Design, synthesis and antiproliferative evaluation of novel disulfides containing 1,3,4-thiadiazole moiety

Article abstract of DOI:10.1248/cpb.c17-00485

A series of novel disulfides containing 1,3,4-thiadiazole moiety were designed, synthesized, and the structures of all products were identified by spectral data (IR, NMR, and high resolution (HR)-MS). Their in vitro antiproliferative activities were evalu

Full text of DOI:10.1248/cpb.c17-00485

950
Chem. Pharm. Bull. 65, 950–958 (2017)
Vol. 65, No. 10
Regular Article
Highlighted Paper selected by Editor-in-Chief
Design, Synthesis and Antiproliferative Evaluation of Novel Disulfides
Containing 1,3,4-Thiadiazole Moiety
Shuai Zhang, Xiao-jia Liu, Rui Tang, Hai-xin Wang, Hai-ying Liu, Yu-ming Liu, and
Bao-quan Chen*
Tianjin Key Laboratory of Organic Solar Cells and Photochemical Conversion, School of Chemistry & Chemical
Engineering, Tianjin University of Technology; Tianjin 300384, P. R. China.
Received June 15, 2017; accepted July 12, 2017
A series of novel disulfides containing 1,3,4-thiadiazole moiety were designed, synthesized, and the
structures of all products were identified by spectral data (IR, NMR, and high resolution (HR)-MS). Their
in vitro antiproliferative activities were evaluated using 2-(2-methoxy-4-nitro-phenyl)-3-(4-nitro-phenyl)-
5-(2,4-disulfopheyl)-2H-tetrazolium monosodium salt (CCK-8) assay against human cancer cell lines, A549
(human lung cancer cell), HeLa (human cervical cancer cell), SMMC-7721 (human liver cancer cell) and nor-
mal cell lines L929. The bioassay results indicated that most of the tested compounds 6a–k, 7a–k and 8a–k
exhibited antiproliferation with different degrees, and some compounds showed better effects than positive
control 5-fluorouracil (5-FU) against various cancer cell lines. Among these compounds, compound 6e exhib-
ited the most potent inhibitory activity against A549 cells with IC50 value of 3.62µM. Compounds 6i, 7a, 7g,
8a and 8b showed significantly antiproliferative activities against HeLa cells with IC50 values of 3.88, 3.76,
3.59, 3.38 and 3.12µM, respectively. Compounds 6a, 7a and 8a owned high antiproliferative activities against
SMMC-7721 cells with IC50 values of 2.54, 2.69 and 2.31µM, respectively. Furthermore, all of the tested com-
pounds showed weak cytotoxic effect against the normal cell lines L929. Based on the preliminary results, the
substituent groups are vital for improving the potency and selectivity of this class of compounds.
Key words 1,3,4-thiadiazole; disulfide; antiproliferative activity
Cancer has become one of the most terrible diseases around fides bearing 1,3,4-oxadiazole moiety and their in vitro anti-
the world because of its low cure and high mortality.1,2) It is proliferative activities were evaluated.37) We observed that
predicted that the number of new cases could further rise to some compounds showed better effects than positive control
19.3 million by 2025.3,4) Despite significant progress has been 5-fluorouracil against various cancer cell lines. Due to their
achieved in anticancer therapy, identification of safe and ef- attractive pharmacological property, in the paper we report
fective anticancer agents are still one of the challenges in the the synthesis of disulfides containing 1,3,4-thiadiazole moi-
field of drug discovery.
ety. These compounds were evaluated for their antiprolifera-
1,3,4-Thiadiazoles are an important class of heterocyclic tive activities against three human cancer cell lines, A549
bioactive compounds with a broad range of biological activi- (human lung cancer cell), HeLa (human cervical cancer cell),
ties such as antioxidant,5,6) antibacterial,7,8) antidepressant,9,10) SMMC-7721 (human liver cancer cell) and one normal cell
antidiabetic,11,12) antifungal,13,14) anticonvulsant,15,16) anti-in- line L929 (Mouse fibroblasts) with the ultimate aim of devel-
flammatory,17,18) anticholinesterase,19) antileishmanial,20) inhibi- oping novel potent antitumor agents.
tion of human protoporphyrinogen oxidase.21) In particular, a
large number of 1,3,4-thiadiazole derivatives display interest-
Results and Discussion
Chemistry As depicted in Chart 1, thirty three disulfides
ing antitumour activities in vitro and in vivo conditions.22–26)
Therefore, the importance of 1,3,4-thiadiazole in the fields of containing 1,3,4-thiadiazole moiety were synthesized and
medicinal chemistry has received much attention in the past reported for the first time. The preparation of S-alkyl-thioiso-
few decades.27) On the other hand, disulfide derivatives are thiourea hydrochloride 2 was carried out by reported literature
also acknowledged to possess a wide spectrum of bioactivi- method.38) The preparation of 2-chloro-N-(substituted-phenyl)-
ties because the disulfide group makes up the core structure acetamide 4 was carried out by reported literature method.39)
of numerous biologically active compounds with many types The reaction of commercially available 2,5-dimercapto-1,3,4-
of biological activities including antibacterial,28,29) anti-human thiadiazole with compound 4 in the presence of NaOH in
immunodeficiency virus (HIV)-1,30) antitumor,31–33) and herbi- water and ethanol at room temperature yielded the desired
cidal properties.34,35)
intermediates 5a–k in 70–81% yields. Finally, the target com-
Particularly, the antitumor character of disulfide deriva- pounds 6a–k, 7a–k and 8a–k were successfully obtained by
tives attracts great interests from medicinal chemists in recent the reaction of intermediates 5a–k and compound 2 in the
years. Moreover, the metabolic evaluation of the most promis- presence of NaHCO3 in methanol and water at room tempera-
ing compound is further performed to reveal that disulfide ture. All of the novel synthesized compounds 6a–k, 7a–k and
bond can be stable in human plasma over 8h, indicating a 8a–k were purified by silica gel column chromatography and
1
good prospect of these compounds for in vitro antitumor ac- their structures were characterized by IR, H-NMR, 13C-NMR
tivities.36)
and high resolution-electrospray ionization (HR-ESI)-MS.
We previously reported the synthesis of a series of disul-
Biological Activity The antiproliferative activities of
*To whom correspondence should be addressed. e-mail: chenbaoquan66@126.com
© 2017 The Pharmaceutical Society of Japan

Vol. 65, No. 10 (2017)
Chem. Pharm. Bull.
951
Reagents and conditions: (a) conc. HCl, H2O2 (30%), 0–5°C, 6h; (b) CH2Cl2–NaOH, r.t. 5–6h; (c) ethanol, NaOH–H2O, r.t. 4–5h; (d) ethanol, NaHCO3–H2O, r.t. 6h.
Chart 1. Synthesis of the Target Compounds 6a–k, 7a–k and 8a–k
target compounds 6a–k, 7a–k and 8a–k against three human displayed higher activities than positive control 5-FU. Among
cancer cell lines, A549, HeLa, SMMC-7721 and one normal them, compounds 6i, 7a, g, 8a and b showed significantly
cell line L929 were evaluated by 2-(2-methoxy-4-nitro- biological activities with IC50 values of 3.88, 3.76, 3.59, 3.38
phenyl)-3-(4-nitro-phenyl)-5-(2,4-disulfopheyl)-2H-tetrazolium and 3.12µM, respectively. As compared with compounds 6a,
monosodium salt (CCK-8) assay in vitro, and their IC50 values 7a and 8a which have no substituent at the phenyl ring, ex-
were calculated and are presented in Table 1. 5-Fluorouracil cept compounds 6i, 7g, h and 8b, the other compounds 6b–k,
(5-FU) was used as a positive control.
7b–k and 8b–k all resulted in a decrease in activity. But, no
As shown in Table 1, some of the tested compounds re- matter R1 is 2-butyl, n-butyl or i-butyl group, the electronic
vealed stronger antiproliferative effect than previous reported effects of substituents at the phenyl ring on antiproliferative
compounds against various cancer cell lines.37) All compounds activity against HeLa cells did not show apparent regularity.
6a–k, 7a–k and 8a–k showed antiproliferation against four In SMMC-7721 cells, compounds 6a, e–i, 7a, b, d, e, 8a and
cell lines with certain degrees, and the substituent groups of e displayed good proliferation inhibitory activities, the other
phenyl ring played important roles in the potency of biologi- compounds showed lower antiproliferative effect than positive
cally active compounds. In A549 cells, some compounds ex- control 5-FU. As compared with 6a, 7a and 8a which have
hibited better activities than positive control 5-FU. In particu- no substituent at phenyl ring and owned high antiprolifera-
lar, compound 6e exhibited the most potent inhibitory activity tive activities with IC50 values of 2.54, 2.69 and 2.31µM
against A549 cells with IC50 value of 3.62µM. As compared respectively, the other compounds bearing electron-donating
with compound 6a which has no substituent at the phenyl ring or electron-withdrawing groups, including 6b–k, 7b–k and
while R1 is 2-butyl group, except compounds 6f, j and k, the 8b–k, all exhibited decreased antitumor effects. However, the
other compounds showed enhanced antiproliferative activi- bioassay results also indicated that the electronic effects of
ties. As compared with compound 7a which has no substitu- substituents on antitumor activity against SMMC-7721 cells
ent at the phenyl ring while R1 is n-butyl group, compounds did not show apparent regularity. In L929 cells, all compounds
7g, h and k carrying electron-donating substituents exhibited exhibited weak cytotoxic activity, and showed lower cytotoxic
increased activities. As compared with compound 8a which effect than positive control 5-FU. Especially noteworthy are
has no substituent at the phenyl ring while R1 is i-butyl group, compounds 6g, i, 7b and 8a, which showed significant anti-
except compound 8e, electron-donating group substituted de- proliferative activities against A549, HeLa and SMMC-7721
rivatives, including 8g, h and k displayed better activities than cells, exhibited weak cytotoxicities against L929 cells. The
compounds 8b–f, 8i and j carrying electron-drawing substitu- results suggested that compounds 6g, i, 7b and 8a displayed
ents. Especially, while R1 is the same substituent, 3-nitro sub- superior selectivity against the tested cancer cell lines. More-
stituted derivatives 6e, 7e and 8e displayed higher activities over, we also found from the results that the 2-butyl substitut-
than other compounds. These results indicated that the influ- ed derivatives showed better biological activities than n-butyl
ence of substituents on antiproliferative activity against A549 and i-butyl substituted derivatives on the whole. Therefore,
cells is complex and unexplained at present. In HeLa cells, ex- it is necessary that the further investigation is carried out
cept compounds 6b and 7f showed moderate antiproliferative through structural transformation for improving the potency
activity with IC50 values of 20.89 and 27.36µM, respectively, and selectivity of this class of compounds.
the other compounds showed good antiproliferative effect, and

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Chem. Pharm. Bull.
Vol. 65, No. 10 (2017)
Table 1. In Vitro Antiproliferative Activities of Compounds 6a–k, 7a–k and 8a–k against Various Cell Lines
IC50 (µM)a)
Compound
A549
HeLa
SMMC-7721
L929
6a
6b
6c
6d
6e
6f
12.65 0.35
9.50 0.24
8.02 0.19
8.26 0.20
3.62 0.06
17.63 0.51
8.69 0.27
8.00 0.38
6.53 0.15
25.86 0.81
19.90 0.26
12.76 1.06
8.71 0.28
8.51 0.32
23.27 0.78
7.70 0.13
22.12 0.57
8.17 0.25
7.84 0.30
25.90 1.08
28.49 1.23
12.19 0.36
8.56 0.21
24.42 0.57
26.72 1.08
29.52 0.89
7.71 0.01
25.47 0.91
9.80 0.38
8.71 0.29
17.29 0.21
20.02 0.17
9.31 0.23
8.13 0.34
4.77 0.06
20.89 0.17
6.11 0.12
5.48 0.08
8.16 0.23
8.07 0.45
6.86 0.37
8.23 0.51
3.88 0.11
4.91 0.07
8.04 0.30
3.76 0.13
6.17 0.02
9.62 0.39
8.93 0.45
6.76 0.24
27.36 1.58
3.59 0.12
4.70 0.15
6.85 0.76
16.10 0.81
12.33 1.02
3.38 0.05
3.12 0.32
9.23 0.23
9.82 0.17
5.80 0.14
11.52 0.25
7.22 0.53
6.19 0.18
10.42 0.28
8.44 0.12
8.36 0.32
17.21 0.67
2.54 0.10
8.21 0.30
18.71 1.28
6.08 0.57
3.74 0.12
4.21 0.22
3.00 0.04
4.49 0.34
3.53 0.26
9.78 0.39
6.50 0.45
2.69 0.22
5.26 0.81
15.43 0.73
4.34 0.35
4.32 0.29
18.06 0.18
6.40 0.25
7.29 0.34
7.55 0.13
26.33 1.67
25.40 0.76
2.31 0.27
7.85 0.36
27.09 1.34
9.23 0.32
3.92 0.05
11.19 0.51
22.87 0.47
7.32 0.55
9.29 0.78
25.17 1.23
12.82 0.04
5.62 0.28
18.28 1.26
62.51 2.85
55.17 3.08
7.81 0.03
5.44 0.12
6.72 0.17
9.91 0.37
33.08 2.17
23.50 0.59
34.60 1.20
18.13 0.38
68.79 2.45
69.76 1.95
67.88 2.06
29.77 1.92
13.69 0.56
18.54 1.78
29.14 0.76
38.65 1.68
31.74 0.97
36.51 2.07
38.17 1.76
57.20 2.58
63.51 1.89
29.32 2.67
8.06 0.33
8.70 0.04
7.41 0.12
10.60 0.27
26.70 0.36
32.41 1.73
29.45 0.67
6.99 0.02
2.98 0.15
6g
6h
6i
6j
6k
7a
7b
7c
7d
7e
7f
7g
7h
7i
7j
7k
8a
8b
8c
8d
8e
8f
8g
8h
8i
8j
8k
5-FUb)
a) IC50 is the drug concentration effective in inhibiting 50% of the cell growth measured by CCK-8 assay. b) Used as a positive control.
Conclusion
Experimental
Chemistry All reagents were obtained from commer-
We successfully prepared a series of novel disulfides con-
taining 1,3,4-thiadiazole moiety, and the newly synthesized cial suppliers and used without further purification, unless
compounds were evaluated for their in vitro antiproliferative specified. All reactions were monitored by TLC performed
activities against A549, HeLa, and SMMC-7721 human cancer on glass packed silica gel GF254 plates. Melting points were
cell lines and L929 normal cell lines by CCK-8 assay. Some of determined by an X-6 microscope melting point apparatus and
the compounds inhibited the proliferation better than positive are uncorrected. Infrared spectra were recorded in KBr pel-
1
control 5-FU. In particular, compound 6e exhibited the most lets on a Nicolet Avatar 370 spectrometer. H- and 13C-NMR
potent inhibitory activity against A549 cells with IC50 value of spectra were collected at resonance frequencies of 400MHz
3.62 µM. Compounds 6i, 7a, g, 8a and b displayed significantly and 100MHz, respectively. NMR spectra were performed on
antiproliferative activities against HeLa cells with IC50 values a Bruker Avance III 400MHz spectrometer using dimethyl
of 3.88, 3.76, 3.59, 3.38 and 3.12µM respectively. Compounds sulfoxide (DMSO)-d6 as solvent and tetramethylsilane as in-
1
6a, 7a and 8a owned high antiproliferative activities against ternal standard. The chemical shifts for H-NMR are reported
SMMC-7721 cells with IC50 values of 2.54, 2.69 and 2.31µM in ppm from tetramethylsilane (0ppm) or referenced to the
respectively. In addition, all the tested compounds showed low solvent (DMSO-d6 2.50) on the δ scale. Chemical shifts (δ)
cytotoxic effect against the normal cell lines L929. Further for 13C-NMR spectra are referenced to the signals for residual
structural optimization and mechanism studies on compounds deuterated solvents (DMSO-d6 39.5). Multiplicities are re-
6a–k, 7a–k and 8a–k are ongoing.
ported by the following abbreviations: s (singlet), d (doublet),
t (triplet), m (multiplet), dd (doublet of doublet), J (coupling
constants in hertz). High-resolution mass data were taken with

Vol. 65, No. 10 (2017)
Chem. Pharm. Bull.
953
a Waters Xevo G2 QT of mass spectrometer. The products
2-Sulfhydryl-5-[(2-methoxyphenylcarbamoyl)-methylthio]-
were purified by flash column chromatography using silica gel 1,3,4-thiadiazole (5g)
(200–300mesh) with indicated solvents. White solid; Yield 78.9%; mp 145.2–146.7°C; IR (KBr)
1
General Procedure for the Synthesis of Intermediates cm−1: 3302, 2540, 1668, 1543, 1489, 741; H-NMR (400MHz,
5a–k A solution of sodium hydroxide (6mmol) in water DMSO-d6) δ (ppm): 14.61 (s, 1H, SH), 9.58 (s, 1H, NH), 7.94
(20mL) was added to a mixture of 2,5-dimercapto-1,3,4-thia- (d, 1H, Ar-H, J=8.0Hz), 7.05–7.12 (m, 2H, Ar-H), 6.92 (t, 1H,
diazole (6mmol), appropriate 2-chloro-N-(substituted-phenyl)- Ar-H, J=7.1Hz), 4.23 (s, 2H, CH2), 3.84 (s, 3H, OCH3); MS-
acetamide 4 (5mmol) and ethanol (10mL). The mixture was ESI (m/z): C11H12N3O2S3 [M+H]+ 314.0.
stirred for 4–5h at room temperature (the end of reaction was
monitored by TLC), after completion, the mixture was poured 1,3,4-thiadiazole (5h)
into water. The resulting precipitate was collected by filtra-
White solid; Yield 74.5%; mp 157.2–158.5°C; IR (KBr)
tion, washed well with water and further purified by recrystal- cm−1: 3296, 2549, 1662, 1545, 1489, 721; H-NMR (400MHz,
lization from ethanol to afford target compounds.
DMSO-d6) δ (ppm): 14.60 (s, 1H, SH), 10.20 (s, 1H, NH), 7.47
2-Sulfhydryl-5-[(phenylcarbamoyl)-methylthio]-1,3,4- (d, 2H, Ar-H, J=9.0Hz), 6.90 (d, 2H, Ar-H, J=9.0Hz), 3.84
2-Sulfhydryl-5-[(4-methoxyphenylcarbamoyl)-methylthio]-
1
thiadiazole (5a)
(s, 2H, CH2), 3.72 (s, 3H, OCH3); MS-ESI (m/z): C10H9N4O3S3
White solid; Yield 76.7%; mp 136.5–138.7°C; IR (KBr) [M+H]+ 314.0.
cm−1: 3273, 2529, 1663, 1538, 1441, 757; H-NMR (400MHz,
2-Sulfhydryl-5-[(4-fluorophenylcarbamoyl)-methylthio]-
1
DMSO-d6) δ (ppm): 14.59 (s, 1H, SH), 10.34 (s, 1H, NH), 1,3,4-thiadiazole (5i)
7.57 (d, 2H, Ar-H, J=8.1Hz), 7.33 (t, 2H, Ar-H, J=7.6Hz),
7.08 (t, 1H, Ar-H, J=7.3Hz), 4.17 (s, 2H, CH2); MS-ESI (m/z): cm−1: 3249, 2524, 1658, 1553, 1510, 715; H-NMR (400MHz,
C10H10N3OS3 [M+H]+ 284.0.
DMSO-d6) δ (ppm): 14.60 (s, 1H, SH), 10.40 (s, 1H, NH), 7.57–
White solid; Yield 72.1%; mp 170.2–172.1°C; IR (KBr)
1
2-Sulfhydryl-5-[(2-chlorophenylcarbamoyl)-methylthio]- 7.60 (d, 2H, Ar-H, J=9.0Hz), 7.17 (t, 2H, Ar-H, J=8.8Hz),
1,3,4-thiadiazole (5b)
4.16 (s, 2H, CH2); MS-ESI (m/z): C10H9N3OS3F [M+H]+ 302.0.
White solid; Yield 75.9%; mp 132.7–134.6°C; IR (KBr)
2-Sulfhydryl-5-[(4-trifluoromethylphenylcarbamoyl)-
cm−1: 3339, 2546, 1653, 1542, 1442, 752; H-NMR (400MHz, methylthio]-1,3,4-thiadiazole (5j)
1
DMSO-d6) δ (ppm): 14.63 (s, 1H, SH), 9.91 (s, 1H, NH), 7.72
White solid; Yield 70.8%; mp 171.5–172.2°C; IR (KBr)
1
(d, 1H, Ar-H, J=7.9Hz), 7.51 (d, 1H, Ar-H, J=7.9Hz), 7.35 (t, cm−1: 3440, 2539, 1670, 1546, 1489, 715; H-NMR (400MHz,
1H, Ar-H, J=7.5Hz), 7.22 (t, 1H, Ar-H, J=7.5Hz), 4.22 (s, 2H, DMSO-d6) δ (ppm): 14.60 (s, 1H, SH), 10.71 (s, 1H, NH), 7.78
CH2); MS-ESI (m/z): C10H9N3OS3Cl [M+H]+ 318.3.
(d, 2H, Ar-H, J=8.4Hz), 7.70 (d, 2H, Ar-H, J=8.4Hz), 4.23 (s,
2-Sulfhydryl-5-[(3-chlorophenylcarbamoyl)-methylthio]- 2H, CH2); MS-ESI (m/z): C11H9N3OS3F3 [M+H]+ 352.0.
1,3,4-thiadiazole (5c) 2-Sulfhydryl-5-[(4-methylphenylcarbamoyl)-methylthio]-
White solid; Yield 73.2%; mp 157.7–159.8°C; IR (KBr) 1,3,4-thiadiazole (5k)
1
cm−1: 3362, 2529, 1645, 1549, 1429, 778; H-NMR (400MHz,
White solid; Yield 77.6%; mp 178.5–180.2°C; IR (KBr)
DMSO-d6) δ (ppm): 14.60 (s, 1H, SH), 10.61 (s, 1H, NH), 7.78 cm−1: 3268, 2532, 1654, 1538, 1495, 719; H-NMR (400MHz,
(s, 1H, Ar-H), 7.44 (d, 1H, Ar-H, J=8.4Hz), 7.36 (t, 1H, Ar-H, DMSO-d6) δ (ppm): 14.59 (s, 1H, SH), 10.25 (s, 1H, NH), 7.45
J=8.0Hz), 7.15 (d, 1H, Ar-H, J=7.8Hz), 4.18 (s, 2H, CH2); (d, 2H, Ar-H, J=8.3Hz), 7.13 (d, 2H, Ar-H, J=8.2Hz), 4.14
1
MS-ESI (m/z): C10H9N3OS3Cl [M+H]+ 318.3.
(s, 2H, CH2), 2.26 (s, 3H, CH3); MS-ESI (m/z): C11H12N3OS3
2-Sulfhydryl-5-[(4-chlorophenylcarbamoyl)-methylthio]- [M+H]+ 298.0.
1,3,4-thiadiazole (5d)
General Procedure for the Synthesis of Compounds
White solid; Yield 80.7%; mp 164.8–166.4°C; IR (KBr) 6a–k, 7a–k and 8a–k S-Alkyl-thioisothiourea hydrochlo-
1
cm−1: 3242, 2522, 1658, 1542, 1490, 744; H-NMR (400MHz, ride
2 (2.2mmol) and 2-sulfhydryl-5-(arylaminoformoxyl
DMSO-d6) δ (ppm): 14.59 (s, 1H, SH), 10.49 (s, 1H, NH), 7.60 methylthio)-1,3,4-thiadiazol 5a–k (2.0mmol) were dissolved
(d, 2H, Ar-H, J=8.8Hz), 7.38 (t, 2H, Ar-H, J=8.8Hz), 4.18 (s, in 2mL water and 15mL ethanol. A solution of NaHCO3
2H, CH2); MS-ESI (m/z): C10H9N3OS3Cl [M+H]+ 318.3.
(3.0mmol) in 4mL water was added dropwise with vigorous
2-Sulfhydryl-5-[(3-nitro-phenylcarbamoyl)-methylthio]- stirring at room temperature. The mixture was stirred for ad-
1,3,4-thiadiazole (5e) ditional 6h. The insoluble solid was collected and purified by
Yellow solid; Yield 70.3%; mp 180.3–182.6°C; IR (KBr) silica gel column chromatography with petroleum ether–ethyl
1
cm−1: 3339, 2548, 1681, 1548, 1432, 736; H-NMR (400MHz, acetate (10:1, volume ratio) as eluent to afford the desired
DMSO-d6) δ (ppm): 14.60 (s, 1H, SH), 10.85 (s, 1H, NH), 8.59 products.
(s, 1H, Ar-H), 7.95 (d, 1H, Ar-H, J=7.9Hz), 7.89 (d, 1H, Ar-H,
J=8.2Hz), 7.64 (t, 1H, Ar-H, J=8.2Hz), 4.22 (s, 2H, CH2); 1,3,4-thiadiazole (6a)
MS-ESI (m/z): C10H9N4O3S3 [M+H]+ 329.0.
Yellow oily liquid; Yield 75.6%; IR (KBr) cm−1: 3446, 1684,
2-Sulfhydryl-5-[(4-nitro-phenylcarbamoyl)-methylthio]- 1558, 1507, 755, 503; H-NMR (400MHz, DMSO-d6) δ (ppm):
1,3,4-thiadiazole (5f) 10.37 (s, 1H, NH), 7.57 (d, 2H, Ar-H, J=7.8Hz), 7.33 (t, 2H,
2-(2-Butyldisulfanyl)-5-[(phenylcarbamoyl)-methylthio]-
1
Yellow solid; Yield 73.8%; mp 194.8–196.8°C; IR (KBr) Ar-H, J=7.7Hz), 7.08 (t, 1H, Ar-H, J=7.4Hz), 4.29 (s, 2H,
1
cm−1: 3323, 2541, 1696, 156, 1497, 751; H-NMR (400MHz, CH2), 3.12–3.21 (m, 1H, CH), 1.51–1.71 (m, 2H, CH2), 1.29 (d,
DMSO-d6) δ (ppm): 14.61 (s, 1H, SH), 10.97 (s, 1H, NH), 8.24 3H, CH3, J=6.8Hz), 0.92 (t, 3H, CH3, J=7.3Hz); 13C-NMR
(d, 2H, Ar-H, J=8.9Hz), 7.82 (d, 2H, Ar-H, J=8.9Hz), 4.22 (s, (100MHz, DMSO-d6) δ (ppm): 172.27, 167.01, 165.49, 139.13,
2H, CH2); MS-ESI (m/z): C10H9N4O3S3 [M+H]+ 329.0.
129.28 (2C), 124.12, 119.66 (2C), 49.37, 38.82, 28.75, 20.13,
11.59; HR-MS (ESI): m/z 438.2515 [M+Na]+ (Calcd for
C14H17N3OS4Na 438.2505).

954
Chem. Pharm. Bull.
Vol. 65, No. 10 (2017)
2-(2-Butyldisulfanyl)-5-[(2-chlorophenylcarbamoyl)-
2-(2-Butyldisulfanyl)-5-[(2-methoxyphenylcarbamoyl)-
methylthio]-1,3,4-thiadiazole (6b)
methylthio]-1,3,4-thiadiazole (6g)
Yellow oily liquid; Yield 72.8%; IR (KBr) cm−1: 3447, 1699,
Yellow oily liquid; Yield 70.1%; IR (KBr) cm−1: 3364, 1687,
1
1
1588, 1523, 753, 526; H-NMR (400MHz, DMSO-d6) δ (ppm): 1602, 1536, 749, 512; H-NMR (400MHz, DMSO-d6) δ (ppm):
9.95 (s, 1H, NH), 7.74 (d, 1H, Ar-H, J=8.0Hz), 7.51 (d, 1H, 9.62 (s, 1H, NH), 7.97 (d, 1H, Ar-H, J=8.0Hz), 7.04–7.12 (m,
Ar-H, J=8.0Hz), 7.34 (t, 1H, Ar-H, J=8.4Hz), 7.21 (t, 1H, 2H, Ar-H), 6.91 (t, 1H, Ar-H, J=8.1Hz), 4.35 (s, 2H, CH2),
Ar-H, J=7.5Hz), 4.36 (s, 2H, CH2), 3.13–3.21 (m, 1H, CH), 3.84 (s, 3H, OCH3), 3.12–3.21 (m, 1H, CH), 1.51–1.72 (m,
1.52–1.72 (m, 2H, CH2), 1.30 (d, 3H, CH3, J=6.8Hz), 0.93 (t, 2H, CH2), 1.30 (d, 3H, CH3, J=6.8Hz), 0.92 (t, 3H, CH3,
3H, CH3, J=7.4Hz); 13C-NMR (100MHz, DMSO-d6) δ (ppm): J=7.4Hz); 13C-NMR (100MHz, DMSO-d6) δ (ppm): 172.33,
172.45, 166.85, 166.23, 134.97, 129.96, 127.91, 126.85, 126.43, 167.16, 165.85, 149.80, 127.42, 125.12, 121.76, 120.77, 111.69,
125.86, 49.40, 38.34, 28.79, 20.12, 11.59; HR-MS (ESI): m/z 56.20, 49.38, 38.63, 28.75, 20.12, 11.57; HR-MS (ESI): m/z
427.9773 [M+Na]+ (Calcd for C14H16N3OS4NaCl 427.9763).
2-(2-Butyldisulfanyl)-5-[(3-chlorophenylcarbamoyl)-
methylthio]-1,3,4-thiadiazole (6c)
402.0448 [M+H]+ (Calcd for C15H20N3O2S4 402.0438).
2-(2-Butyldisulfanyl)-5-[(4-methoxyphenylcarbamoyl)-
methylthio]-1,3,4-thiadiazole (6h)
Yellow oily liquid; Yield 76.7%; IR (KBr) cm−1: 3447, 1684,
Yellow oily liquid; Yield 74.8%; IR (KBr) cm−1: 3437,
1
1
1595, 1541, 779, 526; H-NMR (400MHz, DMSO-d6) δ (ppm): 1665, 1549, 1512, 745, 521; H-NMR (400MHz, DMSO-d6)
10.57 (s, 1H, NH), 7.79 (s, 1H, Ar-H), 7.43 (d, 1H, Ar-H, δ (ppm): 10.25 (s, 1H, NH), 7.48 (d, 2H, Ar-H, J=8.8Hz),
J=8.3Hz), 7.36 (t, 1H, Ar-H, J=7.9Hz), 7.14 (d, 1H, Ar-H, 6.89 (d, 2H, Ar-H, J=8.9Hz), 4.25 (s, 2H, CH2), 3.72 (s, 3H,
J=7.8Hz), 4.29 (s, 2H, CH2), 3.12–3.20 (m, 1H, CH), 1.51–1.71 OCH3), 3.12–3.20 (m, 1H, CH), 1.51–1.71 (m, 2H, CH2), 1.29
(m, 2H, CH2), 1.29 (d, 3H, CH3, J=6.8Hz), 0.93 (t, 3H, CH3, (d, 3H, CH3, J=6.7Hz), 0.92 (t, 3H, CH3, J=7.3Hz); 13C-NMR
J=7.4Hz); 13C-NMR (100MHz, DMSO-d6) δ (ppm): 172.40, (100MHz, DMSO-d6) δ (ppm): 172.25, 167.08, 164.96, 155.98,
166.74, 165.92, 140.55, 133.69, 130.91, 123.81, 119.16, 118.01, 132.27, 121.21 (2C), 114.41 (2C), 55.64, 49.36, 38.74, 28.75,
49.39, 38.76, 28.77, 20.11, 11.57; HR-MS (ESI): m/z 427.9766 20.12, 11.58; HR-MS (ESI): m/z 402.0440 [M+H]+ (Calcd for
[M+Na]+ (Calcd for C14H16N3OS4NaCl 427.9763).
2-(2-Butyldisulfanyl)-5-[(4-chlorophenylcarbamoyl)-
methylthio]-1,3,4-thiadiazole (6d)
C15H20N3O2S4 402.0438).
2-(2-Butyldisulfanyl)-5-[(4-fluorophenylcarbamoyl)-
methylthio]-1,3,4-thiadiazole (6i)
White solid; Yield 74.8%; mp 65.1–67.6°C; IR (KBr) cm−1:
White solid; Yield 73.6%; mp 67.6–68.6°C; IR (KBr) cm−1:
1
1
3447, 1667, 1541, 1490, 746, 503; H-NMR (400MHz, DMSO- 3444, 1666, 1558, 1508, 745, 515; H-NMR (400MHz, DMSO-
d6) δ (ppm): 10.53 (s, 1H, NH), 7.62 (d, 2H, Ar-H, J=8.7Hz), d6) δ (ppm): 10.44 (s, 1H, NH), 7.59 (dd, 2H, Ar-H, J1=5.0Hz,
7.33 (d, 2H, Ar-H, J=8.7Hz), 4.30 (s, 2H, CH2), 3.04–3.12 (m, J2=9.0Hz), 7.17 (d, 2H, Ar-H, J=8.8Hz), 4.28 (s, 2H, CH2),
1H, CH), 1.46–1.67 (m, 2H, CH2), 1.25 (d, 3H, CH3, J=6.7Hz), 3.12–3.21 (m, 1H, CH), 1.51–1.74 (m, 2H, CH2), 1.29 (d, 3H,
0.88 (t, 3H, CH3, J=7.3Hz); 13C-NMR (100MHz, DMSO-d6) δ CH3, J=6.7Hz), 0.92 (t, 3H, CH3, J=7.32Hz); 13C-NMR
(ppm): 172.41, 166.72, 165.62, 138.08, 129.11 (2C), 127.79, (100MHz, DMSO-d6) δ (ppm): 172.33, 166.85, 165.40, 158.68
121.14 (2C), 49.38, 38.78, 28.78, 20.09, 11.59; HR-MS (ESI): (d, JC–F=239.1Hz), 135.53 (d, JC–F=2.3Hz), 121.43 (d, 2C,
m/z 405.9958 [M+H]+ (Calcd for C14H17N3OS4Cl 405.9943).
JC–F=7.8Hz), 115.79 (d, 2C, JC–F=22.1Hz), 49.38, 38.73, 28.76,
2-(2-Butyldisulfanyl)-5-[(3-nitro-phenylcarbamoyl)- 20.08, 11.56; HR-MS (ESI): m/z 390.0245 [M+H]+ (Calcd for
methylthio]-1,3,4-thiadiazole (6e)
C14H17N3OS4F 390.0238).
2-(2-Butyldisulfanyl)-5-[(4-trifluoromethylphenylcarbamoyl)-
White solid; Yield 71.7%; mp 93.1–94.5°C; IR (KBr) cm−1:
1
3439, 1694, 1605, 1525, 741, 509; H-NMR (400MHz, DMSO- methylthio]-1,3,4-thiadiazole (6j)
d6) δ (ppm): 10.90 (s, 1H, NH), 8.61 (s, 1H, Ar-H), 7.94 (d,
White solid; Yield 74.5%; mp 82.7–84.1°C; IR (KBr) cm−1:
1H, Ar-H, J=8.1Hz), 7.88 (t, 1H, Ar-H, J=8.0Hz), 7.63 (d, 1H, 3446, 1676, 1606, 1543, 709, 506; 1H-NMR (400MHz, DMSO-
Ar-H, J=8.2Hz), 4.34 (s, 2H, CH2), 3.11–3.19 (m, 1H, CH), d6) δ (ppm): 10.75 (s, 1H, NH), 7.79 (d, 2H, Ar-H, J=8.5Hz),
1.50–1.70 (m, 2H, CH2), 1.28 (d, 3H, CH3, J=6.7Hz), 0.91 (t, 7.69 (d, 2H, Ar-H, J=8.6Hz), 4.34 (s, 2H, CH2), 3.10–3.19
3H, CH3, J=7.4Hz); 13C-NMR (100MHz, DMSO-d6) δ (ppm): (m, 1H, CH), 1.49–1.70 (m, 2H, CH2), 1.28 (d, 3H, CH3,
172.43, 166.61, 166.31, 148.40, 140.23, 130.64, 125.51, 118.53, J=6.7Hz), 0.91 (t, 3H, CH3, J=7.4Hz); 13C-NMR (100MHz,
113.71, 49.38, 38.68, 28.75, 20.07, 11.53; HR-MS (ESI): m/z DMSO-d6) δ (ppm): 172.41, 166.64, 166.16, 142.66, 126.45 (q,
417.0198 [M+H]+ (Calcd for C14H17N4O3S4 417.0183).
2-(2-Butyldisulfanyl)-5-[(4-nitro-phenylcarbamoyl)- JC–F=31.9Hz), 119.52, 49.35, 38.82, 28.74, 19.99, 11.45; HR-MS
methylthio]-1,3,4-thiadiazole (6f)
(ESI): m/z 440.0216 [M+H]+ (Calcd for C15H17N3OS4F3
2C, JC–F=3.5Hz), 124.70 (q, JC–F=269.8Hz), 124.24 (q, 2C,
White solid; Yield 75.4%; mp 107.0–108.9°C; IR (KBr) 440.0207).
1
cm−1: 3441, 1680, 1563, 1511, 751, 497; H-NMR (400MHz,
2-(2-Butyldisulfanyl)-5-[(4-methylphenylcarbamoyl)-
DMSO-d6) δ (ppm): 10.98 (s, 1H, NH), 8.24 (d, 2H, Ar-H, methylthio]-1,3,4-thiadiazole (6k)
J=9.2Hz), 7.83 (d, 2H, Ar-H, J=9.2Hz), 4.37 (s, 2H, CH2),
White solid; Yield 72.1%; mp 82.7–84.1°C; IR (KBr) cm−1:
3.11–3.19 (m, 1H, CH), 1.50–1.70 (m, 2H, CH2), 1.29 (d, 3442, 1668, 1610, 1542, 747, 510; H-NMR (400MHz, DMSO-
1
3H, CH3, J=6.8Hz), 0.91 (t, 3H, CH3, J=7.4Hz); 13C-NMR d6) δ (ppm): 10.30 (s, 1H, NH), 7.45 (d, 2H, Ar-H, J=8.2Hz),
(100MHz, DMSO-d6)
δ (ppm): 172.44, 166.47, 165.11, 7.13 (d, 2H, Ar-H, J=8.1Hz), 4.27 (s, 2H, CH2), 3.12–3.20 (m,
145.18, 142.88, 125.28 (2C), 119.28 (2C), 49.39, 38.85, 28.77, 1H, CH), 2.25 (s, 3H, CH3), 1.51–1.71 (m, 2H, CH2), 1.29 (d,
20.04, 11.53; HR-MS (ESI): m/z 417.0197 [M+H]+ (Calcd for 3H, CH3, J=6.8Hz), 0.92 (t, 3H, CH3, J=7.4Hz); 13C-NMR
C14H17N4O3S4 417.0183).
(100MHz, DMSO-d6) δ (ppm): 172.26, 167.01, 165.20, 136.66,
133.06, 129.62 (2C), 119.67 (2C), 49.38, 38.85, 28.77, 20.92,
20.11, 11.58; HR-MS (ESI): m/z 386.0498 [M+H]+ (Calcd for

Vol. 65, No. 10 (2017)
Chem. Pharm. Bull.
955
C15H20N3OS4 386.0489).
2-(n-Butyldisulfanyl)-5-[(4-nitro-phenylcarbamoyl)-
2-(n-Butyldisulfanyl)-5-[(phenylcarbamoyl)-methylthio]- methylthio]-1,3,4-thiadiazole (7f)
1,3,4-thiadiazole (7a)
White solid; Yield 73.2%; mp 118.9–121.7°C; IR (KBr)
1
White solid; Yield 72.3%; mp 89.7–91.5°C; IR (KBr) cm−1: cm−1: 3442, 1686, 1566, 1504, 751, 498; H-NMR (400MHz,
1
3447, 1681, 1600, 1542, 753, 502; H-NMR (400MHz, DMSO- DMSO-d6) δ (ppm): 11.0 (s, 1H, NH), 8.25 (d, 2H, Ar-H,
d6) δ (ppm): 10.38 (s, 1H, NH), 7.57 (d, 2H, Ar-H, J=7.72Hz), J=9.2Hz), 7.83 (d, 2H, Ar-H, J=9.2Hz), 4.37 (s, 2H, CH2), 3.0
7.33 (t, 2H, Ar-H, J=7.6Hz), 7.08 (t, 1H, Ar-H, J=7.4Hz), 4.29 (t, 2H, CH2, J=7.2Hz), 1.60–1.67 (m, 2H, CH2), 1.31–1.40 (m,
(s, 2H, CH2), 3.0 (t, 2H, CH2, J=7.2Hz), 1.61–1.68 (m, 2H, 2H, CH2), 0.86 (t, 3H, CH3, J=7.3Hz); 13C-NMR (100MHz,
CH2), 1.32–1.41 (m, 2H, CH2), 0.86 (t, 3H, CH3, J=7.4Hz); DMSO-d6) δ (ppm): 171.77, 166.71, 166.57, 145.21, 142.92,
13C-NMR (100MHz, DMSO-d6) δ (ppm): 171.65, 167.05, 125.40 (2C), 119.34 (2C), 38.87, 38.81, 30.86, 21.31, 13.82;
165.46, 139.18, 129.21 (2C), 124.06, 119.67 (2C), 38.93, 38.90, HR-MS (ESI): m/z 417.0194 [M+H]+ (Calcd for C14H17N4O3S4
30.90, 21.37, 13.87; HR-MS (ESI): m/z 372.0346 [M+H]+ 417.0183).
(Calcd for C14H18N3OS4 372.0333).
2-(n-Butyldisulfanyl)-5-[(2-methoxyphenylcarbamoyl)-
2-(n-Butyldisulfanyl)-5-[(2-chlorophenylcarbamoyl)- methylthio]-1,3,4-thiadiazole (7g)
methylthio]-1,3,4-thiadiazole (7b)
Yellow oily liquid; Yield 72.6%; IR (KBr) cm−1: 3402, 1687,
1
White solid; Yield 71.9%; mp 68.8–69.7°C; IR (KBr) cm−1: 1602, 1536, 749, 513; H-NMR (400MHz, DMSO-d6) δ (ppm):
1
3446, 1684, 1558, 1507, 757, 503; H-NMR (400MHz, DMSO- 9.63 (s, 1H, NH), 7.97 (d, 1H, Ar-H, J=8.0Hz), 7.04–7.12 (m,
d6) δ (ppm): 9.95 (s, 1H, NH), 7.74 (d, 1H, Ar-H, J=7.1Hz), 2H, Ar-H), 6.91 (t, 1H, Ar-H, J=8.1Hz), 4.35 (s, 2H, CH2),
7.51 (d, 1H, Ar-H, J=8.0Hz), 7.35 (t, 1H, Ar-H, J=8.6Hz), 7.22 3.84 (s, 3H, OCH3), 3.0 (t, 2H, CH2, J=7.2Hz), 1.61–1.68
(t, 1H, Ar-H, J=6.6Hz), 4.36 (s, 2H, CH2), 3.01 (t, 2H, CH2, (m, 2H, CH2), 1.32–1.41 (m, 2H, CH2), 0.86 (t, 3H, CH3,
J=7.2Hz), 1.61–1.69 (m, 2H, CH2), 1.32–1.41 (m, 2H, CH2), J=7.4Hz); 13C-NMR (100MHz, DMSO-d6) δ (ppm): 171.69,
0.87 (t, 3H, CH3, J=7.4Hz); 13C-NMR (100MHz, DMSO-d6) 167.28, 165.87, 149.79, 127.44, 125.10, 121.75, 120.76, 111.67,
δ (ppm): 171.81, 167.02, 166.26, 134.95, 129.99, 127.95, 126.95, 56.19, 38.84, 38.63, 30.86, 21.30, 13.85; HR-MS (ESI): m/z
126.53, 126.00, 38.85, 38.31, 30.87, 21.31, 13.86; HR-MS (ESI): 402.0454 [M+H]+ (Calcd for C15H20N3O2S4 402.0438).
m/z 405.9955 [M+H]+ (Calcd for C14H17N3OS4Cl 405.9943).
2-(n-Butyldisulfanyl)-5-[(3-chlorophenylcarbamoyl)- methylthio]-1,3,4-thiadiazole (7h)
2-(n-Butyldisulfanyl)-5-[(4-methoxyphenylcarbamoyl)-
methylthio]-1,3,4-thiadiazole (7c)
White solid; Yield 69.7%; mp 92.0–93.6°C; IR (KBr) cm−1:
1
White solid; Yield 73.7%; mp 80.6–81.8°C; IR (KBr) cm−1: 3430, 1674, 1602, 1512, 828, 521; H-NMR (400MHz, DMSO-
1
3446, 1683, 1594, 1541, 779, 503; H-NMR (400MHz, DMSO- d6) δ (ppm): 10.25 (s, 1H, NH), 7.48 (d, 2H, Ar-H, J=8.9Hz),
d6) δ (ppm): 10.57 (s, 1H, NH), 7.79 (s, 1H, Ar-H), 7.43 (d, 6.90 (t, 2H, Ar-H, J=8.9Hz), 4.25 (s, 2H, CH2), 3.72 (s, 3H,
1H, Ar-H, J=8.3Hz), 7.36 (t, 1H, Ar-H, J=7.9Hz), 7.15 (d, 1H, OCH3), 3.0 (t, 2H, CH2, J=7.2Hz), 1.60–1.68 (m, 2H, CH2),
Ar-H, J=7.8Hz), 4.30 (s, 2H, CH2), 3.0 (t, 2H, CH2, J=7.2Hz), 1.31–1.41 (m, 2H, CH2), 0.86 (t, 3H, CH3, J=7.4Hz); 13C-NMR
1.61–1.68 (m, 2H, CH2), 1.32–1.41 (m, 2H, CH2), 0.86 (t, 3H, (100MHz, DMSO-d6) δ (ppm): 171.64, 167.12, 164.94, 155.99,
CH3, J=7.3Hz); 13C-NMR (100MHz, DMSO-d6) δ (ppm): 132.30, 121.23 (2C), 114.34 (2C), 55.59, 38.92, 38.81, 30.90,
171.72, 166.95, 165.97, 140.55, 133.66, 130.99, 123.84, 119.14, 21.37, 13.85; HR-MS (ESI): m/z 402.0452 [M+H]+ (Calcd for
118.04, 38.85, 38.72, 30.86, 21.29, 13.85; HR-MS (ESI): m/z C15H20N3O2S4 402.0438).
405.9955 [M+H]+ (Calcd for C14H17N3OS4Cl 405.9943).
2-(n-Butyldisulfanyl)-5-[(4-chlorophenylcarbamoyl)- methylthio]-1,3,4-thiadiazole (7i)
2-(n-Butyldisulfanyl)-5-[(4-fluorophenylcarbamoyl)-
methylthio]-1,3,4-thiadiazole (7d)
White solid; Yield 74.3%; mp 101.7–103.0°C; IR (KBr)
1
White solid; Yield 73.6%; mp 102.7–103.4°C; IR (KBr) cm−1: 3430, 1664, 1558, 1509, 838, 518; H-NMR (400MHz,
cm−1: 3447, 1663, 1569, 1541, 745, 510; H-NMR (400MHz, DMSO-d6) δ (ppm): 10.45 (s, 1H, NH), 7.59 (dd, 2H, Ar-H,
1
DMSO-d6) δ (ppm): 10.51 (s, 1H, NH), 7.61 (d, 2H, Ar-H, J1=5.0Hz, J2=9.0Hz), 7.17 (d, 2H, Ar-H, J=8.8Hz), 4.28 (s,
J=8.8Hz), 7.39 (d, 2H, Ar-H, J=8.8Hz), 4.29 (s, 2H, CH2), 2H, CH2), 3.0 (t, 2H, CH2, J=7.2Hz), 1.60–1.68 (m, 2H, CH2),
3.0 (t, 2H, CH2, J=7.2Hz), 1.61–1.68 (m, 2H, CH2), 1.32–1.41 1.31–1.40 (m, 2H, CH2), 0.86 (t, 3H, CH3, J=7.4Hz); 13C-NMR
(m, 2H, CH2), 0.86 (t, 3H, CH3, J=7.4Hz); 13C-NMR (100MHz, DMSO-d6) δ (ppm): 171.70, 166.94, 165.38, 158.70
(100MHz, DMSO-d6) δ (ppm): 171.70, 166.91, 165.64, 138.07, (d, JC–F=239.2Hz), 135.51 (d, JC–F=2.0Hz), 121.43 (d, 2C,
129.13 (2C), 127.80, 121.18 (2C), 38.91, 38.80, 30.88, 21.35, JC–F=7.7Hz), 115.74 (d, 2C, JC–F=22.2Hz), 38.92, 38.75, 30.88,
13.85; HR-MS (ESI): m/z 405.9955 [M+H]+ (Calcd for 21.35, 13.81; HR-MS (ESI): m/z 390.0252 [M+H]+ (Calcd for
C14H17N3OS4Cl 405.9943).
C14H17N3OS4F 390.0238).
2-(n-Butyldisulfanyl)-5-[(3-nitro-phenylcarbamoyl)-
methylthio]-1,3,4-thiadiazole (7e)
2-(n-Butyldisulfanyl)-5-[(4-trifluoromethylphenylcarbamoyl)-
methylthio]-1,3,4-thiadiazole (7j)
White solid; Yield 72.8%; mp 44.9–46.3°C; IR (KBr) cm−1:
White solid; Yield 71.2%; mp 105.9–107.0°C; IR (KBr)
1
1
3426, 1683, 1614, 1527, 737, 511; H-NMR (400MHz, DMSO- cm−1: 344, 1684, 1608, 1543, 840, 506; H-NMR (400MHz,
d6) δ (ppm): 10.89 (s, 1H, NH), 8.61 (s, 1H, Ar-H), 7.94 (d, DMSO-d6) δ (ppm): 10.76 (s, 1H, NH), 7.79 (d, 2H, Ar-H,
1H, Ar-H, J=8.0Hz), 7.89 (d, 1H, Ar-H, J=8.1Hz), 7.63 (t, J=8.6Hz), 7.7 (d, 2H, Ar-H, J=8.6Hz), 4.34 (s, 2H, CH2), 3.0
1H, Ar-H, J=8.2Hz), 4.34 (s, 2H, CH2), 2.98 (t, 2H, CH2, (t, 2H, CH2, J=7.2Hz), 1.60–1.67 (m, 2H, CH2), 1.31–1.40 (m,
J=7.2Hz), 1.59–1.66 (m, 2H, CH2), 1.30–1.39 (m, 2H, CH2), 2H, CH2), 0.85 (t, 3H, CH3, J=7.4Hz); 13C-NMR (100MHz,
0.85 (t, 3H, CH3, J=7.4Hz); 13C-NMR (100MHz, DMSO-d6) DMSO-d6) δ (ppm): 171.72, 166.91, 166.23, 142.67, 126.57 (q,
δ (ppm): 166.41, 166.35, 165.23, 148.40, 140.22, 130.67, 125.54, 2C, JC–F=3.6Hz), 124.74 (q, JC–F=269.7Hz), 124.18 (q, 2C,
118.56, 113.72, 38.88, 38.61, 30.85, 21.29, 13.80; HR-MS (ESI): JC–F=31.8Hz), 119.56, 38.83, 38.78, 30.84, 21.27, 13.78; HR-MS
m/z 417.0197 [M+H]+ (Calcd for C14H17N4O3S4 417.0183).
(ESI): m/z 440.0217 [M+H]+ (Calcd for C15H17N3OS4F3

956
Chem. Pharm. Bull.
Vol. 65, No. 10 (2017)
440.0207).
2-(i-Butyldisulfanyl)-5-[(3-nitro-phenylcarbamoyl)-
2-(n-Butyldisulfanyl)-5-[(4-methylphenylcarbamoyl)- methylthio]-1,3,4-thiadiazole (8e)
methylhio]-1,3,4-thiadiazole (7k)
White solid; Yield 65%; mp 44.7–46.5°C; IR (KBr) cm−1:
White solid; Yield 70.7%; mp 79.7–82.0°C; IR (KBr) cm−1: 3431, 1692, 1620, 1528, 737, 514; 1H-NMR (400 MHz,
3450, 1677, 1605, 1544, 817, 506, 7.46 (d, 2H, Ar-H, J=8.3Hz), DMSO-d6) δ (ppm): 10.89 (s, 1H, NH), 8.61 (s, 1H, Ar-H),
7.13 (d, 2H, Ar-H, J=8.2Hz), 4.27 (s, 2H, CH2), 3.0 (t, 2H, 7.95 (d, 1H, Ar-H, J=8.0Hz), 7.89 (d, 1H, Ar-H, J=7.8Hz),
CH2, J=7.2Hz), 2.25 (s, 3H, CH3), 1.60–1.68 (m, 2H, CH2), 7.64 (t, 1H, Ar-H, J=8.2Hz), 4.35 (s, 2H, CH2), 2.91 (d, 2H,
1.31–1.41 (m, 2H, CH2), 0.86 (t, 3H, CH3, J=7.3Hz); 13C-NMR CH2, J=6.8Hz), 1.84–1.98 (m, 1H, CH), 0.95 (d, 6H, CH3,
(100MHz, DMSO-d6) δ (ppm): 171.60, 167.14, 165.21, 136.67, J=6.6Hz); 13C-NMR (100 MHz, DMSO-d6) δ (ppm): 171.61,
133.06, 129.62 (2C), 119.66 (2C), 39.01, 38.87, 30.88, 21.33, 166.84, 166.34, 148.41, 140.22, 130.68, 125.54, 118.56, 113.72,
20.91, 13.86; HR-MS (ESI): m/z 386.0498 [M+H]+ (Calcd for 48.21, 38.65, 28.14, 21.62 (2C); HR-MS (ESI): m/z 417.0195
C15H20N3OS4 386.0489).
[M+H]+ (Calcd for C14H17N4O3S4 417.0183).
2-(i-Butyldisulfanyl)-5-[(4-nitro-phenylcarbamoyl)-
methylthio]-1,3,4-thiadiazole (8f)
2-(i-Butyldisulfanyl)-5-[(phenylcarbamoyl)-methylthio]-
1,3,4-thiadiazole (8a)
White solid; Yield 73.6%; mp 90.8–92.1°C; IR (KBr) cm−1:
White solid; Yield 71.8%; mp 120.9–122.7°C; IR (KBr)
3447, 1682, 1600, 1541, 751, 503; H-NMR (400MHz, DMSO- cm−1: 3441, 1687, 1615, 1504, 751, 497; H-NMR (400MHz,
d6) δ (ppm): 10.38 (s, 1H, NH), 7.57 (d, 2H, Ar-H, J=8.0Hz), DMSO-d6) δ (ppm): 10.98 (s, 1H, NH), 8.24 (d, 2H, Ar-H,
7.33 (t, 2H, Ar-H, J=7.6Hz), 7.08 (t, 1H, Ar-H, J=7.3Hz), J=9.2Hz), 7.83 (d, 2H, Ar-H, J=9.2Hz), 4.37 (s, 2H, CH2),
4.30 (s, 2H, CH2), 2.91 (d, 2H, CH2, J=6.8Hz), 1.85–1.98 (m, 2.90 (d, 2H, CH2, J=6.8Hz), 1.84–1.97 (m, 1H, CH), 0.95
1H, CH), 0.96 (d, 6H, CH3, J=6.6Hz); 13C-NMR (100MHz, (d, 6H, CH3, J=6.6Hz); 13C-NMR (100MHz, DMSO-d6) δ
DMSO-d6) δ (ppm): 171.44, 167.16, 165.48, 139.16, 129.25 (ppm): 171.60, 166.75, 166.54, 145.20, 142.91, 125.39 (2C),
(2C), 124.09, 119.68 (2C), 48.22, 38.87, 28.16, 21.68 (2C); 119.34 (2C), 48.21, 38.81, 28.15, 21.63 (2C); HR-MS (ESI): m/z
HR-MS (ESI): m/z 372.0349 [M+H]+ (Calcd for C14H18N3OS4 417.0187 [M+H]+ (Calcd for C14H17N4O3S4 417.0183).
1
1
372.0333).
2-(i-Butyldisulfanyl)-5-[(2-methoxyphenylcarbamoyl)-
2-(i-Butyldisulfanyl)-5-[(2-chlorophenylcarbamoyl)- methylthio]-1,3,4-thiadiazole (8g)
methylthio]-1,3,4-thiadiazole (8b)
White solid; Yield 65.3%; mp 51.1–53.0°C; IR (KBr) cm−1:
1
White solid; Yield 70.4%; mp 90.7–91.7°C; IR (KBr) cm−1: 3374, 1675, 1602, 1529, 746, 512; H-NMR (400MHz, DMSO-
1
3447, 1685, 1590, 1524, 757, 503; H-NMR (400MHz, DMSO- d6) δ (ppm): 9.62 (s, 1H, NH), 7.97 (d, 1H, Ar-H, J=7.32Hz),
d6) δ (ppm): 9.95 (s, 1H, NH), 7.75 (d, 1H, Ar-H, J=7.8Hz), 7.05–7.12 (m, 2H, Ar-H), 6.91 (t, 1H, Ar-H, J=8.1Hz), 4.35 (s,
7.50 (d, 1H, Ar-H, J=7.4Hz), 7.34 (t, 1H, Ar-H, J=7.3Hz), 2H, CH2), 3.84 (s, 3H, OCH3), 2.92 (d, 2H, CH2, J=6.8Hz),
7.21 (t, 1H, Ar-H, J=7.3Hz), 4.37 (s, 2H, CH2), 2.91 (d, 2H, 1.86–1.99 (m, 1H, CH), 0.96 (d, 6H, CH3, J=6.7Hz); 13C-NMR
CH2, J=6.8Hz), 1.85–1.99 (m, 1H, CH), 0.96 (d, 6H, CH3, (100MHz, DMSO-d6) δ (ppm): 171.52, 167.28, 165.83, 149.70,
J=6.7Hz); 13C-NMR (100MHz, DMSO-d6) δ (ppm): 171.65, 127.51, 125.02, 121.64, 120.76, 111.60, 56.17, 48.24, 38.68,
166.98, 166.21, 135.00, 129.93, 127.87, 126.74, 126.29, 125.70, 28.17, 21.67 (2C); HR-MS (ESI): m/z 402.0449 [M+H]+ (Calcd
48.30, 38.40, 28.20, 21.70 (2C); HR-MS (ESI): m/z 405.9941 for C15H20N3O2S4 402.0438).
[M+H]+ (Calcd for C14H17N3OS4Cl 405.9943).
2-(n-Butyldisulfanyl)-5-[(3-chlorophenylcarbamoyl)- methylthio]-1,3,4-thiadiazole (8h)
2-(i-Butyldisulfanyl)-5-[(4-methoxyphenylcarbamoyl)-
methylthio]-1,3,4-thiadiazole (8c)
White solid; Yield 70.5%; mp 95.0–95.9°C; IR (KBr)
1
White solid; Yield 68.7%; mp 62.8–64.5°C; IR (KBr) cm−1: 3431, 1673, 1603, 1511, 829, 522; H-NMR (400MHz,
cm−1: 3447, 1684, 1593, 1541, 779, 503; H-NMR (400 MHz, DMSO-d6) δ (ppm): 10.25 (s, 1H, NH), 7.48 (d, 2H, Ar-H,
1
DMSO-d6) δ (ppm): 10.57 (s, 1H, NH), 7.79 (s, 1H, Ar-H), J=8.8Hz), 6.90 (t, 2H, Ar-H, J=8.9Hz), 4.26 (s, 2H, CH2),
7.42 (d, 1H, Ar-H, J=8.3Hz), 7.36 (t, 1H, Ar-H, J=8.0Hz), 3.72 (s, 3H, OCH3), 2.91 (d, 2H, CH2, J=6.8Hz), 1.85–1.98 (m,
7.14 (d, 1H, Ar-H, J=7.9Hz), 4.30 (s, 2H, CH2), 2.91 (d, 2H, 1H, CH), 0.96 (d, 6H, CH3, J=6.6Hz); 13C-NMR (100MHz,
CH2, J=6.8Hz), 1.85–1.98 (m, 1H, CH), 0.96 (d, 6H, CH3, DMSO-d6) δ (ppm): 171.14, 167.19, 164.94, 155.98, 132.30,
J=6.7Hz); 13C-NMR (100 MHz, DMSO-d6) δ (ppm): 171.54, 121.23 (2C), 114.37 (2C), 55.61, 48.23, 38.80, 28.17, 21.67 (2C);
166.98, 165.95, 140.55, 133.67, 130.97, 123.83, 119.15, 118.04, HR-MS (ESI): m/z 402.0443 [M+H]+ (Calcd for C15H20N3O2S4
48.20, 38.74, 28.15, 21.67 (2C); HR-MS (ESI): m/z 405.9958 402.0438).
[M+H]+ (Calcd for C14H17N3OS4Cl 405.9943).
2-(i-Butyldisulfanyl)-5-[(4-chlorophenylcarbamoyl)- methylthio]-1,3,4-thiadiazole (8i)
methylthio]-1,3,4-thiadiazole (8d)
White solid; Yield 75.6%; mp 89.9–91.3°C; IR (KBr) cm−1:
2-(i-Butyldisulfanyl)-5-[(4-f luorophenylcarbamoyl)-
1
White solid; Yield 69.8%; mp 101.6–103.5°C; IR (KBr) 3431, 1680, 1557, 1500, 834, 515; H-NMR 400MHz, DMSO-
1
cm−1: 3447, 1663, 1558, 1541, 836, 510; H-NMR (400 MHz, d6): δ (ppm): 10.45 (s, 1H, NH), 7.59 (dd, 2H, Ar-H, J1=5.0Hz,
DMSO-d6) δ (ppm): 10.54 (s, 1H, NH), 7.61 (d, 2H, Ar-H, J2=9.2Hz), 7.17 (d, 2H, Ar-H, J=8.8Hz), 4.29 (s, 2H, CH2),
J=8.8Hz), 7.38 (d, 2H, Ar-H, J=8.8Hz), 4.30 (s, 2H, CH2), 2.91 (d, 2H, CH2, J=6.8Hz), 1.85–1.98 (m, 1H, CH), 0.96
2.89 (d, 2H, CH2, J=6.8Hz), 1.83–1.97 (m, 1H, CH), 0.95 (d, 6H, CH3, J=6.6Hz); 13C-NMR (100MHz, DMSO-d6):
(d, 6H, CH3, J=6.6Hz); 13C-NMR (100 MHz, DMSO-d6) δ δ (ppm): 171.50, 167.04, 165.40, 158.68 (d, JC–F=239.0Hz),
(ppm): 171.55, 167.06, 165.72, 138.09, 129.23 (2C), 127.71, 135.53 (d, JC–F=2.1Hz), 121.44 (d, 2C, JC–F=7.7Hz), 115.79
121.17 (2C), 48.10, 38.71, 28.13, 21.67 (2C); HR-MS (ESI): m/z (d, 2C, JC–F=22.1Hz), 48.22, 38.74, 28.16, 21.65 (2C); HR-MS
405.9950 [M+H]+ (Calcd for C14H17N3OS4Cl 405.9943).
(ESI): m/z 390.0246 [M+H]+ (Calcd for C14H17N3OS4F
390.0238).

Vol. 65, No. 10 (2017)
Chem. Pharm. Bull.
957
2-(i-Butyldisulfanyl)-5-[(4-trifluoromethylphenylcarbamoyl)-
methylthio]-1,3,4-thiadiazole (8j)
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1
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