Metal- and Oxidant-free Electrosynthesis of 1,2,3-Thiadiazoles from Element Sulfur and N-tosyl Hydrazones

Article abstract of DOI:10.1002/adsc.201801700

A metal- and oxidant-free electrochemical method for synthesizing 1,2,3-thiadiazoles by inserting element sulfur into N-tosyl hydrazones is reported. This electrochemical transformation engages electrons as reagents to achieve redox processes, and avoid e

Full text of DOI:10.1002/adsc.201801700

Title: Metal- and Oxidant-free Electrosynthesis of 1,2,3-Thiadiazoles
from Element Sulfur and N-tosyl Hydrazones
Authors: Shi-Kun Mo, Qing-hu Teng, Ying-ming Pan, and Hai-Tao
Tang
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To be cited as: Adv. Synth. Catal. 10.1002/adsc.201801700
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10.1002/adsc.201801700
Advanced Synthesis & Catalysis
COMMUNICATION
DOI: 10.1002/adsc.201((will be filled in by the editorial staff))
Metal- and Oxidant-free Electrosynthesis of 1,2,3-Thiadiazoles from Element
Sulfur and N-tosyl Hydrazones
Shi-Kun Mo,a Qing-Hu Teng,a,b Ying-Ming Pana and Hai-Tao Tanga,*
a
State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, School of Chemistry and
Pharmaceutical Sciences of Guangxi Normal University, Guilin 541004, People’s Republic of China
E-mail: httang@gxnu.edu.cn.
School of Chemistry and Chemical Engineering, Beijing Institute of Technology, 6 LiangxiangEast Street, Beijing
b
100081, China
Received: ((will be filled in by the editorial staff))
Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/adsc.201######.((Please
delete if not appropriate))
Abstract. A metal- and oxidant-free electrochemical
method for synthesizing 1,2,3-thiadiazoles by inserting
element sulfur into N-tosyl hydrazones is reported. This
diazotization of α-enolicdithioesters (Scheme 1, Path
d)[11] and the reaction of α-chlorosulfonohydrazones
and potassium sulfide in the presence of potassium
carbonate with elevated temperatures (Scheme 1,
Path e)[12] are two new methods for synthesizing
1,2,3-thiadiazoles. However, these methods require
highly reactive reagents, such as SCl2, SOCl2,
diazo/azide, or prefunctionalized compounds, that
have safety concerns. To solve these problems, the
direct oxidative cyclization of readily available N-
tosylhydrazones and sulfur into 1,2,3-thiadiazoles is a
satisfactory strategy. Existing methods that use this
strategy need excessive oxidants and complex flavins,
and thus a relatively expensive process and/or
generates copious amounts of waste (Scheme 1, Path
electrochemical transformation engages electrons as
reagents to achieve redox processes, and avoid excess
oxidants. The cyclic voltammograms are examined to
explore the mechanism of this electrolysis reaction.
Keywords: electrosynthesis; metal- and oxidant-free;
NH4I-mediated; element sulfur; 1,2,3-thiadiazoles
1,2,3-Thiadiazoles contain three heteroatoms that are
common in nature and have attracted attention due to
their utility in pharmaceutical agents[1] and
[2]
f).[13] Thus,
a mild, metal, oxidant-free, and
sustainable synthetic method that overcomes the
above limitations is needed.
materials.
Moreover, they have a series of
biological activities, such as antibacterial, [3] antiviral,
antitumor,[5] antifungal,[6] and herbicidal growth
[4]
regulating (plants)[7] activities (Figure 1).
Thus, considerable attention has been devoted to
the development of many methods for synthesizing
1,2,3-thiadiazoles (Scheme 1). The traditional
protocols include Hurd–Mori synthesis (Scheme 1,
Path a),[8] Wolff synthesis (Scheme 1, Path b),[9] and
Pechmann synthesis (Scheme 2, Path c).[10] The
Scheme 1. Different methods for the preparation of 1,2,3-
thiadiazoles.
Organic electrosynthesis has recently drawn
considerable attention as an environment-friendly and
enabling synthetic tool because it employs mass free
electrons as reagents to accomplish redox processes.
[14]
The replacement of metal catalysts by iodine has
Figure 1. Bioactive molecules containing
thiadiazole moiety.
a 1,2,3-
emerged as a green strategy in recent years.[15] In
1
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10.1002/adsc.201801700
Advanced Synthesis & Catalysis
organic electrosynthesis, the anodic oxidation of
iodide generates an iodine radical or cation, which
can be interconverted during the reaction cycle. Thus,
catalytic amounts of iodide salts are sufficient to
complete the chemical transformation.[16] For
Entries 6–9). Changing the LiClO4 to n-BuNBF4
slightly decreased the reaction efficiency (77% yield,
Table 1, Entry 9). Fortunately, the reaction could
occur in the absence of electrolyte (LiClO4) without
reducing the yield of 3a (85% yield, Table 1, Entry
10). However, Na2S and (NH4)2S could not
participate in this transformation to afford the desired
product 3a (Table 1, Entries 11 and 12). Therefore,
the best conditions for this transformation are
constant current electrolysis at a current density of 10
mA/cm2, undivided cell equipped with a RVC anode
and a platinum plate cathode, and NH4I (20 mol%) as
the redox catalyst and electrolyte in DMAC at 120 °C
for 6 h.
example,
we
previously
reported
two
dehydrogenation cross-coupling reactions with this
green and sustainable catalytic system.[17] With our
continued interest in the development of green
methods for the synthesis of N-heterocycles,[18] we
would like to develop a new method for forming
1,2,3-thiadiazoles from N-tosylhydrazones and sulfur
using a metal- and oxidant-free electrochemical
iodine-catalyzed strategy (Scheme 1, Path f).
Scheme 2. Substrate scope.a,b
Table 1. Optimization of the reaction conditions.a, b
Entry Catalyst
Solvent
DMAC
DMAC
DMAC
DMAC
DMAC
DMF
1,4-Dioxane
n-BuOH
EtOH
Electrolyte Yield (%)
1
2
TBAI
NaI
LiClO4
LiClO4
LiClO4
LiClO4
LiClO4
LiClO4
LiClO4
LiClO4
LiClO4
-
80
0
0
84
43
56
52
0
3
KI
4
5
6
7
8
9
10
11c
12d
NH4I
NH4Br
NH4I
NH4I
NH4I
NH4I
NH4I
NH4I
NH4I
0
85
0
DMAC
DMAC
DMAC
-
-
0
aReaction conditions: Reticulated vitreous carbon (RVC)
as anode (100 PPI, 1 cm × 1 cm ×1.2 cm), Pt plate as
cathode (1 cm × 1 cm), undivided cell, constant current =
10 mA, 1a (0.5 mmol), catalyst (20 mol%), 2 (0.6 mmol),
electrolyte (0.5 mmol), and solvent (6 mL) at 120 °C under
b
c
air for 6 h. Isolated yield. Na2S as the sulfur source (0.6
d
mmol), (NH4)2S as the sulfur source (0.6 mmol). DMAC
= dimethylacetamide, DMF = N,N-Dimethylformamide.
aReaction conditions: Reticulated vitreous carbon (RVC)
as anode (100 PPI, 1 cm × 1 cm ×1.2 cm), Pt plate as
cathode (1 cm × 1 cm), undivided cell, constant current =
10 mA, 1 (0.5 mmol), NH4I (20 mol%), 2 (0.6 mmol), and
DMAC (6 mL) at 120 °C under air for 6 h. bIsolated yield.
We selected the tosylhydrazone derived from
acetophenone 1a and sulfur 2 as model substrates for
the optimization studies (Table 1). Initially, the
reaction of 1a and 2 was carried out in an undivided
cell with TBAI (20 mol%) and LiClO4 (1 equiv) in
DMAC at 120 °C for 6 h and offered annulation
product 3a in 80% yield (Table 1, Entry 1). NaI and
KI failed to work, whereas NH4I was optimal and
provided the desired product 3a with 84% yield
(Table 1, Entry 1 versus Entries 2–4). These results
were mainly due to the good solubility of NH4I in
DMAC. No progress was observed in the reaction
with NH4Br (Table 1, Entry 5). A solvent screen
revealed that DMAC was the most suitable solvent
for this transformation (Table 1, Entry 1 versus
With the optimal reaction conditions defined, we
studied the substrate scope by varying the
substituents of tosylhydrazones 1 (Scheme 2).
Various tosylhydrazones were tolerated well. The
electrolysis reaction exhibited excellent compatibility
with several electron-donating groups at the phenyl
ring, thereby providing a high yield of 4-aryl-1,2,3-
thiadiazoles (Scheme 2, 3a-3g). Tosylhydrazones 1c
and 1d with electron-donating groups at the meta and
2
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10.1002/adsc.201801700
Advanced Synthesis & Catalysis
ortho aryl rings (1c: R = 3-Me; 1d: R = 2-Me)
reacted successfully and afforded the desired
products 3c and 3d with yields of 86% and 83%,
respectively (Scheme 2, 3c and 3d). Substrates
bearing electron-drawing groups at the phenyl ring
produced low yields (Scheme 2, 3h-3o). Moreover,
functional groups ester and acetamino were found
suitable for procedure and gained desired products 3n
and 3o with 79% and 75% yields, respectively. The
alkene-bearing tosylhydrazone worked smoothly
without transforming alkene to provide the
corresponding product 3p with 88% yield (Scheme 2,
3p). Heteroaryl tosylhydrazones were subjected to
electrolysis and formed the corresponding products
3q and 3r with 70% and 83% yields, respectively
(Scheme 2, 3q and 3r). Unfortunately, this
electrolysis reaction did not fit the aliphatic analogues
of the N-Ts hydrazone under the standard conditions
(Scheme 2, 3s and 3t). 4,5-Disubstituted 1,2,3-
thiadiazoles and 5-benzyl-1,2,3-thiadiazole 3w could
not be synthesized with our method (Scheme 2, 3u,
3v, and 3w).
To further investigate the possible reaction
mechanism of this oxidant-free transformation, cyclic
voltammogram was performed, and the results are
shown in Figure 2. Curves b and c of Figure 2 show
no apparent oxidation peak for sulfur 2 and
tosylhydrazone 1a in the 0.0−1.3 V region versus
Ag/AgCl. The CV of NH4I (curve d) exhibits two
couples of reversible redox waves, with the oxidation
peaks at 0.41 V (Ox1) and 0.75 V (Ox2) versus
Ag/AgCl corresponding to the oxidation of iodide to
form I3− and I3− to I2, respectively.[16] Compared with
curve d, no apparent change was observed for curve e,
indicating that the in situ generated iodine could not
oxidize sulfur 2. By contrast, the mixture of
tosylhydrazone 1a and NH4I exhibited an additional
marked increase in catalytic current (curve f), and the
peak currents of Ox1 and Ox2 increased dramatically
from 19.22 to 58.79 μA, suggesting that NH4I was the
catalyst for this hydrazone transformation. As
expected, the oxidation peaks and peak currents of
the CV curve of the three components were only
slightly higher than the curve of the mixture of 1a
and NH4I (curve f versus curve g).
Figure 2. Cyclic voltammograms of reactants and their
mixtures in 0.1 M LiClO4/DMAC using a glassy carbon
disk working electrode (diameter, 3 mm), Pt disk and
Ag/AgCl (KCl saturated solution) as counter and reference
electrode at 100 mV s−1 scan rate: (a) background, (b) 2
(10 mmol L−1), (c) 1a (10 mmol L−1), (d) NH4I (2 mmol
L−1), (e) 2 (10 mmol L−1) + NH4I (2 mmol L−1), (f ) 1a (10
mmol L−1) + NH4I (2 mmol L−1), and (g) 1a (10 mmol L−1)
+ 2 (10 mmol L−1) + NH4I (2 mmol L−1).
Scheme 3. Controlled experiments.
According to previous reports, iodine anions can
be oxidized to iodine free radicals or iodine cations at
the anode.[16] To study the possible pathways, control
experiments were performed. A reaction between 1a
and 2 was performed in the presence of I2 (2 equiv.)
o
in DMAC at 120 C for 6 h in the absence of a
current, and product 3a was isolated with 36% yield
(Scheme 3, Eq. 1). Subsequently, TEMPO or 1, 1-
diphenylethylene, and substrates 1a and 2 were
performed under standard conditions, and the desired
product 3a was observed with 78%/81% isolated
yield (Scheme 3, Eq. 2). The above results might
exclude the presumption of a radical pathway.
Control experiments without electricity or iodine
reagent were also conducted, but the reactions failed
to form the corresponding product 3a (Scheme 3, Eq.
3).
Scheme 4. Plausible mechanism.
3
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10.1002/adsc.201801700
Advanced Synthesis & Catalysis
References
Based on the above results, a plausible mechanism
was proposed (Scheme 4). At the anode, the
electrochemical oxidation of 2I- led to the formation
of I2, which easily generated I- and I+. The α-iodation
of acetophenone tosylhydrazone 1a formed
intermediate A, and the elimination of HI provided
azoalkene B. In these processes, the released iodine
anions could be further oxidized to complete the
cycle of the reaction. S8 was added to azoalkene B to
produce zwitterionic C, which underwent cyclization
that furnished intermediate E. Finally, the elimination
of S7 and TsH led to the formation of the desired
product 3a. At the cathode, reduction occurred to
[1] a) H. Dai, S. Ge, G. Li, J. Chen, Y. Shi, L. Ye, Y. Ling,
Bioorg. Med. Chem. Lett. 2016, 26, 4504–4507; b) F.
Hayat, A. Salahuddin, J. Zargan, A. Azam, Eur. J.
Med. Chem. 2010, 45, 6127-6134; c) L. Chen, Y.-J.
Zhu, Z.-J. Fan, X.-F. Guo, Z.-M. Zhang, J.-H. Xu, Y.-
Q. Song, M. Y. Yurievich, N. P. Belskaya, and V. A.
Bakulev, J. Agric. Food Chem. 2017, 65, 745−751; d)
H. Wang, Z. Yang, Z. Fan, Q. Wu, Y. Zhang, N. Mi, S.
Wang, Z. Zhang, H. Song, F. Liu, J. Agric. Food
Chem. 2011, 59, 628–634; e) I. Cikotiene, E.
Kazlauskas, J. Matuliene, V. Michailoviene, J.
Torresan, J. Jachno, D. Matulis, Bioorg. Med. Chem.
Lett. 2009, 19, 1089–1092; f) T. Balasankar, M.
Gopalakrishnan, S. Nagarajan, Eur. J. Med. Chem.
2005, 40, 728–731;
deliver
hydrogen,
which
completed
the
electrochemical cycle.
In conclusion, we developed a metal- and oxidant-
free electrosynthesis of 1,2,3-thiadiazoles from sulfur
and N-tosylhydrazones. Readily available raw
materials, good yields, and an experimentally
convenient catalytic process make this protocol
practical and attractive. Importantly, the present
electrochemical protocol employs mass free electrons
as reagents to oxidize iodine anion to I2 without using
excess amounts of external oxidant, thereby
providing an environmentally benign method for
diverse iodine-catalyzed transformations that have
conventionally required stoichiometric oxidants. This
electrochemical transformation is being studied
further in our laboratory.
[2] Z. Chen, J. Brown, M. Drees, M. Seger, Y. Hu, Y. Xia,
D. Boudinet, M. McCray, M. Delferro, T. J. Marks,
C.-Y. Liao, C.-W. Ko, Y.-M. Chang, A. Facchetti,
Chem. Mater. 2016, 28, 6390−6400.
[3] a) T. Fan, X. Hu, S. Tang, X. Liu, Y. Wang, H. Deng,
X. You, J. Jiang, Y. Li, D. Song, ACS Med. Chem.
Lett. 2018, 9, 484−489; b) W.-M. Xu, S.-Z. Li, M. He,
S. Yang, X.-Y. Li, P. Li, Bioorg. Med. Chem. Lett.
2013, 23, 5821–5824.
[4] a) W.-G. Zhao, J.-G. Wang, Z.-M. Li, Z. Yang, Bioorg.
Med. Chem. Lett. 2006, 16, 6107–6111; b) S.-X.
Wang, J. Huang, Z.-J. Fan, H. Wang, Y.-F. Fu, N. Mi,
Z.-C. Zhang, H.-B. Song, N. P. Belskaya, V. A.
Bakulev, J. Chem. Crystallogr. 2011, 41, 1348–1354.
[5] H.-W. Cui, S. H. Peng, X.-Z. Gu, H. Chen, Y. He, W.
Gao, F. Lv, J.-H. Wang, Y. Wang, J. Xie, M.-Y. Liu, Z.
F. Yi, W.-W. Qiu, Eur. J. Med. Chem. 2016, 111, 126-
137.
Experimental Section
N‑ tosylhydrazones 1 (0.5 mmol, 1.0 equiv), sulfur 2 (0.6
mmol, 1.2 equiv), and NH4I (0.1 mmol, 20 mol%) were
placed in a 10-mL three-necked round-bottomed flask. The
flask was equipped with a condenser, a RVC (100 PPI, 1
cm × 1 cm × 1.2 cm) anode and a platinum plate (1 cm × 1
cm) cathode. DMAC (6 mL) was added. Electrolysis was
performed at 120 °C using a constant current of 10 mA
until the complete consumption of the substrate (monitored
by TLC, approximately 6 h). The reaction mixture was
cooled to room temperature. Water (30 mL) and ethyl
acetate (30 ml) were added. The phases were separated,
and the aqueous phase was extracted with ethyl acetate (2
× 30 mL). The combined organic solution was dried over
anhydrous MgSO4, filtered, and concentrated under
reduced pressure. The residue was chromatographed
through silica gel elution with ethyl acetate/petroleum
ether to yield product 3.
[6] a) Z. Li, Z. Wu, F. Luo, J. Agric. Food Chem. 2005,
53, 3872–3876; b) Q. Zheng, N. Mi, Z. Fan, X. Zuo,
H. Zhang, H. Wang, Z. Yang, J. Agric. Food Chem.
2010, 58, 7846–7855.
[7] a) Z. J. Fan, Z. K. Yang, H. K. Zhang, N. Mi, H.
Wang, F. Cai, X. Zuo, Q. X. Zheng, and H. B. Song, J.
Agric. Food Chem. 2010, 58, 2630–2636.
[8] a) C. D. Hurd, R. I. Mori, J. Am. Chem. Soc. 1955, 77,
5359-5364; b) O. A. Attanasi, G. Baccolini, C. Boga,
L. D. Crescentini, P. Filippone, F. Mantellini, J. Org.
Chem. 2005, 70, 4033-4037; c) Y. Hu, S. Baudart, J.
A. Porco, Jr., J. Org. Chem. 1999, 64, 1049-1051.
[9] a) L. Wolff, Justus Liebigs Ann. Chem. 1904, 333,
1−21; b) M. Caron, J. Org. Chem. 1986, 51,
4075−4077.
[10] J. C. Sheehan, P. T. Izzo, J. Am. Chem. Soc. 1949, 71,
4059–4062;
[11] a) V. O. Filimonov, L. N. Dianova, K. A. Galata, T. V.
Beryozkina, M. S. Novikov, V. S. Berseneva, O. S.
Eltsov, A. T. Lebedev, P. A. Slepukhin, V. A. Bakulev,
J. Org. Chem. 2017, 82, 4056−4071; b) M. S. Singh,
A. Nagaraju, G. K. Verma, G. Shukla, R. K. Verma, A.
Srivastava, K. Raghuvanshi, Green Chem. 2013, 15,
954–962.
[12] B.-B. Liu, H.-W. Bai, H. Liu, S.-Y. Wang, S.-J. Ji, J.
Org. Chem. 2018, 83, 10281−10288.
[13] a) J. Chen, Y. Jiang, J.-T. Yu, J. Cheng, J. Org. Chem.
2016, 81, 271−275; b) T. Ishikawa, M. Kimura, T.
Acknowledgements
We thank the National Natural Science Foundation of China
(21861006), Guangxi Natural Science Foundation of China
(2016GXNSFEA380001 and 2016GXNSFGA380005) and State
Key Laboratory for Chemistry and Molecular Engineering of
Medicinal Resources (CMEMR2017-A02 and CMEMR2017-A07)
for financial support.
4
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10.1002/adsc.201801700
Advanced Synthesis & Catalysis
Kumoi, H. Iida, ACS Catal. 2017, 7, 4986−4989.
Midorikawa, S. Suga, J.-I. Yoshida, Chem. Commun.
2006, 36, 3794-3796; g) L.-S. Kang, M.-H. Luo, C.
M. Lam, L.-M. Hu, R. D. Little, C.-C. Zeng, Green
Chem. 2016, 18, 3767-3774; h) Q.-Q. Wang, K. Xu,
Y.-Y. Jiang, Y.-G. Liu, B.-G. Sun, C.-C. Zeng, Org.
Lett. 2017, 19, 5517-5520; i) S. Liang, C.-C. Zeng, H.
Tian, B. Sun, X. Luo, F. Ren, Adv. Synth. Catal. 2018,
360, 1444-1452; j) P. Qian, Z. Yan, Z. Zhou, K. Hu, J.
Wang, Z. Li, Z. Zha, Z. Wang, Org. Lett. 2018, 20,
6359-6363.
[14] For reviews: a) J. B. Sperry, D. L. Wright, Chem. Soc.
Rev. 2006, 35, 605-621. b) J. Yoshida, K. Kataoka, R.
Horcajada, A. Nagaki, Chem. Rev. 2008, 108, 2265-
2299. c) R. Francke, R. D. Little, Chem. Soc. Rev.
2014, 43, 2492-2521. d) M. Yan, Y. Kawamata, P. S.
Baran, Chem. Rev. 2017, 117, 13230-13319. e) Y.
Jiang, K. Xu, C. Zeng, Chem. Rev. 2018, 118,
4485−4540. f) S. Tang, Y. Liu, A. Lei, Chem. 2018, 4,
27-45.
[15] a) A. Yoshimura, V. V. Zhdankin, Chem. Rev. 2016,
116, 3328-3435. b) J. Charpentier, N. Frꢀh, A.Togni,
Chem. Rev. 2015, 115, 650-682. c) Q.-R. Liu, C.-X.
Pan, X.-P. Ma, D.-L. Mo, G.-F. Su, J. Org. Chem.
2015, 80, 6496-6501. d) S.-Y. Wu, X.-P. Ma, C. Liang,
D.-L. Mo, J. Org. Chem. 2017, 82, 3232-3238.
[16] a) M. N. Elinson, O. O. Sokolova, A. D. Korshunov,
F. Barba, B. Batanero, Electrocatalysis 2018, 9, 602–
607; b) M. N. Elinson, S. K. Feducovich, A. N.
Vereshchagin, S. V. Gorbunov, P. A. Belyakov, G. I.
Nikishin, Tetrahedron lett. 2006, 47, 9129-9133; c) T.
Shono, Y. Matsumura, K. Tsubata, T. Kamada, K.
Kishi, J. Org. Chem. 1989, 54, 2249-2251; d) T.
Shono, Y. Matsumura, K. Inoue, J. Am. Chem .Soc.
1984, 106, 6075-6076; e) J.-I. Yoshida, A. Shimizu,
R. Hayashi, Chem. Rev. 2018, 118, 4702-4730; f) K.
[17] a) Z.-Y. Mo, T. R. Swaroop, W. Tong, Y.-Z. Zhang,
H.-T. Tang, Y.-M. Pan, H.-B. Sun, Z.-F. Chen, Green
Chem. 2018, 20, 4428–4432. B) Z.-Q. Wang, Xi.-J.
Meng, Q.-Y. Li, H.-T. Tang, H.-S. Wang, Y.-M. Pan,
Adv. Synth. Catal. 2018, 360, 4043-4048.
[18] a) Q.-H. Teng, X.-J. Peng, Z.-Y. Mo, Y.-L. Xu, H.-T.
Tang, H.-S. Wang, H.-B. Sun, Y. -M. Pan, Green
Chem. 2018, 20, 2007–2012; b) W. Tong, W.-H. Li, Y.
He, Z.-Y. Mo, H.-T. Tang, H.-S. Wang, Y.-M. Pan,
Org. Lett. 2018, 20, 2494-2498; c) X. Wang, S.-Y. Li,
Y.-M. Pan, H.-S. Wang, H. Liang, Z.-F. Chen, X.-H.
Qin, Org. Lett. 2014, 16, 580−583; d) Y.-C. Wang, Y.-
Y. Xie, H.-E. Qu, H.-S. Wang, Y.-M. Pan, F.-P. Huang,
J. Org. Chem. 2014, 79, 4463−4469;
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10.1002/adsc.201801700
Advanced Synthesis & Catalysis
COMMUNICATION
Metal- and Oxidant-free Electrosynthesis of 1,2,3-
Thiadiazoles from Element Sulfur and N-tosyl
hydrazones
Adv. Synth. Catal. Year, Volume, Page – Page
Shi-Kun Mo,a Qing-Hu Teng,a,b Ying-Ming Pana
and Hai-Tao Tanga,*
6
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