Synthesis and antitumor effects of a new class of 1,2,4-triazole derivatives

Article abstract of DOI:10.1007/s00044-020-02652-y

In order to obtain more effective antitumor agents, a new class of 1,2,4-triazole derivatives bearing disulfide bond were designed and synthesized. All the final compounds were confirmed by IR, ¹H NMR, ¹³C NMR and HR-ESI-MS. The in vitro cytotoxicity of the compounds on the SMMC-7721, Hela, A549 cancer cell lines and the L929 normal cell lines were assessed by cell counting kit-8 (CCK-8). Many of tested compounds 8a–h, 9a–h, 10a–h had better cytotoxic activity on various cancer cell lines than positive control 5-fluorouracil, and they were less cytotoxic to normal cell line L929 than cancer cells. Among them, compounds 9e, 9g, and 10h showed better cytotoxic activity on SMMC-7721 cells with IC₅₀ values 4.12, 2.92, and 4.53 μM, respectively. Compounds 8a, 9g, 10g and 10h displayed high antiproliferative activity against Hela cells with IC₅₀ values 6.31, 4.31, 6.31 and 3.97 μM, respectively. Compounds 8c, 10a and 10h revealed effective biological potency on A549 cells with IC₅₀ values 4.75, 4.92 and 3.73 μM, respectively. Moreover, a great majority of tested compounds revealed low cytotoxicity on normal cell line L929.

Full text of DOI:10.1007/s00044-020-02652-y

MEDICINAL
CHEMISTRY
RESEARCH
Medicinal Chemistry Research
https://doi.org/10.1007/s00044-020-02652-y
ORIGINAL RESEARCH
Synthesis and antitumor effects of a new class of 1,2,4-triazole
derivatives
Zheng Wu1 Xin Li1 Chun-Lan Chi1 Lu Xu1 Yong-Yue Sun1 Bao-Quan Chen1
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Received: 4 June 2020 / Accepted: 8 October 2020
© Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract
In order to obtain more effective antitumor agents, a new class of 1,2,4-triazole derivatives bearing disulfide bond were
designed and synthesized. All the final compounds were confirmed by IR, 1H NMR, 13C NMR and HR-ESI-MS. The in vitro
cytotoxicity of the compounds on the SMMC-7721, Hela, A549 cancer cell lines and the L929 normal cell lines were
assessed by cell counting kit-8 (CCK-8). Many of tested compounds 8a–h, 9a–h, 10a–h had better cytotoxic activity on
various cancer cell lines than positive control 5-fluorouracil, and they were less cytotoxic to normal cell line L929 than
cancer cells. Among them, compounds 9e, 9g, and 10h showed better cytotoxic activity on SMMC-7721 cells with IC50
values 4.12, 2.92, and 4.53 μM, respectively. Compounds 8a, 9g, 10g and 10h displayed high antiproliferative activity
against Hela cells with IC50 values 6.31, 4.31, 6.31 and 3.97 μM, respectively. Compounds 8c, 10a and 10h revealed
effective biological potency on A549 cells with IC50 values 4.75, 4.92 and 3.73 μM, respectively. Moreover, a great majority
of tested compounds revealed low cytotoxicity on normal cell line L929.
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Keywords 1,2,4-Triazole Disulfides Synthesis Antiproliferative activity Cytotoxicity
Introduction
and been a most referenced building blocks in the field of
pharmaceutical research [3–7]. Particularly, further litera-
ture survey revealed that 1,2,4-triazoles and their fused
heterocyclic derivatives have expressed a high level of
selectivity with versatile biological activities, such as anti-
oxidant [3, 8, 9], anticonvulsant [10, 11], anticancer
[12, 13], antibacterial [14–19], anti-inflammatory [20–23],
analgesic [24, 25], antifungal [26], antitubercular [27, 28],
antimalarial [29], antidepressant [30], hypoglycemic [31]
and thymidine phosphorylase inhibitory properties [32–34].
In addition to this, as a nitrogen-containing heterocyclic
compound, 1,2,4 triazole has high metabolic stability and
unique ability to interact with biomolecular targets [35–37].
In recent years, more and more reports on the synthesis of
1,2,4-triazole derivatives have also been reported [38–41],
which provides many ideas for the design of our subject.
Meanwhile, disulfide derivatives are reported to show
extensive pharmacological activities including targeting
antitumor activity [42–44]. Consequently, the importance of
disulfide group in making up biologically active compounds
has received much attention.
Cancer is a disease with high mortality characterized by
abnormal cell proliferation and spread, and has become a
disease that needs to be solved urgently [1]. Therefore,
designing and synthesizing new anticancer drugs with high
efficiency and selectivity has important modern sig-
nificance [2].
Five-membered heterocyclic compounds, such as 1,3,4-
oxadiazoles, 1,3,4-thiadiazoles, and 1,2,4-triazoles, have
been found to possess a wide array of biological properties
Supplementary information The online version of this article (https://
doi.org/10.1007/s00044-020-02652-y) contains supplementary
material, which is available to authorized users.
* Yong-Yue Sun
sunyy1977@hotmail.com
* Bao-Quan Chen
chenbaoquan66@126.com
In view of the above observations, some derivatives of
1,2,4-triazole bearing disulfide bond were synthesized in
this research work and found to be good cytotoxic agents
against some cancer cell. Therefore, we researched for their
1
Tianjin Key Laboratory of Organic Solar Cells and Photochemical
Conversion, Tianjin Key Laboratory of Drug Targeting and
Bioimaging, School of Chemistry and Chemical Engineering,
Tianjin University of Technology, Tianjin 300384, China

Medicinal Chemistry Research
in vitro cytotoxic activities on a panel of the selected human
cancer cell in lines, including SMMC-7721, Hela, A549 and
L929 normal cell lines.
temperature for 30 min, and then refluxed for 3 h. After
monitoring by thin layer chromatography until the end of
the reaction, hydrochloric acid is slowly dropped into the
reaction mixture at 0–5 °C until the solids precipitate out,
and recrystallized from ethanol to afford pure compounds.
Materials and methods
2,3-diphenyl-5-sulfhydryl-1,2,4-triazole(7a)
Chemistry
Yellow solid, Yield 61%, m.p.: 176–177 °C. IR (KBr)
1
All reagents and solvents used in this study were supplied
from Tianjin Hengshan (P.R. China), Tianjin Jiangtianton-
gyi (P.R. China) and Energy Chemical (P.R. China), and
used without further purification. In addition, some biolo-
gical reagents were purchased from Dojindo.
cm−1: 2360, 1733, 1500, 1257, 688. H NMR (400 MHz,
CDCl3) δ (ppm): 7.53–7.49 (m, 2H, Ar-H), 7.45–7.40
(m, 4H, Ar-H), 7.40–7.33 (m, 4H, Ar-H), 5.09 (s, 1H, SH).
MS-ESI (m/z): C14H11N3S: [M+H]+ 254.0.
Thin-layer chromatography (TLC) analysis was accom-
plished with Silica gel plates GF254 and visualization on
TLC was achieved by UV light. Melting points (m.p.) were
determined on an X-6 microscope melting point apparatus
and were given uncorrected. Infrared spectra were recorded
on a Nicolet Avatar 370 spectrometer with KBr as diluents.
The high-resolution mass spectra were taken with a Waters
Xevo G2. 13C NMR and 1H NMR spectra were collected at
frequencies of 100 and 400 MHz. NMR spectra were
obtained by a Bruker Avance III 400 MHz spectrometer
using CDCl3 as solvent and tetramethylsilane as internal.
The chemical shifts are illustrated in values (ppm) and the
coupling constant values (J) are shown in Hertz. Signal
multiplicities are reported by the following abbreviations: s
(singlet), d (doublet), t (triplet), dd (double doublet),
q (quartet), m (multiplet), and brs (broad signal).
2-phenyl-3-(4-methylphenyl)-5-sulfhydryl-1,2,4-triazole(7b)
Yellow solid, Yield 77%, m.p.: 235–236 °C. IR (KBr)
1
cm−1: 2360, 1637, 1455, 1239, 771. H NMR (400 MHz,
CDCl3) δ (ppm): 7.45–7.41 (m, 3H, Ar-H), 7.40 (s, 1H,
Ar-H), 7.38 (d, J = 4.0 Hz, 3H, Ar-H), 7.15 (d, J = 8.0 Hz,
2H, Ar-H), 5.07 (s, 1H, SH), 2.38 (s, 3H, CH3). MS-ESI
(m/z): C15H13N3S: [M+H]+ 268.0.
2-phenyl-3-(4-chlorophenyl)-5-sulfhydryl-1,2,4-triazole(7c)
White solid, Yield 55%, m.p.: 168–169 °C. IR (KBr) cm−1
:
1
2360, 1596, 1454, 1276, 736, 690. H NMR (400 MHz,
CDCl3) δ (ppm): 7.49–7.44 (m, 4H, Ar-H), 7.44 (d, J =
4.0 Hz, 1H, Ar-H), 7.39 – 7.35 (m, 2H, Ar-H), 7.34 (d, J =
4.0 Hz, 1H, Ar-H), 7.32 (d, J = 4.0 Hz, 1H, Ar-H), 5.06 (s,
1H, SH). MS-ESI (m/z): C14H10N3SCl: [M+H]+ 288.0.
Tumor cell growth inhibitory assay
General procedure for the synthesis of compounds
The various cells used in the following cell experiments
were obtained from the Tumor Cell Resources Bank of the
Chinese Academy of Medical Sciences. Cell counting kit-8
was purchased from Dojindo (Japan). The in vitro human
cancer cell lines SMMC-7721, A549, Hela, and normal cell
lines L929 were maintained and cultured in proper medium
in a 5% CO2 at 37 °C during the experiment. In the anti-
tumor cell test, we repeated the biological test three times,
and used the Origin software for statistical analysis. The
inhibition (IC50) of the selected cells proliferation by target
compounds 8a–h, 9a–h, 10a–h and reference drug was
assessed by CCK-8 assay as described in the literature [45].
8a–h, 9a–h and 10a–h
S-Alkyl-thioisothiourea hydrochloride 2 (2.2 mmol) and 2-
phenyl-3-(4-substituted phenyl)-5- sulfhydryl-1,2,4-triazole
7a–h (2 mmol) were dissolved in ethanol (15 mL) and water
(5 mL). Then, a solution of saturated NaHCO3 (20 mL) was
added dropwise with stirring for 4 h at 0-5 °C. After mon-
itoring by thin layer chromatography until the end of the
reaction, the reaction mixture was extracted with dichlor-
omethane and water, the organic phase was collected and
concentrated. The final products were obtained by filtration
and purification of crude solids by silica gel column chro-
matography eluting with petroleum ether/ethyl acetate
(24:1, by volume).
General procedure for the synthesis of
intermediates 7a–c
2,3-diphenyl-5-ethyldisulfanyl-1,2,4-triazole(8a)
The compound 1-phenyl-1-(4-substituted phenyl)-3-thiose-
micarbazide 6 (17 mmol) was dissolved in a mixed solution
of 60 mL 10% NaOH aqueous solution and methanol with a
volume ratio of 5:1, the reaction mixture was stirred at room
Yellow solid, Yield 85%, m.p.: 87–88 °C. IR (KBr) cm−1
2920, 1592, 1496, 1246, 696, 511. H NMR (400 MHz,
CDCl3) δ (ppm): 7.51 (t, J = 4.0 Hz, 1H, Ar-H), 7.49 (t,
:
1

Medicinal Chemistry Research
J = 4.0 Hz, 1H, Ar-H), 7.46–7.39 (m, 4H, Ar-H), 7.38–7.31
(m, 4H, Ar-H), 3.03 (m, 2H, CH2), 1.45 (t, J = 8.0 Hz, 3H,
CH3). 13C NMR (CDCl3, 100 MHz) δ (ppm): 161.44 (C-5),
155.37 (C-3), 137.84 (C-4”), 130.29 (C-1”), 129.41 (C-2’,
C-6’), 129.09 (C-4’), 128.96 (C-3”, C-5”), 128.55 (C-3’, C-
5’), 127.31 (C-1’), 125.39 (C-2”, C-6”), 33.23 (-SCH2CH3),
14.17 (-SCH2CH3). HR-ESI-MS (m/z): Calcd. for
C16H15N3S2: 314.0786 [M+H]+, Found 314.0797.
(-SCH2CH2CH2CH3), 13.71 (-SCH2CH2CH2CH3). HR-
ESI-MS (m/z): Calcd. for C18H19N3S2: 342.1099
[M+H]+, Found 342.1104.
2,3-diphenyl-5-(2-butyldisulfanyl)-1,2,4-triazole(8e)
Yellow-brown solid, Yield 74%, m.p.: 64–65 °C. IR (KBr)
cm−1: 2956, 1595, 1501, 1264, 696, 495. 1H NMR
(400 MHz, CDCl3) δ (ppm): 7.52 (t, J = 4.0 Hz, 1H, Ar-H),
7.50 (t, J = 4.0 Hz, 1H, Ar-H), 7.47–7.40 (m, 4H, Ar-H),
7.40–7.33 (m, 4H, Ar-H), 2.92 (d, J = 8.0 Hz, 2H, CH2),
2.13 (m, 1H, CH), 1.07 (d, J = 4.0 Hz, 6H, CH3). 13C NMR
(CDCl3, 100 MHz) δ (ppm): 161.46 (C-5), 155.36 (C-3),
137.87 (C-4”), 130.28 (C-1”), 129.40 (C-2’, C-6’), 129.07
(C-4’), 128.96 (C-3”, C-5”), 128.55 (C-3’, C-5’), 127.33
(C-1’), 125.39 (C-2”, C-6”), 48.75 (-SCH2CH2(CH3)2),
27.90 (-SCH2CH2(CH3)2), 21.78 (-SCH2CH2(CH3)2). HR-
ESI-MS(m/z): Calcd. for C18H19N3S2: 342.1099 [M+H]+,
Found 342.1102.
2,3-diphenyl-5-(n-propyldisulfanyl)-1,2,4-triazole(8b)
White solid, Yield 80%, m.p.: 50–51 °C. IR (KBr) cm−1
:
1
2960, 1595, 1501, 1255, 697, 470. H NMR (400 MHz,
CDCl3) δ (ppm): 7.49 (t, J = 4.0 Hz, 1H, Ar-H), 7.47 (t,
J = 4.0 Hz, 1H, Ar-H), 7.42–7.35 (m, 4H, Ar-H), 7.36–7.28
(m, 4H, Ar-H), 2.97 (t, J = 8.0 Hz, 2H, CH2), 1.83 (m, 2H,
CH2), 1.02 (t, J = 8.0 Hz, 3H, CH3). 13C NMR (CDCl3,
100 MHz) δ (ppm): 161.38 (C-5), 155.33 (C-3), 137.79 (C-
4”), 130.32 (C-1”), 129.43 (C-2’, C-6’), 129.11 (C-4’),
128.93 (C-3”, C-5”), 128.57 (C-3’, C-5’), 127.25 (C-1’),
125.35 (C-2”, C-6”), 41.29 (-SCH2CH2CH3), 22.04
(-SCH2CH2CH3), 13.11 (-SCH2CH2CH3). HR-ESI-MS (m/
z): Calcd. for C17H17N3S2: 328.0942 [M+H]+, Found
328.0956.
2,3-diphenyl-5-(i-butyldisulfanyl)-1,2,4-triazole(8f)
Yellow oily liquid, Yield 65%. IR (KBr) cm−1: 2964,
1596, 1498, 1259, 692, 505. 1H NMR (400 MHz, CDCl3)
δ (ppm): 7.51 (t, J = 4.0 Hz, 1H, Ar-H), 7.49 (t, J =
4.0 Hz, 1H, Ar-H), 7.46–7.39 (m, 4H, Ar-H), 7.39–7.32
(m, 4H, Ar-H), 3.15 (m, 1H, CH), 1.93–1.81 (m, 1H,
CH), 1.69-1.58 (m, 1H, CH), 1.43 (d, J = 8.0 Hz, 3H,
CH3), 1.03 (t, J = 8.0 Hz, 3H, CH3). 13C NMR (CDCl3,
100 MHz) δ (ppm): 161.74 (C-5), 155.22 (C-3), 137.86
(C-4”), 130.26 (C-1”), 129.40 (C-2’, C-6’), 129.05 (C-
4’), 128.95 (C-3”, C-5”), 128.55 (C-3’, C-5’), 127.33 (C-
1’), 125.36 (C-2”, C-6”), 48.58 (-SCH(CH3)CH2CH3),
2,3-diphenyl-5-(2-propyldisulfanyl)-1,2,4-triazole(8c)
White solid, Yield 71%, m.p.: 90–91 °C. IR (KBr) cm−1
:
1
2958, 1594, 1501, 1262, 697, 495. H NMR (400 MHz,
CDCl3) δ (ppm): 7.52 (t, J = 4.0 Hz, 1H, Ar-H), 7.50
(t, J = 4.0 Hz, 1H, Ar-H), 7.47–7.40 (m, 4H, Ar-H),
7.40–7.32 (m, 4H, Ar-H), 3.40 (m, 1H, CH), 1.44 (d, J =
8.0 Hz, 6H, CH3). 13C NMR (CDCl3, 100 MHz) δ (ppm):
161.70 (C-5), 155.26 (C-3), 137.85 (C-4”), 130.28 (C-1”),
129.40 (C-2’, C-6’), 129.06 (C-4’), 128.97 (C-3”, C-5”),
128.55 (C-3’, C-5’), 127.31 (C-1’), 125.39 (C-2”, C-6”),
41.72 (-SCH2(CH3)2), 22.39 (-SCH2(CH3)2). HR-ESI-MS
(m/z): Calcd. for C17H17N3S2: 328.0942 [M+H]+, Found
328.0946.
28.67
(-SCH(CH3)CH2CH3),
19.90
(-SCH(CH3)
CH2CH3), 11.43 (-SCH(CH3)CH2CH3). HR-ESI-MS (m/
z): Calcd. for C18H19N3S2: 342.1099 [M+H]+, Found
342.1106.
2,3-diphenyl-5-(n-pentyldisulfanyl)-1,2,4-triazole(8g)
2,3-diphenyl-5-(n-butyldisulfanyl)-1,2,4-triazole(8d)
Colorless oily liquid, Yield 77%. IR (KBr) cm−1: 2925,
1595, 1505, 1259, 695, 505. 1H NMR (400 MHz, CDCl3) δ
(ppm): 7.52 (t, J = 4.0 Hz, 1H, Ar-H), 7.50 (t, J = 4.0 Hz,
1H, Ar-H), 7.46–7.39 (m, 4H, Ar-H), 7.39–7.32 (m, 4H,
Ar-H), 3.01 (t, J = 8.0 Hz, 2H, CH2), 1.82 (m, 2H, CH2),
1.47–1.39 (m, 2H, CH2), 1.38–1.30 (m, 2H, CH2), 0.90 (t,
J = 8.0 Hz, 3H, CH3). 13C NMR (CDCl3, 100 MHz) δ
(ppm): 161.48 (C-5), 155.35 (C-3), 137.85 (C-4”), 130.28
(C-1”), 129.40 (C-2’, C-6’), 129.08 (C-4’), 128.96 (C-3”,
C-5”), 128.55 (C-3’, C-5’), 127.31 (C-1’), 125.38 (C-2”,
C-6”), 39.48 (-SCH2CH2CH2CH2CH3), 30.58 (-SCH2CH2
CH2CH2CH3), 28.41 (-SCH2CH2CH2CH2CH3), 22.33
(-SCH2CH2CH2CH2CH3), 13.98 (-SCH2CH2CH2CH2CH3).
Yellow oily liquid, Yield 77%. IR (KBr) cm−1: 2956, 1595,
1498, 1300, 692, 509. 1H NMR (400 MHz, CDCl3) δ
(ppm): 7.52 (t, J = 4.0 Hz, 1H, Ar-H), 7.50 (t, J = 4.0 Hz,
1H, Ar-H), 7.47–7.40 (m, 4H, Ar-H), 7.40–7.32 (m, 4H,
Ar-H), 3.05–3.00 (m, 2H, CH2), 1.85–1.75 (m, 2H, CH2),
1.49 (t, J = 4.0 Hz, 2H, CH2), 0.95 (t, J = 8.0 Hz, 3H, CH3).
13C NMR (CDCl3, 100 MHz) δ (ppm): 161.48 (C-5),
155.36 (C-3), 137.86 (C-4”), 130.27 (C-1”), 129.40 (C-2’,
C-6’), 129.07 (C-4’), 128.96 (C-3”, C-5”), 128.55 (C-3’,
C-5’), 127.33 (C-1’), 125.39 (C-2”, C-6”), 39.16
(-SCH2CH2CH2CH3), 30.78 (-SCH2CH2CH2CH3), 21.57

Medicinal Chemistry Research
HR-ESI-MS (m/z): Calcd. for C19H21N3S2: 356.1255
HR-ESI-MS (m/z): Calcd. for C18H19N3S2: 342.1099
[M+H]+, Found 356.1271.
[M+H]+, Found 342.1107.
2,3-diphenyl-5-(benzyldisulfanyl)-1,2,4-triazole(8h)
2-phenyl-3-(4-methylphenyl)-5-(2-propyldisulfanyl)-1,2,4-
triazole(9c)
Yellow solid, Yield 71%, m.p.: 73–74 °C. IR (KBr) cm−1
:
1
3028, 2912, 1601, 1541, 695, 468. H NMR (400 MHz,
CDCl3) δ (ppm): 7.53 (t, J = 4.0 Hz, 1H, Ar-H), 7.51 (t,
J = 4.0 Hz, 1H, Ar-H), 7.47–7.43 (m, 4H, Ar-H), 7.42 (m,
2H, Ar-H), 7.40–7.36 (m, 3H, Ar-H), 7.36–7.33 (m, 1H,
Ar-H), 7.32 (d, J = 4.0 Hz, 1H, Ar-H), 7.31 (d, J =
4.0 Hz, 1H, Ar-H), 7.29–7.24 (m, 1H, Ar-H), 4.29 (s, 2H,
CH2). 13C NMR (CDCl3, 100 MHz) δ (ppm): 161.16 (C-
5), 155.25 (C-3), 137.86 (C-4”), 136.65 (-SCH2C(CH)2
(CH)2CH), 130.34 (C-1”), 129.69 (-SCH2C(CH)2(CH)
2CH), 129.44 (C-2’, C-6’), 129.12 (C-4’), 128.99 (C-3”,
C-5”), 128.61 (-SCH2C(CH)2(CH)2CH), 128.45 (C-3’, C-
5’), 127.50 (-SCH2C(CH)2(CH)2CH), 127.35 (C-1’),
125.36 (C-2”, C-6”), 43.92 (-SCH2Ph). HR-ESI-MS (m/
z): Calcd. for C21H17N3S2: 376.0942 [M+H]+, Found
376.0952.
White solid, Yield 68%, m.p.: 90–91 °C. IR (KBr) cm−1
:
1
2960, 1595, 1499, 1260, 773, 497. H NMR (400 MHz,
CDCl3) δ (ppm): 7.46–7.42 (m, 3H, Ar-H), 7.40 (d, J =
4.0 Hz, 1H, Ar-H), 7.39–7.35 (m, 3H, Ar-H), 7.15 (d, J =
8.0 Hz, 2H, Ar-H), 3.39 (m, 1H, CH), 2.38 (s, 3H, CH3),
1.43 (d, J = 4.0 Hz, 6H, CH3). 13C NMR (CDCl3,
100 MHz) δ (ppm): 161.54 (C-5), 155.41 (C-3), 140.55 (C-
4”), 137.97 (C-4’), 129.37 (C-2’, C-6’), 129.24 (C-3”, C-
5”), 128.99 (C-1’), 128.86 (C-3’, C-5’), 125.43 (C-2”, C-
6”), 124.41(C-1”), 47.71 (-SCH2(CH3)2), 22.39 (-SCH2
(CH3)2), 21.46 (PhCH3). HR-ESI-MS (m/z): Calcd. for
C18H19N3S2: 342.1099 [M+H]+, Found 342.1100.
2-phenyl-3-(4-methylphenyl)-5-(n-butyldisulfanyl)-1,2,4-
triazole(9d)
2-phenyl-3-(4-methylphenyl)-5-ethyldisulfanyl-1,2,4-
triazole(9a)
Yellow solid, Yield 67%, m.p.: 74–75 °C. IR (KBr) cm−1
:
1
2922, 1595, 1499, 1264, 691, 501. H NMR (400 MHz,
CDCl3) δ (ppm): 7.46–7.42 (m, 3H, Ar-H), 7.41 (d, J =
4.0 Hz, 1H, Ar-H), 7.40–7.35 (m, 3H, Ar-H), 7.15 (d, J =
8.0 Hz, 2H, Ar-H), 3.02 (t, J = 8.0 Hz, 2H, CH2), 2.38 (s,
3H, CH3), 1.80 (m, 2H, CH2), 1.48 (m, 2H, CH2), 0.95 (t,
J = 8.0 Hz, 3H, CH3). 13C NMR (CDCl3, 100 MHz) δ
(ppm): 161.32 (C-5), 155.51 (C-3), 140.56 (C-4”), 137.99
(C-4’), 129.37 (C-2’, C-6’), 129.24 (C-3”, C-5”), 128.99 (C-
1’), 128.85 (C-3’, C-5’), 125.44 (C-11,C-14), 124.42 (C-1”),
39.15 (-SCH2CH2CH2CH3), 30.78 (-SCH2CH2CH2CH3),
21.57 (-SCH2CH2CH2CH3), 21.44 (PhCH3), 13.71
(-SCH2CH2CH2CH3). HR-ESI-MS (m/z): Calcd. for
C19H21N3S2: 356.1255 [M+H]+, Found 356.1272.
White solid, Yield 76%, m.p.: 91–92 °C. IR (KBr) cm−1
:
1
2957, 1592, 1493, 1257, 693, 519. H NMR (400 MHz,
CDCl3) δ (ppm): 7.44 (m, 3H, Ar-H), 7.40 (d, J = 4.0 Hz,
1H, Ar-H), 7.40–7.35 (m, 3H, Ar-H), 7.15 (d, J = 8.0 Hz,
2H, Ar-H), 3.06–3.01 (m, 2H, CH2), 2.37 (s, 3H, CH3), 1.45
(t, J = 8.0 Hz, 3H, CH3). 13C NMR (CDCl3, 100 MHz) δ
(ppm): 161.29 (C-5), 155.52 (C-3), 140.57 (C-4”), 137.98
(C-4’), 129.38 (C-2’, C-6’), 129.25 (C-3”, C-5”), 129.01
(C-1’), 128.86 (C-3’, C-5’), 125.45 (C-2”, C-6”), 124.40
(C-1”), 33.22 (-SCH2CH3), 21.44 (PhCH3), 14.16
(-SCH2CH3). HR-ESI-MS (m/z): Calcd. for C17H17N3S2:
328.0942 [M+H]+, Found 328.0942.
2-phenyl-3-(4-methylphenyl)-5-(2-butyldisulfanyl)-1,2,4-
triazole(9e)
2-phenyl-3-(4-methylphenyl)-5-(n-propyldisulfanyl)-1,2,4-
triazole(9b)
Yellow solid, Yield 75%, m.p.: 65–66 °C. IR (KBr) cm−1: 2954,
1596, 1500, 1266, 762, 503. H NMR (400 MHz, CDCl3) δ
White solid, Yield 72%, m.p.: 79–80 °C. IR (KBr) cm−1
:
1
1
2960, 1541, 1496, 1259, 768, 508. H NMR (400 MHz,
CDCl3) δ (ppm): 7.44 (m, 3H, Ar-H), 7.41 (d, J = 4.0 Hz,
1H, Ar-H), 7.40–7.36 (m, 3H, Ar-H), 7.15 (d, J = 8.0 Hz,
2H, Ar-H), 2.99 (t, J = 8.0 Hz, 2H, CH2), 2.38 (s, 3H, CH3),
1.86 (m, 2H, CH2), 1.05 (t, J = 8.0 Hz, 3H, CH3). 13C NMR
(CDCl3, 100 MHz) δ (ppm): 161.27 (C-5), 155.51 (C-3),
140.58 (C-4”), 137.96 (C-4’), 129.39 (C-2’, C-6’), 129.26
(C-3”, C-5”), 129.02 (C-1’), 128.85 (C-3’, C-5’),125.44 (C-
2”, C-6”), 124.38 (C-1”), 41.33 (-SCH2CH2CH3), 22.06
(-SCH2CH2CH3), 21.46 (PhCH3), 13.09 (-SCH2CH2CH3).
(ppm): 7.47–7.42 (m, 3H, Ar-H), 7.41 (d, J = 4.0 Hz, 1H, Ar-
H), 7.40–7.36 (m, 3H, Ar-H), 7.15 (d, J = 8.0 Hz, 2H, Ar-H),
2.92 (d, J = 4.0 Hz, 2H, CH2), 2.38 (s, 3H, CH3), 2.14 (m, 1H,
CH), 1.06 (d, J = 8.0 Hz, 6H, CH3). 13C NMR (CDCl3,
100 MHz) δ (ppm): 161.30 (C-5), 155.50 (C-3), 140.55 (C-4”),
138.01 (C-4’), 129.37 (C-4,C-8), 129.25 (C-3”, C-5”), 128.98
(C-1’), 128.85 (C-3’, C-5’), 125.43 (C-11, C-14), 124.44 (C-1”),
48.74 (-SCH2CH2(CH3)2), 27.89 (-SCH2CH2(CH3)2), 21.78
(-SCH2CH2(CH3)2), 21.44 (PhCH3). HR-ESI-MS (m/z): Calcd.
for C19H21N3S2: 356.1255 [M+H]+, Found 356.1248.

Medicinal Chemistry Research
2-phenyl-3-(4-methylphenyl)-5-(i-butyldisulfanyl)-1,2,4-
triazole(9f)
127.49 (-SCH2C(CH)2(CH)2CH), 125.40 (C-2”, C-6”),
124.44 (C-1”), 43.89 (-SCH2Ph), 21.51 (PhCH3). HR-ESI-
MS (m/z): Calcd. for C22H19N3S2: 390.1099 [M+H]+,
Found 390.1113.
Colorless oily liquid, Yield 72%. IR (KBr) cm−1: 2923,
1615, 1505, 1269, 690, 507. 1H NMR (400 MHz, CDCl3) δ
(ppm): 7.46–7.42 (m, 3H, Ar-H), 7.40 (d, J = 4.0 Hz, 1H,
Ar-H), 7.39–7.34 (m, 3H, Ar-H), 7.15 (d, J = 8.0 Hz, 2H,
Ar-H), 3.21–3.10 (m, 1H, CH), 2.37 (s, 3H, CH3),
1.92–1.80 (m, 1H, CH), 1.69–1.58 (m, 1H, CH), 1.42 (d,
J = 4.0 Hz, 3H, CH3), 1.02 (t, J = 8.0 Hz, 3H, CH3). 13C
NMR (CDCl3, 100 MHz) δ (ppm): 161.58 (C-5), 155.36 (C-
3), 140.54 (C-4”), 138.00 (C-4’), 129.36 (C-2’, C-6’),
129.24 (C-3”, C-5”), 128.97 (C-1’), 128.84 (C-3’, C-5’),
125.41 (C-11, C-14), 124.43 (C-1”), 48.58 (-SCH(CH3)
CH2CH3), 28.67 (-SCH(CH3)CH2CH3), 21.45 (PhCH3),
19.89 (-SCH(CH3)CH2CH3), 11.42 (-SCH(CH3)CH2CH3).
HR-ESI-MS (m/z): Calcd. for C19H21N3S2: 356.1255
[M+H]+, Found 356.1252.
2-phenyl-3-(4-chlorophenyl)-5-ethyldisulfanyl-1,2,4-triazole
(10a)
Yellow solid, Yield 79%, m.p.: 86–87 °C. IR (KBr) cm−1
:
2919, 1596, 1497, 1267, 778, 698, 494. 1H NMR
(400 MHz, CDCl3) δ (ppm): 7.46–1.43 (m, 4H, Ar-H), 7.43
(s, 1H, Ar-H), 7.38–7.33 (m, 2H, Ar-H), 7.32 (d, J =
4.0 Hz, 1H, Ar-H), 7.30 (d, J = 4.0 Hz, 1H, Ar-H), 3.01 (m,
2H, CH2), 1.44 (t, J = 8.0 Hz, 3H, CH3). 13C NMR (CDCl3,
100 MHz) δ (ppm): 161.64 (C-5), 154.35 (C-3), 137.63 (C-
4”), 136.59 (C-1”), 130.23 (C-2’, C-6’), 129.58 (C-3”,
C-5”), 129.37 (C-4’), 128.92 (C-2”, C-6”), 125.71
(C-1’), 125.44 (C-3’, C-5’), 33.22 (-SCH2CH3), 14.15
(-SCH2CH3). HR-ESI-MS (m/z): Calcd. for C16H14N3S2Cl:
348.0396 [M+H]+, Found 348.0404.
2-phenyl-3-(4-methylphenyl)-5-(n-pentyldisulfanyl)-1,2,4-
triazole(9g)
2-phenyl-3-(4-chlorophenyl)-5-(n-propyldisulfanyl)-1,2,4-
triazole(10b)
White solid, Yield 63%, m.p.: 54–55 °C. IR (KBr) cm−1
:
1
2951, 1594, 1497, 1257, 693, 503. H NMR (400 MHz,
CDCl3) δ (ppm): 7.46–7.42 (m, 3H, Ar-H), 7.40 (d, J =
4.0 Hz, 1H, Ar-H), 7.40–7.35 (m, 3H, Ar-H), 7.15 (d, J =
8.0 Hz, 2H, Ar-H), 3.01 (t, J = 8.0 Hz, 2H, CH2), 2.37 (s,
3H, CH3), 1.85–1.78 (m, 2H, CH2), 1.47–1.39 (m, 2H,
CH2), 1.38–1.29 (m, 2H, CH2), 0.91 (t, J = 8.0 Hz, 3H,
CH3). 13C NMR (CDCl3, 100 MHz) δ (ppm): 161.32 (C-
5), 155.50 (C-3), 140.57 (C-4”), 137.98 (C-4’), 129.37
(C-2’, C-6’), 129.25 (C-3”, C-5”), 129.00 (C-1’), 128.85
(C-3’, C-5’), 125.43 (C-2”, C-6”), 124.40 (C-1”), 39.47
(-SCH2CH2CH2CH2CH3), 30.59 (-SCH2CH2CH2 CH2CH3),
28.42 (-SCH2CH2CH2CH2CH3), 22.34 (-SCH2CH2CH2CH2
CH3), 21.45 (PhCH3), 13.99 (-SCH2CH2CH2CH2CH3). HR-
ESI-MS (m/z): Calcd. for C20H23N3S2: 370.1412 [M+H]+,
Found 370.1423.
White solid, Yield 73%, m.p.: 88–89 °C. IR (KBr) cm−1
:
2956, 1596, 1498, 1268, 778, 700, 491. 1H NMR
(400 MHz, CDCl3) δ (ppm): 7.49–7.46 (m, 4H, Ar-H),
7.45 (s, 1H, Ar-H), 7.39-7.35 (m, 2H, Ar-H), 7.34 (d, J =
4.0 Hz, 1H, Ar-H), 7.33 (d, J = 4.0 Hz, 1H, Ar-H), 2.99 (t,
J = 8.0 Hz, 2H, CH2), 1.90–1.81 (m, 2H, CH2), 1.06 (t,
J = 8.0 Hz, 3H, CH3). 13C NMR (CDCl3, 100 MHz) δ
(ppm): 161.65 (C-5), 154.34 (C-3), 137.64 (C-4”), 136.59
(C-1”), 130.23 (C-2’, C-6’), 129.58 (C-3”, C-5”), 129.36
(C-4’), 128.92 (C-2”, C-6”), 125.72 (C-1’), 125.43 (C-3’,
C-5’), 41.34 (-SCH2CH2CH3), 22.06 (-SCH2CH2CH3),
13.08 (-SCH2CH2CH3). HR-ESI-MS (m/z): Calcd. for
C17H16N3S2Cl: 362.0552 [M+H]+, Found 362.0566.
2-phenyl-3-(4-chlorophenyl)-5-(2-propyldisulfanyl)-1,2,4-
triazole(10c)
2-phenyl-3-(4-methylphenyl)-5-(benzyldisulfanyl)-1,2,4-
triazole(9h)
White solid, Yield 75%, m.p.: 107–108 °C. IR (KBr) cm−1
:
Pink solid, Yield 70%, m.p.: 86–87 °C. IR (KBr) cm−1
:
2960, 1595, 1497, 1270, 776, 696, 489. 1H NMR
(400 MHz, CDCl3) δ (ppm): 7.49–7.44 (m, 4H, Ar-H), 7.43
(s, 1H, Ar-H), 7.38–7.34 (m, 2H, Ar-H), 7.33 (s, 1H, Ar-H),
7.31 (d, J = 4.0 Hz, 1H, Ar-H), 3.42–3.35 (m, 1H, CH),
1.42 (d, J = 4.0 Hz, 6H, CH3). 13C NMR (100 MHz,
CDCl3) δ (ppm): 161.89 (C-5), 154.23 (C-3), 137.64 (C-
4”), 136.58 (C-1”), 130.24 (C-2’, C-6’), 129.56 (C-3”, C-
5”), 129.34 (C-4’), 128.91 (C-2”, C-6”), 125.72 (C-1’),
125.43 (C-3’, C-5’), 41.75 (-SCH2(CH3)2), 22.37 (-SCH2
(CH3)2). HR-ESI-MS (m/z): Calcd. for C17H16N3S2Cl:
[M+H]+ 362.0552, Found 362.0540.
1
3054, 2916, 1592, 1496, 706, 509. H NMR (400 MHz,
CDCl3) δ (ppm): 7.47–7.42 (m, 4H, Ar-H), 7.42 (s, 2H, Ar-
H), 7.40 (d, J = 4.0 Hz, 1H, Ar-H), 7.39–7.35 (m, 2H, Ar-
H), 7.35–7.30 (m, 2H, Ar-H), 7.29–7.24 (m, 1H, Ar-H),
7.17 (d, J = 8.0 Hz, 2H, Ar-H), 4.28 (s, 2H, CH2), 2.39 (s,
3H, CH3). 13C NMR (CDCl3, 100 MHz) δ (ppm): 161.00
(C-5), 155.40 (C-3), 140.62 (C-4”), 137.98 (C-4’), 136.67
(-SCH2C(CH)2(CH)2CH), 129.69 (-SCH2C(CH)2(CH)
2CH), 129.41 (C-2’, C-6’), 129.32 (C-3”, C-5”), 129.05 (C-
1’), 128.89 (C-3’, C-5’), 128.45 (-SCH2C(CH)2(CH)2CH),

Medicinal Chemistry Research
2-phenyl-3-(4-chlorophenyl)-5-(n-butyldisulfanyl)-1,2,4-
2-phenyl-3-(4-chlorophenyl)-5-(n-pentyldisulfanyl)-1,2,4-
triazole(10d)
triazole(10g)
White solid, Yield 78%, m.p.: 62–63 °C. IR (KBr) cm−1
:
White solid, Yield 65%, m.p.: 72–73 °C. IR (KBr) cm−1
:
2924, 1596, 1499, 1272, 769, 695, 494. 1H NMR
(400 MHz, CDCl3) δ (ppm): 7.49–7.45 (m, 4H, Ar-H),
7.45 (d, J = 4.0 Hz, 1H, Ar-H), 7.39-7.35 (m, 2H, Ar-H),
7.35 (s, 1H, Ar-H), 7.32 (d, J = 4.0 Hz, 1H, Ar-H), 3.02 (t,
J = 8.0 Hz, 2H, CH2), 1.80 (m, 2H, CH2), 1.48 (m, 2H,
CH2), 0.95 (t, J = 8.0 Hz, 3H, CH3). 13C NMR (100 MHz,
CDCl3) δ (ppm): 161.66 (C-5), 154.34 (C-3), 137.63 (C-
4”), 136.58 (C-1”), 130.23 (C-2’, C-6’), 129.58 (C-3”, C-
5”), 129.36 (C-4’), 128.92 (C-2”, C-6”), 125.72 (C-1’),
125.43 (C-3’, C-5’), 39.13 (-SCH2CH2CH2CH3), 30.77
(-SCH2CH2CH2CH3), 21.57 (-SCH2CH2CH2CH3), 13.72
(-SCH2CH2CH2CH3). HR-ESI-MS (m/z): Calcd. for
C18H18N3S2Cl: 376.0709 [M+H]+, Found 376.0720.
2926, 1595, 1453, 1266, 768, 692, 491. 1H NMR
(400 MHz, CDCl3) δ (ppm): 7.46–7.42 (m, 3H, Ar-H),
7.41 (d, J = 4.0 Hz, 2H, Ar-H), 7.35–7.30 (m, 2H, Ar-H),
7.30 (d, J = 4.0 Hz, 1H, Ar-H), 7.28 (d, J = 4.0 Hz, 1H,
Ar-H), 2.98 (t, J = 8.0 Hz, 2H, CH2), 1.82–1.74 (m, 2H,
CH2), 1.45–1.36 (m, 2H, CH2), 1.35–1.25 (m, 2H, CH2),
0.87 (t, J = 8.0 Hz, 3H, CH3). 13C NMR (CDCl3,
100 MHz) δ (ppm): 161.64 (C-5), 154.29 (C-3), 137.61
(C-4”), 136.55 (C-1”), 130.22 (C-2’, C-6’), 129.58 (C-3”,
C-5”), 129.36 (C-4’), 128.91 (C-2”, C-6”), 125.70 (C-1’),
125.40 (C-3’, C-5’), 39.44 (-SCH2CH2CH2CH2CH3), 30.57
(-SCH2CH2CH2 CH2CH3), 28.40 (-SCH2CH2CH2CH2CH3),
22.34
(-SCH2CH2CH2CH2CH3),
14.02
(-SCH2CH2
CH2CH2CH3). HR-ESI-MS (m/z): Calcd. for C19H20N3S2Cl:
2-phenyl-3-(4-chlorophenyl)-5-(2-butyldisulfanyl)-1,2,4-
triazole(10e)
390.0865 [M+H]+, Found 390.0874.
2-phenyl-3-(4-chlorophenyl)-5-(benzyldisulfanyl)-1,2,4-
triazole(10h)
White solid, Yield 64%, m.p.: 83–84 °C. IR (KBr) cm−1
:
2951, 1595, 1455, 1271, 775, 696, 489. 1H NMR
(400 MHz, CDCl3) δ (ppm): 7.49–7.46 (m, 4H, Ar-H),
7.45 (d, J = 4.0 Hz, 1H, Ar-H), 7.39–7.36 (m, 2H, Ar-H),
7.34 (s, 1H, Ar-H), 7.32 (d, J = 4.0 Hz, 1H, Ar-H), 2.90 (d,
J = 4.0 Hz, 2H, CH2), 2.12 (m, 1H, CH), 1.06 (d, J =
8.0 Hz, 6H, CH3). 13C NMR (CDCl3, 100 MHz) δ (ppm):
161.62 (C-5), 154.33 (C-3), 137.62 (C-4”), 136.58 (C-1”),
130.23 (C-2’, C-6’), 129.59 (C-3”, C-5”), 129.36 (C-4’),
128.93 (C-2”, C-6”), 125.71 (C-1’), 125.41 (C-3’, C-5’),
48.69 (-SCH2CH2(CH3)2), 27.88 (-SCH2CH2(CH3)2),
21.79 (-SCH2CH2(CH3)2). HR-ESI-MS (m/z): Calcd. for
C18H18N3S2Cl: 376.0709 [M+H]+, Found 376.0702.
White solid, Yield 61%, m.p.: 85–86 °C. IR (KBr) cm−1
:
3045, 2933, 1595, 1454, 774, 698, 488. 1H NMR
(400 MHz, CDCl3) δ (ppm): 7.49–7.46 (m, 4H, Ar-H), 7.43
(d, J = 4.0 Hz, 2H, Ar-H), 7.41 (d, J = 4.0 Hz, 1H, Ar-H),
7.38-7.35 (m, 3H, Ar-H), 7.33 (d, J = 4.0 Hz, 1H, Ar-H),
7.31 (d, J = 4.0 Hz, 1H, Ar-H), 7.30 (d, J = 4.0 Hz, 1H, Ar-
H), 7.27 (m, 1H, Ar-H), 4.26 (s, 2H, CH2). 13C NMR
(CDCl3, 100 MHz) δ (ppm): 161.31 (C-5), 154.18 (C-3),
137.60 (C-4”), 136.60 (C-1”), 136.56 (-SCH2C(CH)2(CH)
2CH), 130.24 (C-2’, C-6’), 129.66 (-SCH2C(CH)2(CH)
2CH), 129.59 (C-3”, C-5”), 129.37 (C-4’), 128.94 (C-2”, C-
6”), 128.43 (-SCH2C(CH)2(CH)2CH), 127.49 (-SCH2C
(CH)2(CH)2CH), 125.70 (C-1’), 125.38 (C-3’, C-5’), 43.87
(-SCH2Ph). HR-ESI-MS (m/z): Calcd. for C21H16N3S2Cl:
410.0552 [M+H]+, Found 410.0570.
2-phenyl-3-(4-chlorophenyl)-5-(i-butyldisulfanyl)-1,2,4-
triazole(10f)
White solid, Yield 70%, m.p.: 76–77 °C. IR (KBr) cm−1
:
2962, 1594, 1455, 1270, 775, 696, 489. 1H NMR (400 MHz,
CDCl3) δ (ppm): 7.46–7.44 (m, 4H, Ar-H), 7.43 (d, J =
4.0 Hz, 1H, Ar-H), 7.37-7.33 (m, 2H, Ar-H), 7.32 (d, J =
4.0 Hz, 1H, Ar-H), 7.30 (d, J = 4.0 Hz, 1H, Ar-H),
3.16–3.09 (m, 1H, CH), 1.90–1.78 (m, 1H, CH), 1.69–1,58
(m, 1H, CH), 1.41 (d, J = 8.0 Hz, 3H, CH3), 1.01 (t, J =
8.0 Hz, 3H, CH3). 13C NMR (CDCl3, 100 MHz) δ (ppm):
161.93 (C-5), 154.19 (C-3), 137.64 (C-4”), 136.56 (C-1”),
130.22 (C-2’, C-6’), 129.57 (C-3”, C-5”), 129.33 (C-4’),
128.91 (C-2”, C-6”), 125.73 (C-1’), 125.40 (C-3’,C-5’),
48.59 (-SCH(CH3)CH2CH3), 28.66 (-SCH(CH3)CH2CH3),
19.88 (-SCH(CH3)CH2CH3), 11.44 (-SCH(CH3)CH2CH3).
HR-ESI-MS (m/z): Calcd. for C18H18N3S2Cl: 376.0709
[M+H]+, Found 376.0695.
Results and discussion
According to the reaction described in Scheme 1, the 24
novel 1,2,4-triazole derivatives bearing disulfide bond
8a–h, 9a–h, 10a–h were synthesized. The synthesis of 1-
phenylthiosemicarbazide 4 was performed as outlined in
Scheme 1 following the reported literature [46]. Under the
protection of nitrogen, the compound 1-phenyl-1-(4-sub-
stituted phenyl)-3-thiosemicarbazide 6 was synthesized by
treatment of 1-phenylthiosemicarbazide 4 with 4-substituted
benzoyl chloride in dry acetone. And then 1-phenyl-1-(4-
substituted phenyl)-3-thiosemicarbazide 6 was refluxed in
the presence of methanol and NaOH in aqueous solution to

Medicinal Chemistry Research
Table 1 In vitro antiproliferative activities of compounds 8a–h, 9a–h,
10a–h against three cancer cell lines
Compounds
IC50 (μM)
SMMC-7721
Hela
6.31 0.28
A549
8a
21.72 0.81
40.52 2.31
18.11 1.18
8.53 0.34
17.31 0.27
19.72 0.92
21.33 0.88
46.71 2.76
38.10 1.99
8.12 0.46
9.31 0.31
26.91 0.76
4.12 0.37
9.73 0.41
2.92 0.08
30.11 2.01
6.12 0.37
8.53 0.43
7.31 0.36
30.52 2.02
35.72 1.79
42.13 2.46
10.53 0.27
4.53 0.09
5.62 0.28
8.92 0.87
7.73 0.61
4.75 0.22
28.91 1.68
28.52 1.65
23.72 1.01
33.72 1.08
38.13 2.07
31.33 1.92
13.72 0.37
5.12 0.28
29.72 1.22
32.11 1.06
35.72 1.89
25.72 1.12
29.72 1.22
4.92 0.37
26.52 1.66
7.31 0.37
21.72 0.79
6.53 0.38
43.31 0.89
6.53 0.12
3.73 0.04
8.13 0.34
8b
11.73 0.33
18.53 0.96
25.33 1.41
32.91 1.51
31.72 1.24
45.32 2.36
42.90 2.16
38.13 2.07
9.73 0.41
23.72 0.88
37.33 1.99
16.53 1.08
21.33 1.02
4.31 0.28
8.92 0.46
9.73 0.41
32.52 0.98
43.54 2.36
43.32 2.86
29.72 1.59
42.90 2.58
6.31 0.15
3.97 0.06
17.21 0.27
8c
8d
8e
8f
8g
8h
9a
9b
9c
Scheme 1 Synthesis of target compounds 8a–h, 9a–h, 10a–h. Reac-
tion conditions and reagents: a Conc. HCl, H2O2 (30%), 0–5 °C,
8–10 h; b NH4SCN, EtOH, reflux, 12 h; c Substituted benzoyl chlor-
ide, dry acetone, triethylamine, reflux, 4–6 h; d NaOH, MeOH, reflux,
3–5 h; e Compound 2, EtOH, NaHCO3/H2O, rt, 4–6 h
9d
9e
9f
9g
9h
10a
10b
10c
10d
10e
10f
10g
10h
5-FU
Fig. 1 The structure of target compounds 8a–h, 9a–h, 10a–h
form 7a–c. In the presence of NaHCO3 in water and ethanol
at 0–5 °C, the final products 8a–h, 9a–h and 10a–h were
prepared by the reaction of intermediates 7a–c and com-
pound 2. All final products 8a–h, 9a–h and 10a–h were
extracted and then purified by column chromatography.
The structure of all the final compounds 8a–h, 9a–h and
structure characteristics and pharmacological activities of
the compounds studied in this research, and a few com-
pounds have certain selectivity to tumor cells.
1
10a–h was confirmed by IR, H NMR, 13C NMR and HR-
ESI-MS (Fig. 1). The IR spectrum of compounds 8a–h,
9a–h and 10a–h revealed absorption bands between 519
and 468 cm−1 corresponding to S-S, 1615-1592 cm−1 cor-
Pharmacology and discussion
1
responding to C=N function. For the H-NMR spectra of
compound 9a, a triplet at δ 1.45 ppm and a multiplet at δ
3.01–3.06 ppm that corresponded to S-CH2CH3 function-
ality, a singlet at δ 2.37 ppm revealed the presence of the
methyl group was attached to the benzene ring. In the 13C-
NMR spectra of compound 9a, the methyl carbon signal on
the benzene ring appeared at 21.44 ppm. The structure of 9a
was also confirmed by its mass spectral data. In its mass
spectrum, the molecular ion peak was noticed m/z at
328.0942 [M+H]+ corresponding to its molecular weight.
Our laboratory team has done previous studies on the
antitumor activity of triazole compounds [41]. On the basis
of previous studies, this project is designed. Compared with
the previous research, there are some differences in the
The final products 8a–h, 9a–h and 10a–h were evaluated
for their in vitro antiproliferative activity against Hela,
SMMC-7721, A549 and L929 cell lines by CCK-8 assay.
The proliferation inhibitory activity of these compounds
was measured at different concentrations and their IC50
values (concentration leading to 50% cell proliferation
inhibition) were calculated. The results are presented in
Table 1.
Antitumor activity
As exhibited in Table 1, the final products 8a–h, 9a–h and
10a–h revealed different degrees of antitumor activity, and

Medicinal Chemistry Research
the antitumor effect of most compounds on different cancer
cell lines was superior to the 5-fluorouracil positive control.
The majority of the compounds showed moderate to good
activity on all the tested cancer cell lines. In SMMC-7721
cells, compounds 9e, 9g, and 10h showed high antitumor
activity with IC50 values 4.12, 2.92, and 4.53 μM, respec-
tively. Obviously, As compared with compound 9g, which
has 4-methyl substitution at the phenyl ring while R’ is n-
pentyl group, the other compounds showed reduced anti-
tumor activity. Compared with compounds 8a and 10a, R’
is the same, compound 9g electron-donating group sub-
stituted displayed better activity. In Hela cells, compounds
8a, 9g, 10g and 10h exhibited more potent antiproliferative
activity with IC50 values 6.31, 4.31, 6.31, and 3.97 μM,
respectively. It is clear that other compounds have lower
antiproliferative activity than compound 10h which has a 4-
chloro substitution on the phenyl ring while R’ is a benzyl
group. The compound 10h carrying electron-withdrawing
substituents has better activity than compounds of 8h and
9h which have the same R’ group. In A549 cells, com-
pounds 8c, 10a and 10h displayed high antitumor activity
with IC50 values 4.75, 4.92 and 3.73 μM, respectively. It is
apparent that other compounds exhibited lower antitumor
activity than compound 10h which has a 4-chloro sub-
stitution on the phenyl ring while R’ is a benzyl group.
While R2 is the same substituent, the activity of the benzyl
derivative 10h is higher than that of the ethyl derivative
10a. Moreover, the cytotoxicity of all compounds on L929
cells was inferior to the 5-fluorouracil. The above results
illustrate that the change of substituent can affect anticancer
activity to some extent, but it also does not show apparent
regularity Table 2.
Conclusion
In this study, the 24 target compounds 8a–h, 9a–h and
10a–h, which are 1,2,4-triazole derivatives bearing disulfide
bond, were synthesized and evaluated for their in vitro
antiproliferative activities against human cancer cell lines
SMMC-7721, Hela, A549 and normal cell lines L929 by
CCK-8 assay. Among these compounds, compound 10h
was found to exhibit better selectivity against all three
cancer cells at IC50 values of 4.53, 3.97, and 3.73 μM,
respectively. In addition, compounds 9e, 9g, and 10h
revealed better cytotoxic activity on against SMMC-7721
cells with IC50 values 4.12, 2.92, and 4.53 μM, respectively.
Compounds 8a, 9g, 10g and 10h showed effective biolo-
gical potency on Hela cells with IC50 values 6.31, 4.31,
6.31, and 3.97 μM, respectively. Compounds 8c, 10a and
10h revealed excellent antitumor activity on A549 cells
with IC50 values 4.75, 4.92 and 3.73 μM, respectively.
Moreover, most of the final products revealed low cyto-
toxicity on normal cell line L929. Therefore, the above
findings will be of great significance for the development of
potential antitumor agents.
Acknowledgements This study was financial supported by Tianjin
Municipal Natural Science Foundation (18JCYBJC94900) and
Training Project of Innovation Team of Colleges and Universities in
Tianjin (TD13-5020).
Compliance with ethical standards
Conflict of interest The authors declare that they have no conflict of
interest.
Publisher’s note Springer Nature remains neutral with regard to
jurisdictional claims in published maps and institutional affiliations.
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