208
0.232
0.234
0.224
0. 108
0.178
0.298
0.315
0.258
0.208
0.312
0.324
0.234
0.078
BEL7402
0.042
0.086
0.118
0.123
0.126
0.203
0.238
0.225
0.112
0.156
0.276
0.318
0.293
0.126
0.323
0.328
0.265
0.080
MCF7
0.085
0.105
0.109
0.135
0.192
0.217
0.241
0.238
0.125
0.145
0.295
0.305
0.312
0.192
0.316
0.411
0.278
0.084
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2a
2b
2c
12. L.H. Shen, S.L. Wang, H.Y. Li, Y.S. Lai and L.J. Liu, Asian J. Chem.,
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2d
2e
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2f
2g
14. Data of selected compounds: 2b: yield 83 %, m.p. 165-167 °C, IR
(KBr, νmax, cm-1): 3370, 3280, 1665, 1613, 1491, 1456; 1H NMR
(CDCl3, 300 MHz, δ ppm): 1.79 (s, 3H, COCH3), 3.13 (d, 3H, NCH3),
3.64 (s, 3H, MeO-1), 3.87 (s, 3H, MeO-2), 3.93 (s, 3H, MeO-3), 4.70
(m, 1H, H-7), 6.50 (s, 1H, H-4), 6.65 (d, 1H,11.2 Hz, H-11), 7.52 (d,
1H, 11.2 Hz, H-12), 7.60 (s, 1H, H-8); MS (ESI, m/z): 398.4 [M]+;
Anal. Calcd. for C22H26O5N2: C 66.32, H 6.58, N 7.03; Found: C 67.08,
H 6.65, N 7.06. 2e: yield 90 %, m.p. 128-130 °C, IR (KBr, νmax, cm-1):
2h
3a
3b
3c
3d
3e
1
3f
3420, 3280,1655, 1528, 1476; H NMR (CDCl3, 300 MHz, δ ppm):
3g
3h
1.25 [t, 6H, N(CH2CH3)2], 1.98 (s, 3H, COCH3), 1.92-2.58 (m, 4H, 2 ×
CH2), 3.26-3.42 [m, 4H, N(CH2CH3)2], 3.65 (s, 3H, MeO-1), 3.89 (s,
3H, MeO-2), 3.95 (s, 3H, MeO-3), 4.65 (m, 1H, H-7), 6.51 (s, 1H, H-
4), 6.83 (d, 1H,10.4 Hz, H-11), 7.30 (d, 1H, 10.4 Hz, H-12), 7.64
(s, 1H, H-8); MS (ESI, m/z): 412.3 [M]+; Anal. Calcd. for C23H28O5N2:
C 66.97, H 6.84, N 6.79; Found: C 67.08, H 6.89, N 7.01. 2h: yield 90
%, m.p. 166-168 °C, IR (KBr, νmax, cm-1): 3456, 2985, 1739, 1605,
1560, 1447; 1H NMR (CDCl3, 300 MHz, δ ppm): 1.95 (s, 3H, COCH3),
1.90-2.58 (m, 4H, 2 × CH2), 3.45 (m, 2H, NCH2), 3.66 (s, 3H, MeO-1),
3.90 (s, 3H, MeO-2), 3.94 (s, 3H, MeO-3), 4.15 (t, 2H, CH2OH), 4.65-
4.72 (m, 1H, H-7), 6.52 (s, 1H, H-4), 7.18 (m, 2H, H-11 and H-12),
7.54 (s, 1H, H-8); MS (ESI, m/z): 428.2 [M]+; Anal. Calcd. for
C23H28O6N2: C 64.47, H 6.59, N 6.54; Found: C 64.58, H 6.56, N 6.61.
3d: yield 63 %, IR (KBr, νmax, cm-1): 3420, 2920, 1663, 1568, 1450; 1H
NMR (CDCl3, 300 MHz, δ ppm): 0.99-1.17 (t, 3H, NCH2CH2CH3),
1.50-1.60 (m, 2H, NCH2CH2CH3), 1.90-2.48 (m, 4H, 2 × CH2), 3.25-
3.40 (m, 2H, NCH2), 3.60 (s, 3H, MeO-1), 3.90 (s, 3H, MeO-2), 3.94
(s, 3H, MeO-3), 4.70 (m, 1H, H-7), 6.52 (s, 1H, H-4), 7.20 (m, 2H, H-
11 and H-12), 7.66 (s, 1H, H-8); MS (ESI, m/z): 384.3 [M]+; Anal.
Calcd. for C22H28O4N2: C 68.73, H 7.34, N 7.29; Found: C 68.87, H
7.49, N 7.37. 3g: yield 72 %, IR (KBr, νmax, cm-1): 3400, 3280, 1663,
1510; 1H NMR (CDCl3, 300 MHz, δ ppm): 1.50-1.90 [m, 6H, N-
CH2(CH2)3CH2], 1.70-2.45 (m, 4H, 2 × CH2), 3.35-3.48 [m, 4H, N-
CH2(CH2)3CH2], 3.65 (s, 3H, MeO-1), 3.88 (s, 3H, MeO-2), 3.92 (s,
3H, MeO-3), 4.67 (m, 1H, H-7), 6.52 (s, 1H, H-4), 7.20 (m, 2H, H-11
and H-12), 7.70 (s, 1H, H-8); MS (ESI, m/z): 410.2 [M]+; Anal. Calcd.
for C24H30O4N2: C 70.22, H 7.37, N 6.82; Found: C 70.97, H 7.39, N
6.87.
3i
Colchicine
The study results indicate that these new C-10 derivatives
showed superior or comparable cytotoxic activity to colchicine
in vitro. For all four tumor cell lines, compounds 2a and 2b
have better cytotoxicity than colchicine. In human hepatoma
cell line (BEL7402), compounds 2b has similar cytotoxicity
as colchicine, whereas compounds 2a exhibited almost twofold
potent activities than colchicine.As to human breast carcinoma
cell line (MCF7), compound 2a exhibited similar cytotoxicity
as colchicine. The results demonstrated that new C-10 deriva-
tives could really improve colchicine's antitumor activity
in vitro.
In summary, a series of novel colchicine C-10 conjugates
were synthesized and evaluated for their in vitro cytotoxicity
against four human tumor cell lines. It was found that 2a and
2b showed significant cytotoxic activities. Further biological
evaluations are currently in progress and will be reported in
due course.
ACKNOWLEDGEMENTS
15. J. Tatsuzaki, M. Taniguchi, K.F. Bastow, K. Nakagawa-Goto, S.L. Morris-
Natschke, H. Itokawa, K. Baba and K.-H. Lee, Bioorg. Med. Chem.,
15, 6193 (2007).
This work was supported by the Higher School Science
and Technology Projects of Hebei Province (No. Z2014131)
and the Science Research Project of Handan College (No.
14106).