Synthesis and anticancer activities of novel 8-azapurine carbocyclic nucleoside hydrazones

Article abstract of DOI:10.1016/j.bmcl.2015.09.002

A series of novel 8-azapurine carbocyclic nucleoside hydrazones were synthesized through a useful procedure starting from amino alcohol and pyrimido dichloride. All the products were characterized by ¹H NMR, ¹³C NMR and HRMS spectral analysis and the stereochemical structure of key intermediate was also confirmed by a single crystal X-ray diffraction crystallographic analysis. Moreover, the anticancer activities were evaluated in vitro against human liver cancer Huh-7 cell line and human breast cancer A549 cell line.

Full text of DOI:10.1016/j.bmcl.2015.09.002

Bioorganic & Medicinal Chemistry Letters xxx (2015) xxx–xxx
Contents lists available at ScienceDirect
Bioorganic & Medicinal Chemistry Letters
journal homepage: www.elsevier.com/locate/bmcl
Synthesis and anticancer activities of novel 8-azapurine carbocyclic
nucleoside hydrazones
b
b
Yeming Wang a, Hong Yan a, , Chao Ma , Dan Lu
⇑
a College of Life Science and Bio-engineering, Beijing University of Technology, No. 100 Pingleyuan, Chaoyang District, Beijing 100124, PR China
b Beijing Medking Pharmaceutical Technology Co. Ltd, Hongxianghong Business Incubator Block C, Room 301, Changping District, Beijing 102209, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
A series of novel 8-azapurine carbocyclic nucleoside hydrazones were synthesized through a useful pro-
cedure starting from amino alcohol and pyrimido dichloride. All the products were characterized by 1H
NMR, 13C NMR and HRMS spectral analysis and the stereochemical structure of key intermediate was also
confirmed by a single crystal X-ray diffraction crystallographic analysis. Moreover, the anticancer activ-
ities were evaluated in vitro against human liver cancer Huh-7 cell line and human breast cancer A549
cell line.
Received 31 July 2015
Revised 28 August 2015
Accepted 1 September 2015
Available online xxxx
Keywords:
Ó 2015 Published by Elsevier Ltd.
8-Azapurine
Carbocyclic nucleoside
Hydrazones
Anticancer
Carbocyclic nucleosides, where the furanose oxygen atom of the
normal nucleosides is replaced by a methylene group, have
received extraordinary attention over the last few years.1–5 And
attention has been increasingly focused on structural modifica-
tions of carbocyclic nucleosides. Many modified carbocyclic nucle-
osides have been reported to exhibit a variety of medicinal uses
such as antiviral and antitumor activities.6–10 Another useful class
of compounds are purines, which are considered as a promising
source of new drugs for the treatment of viral, tumor, and other
disorders.11–14 Replacement of the C-8 of purines with a N gives
1,2,3-triazolo-[4,5-d]pyrimidines (8-azapurines). It is pointed out
that 8-azapurines also possess a broad spectrum of biological
activity, exhibiting much more pronounced antitumor,15–17
properties as compared to other purines. The modification of
carbocyclic nucleosides as anticancer agents became interested
by 8-azapurines to strengthen the activities, for example, the car-
bocyclic 8-aza derivative A exhibited significant in vivo antitumor
A series of novel 8-azapurine carbocyclic nucleoside hydrazones
1a–p were successfully synthesized through a useful procedure
starting from amino alcohol
2 and pyrimido dichloride 3
(Scheme 1). Firstly, the preparation of amino pyrimidine 4 was a
nucleophilic substitution at C6 position in pyrimido dichloride 3
with amino alcohol 2 in 1,4-dioxane, triethylamine or N,N-diiso-
propyl-N-ethylamine used as an auxiliary base, in 91% yield. Sec-
ondly, the intermediate 5 was prepared by the cyclization of 4 in
methanol using 6 equiv of NaNO2 as an diazotization reagent in
presence of 15 equiv of hydrochloric acid at 0 °C in 83% yield.
Finally, the products 1a–p were prepared from three constituents
of 5, hydrazine monohydrate and aldehydes in tetrahydrofuran at
room temperature in 76–83% yield.
All the products were isolated as solids in color from white to
yellow and characterized by 1H NMR, 13C NMR and HRMS spectral
analysis. To unambiguously assign the stereochemical structures of
1, the intermediate 5 was performed a single crystal X-ray diffrac-
tion study. The X-ray diffraction crystallographic analysis of inter-
mediate 5 confirmed the stereochemical structure assignment
(Fig. 2). And crystallographic data for 5 has been deposited with
Cambridge Crystallographic Data Centre as supplementary number
CCDC 1054273.
activity (ED50 = 0.38
ited potent anticancer activities, for example, hydrazone derivative
showed potent anticancer activity against A549 cell line
(GI50 = 1.6
M),19–22 so the 8-azapurine carbocyclic nucleoside
l
M),18 and the hydrazone moiety also exhib-
B
l
hydrazones were designed as new anticancer agents (Fig. 1).
Herein, we described our chemistry efforts to prepare a series of
novel 8-azapurine carbocyclic nucleoside hydrazones and evalu-
ated their in vitro anticancer activities.
All synthesized 1a–p were tested for anticancer activity against
human liver cancer cell line Huh-7 and human breast cancer cell
line A549. The resulting data was presented in Table 1 and it
showed that all the tested compounds had generally considerable
activity against human liver cancer Huh-7 cells with 20.09–
68.04% inhibition and human breast cancer A549 cell line with
⇑
Corresponding author. Tel./fax: +86 010 67396642.
E-mail address: hongyan@bjut.edu.cn (H. Yan).
http://dx.doi.org/10.1016/j.bmcl.2015.09.002
0960-894X/Ó 2015 Published by Elsevier Ltd.
Please cite this article in press as: Wang, Y.; et al. Bioorg. Med. Chem. Lett. (2015), http://dx.doi.org/10.1016/j.bmcl.2015.09.002

2
Y. Wang et al. / Bioorg. Med. Chem. Lett. xxx (2015) xxx–xxx
NH2
N
N
OH
OH
S
N
HO
N
N
N
N
H
N
H
OH
HO
A
B
N
N
R
HN
N
N
N
N
HO
S
OH
HO
1c
1b
: R = 2-hydroxyphenyl
: R = 2,4-dihydroxyphenyl
: R = 3,4-methoxyphenyl
: R = 3,4-difluorophenyl
1a
1d
1g
: R = phenyl
1f
1i
1e
1h
: R = 3-hydroxyphenyl
: R = 2-methoxyphenyl
: R = 4-hydroxyphenyl
: R = 4-methoxyphenyl
1l
: R = 2,4-chlorophenyl
1k
1n
1j
: R = 4-chlorophenyl
: R = 2-chlorophenyl
: R = 4-nitrophenyl
1o
1m
: R = pyridin-2-yl
: R = 3-nitrophenyl
1p
: R = 2-thiophen-2-yl
Figure 1. Design strategy of novel 8-azapurine carbocyclic nucleoside hydrazones 1 from A and B.
Cl
NH2
H2N
HN
NH2
HO
Cl
Cl
N
a
HO
N
N
S
N
S
O
O
O
O
2
3
4
N
R
Cl
HN
N
N
N
N
N
N
N
b
c
N
N
HO
S
N
HO
S
OH
HO
OH
HO
5
1a-p
Scheme 1. Reagents and conditions: (a) 1,4-dioxane, DIEA, 100 °C, 16 h; (b) HClaq, MeOH, NaNO2, 0 °C, 1 h; (c) NH2NH2ÁH2O, THF, DIEA, rt, 1 h; then (het)aryl-aldehyde, rt,
0.5–1 h.
21.44–69.19% inhibition at 10
(R = 4-nitrophenyl) was the most active agent against human liver
cancer Huh-7 cells with IC50 value of 11.69 M.
The anticancer activity against human liver cancer Huh-7 cell
line revealed that the position of substitution at benzene ring
was a critical element determining potency anticancer activity.
l
M concentration, respectively. 1n
The replacement of benzene ring with heterocyclic compounds,
1o (R = pyridin-2-yl) and 1p (R = thiophen-2-yl) improved the bio-
logical activity with 52.54% and 49.95% inhibition, which provided
useful information for further development of new anticancer inhi-
bitors. 1a (R = phenyl) with no substitution at benzene ring was
tested with 20.09% inhibition. The introduction of 3,4-difluoro
l
Please cite this article in press as: Wang, Y.; et al. Bioorg. Med. Chem. Lett. (2015), http://dx.doi.org/10.1016/j.bmcl.2015.09.002

Y. Wang et al. / Bioorg. Med. Chem. Lett. xxx (2015) xxx–xxx
3
yield. All the products were characterized by 1H NMR, 13C NMR
and HRMS spectral analysis, especially the stereochemical struc-
ture of intermediate 5 was also confirmed by a single crystal X-
ray diffraction crystallographic analysis. The anticancer activities
of target compounds were evaluated for their in vitro against
human cancer Huh-7 and A549 cell lines with 20.09–68.04% and
21.44–69.19% inhibition at 10 lM concentration, respectively.
The results showed that all the tested compounds had generally
considerable activities. In particular, 1n was found to be a potent
inhibitor against Huh-7 cancer cell line with IC50 value of
11.69 lM and it also exhibited anticancer activity against human
breast cancer A549 cell line with the 67.98% inhibition at 10
lM
concentration.
Acknowledgments
Figure 2. The X-ray crystal structure of intermediate 5 monohydrate with the
atom-numbering and displacement ellipsoids are drawn at 50% probability level.
We thank Beijing Medking Pharmaceutical Technology Co. Ltd
for financial support and we are also grateful to professor Honggen
Wang in Nankai University for single crystal X-ray diffraction tech-
nical assistance.
Table 1
Anticancer activities of compounds 1a–pa
Compound
Inhibition (%)
Supplementary data
Huh-7
A549
1a
1b
1c
1d
1e
1f
1g
1h
1i
1j
1k
1l
1m
1n
1o
1p
20.09
31.48
34.45
36.46
43.83
38.28
43.82
57.32
26.89
37.71
47.75
51.20
58.49
68.04b
52.54
49.95
78.66
22.93
26.87
24.33
21.44
32.30
33.01
31.62
69.19
28.95
30.53
34.19
41.64
67.98
67.58
38.60
38.81
64.47
Supplementary data associated with this article can be found, in
the online version, at http://dx.doi.org/10.1016/j.bmcl.2015.09.
002.
References and notes
1. Jiang, M. X.-W.; Jin, B.; Gage, J. L.; Priour, A.; Savela, G.; Miller, M. J. J. Org. Chem.
2006, 71, 4164.
2. Ye, W.; He, M.; Schneller, S. W. Tetrahedron Lett. 2009, 50, 7156.
3. Chandra, G.; Majik, M. S.; Lee, J. Y.; Jeong, L. S. Org. Lett. 2012, 14, 2134.
4. Scagnelli, L.; Memeo, M. G.; Carosso, S.; Bovio, B.; Quadrelli, P. Eur. J. Org. Chem.
2013, 2013, 3835.
5. Jung, Y. H.; Kim, S. I.; Hong, Y. J.; Park, S. J.; Kang, K. T.; Kim, S. Y.; Kim, I. S.
Tetrahedron 2015, 71, 1068.
6. Kojima, H.; Kozaki, A.; Iwata, M.; Ando, T.; Kitade, Y. Bioorg. Med. Chem. 2008,
16, 6575.
7. Lee, K. M.; Choi, W. J.; Lee, Y.; Lee, H. J.; Zhao, L. X.; Lee, H. W.; Park, J. G.; Kim, H.
O.; Hwang, K. Y.; Heo, Y.-S. J. Med. Chem. 2011, 54, 930.
8. Ugliarolo, E. A.; Gagey, D.; Lantaño, B.; Moltrasio, G. Y.; Campos, R. H.;
Cavallaro, L. V.; Moglioni, A. G. Bioorg. Med. Chem. 2012, 20, 5986.
9. Choi, W. J.; Chung, H.-J.; Chandra, G.; Alexander, V.; Zhao, L. X.; Lee, H. W.;
Nayak, A.; Majik, M. S.; Kim, H. O.; Kim, J.-H. J. Med. Chem. 2012, 55, 4521.
10. Chen, Q.; Liu, C.; Komazin, G.; Bowlin, T. L.; Schneller, S. W. Bioorg. Med. Chem.
2014, 22, 6961.
Fluorouracil
a
Huh-7 and A549 cells were treated with 10
72 h.
lmol/L compounds 1a–p for the
b
IC50 value of 11.69 lM against human liver cancer cells Huh-7.
substitution at benzene ring affording 1b (R = 3,4-difluorophenyl)
potentiated the antitumor activity with 31.48% inhibition. Simi-
larly, introduction of 2-hydroxyl, 3-hydroxyl or 4-hydroxyl substi-
tution at benzene ring affording 1c (R = 2-hydroxyphenyl), 1d
(R = 3-hydroxyphenyl) and 1e (R = 4-hydroxyphenyl) also
improved anticancer activity in different extent with 34.45%,
36.46% and 43.83% inhibition. Concerning 1c, 1d and 1e, it was
found that the different inhibitory activity was depended on the
hydroxyl substituent different position at benzene ring. When
the hydroxyl group takes the para direction, 1e exhibited higher
inhibitory activity than 1c, 1d and 1e. The presence of a methoxyl
group at benzene ring, for example, 1g (R = 2-methoxyphenyl) and
1h (R = 4-methoxyphenyl) also improved anticancer activity with
43.82% and 57.32% inhibition. Halogenated benzyl derivatives 1j
and 1k also have been shown a positive effect on anticancer
activity.
11. Biagi, G.; Franchi, M.; Giorgi, I.; Livi, O.; Scartoni, V. J. Heterocycl. Chem. 1989,
26, 39.
12. Barili, P. L.; Biagi, G.; Giorgi, I.; Livi, O.; Scartoni, V. J. Heterocycl. Chem. 1991, 28,
1351.
13. Seela, F.; Lampe, S. Helv. Chim. Acta 1993, 76, 2388.
14. Konkel, M. J.; Vince, R. J. Org. Chem. 1996, 61, 6199.
15. Vince, R.; Turakhia, R. H.; Shannon, W. M.; Arnett, G. J. Med. Chem. 1987, 30,
2026.
16. Vince, R.; Hua, M. J. Med. Chem. 1990, 33, 17.
17. Peterson, M. L.; Vince, R. J. Med. Chem. 1990, 33, 1214.
18. Vince, R.; Brownell, J.; Daluge, S. J. Med. Chem. 1984, 27, 1358.
19. Kang, D.-H.; Kim, J.-S.; Jung, M.-J.; Lee, E.-S.; Jahng, Y.; Kwon, Y.; Na, Y. Bioorg.
Med. Chem. Lett. 2008, 18, 1520.
20. Calcatierra, V.; López, Ó.; Fernández-Bolaños, J. G.; Plata, G. B.; Padrón, J. M. Eur.
J. Med. Chem. 2015, 94, 63.
21. Yong, X.; Fan, C.; Zhao, B.; Zhao, J.; Shin, D.; Miao, J. Eur. J. Med. Chem. 2008, 43,
2347.
22. Cui, Z.; Li, Y.; Ling, Y.; Huang, J.; Cui, J.; Wang, R.; Yang, X. Eur. J. Med. Chem.
2010, 45, 5576.
In summary, the 8-azapurine carbocyclic nucleoside hydra-
zones were synthesized by three-step reaction with appropriate
Please cite this article in press as: Wang, Y.; et al. Bioorg. Med. Chem. Lett. (2015), http://dx.doi.org/10.1016/j.bmcl.2015.09.002