Terminal Alkyne-Assisted One-Pot Synthesis of Arylamidines: Carbon Source of the Amidine Group from Oxime Chlorides

Article abstract of DOI:10.1021/acs.joc.9b00538

A terminal alkyne-assisted protocol for the one-pot formation of a diverse range of arylamidines from a novel cascade reaction of in situ generated nitrile oxides, sulfonyl azides, terminal alkynes, and water by [3 + 2] cycloaddition and ring opening sequ

Full text of DOI:10.1021/acs.joc.9b00538

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Article
Terminal Alkyne-Assisted One-Pot Synthesis of Arylamidines:
Carbon Source of Amidine Group from Oxime Chlorides
Fengping Yi, Qihui Sun, Jing Sun, Chao Fu, and Weiyin Yi
J. Org. Chem., Just Accepted Manuscript • DOI: 10.1021/acs.joc.9b00538 • Publication Date (Web): 10 May 2019
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Terminal Alkyne-Assisted One-Pot Synthesis of Arylamidines:
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Carbon Source of Amidine Group from Oxime Chlorides
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Fengping Yi, Qihui Sun, Jing Sun, Chao Fu and Weiyin Yi*
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School of Perfume and Aroma Technology, Shanghai Institute of Technology,
Shanghai 201418, P. R. China
Cl
OH
R2
N
CuI, TEA
R2SO2N3
+
N
+
S
R3
DCM/H2O, rt,12h
R3
O
O
NH2
R2=aryl, alkyl
catalytic amount
one-pot green fashion
mild condition
cheap/easily accessible substrates
cleavage of multiple bonds (C-N, C-O, N-O et al)
32 examples
68-92% yields
ABSTRACT:
A terminal alkyne-assisted protocol for the one-pot formation of a
diverse range of arylamidines from a novel cascade reaction of in situ generated nitrile
oxides, sulfonyl azides, terminal alkynes and water by [3+2] cycloaddition and ring
opening sequence was developed. The use of aryl oxime chlorides as the carbon source
of amidine group and the addition of water proved to be critical for the reaction.
Moreover, terminal alkynes, which can lead to high yields of products by employing
less amount, may play a catalytic role in the reaction. A broader range of substrates was
investigated.
INTRODUCTION
Amidines are of great importance on account of their many important applications in the
field of organic synthesis, which, as synthetic precursor, were frequently used to
prepare various heterocyclic ring systems such as quinazolines,1 quinazolinones,2
pyrimidines,3 triazoles,4 and benzimidazoles.5 Meanwhile, the compounds containing
amidine structural motif also exhibited excellent bioactivity in the area of
pharmaceuticals. For example, the amidine functional group was found in a wide range
of biologically active molecules, which have been shown to have a wide range of
interesting biological activities including antimicrobial agents,6 ASIC inhibitors,7
muscarinic against for the treatment of Alzheimer’s disease,8 platelet aggregation
inhibitors,9 and serine protease inhibitors.10 Consequently, various research groups are
engaging themselves to access amidines via new and convenient protocols.
Conventionly, the typical methodologies for the synthesis of amidine and its derivatives
involve the nucleophilic addition of amines or ammonia equivalents to nitriles under
forcing conditions or the direct condensation of amines or ammonia equivalents with
suitably activated carboxylate equivalents, such as imidoyl chlorides, imidoyl
benzotriazoles, imidates, and thioimidates under harsh conditions.11 In recent years, in
order to further expand the desirable molecular library of amidines for the high-throught
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screening of pharmaceutically active compounds, many efficient protocols to amidine
and its derivatives have also been further developed. For example, a series of Pd-
catalyzed reactions to synthesize amidine and its derivatives from ynamides,11c
aryltrifluoroborates,12a amidoximes,12b aryl halides,12c-e were reported. More recently,
synthetic methodologies employing the reaction of arynes with thioureas or N-
tosylacetimidates/acetimidamides under certain conditions have also been exploited for
constructing amidines by Greaney13 and Chandrasekhar14. Every above-mentioned
method has its advantages and disadvantages, therefore, it is still highly desirable to
further develop more convenient, efficient and economical methods for the generation
of amidines under mild conditions.
In 2005, Chang’s group first devised a highly efficient copper-catalyzed
multicomponent reactions (MCRs), in which sulfonyl azides react with a series of
terminal alkynes and amines to give amidines under fairly mild conditions (Scheme
1a).15a It was presumed that the environment-friendly reaction was proposed to proceed
via active sulfonylketenimine intermediates generated from sulfonyl azides and
terminal alkynes under Cu (I) and base. Subsequently, a series of similar MCRs for the
synthesis of amidines (alkyl amidines only!) were also investigated (Scheme 1a).15 In
contrast to other synthetic methods, these reactions to furnish amidines are convenient
and mild, but the carbon source of amidine functional group were from terminal alkynes.
However, it is generally known that terminal alkynes are more expensive. As a result,
this factor will limit the wide application of this methodology. To address the problem
of this methodology, a further synthetic idea to furnish amidines by utilizing such
MCRs, in which the carbon source of amidine functional group is from available
substrates rather than expensive terminal alkynes, is conceived. Therefore, the
appropriate choices of other easily accessible substrates or reagents, which will be able
to participate in the reaction and alter the reaction route under certain condition to
access the desired results, are of tremendous significance.
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ref 15
a) Previous works on the synthesis of amidines from sulfonyl azides, terminal alkynes and amines
NR4R5
R1
b)
Cu(I), base
R2SO2N3
O
S
HNR4R5
+
R1
+
R2
N
O
this work
NH
2 O
R2
Cl
R1
Cu(I), base
R2SO2N3
S
+
+
R3
N
OH
+
H2O
R3
N
O
Scheme 1. Previous works on the synthesis of amidines from sulfonyl azides, terminal
alkynes and amines and this work.
Nitrile oxides from cheap/easily accessible oxime halides under bases are frequently
employed as excellent synthons for the preparation of a wide variety of important
heterocycles compounds with biological activities by cycloaddition reaction with
unsaturated organic molecules.16 In view of the unsaturated nature of
sulfonylketenimine intermediates, the cycloaddition reaction of in situ generated nitrile
oxide with active sulfonylketenimine intermediate will also occur. Therefore, herein,
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we disclosed a Cu(I)-catalyzed protocol for the formation of amidines from the reaction
of aryl oxime chlorides, terminal alkynes, sulfonyl azides with water by cycloaddition
and ring opening sequence, in which the carbon source of amidines were from nitrile
oxides rather than terminal alkynes (Scheme 1b, this work).
9
RESULTS AND DISCUSSION
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Preliminary investigation of the reaction of alkyne 1a, tosyl azide 2a, oxime halide 3a,
and water 4 in the presence of Cu (I) salt and triethylamine (Et3N or TEA) in
dichloromethane (DCM) at room temperature for 12h under open air revealed that the
results of reaction strongly depended on the common Cu (I) salt used. As shown in
Table 1 (Table 1, entries 1-4), It was found that CuI turned out to be the best catalyst in
improving the yield of MCRs (entry 4, 87%), but Cu2O would be not able to afford any
the desired products we wanted (entry 2). 5a had been confirmed by1H NMR, 13C NMR,
and HRMS. Meanwhile, the amount of
Table 1. Optimization of the reaction conditionsa)
Cl
OH
condition
N
N
+
TsN3
+
+
H2O
S
O
O
NH2
1a
2a
3a
4
5a
Entry
Catalyst
CuBr
Cu2O
CuCl
CuI
Base
Solvent
DCM
DCM
DCM
DCM
DCM
DCM
DCM
DCM
DCM
CHCl3
MeCN
THF
Temp(℃)
Yieldd)(%)
65
1
2
Et3N
Et3N
rt
rt
rt
rt
rt
rt
rt
40
60
rt
rt
rt
rt
rt
rt
rt
rt
ndb)
3
Et3N
63
4
Et3N
87
5
CuI
Et3N
87
6
CuI
Et3N
86
7
CuI
Et3N
71
8
CuI
Et3N
81
9
CuI
Et3N
78
10
11
12
13
14
15
16
17
CuI
Et3N
53
CuI
Et3N
83
CuI
Et3N
17
CuI
Et3N
Dioxane
DMSO
DCM
37
CuI
Et3N
80
CuI
K2CO3
Cs2CO3
tBuOK
22
CuI
DCM
20
CuI
DCM
Trace
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19c)
CuI
CuI
DBU
Et3N
DCM
DCM
rt
rt
Trace
72
7
8
9
a) Reaction conditions: entries 1-4, 1a (0.5 mmol), 2a (0.5 mmol), 3a (0.5 mmol), 4 (0.5
mmol), Cu catalyst (0.1 mmol), base (1 mmol) in solvent (2 mL), stired at rt for 12h
under open air; entry 5, 1a:2a:3a:4 = 0.4:1:1:1, the amount of other reagents are
unchanged; entries 6, 8-19 1a:2a:3a:4 = 0.2:1:1:1, the amount of other reagents are
unchanged; entries 7, 1a:2a:3a:4 = 0.1:1:1:1, the amount of other reagents are
unchanged. b) n.d. = not detected. c) Reaction carried out for 8h. d) Isolated yields of 5a
are given, 3a as reference.
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reaction substrates, which would change the chemical yields of the desired products,
were also investigated. To our surprise, the results indicated that a change in the amount
of reaction substrates, especially phenylacetylene, did not affected obviously the yield
of the reaction (Table 1, entries 4-7). In contrast to the stoichiometry of phenylacetylene
(87%, entry 4), lower amount can also afford almost equal yield of 5a. For example,
when MCRs were carried out according to the 0.2:1:1:1 ratio of 1a:2a:3a:4 under
above-mentioned optimal condition, 5a would be also achieved in 86% yield
(entry 6). Therefore, phenylacetylene may act as a catalyst in the reaction. We
also observed that the temperature had little effect on this novel transformation,
but the lower temperature was more favorable to increase the yield of the reaction
(Table 1, entry 6, entries 8-9). We, subsequently, attempted to perform the reaction
in various commonly used solvents. It was shown that DCM was best for this
tandem reaction in term of the yields of product 5a (Table 1, entry 6, entries 10-
14). Among the evaluation of bases, Et3N was found to be the best base, whereas
K2CO3 and Cs2CO3 just provided the desired products in 22% and 20% yields,
respectively (Table 1, entries 15-16). However, for KOtBu and DBU, only a trace
amount of product 5a was detected (Table 1, entries 17-18). In addition, it was
noteworthy that the longer reaction time was required for the formation of 5a (Table 1,
entry 6, entry19). Therefore, according to the results, it was determined that the MCRs
reaction system with the ratio of 0.2:1:1:1(1a:2a:3a:4) at rt in dichloromethane for
12h under CuI in the presence of Et3N (2eq, 3a as reference) were the optimal
reaction conditions
Subsequently, we evaluated the generality of MCRs to prompt the generation of 5
by varying the scopes of various substrates other than terminal alkynes under the
optimized conditions. As depicted in Table 2, all tested substrates were cleanly
transformed into their corresponding products (5a-5ag) with good to excellent yields,
reflecting wide scope of this MCRs. The structure of product 5a was also confirmed
by single-crystal X-ray diffraction, as also shown in Table 2. Moreover, it was
found that the substituent groups on various substrates had no obvious influence
on the chemical yields of the corresponding products 5, only the substrates
bearing electron-withdrawing groups furnish a slightly lower yields (for example
5p in Table 2) than those with other substituents.
Because of the mild reaction conditions and convenience of the procedure,
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therefore, in order to verify the practicability of this reaction, we carried out a
5
6
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Table 2. Substrate scopes of MCRs for the formation of 5a)
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Cl
R3
N
R2
CuI, TEA
OH
R2SO2N3
S
+
H2O
R3
N
+
+
O
O
NH2
DCM, rt,12h
1a
4
2
3
5
7
8
9
NO2
N
10
11
12
13
14
15
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N
N
S
S
S
O
NH2
O
O
NH2
O
O
NH2
O
86%b) for phenylacetylene
5a
5b 89%
5c
CCDC: 1855635
81%
73% for p-Tolyacetylene
23% for p-Ethynylchlorobenzene
NO2
N
N
S
S
O
NH2
N
N
S
S
O
O
NH2
O
O
O
NH2
NH2
O
O
5d
85%
5e
88%
5f
87%
5g
80%
O
O
N
N
N
N
S
S
S
S
O
NH2
O
O
NH2
O
O
O
NH2
O
NH2
O
5h
83%
5i
87%
O
5j
81%
5k
77%
Cl
O
NO2
Cl
N
N
N
N
S
S
S
S
O
NH2
Cl
O
O
NH2
O
NH2
O
O
O
NH2
Cl
O
5l
79%
5m
80%
5o 83%
5n
84%
Cl
NO2
Cl
Cl
Br
Cl
N
N
S
S
N
N
S
S
O
Cl
NH2
O
O
NH2
Cl
O
O
NH2
O
O
O
NH2
5p
5q
72%
68%
5r
5s
91%
89%
Cl
Cl
NO2
Br
N
N
N
N
S
S
S
S
O
NH2
O
O
NH2
O
O
NH2
O
NH2
O
O
5t
85%
5u
88%
5v
5w
92%
90%
Cl
Br
NO2
Br
N
N
S
S
N
S
O
NH2
O
N
O
NH2
O
O
NH2
O
5x
88%
5y
86%
5z
88%
Cl
Cl
Cl
NO2
N
N
S
S
S
O
NH2
O
O
NH2
O
O
NH2
O
5ab
87%
5ac
79%
5ad 84%
Br
Br
Br
NO2
N
N
N
S
S
S
O
NH2
O
O
NH2
O
O
73%
NH2
5ag
O
5af
5ae
81%
82%
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a) Optimal reaction conditions: 1a (0.1 mmol), 2 (0.5 mmol), 3 (0.5 mmol), 4 (0.5mmol),
CuI (0.1 mmol), Et3N (1 mmol) in DCM (2 mL), stired at rt for 12h under open air. b)
Isolated yields of 5 are given, 3 as reference.
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scale-up experiment on substrate 3a under the optimized conditions according
the procedure (Scheme 2). It was found that the reaction of 1.56 g (10 mmol) of
substrate 3a afforded 2.19 g of 5a in 77% yield, indicating that a large-scale
synthesis of α-arylamidine is practical using this method.
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Cl
OH
N
CuI, TEA
N
N3
+
+
S
H2O
+
S
O
DCM, rt,12h
O
O
O
NH2
1a
2a
3a
(1.56 g, 10mmol)
4
5a
(2.11g, 77%)
Scheme 2 Amplification Reaction for the synthesis of 5a
When the other terminal alkynes rather than phenyl acetylene as the substrate,
for example p-tolyacetylene and p-ethynylchlorobenzene, were selected to apply
this model strategy under the optimized conditions, the corresponding amidines
containing p-tolyl and p-chlorophenyl were not observed. However, to our
surprise, only the same product 5a was furnished in 73% and 23% yield,
respectively (Table 2 (5a) and Scheme 3 eq 1). The results prompted us to
speculate that the terminal alkynes might not incorporate into the reaction. To
gain better insight into the reaction mechanism, a series of control experiments
were conducted in accordance with the optimal conditions.
(Scheme 3).
However, when the reactions were carried out according to eq 2-4 in Scheme 3
under the standard reaction conditions or even strict anhydrous standard reaction
conditions, the desired product 5a was not isolated. These results indicated that
the participation of terminal alkynes and water was essential for the successful
completion of the reaction. As a consequence, the investigations also further
confirmed that terminal alkynes might play a catalytic role in the reaction.
Meanwhile, to clarify whether compound 6 as an intermediate achieved from the
reaction of 3a with H2O in this reaction system in advance are involved in this
reaction, the reactions 5-6 were investigated (Scheme 3). Unfortunately, the
product 5a was not afforded as well. The results suggested that compound 6 was
not the intermediate of the mechanistic process. In order to confirm the carbon
source of amidine functional group, the reaction 7 was performed under standard
reaction conditions (Scheme 3, eq 7). Pleasingly, the product 5r was furnished
in 91% yield. Therefore, we can conclude that the carbon source comes from
oxime chloride 3f
.
According to these results and previous reports,15 we are able to propose the
tentative mechanism of the reactions, as shown in Scheme 4. Taking the reaction
of eq 7 in Scheme 3 for the formation of 5r as example, phenyl acetylene 1a first
reacts readily with tosyl azide 2a to give a ketenimine intermediate A in the presence
of CuI and Et3N, which then undergo a formal [3+2]
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Cl
OH
N
CuI, TEA
5
6
R1
H2O
+
+
(1)
TsN3
+
N
DCM, rt, 12h
S
O
7
8
9
O
NH2
1
2a
4
3a
5a
R1 = phenyl
86%
73%
23%
R1 = p-tolyl
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R1 = p-chlorophenyl
Cl
OH
N
+
CuI, TEA
(2)
+
TsN3
H2O
+
N
DCM, rt, 12h
S
O
O
NH2
5a
2a
3a
4
Cl
OH
N
CuI, TEA
+
TsN3
(3)
N
DCM, rt, 12h
strict anhydrous
condition
S
O
O
NH2
1a
2a
3a
5a
Cl
OH
N
CuI, TEA
DCM, rt, 12h
TsN3
+
(4)
(5)
N
S
O
O
NH2
5a
2a
3a
O
OH
CuI, TEA
N
+
TsN3
+
+
H2O
H
N
DCM, rt, 12h
S
O
O
NH2
5a
2a
1a
4
6
O
OH
CuI, TEA
N
+
TsN3
+
(6)
H
N
DCM, rt, 12h
S
O
O
NH2
2a
1a
6
5a
Cl
Cl
CuI, TEA
OH
N
(7)
H2O
+
+
N
+
TsN3
DCM, rt, 12h
S
Cl
O
O
NH2
1a
2a
4
3f
5r, 91%
Scheme 3. Control experiments
cycloaddition reaction with in situ generated nitrile oxide B from oxime halide 3f under
Et3N to offer intermediate C (HRMS: calcd. for C or D [M+H] 425.07212; found
+
425.07270 ， see SI).17 Subsequently, electronic ring opening of intermediate C
occurs in the help of H2O (or OH-) under such reaction conditions,18 leading to the
formation of intermediate D. Intermediate E will be generated by the reaction of
OH- (or H2O ) with intermediate D accompanied by the formation of phenyl
acetylene, which will be further recycled. And then, intermediate E will
transformed into the desired isomer amidine 5r’ with the release of O2 in the
presence of OH- (or H2O). Finally, 5r’ will further isomerize into 5r. Therefore,
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the role of added water in the whole reaction may promote the cleavage of bonds
(C-O and N-O) and provide the proton source15f and OH- anion under such
reaction conditions (OH- anion may be afforded from the reaction of Et3N and
H2O),18 resulting in the generation of the desired product.
9
NH
NH2
NTs
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Cl
Cl
+
-
.
Et3N
Et3N
H
+
+
H2O
OH
NHTs
5r'
5r
O2
H2O
TsN3
2a
Cl
Cl
OH
H
N
CuI, TEA
NTs
Cl
O
N2
1a
H
O
N
.
NTs
3f
HCl
OH
H2O
4
E
A
H OH
TEA
Cl
H OH
OH
H
N
[3+2]
Cl
N
O
O
B
NTs
Cl
D
Ts
N
OH
H2O
H
N
O
H OH
C
D
calcd: for or [M+1] 425.07212
found: [M+1] 425.07270
HRMS:
C
Scheme 4. Proposed mechanistic pathway for the formation of 5r
CONCLUSION
In conclusion, we have developed a robust protocol for the one-pot formation of
a diverse range of arylamidines from a novel cascade reaction of in situ generated
nitrile oxides, sulfonyl azides, terminal alkynes and water by [3+2] cycloaddition and
ring opening sequence. In combination with previous reports15 that can only get
alkyl amidines by MCRs, the present strategy, which is an important supplement
to those methods, can provide a powerful tool to the synthesis of various amidine
s
using easily accessible substrates under very mild conditions. Importantly, the
reaction, which is devoid of various terminal alkynes as substrates, can also lead to
the generation of corresponding arylamidines only by using the catalytic amount of
phenyl acetylene. Furthermore, the use of oxime chlorides as the carbon source of
amidine group and the addition of water proved to be critical for the reaction. The
methodology further gave an excellent example that the use of appropriate substrates
would alter the typical product composition by changing the mechanistic process. We
anticipate that the methodology will continue to expand an evergrowing toolbox of
synthetic tools for medicinal chemists.
EXPERIMENTAL SECTION
General Remarks: All reagents were purchased from commercial suppliers, and were
used without further purification. All solvents were treated according to standard
procedures. The progress of reactions was monitored by TLC. For chromatographic
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purifications, 200–300 mesh silica gel was used. 1H (500 MHz) and 13C (126 MHz)
NMR spectra were recorded with tetramethylsilane as an internal standard. HRMS
measurements were carried out using the ESI ionization technique with an FT-ICR
analyzer. Data are reported as follows: chemical shift, multiplicity (s = singlet, d =
doublet, t = triplet, q = quartet, m = multiplet), coupling constants (Hz) and integration.
Procedure for generation of hydroximoyl chlorides 3: Hydroximoyl chlorides 3a-c
was prepared as reported in the literature19-21 according to the reaction equation (see SI
part). Other hydroximoyl chlorides 3 are commercially available, and their
spectroscopic data are also consistent with the reported literatures.22-24
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OH
N
Cl
3a
1
(Z)-N-hydroxybenzimidoyl chloride 3a. H NMR (501 MHz, Chloroform-d) δ 8.72
(s, 1H), 7.87 (d, J = 7.3 Hz, 2H), 7.46 (dt, J = 14.7, 7.0 Hz, 3H).
OH
N
Cl
3b
(Z)-N-hydroxy-4-methylbenzimidoyl chloride 3b. 1H NMR (501 MHz, Chloroform-
d) δ 9.57 (s, 1H), 7.76 (s, 2H), 7.25 (s, 2H), 2.41 (s, 3H).
OH
N
Cl
Cl
Cl
3c
(Z)-2,4-dichloro-N-hydroxybenzimidoyl chloride 3c. 1H NMR (501 MHz,
Chloroform-d) δ 9.61 (s, 1H), 7.47 (d, J = 1.9 Hz, 1H), 7.42 (d, J = 8.4 Hz, 1H), 7.31
(dd, J = 8.3, 2.0 Hz, 1H).
General Procedure for the synthesis of (5): To a stirred mixture of alkynes 1 (0.1
mmol), azides 2 (0.5 mmol), and CuI (0.1 mmol) in dry DCM (2 mL) was slowly added
triethylamine (1 mmol) at room temperature, stired at rt for 1-2h under open air. And
then, hydroximoyl chlorides 3 (0.5 mmol) and water 4 (0.5 mmol) were added into the
stirred reaction, the reaction mixture continued to react for 12 hours. After the reaction
was completed, which was monitored with TLC, the reaction mixture was diluted by
adding CH2Cl2 (6 mL) and aqueous NH4Cl solution (9 mL). The mixture was stirred
for an additional 30min and two layers were separated. The aqueous layer was extracted
with CH2Cl2 (9 mL x 3). The combined organic layers were dried over MgSO4, filtered,
and concentrated in vacuo. The crude residue was purified by flash column
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chromatograph with an appropriate eluting solvent system.
5
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Gram synthesis method on 5a mmol scale: To a stirred mixture of phenylacetylene
1a (2 mmol), azide 2a (10 mmol), and CuI (1 mmol) in dry DCM (30 mL) was slowly
added triethylamine (20 mmol) at room temperature, stired at rt for 1-2h under open
air. And then, hydroximoyl chloride 3a (10 mmol) and water 4 (10 mmol) were added
into the stirred reaction, the reaction mixture continued to react for 12 hours at rt. After
the reaction was completed, which was monitored by TLC, the reaction mixture was
diluted by adding CH2Cl2 (60 mL) and aqueous NH4Cl solution (200 mL). The mixture
was stirred for an additional 30min and two layers were separated. The aqueous layer
was extracted with CH2Cl2 (30 mL x 3). The combined organic layers were dried over
MgSO4, filtered, and concentrated in vacuo. The crude residue was purified by flash
column chromatograph using petroleum ether/ethyl acetate as the eluent to afford 2.11
g product 5a, 77% yield.
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Characterization data for 5.
(Z)-N'-tosylbenzimidamide(5a). A Light yellow solid. Yield: 86% (118 mg). mp
147−149 °C. 1H NMR (500 MHz, Chloroform-d) δ 8.30 (s, 1H), 7.87 (d, J = 8.0 Hz,
2H), 7.80 (d, J = 7.6 Hz, 2H), 7.49 (t, J = 7.4 Hz, 1H), 7.36 (t, J = 7.7 Hz, 2H), 7.27 (d,
J = 8.0 Hz, 2H), 6.97 (s, 1H), 2.40 (s, 3H). 13C{1H} NMR (126 MHz, Chloroform-d) δ
163.1, 143.1, 139.3, 133.1, 132.7, 129.4, 128.7, 127.5, 126.4, 21.5. HRMS: calcd. for
C14H14N2O2S [M+H]+ 275.0848; found 275.0830.
(Z)-N'-(phenylsulfonyl)benzimidamide(5b). A Light yellow solid. Yield: 89% (116
mg). mp 149−151 °C. 1H NMR (500 MHz, Chloroform-d) δ 8.35 (s, 1H), 8.02 (d, J =
7.6 Hz, 2H), 7.81 (d, J = 7.5 Hz, 2H), 7.54 (d, J = 5.9 Hz, 2H), 7.50 (t, J = 7.6 Hz, 2H),
7.42 (t, J = 7.7 Hz, 2H), 6.67 (s, 1H). 13C{1H} NMR (126 MHz, Chloroform-d) δ 163.1,
142.1, 133.2, 132.8, 132.4, 128.8, 127.4, 126.4. HRMS: calcd. for C13H13N2O2S
[M+H]+ 261.0692; found 261.0693.
(Z)-N'-((4-nitrophenyl)sulfonyl)benzimidamide(5c). A Light yellow solid. Yield: 81%
(124 mg). mp 176−178°C. 1H NMR (500 MHz, DMSO-d6) δ 9.30 (s, 1H), 8.45 (s, 1H),
8.41 (dd, J = 16.1, 8.7 Hz, 3H), 8.20 (d, J = 8.6 Hz, 1H), 8.08 (d, J = 8.6 Hz, 1H), 7.87
(d, J = 7.9 Hz, 1H), 7.75 (s, 1H), 7.61 (t, J = 7.2 Hz, 1H), 7.50 (d, J = 7.7 Hz, 1H).
13C{1H} NMR (126 MHz, DMSO-d6) δ 163.8, 149.9, 148.4, 133.4, 133.2, 129.0, 128.5,
128.1, 127.7, 124.9, 124.8. HRMS: calcd. for C13H12N3O4S [M+H]+ 306.0543; found
306.0543.
(Z)-N'-(methylsulfonyl)benzimidamide(5d). A yellow solid. Yield: 85% (85 mg). mp
122−124°C. 1H NMR (500 MHz, Chloroform-d) δ 8.05 (s, 1H), 7.83 (dd, J = 8.4, 1.2
Hz, 2H), 7.59 – 7.52 (m, 1H), 7.45 (t, J = 7.8 Hz, 2H), 6.75 (s, 1H), 3.09 (s, 3H). 13C{1H}
NMR (126 MHz, Chloroform-d) δ 163.1 , 133.2 , 132.8 , 128.8 , 127.4 , 42.2 .HRMS:
calcd. for C8H11N2O2S [M+H]+ 199.0535; found 199.0534.
(Z)-4-methyl-N'-tosylbenzimidamide(5e). A yellow solid. Yield: 88% (127 mg). mp
1
103−105 °C. H NMR (500 MHz, Chloroform-d) δ 8.28 (s, 1H), 7.88 (d, J = 7.9 Hz,
2H), 7.71 (d, J = 7.9 Hz, 2H), 7.27 (d, J = 8.1 Hz, 2H), 7.18 (d, J = 7.8 Hz, 2H), 6.75
13
(s, 1H), 2.41 (s, 3H), 2.37 (s, 3H). C{1H} NMR (126 MHz, Chloroform-d) δ 162.7,
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143.5, 142.9, 130.4, 129.4, 129.3, 127.4, 126.42 21.5. HRMS: calcd. for C15H16N2O2S
[M+H]+ 289.1005; found 289.1033.
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(Z)-4-methyl-N'-(phenylsulfonyl)benzimidamide(5f). A Light yellow solid. Yield: 87%
(120 mg). mp 141−143 °C. 1H NMR (500 MHz, Chloroform-d) δ 8.32 (s, 1H), 8.03 –
7.99 (m, 2H), 7.72 (d, J = 8.3 Hz, 2H), 7.57 – 7.54 (m, 1H), 7.50 (t, J = 7.5 Hz, 2H),
7.22 (d, J = 8.1 Hz, 2H), 6.59 (s, 1H), 2.39 (s, 3H). 13C{1H} NMR (126 MHz,
Chloroform-d) δ 163.0, 143.7, 142.3 132.2, 130.2, 129.5, 128.8, 127.4, 126.4, 21.5.
HRMS: calcd. for C14H15N2O2S [M+H]+ 275.0848; found 275.0849.
(Z)-4-methyl-N'-((4-nitrophenyl)sulfonyl)benzimidamide(5g). A Light yellow solid.
Yield: 80% (128 mg). mp 145−147 °C. 1H NMR (500 MHz, Chloroform-d) δ 8.35 (s,
1H), 8.33 (s, 1H), 8.19 (d, J = 8.7 Hz, 2H), 7.72 (d, J = 8.2 Hz, 2H), 7.26 (d, J = 8.2
Hz, 2H), 6.70 (s, 1H), 2.41 (s, 3H). 13C{1H} NMR (126 MHz, Chloroform-d) δ 163.6,
149.8, 147.9, 144.4, 129.7, 127.8, 127.7, 127.4, 124.3, 124.1, 21.6. HRMS: calcd. for
C14H14N3O4S [M+H]+ 320.0699; found 320.0699.
(Z)-4-methyl-N'-(methylsulfonyl)benzimidamide(5h). A yellow solid. Yield: 83% (88
mg). mp 139−141 °C. 1H NMR (500 MHz, Chloroform-d) δ 8.01 (s, 1H), 7.73 (d, J =
8.0 Hz, 2H), 7.24 (d, J = 7.8 Hz, 2H), 6.69 (s, 1H), 3.07 (s, 3H), 2.40 (s, 3H). 13C{1H}
NMR (126 MHz, Chloroform-d) δ 163.0, 143.6, 130.3, 129.5, 127.4, 42.2, 21.5. HRMS:
calcd. for C9H13N2O2S [M+H]+ 213.0692; found 213.0690.
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(Z)-3-methyl-N'-tosylbenzimidamide(5i). A Light yellow solid. Yield: 87% (126 mg).
1
mp 110−112 °C. H NMR (501 MHz, Chloroform-d) δ 8.27 (s, 1H), 7.85 (d, J = 8.1
Hz, 2H), 7.78 (d, J = 8.1 Hz, 1H), 7.63 (s, 1H), 7.58 (d, J = 7.6 Hz, 1H), 7.24 (t, J = 7.4
Hz, 3H), 7.06 (s, 1H), 2.38 (s, 3H), 2.32 (s, 3H). 13C{1H} NMR (126 MHz, Chloroform-
d) δ 178.2, 163.3, 143.0, 143.0, 139.4, 139.3, 139.2, 139.2, 138.6, 133.1, 130.0, 129.2,
129.0, 128.9, 128.8, 128.8, 127.9, 127.6, 127.1, 127.0, 125.8, 125.7, 125.6, 125.2, 123.9,
22.0, 21.9, 21.0. HRMS: calcd. for C15H17N2O2S [M+H]+ 289.1005; found 289.1007.
(Z)-4-methoxy-N'-tosylbenzimidamide(5j). A Light yellow solid. Yield: 81% (124mg).
1
mp 148−150 °C. H NMR (500 MHz, Chloroform-d) δ 8.24 (s, 1H), 7.86 (d, J = 8.0
Hz, 2H), 7.79 (d, J = 8.6 Hz, 2H), 7.26 (d, J = 8.0 Hz, 2H), 6.85 (d, J = 8.6 Hz, 2H),
13
6.82 (s, 1H), 3.80 (s, 3H), 2.40 (s, 3H). C{1H} NMR (126 MHz, Chloroform-d) δ
163.3, 162.4, 142.8, 129.5, 129.3, 126.4, 114.0, 55.5, 21.5. HRMS: calcd. for
C15H16N2O3S [M+H]+ 305.0954; found 305.0971.
(Z)-4-methoxy-N'-(phenylsulfonyl)benzimidamide(5k). A Light yellow solid. Yield:
1
77% (112 mg). mp 146−148 °C. H NMR (500 MHz, Chloroform-d) δ 8.29 (s, 1H),
8.00 (d, J = 8.0 Hz, 2H), 7.80 (d, J = 8.5 Hz, 2H), 7.55 (t, J = 6.9 Hz, 1H), 7.49 (t, J =
7.3 Hz, 2H), 6.89 (d, J = 8.5 Hz, 2H), 6.62 (s, 1H), 3.83 (s, 3H). 13C{1H} NMR (126
MHz, Chloroform-d) δ 163.4, 162.6, 132.2, 129.5, 128.8, 126.3, 124.9, 114.0, 55.5.
HRMS: calcd. for C14H15N2O3S [M+H]+ 291.0797; found 291.0799.
(Z)-4-methoxy-N'-((4-nitrophenyl)sulfonyl)benzimidamide(5l). A yellow solid. Yield:
79% (133 mg). mp 155−157 °C. 1H NMR (500 MHz, Chloroform-d) δ 8.34 (d, J = 8.8
Hz, 2H), 8.31 (s, 1H), 8.19 (d, J = 8.8 Hz, 2H), 7.80 (d, J = 8.9 Hz, 2H), 6.94 (d, J = 8.9
Hz, 2H), 6.60 (s, 1H), 3.87 (s, 3H). 13C{1H} NMR (126 MHz, Chloroform-d) δ 163.9,
162.9, 149.8, 148.1, 129.4, 127.7, 124.4, 124.1, 114.3, 55.6. HRMS: calcd. for
C14H14N3O5S [M+H]+ 336.0648; found 336.0649.
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(Z)-4-methoxy-N'-(methylsulfonyl)benzimidamide(5m). A Light yellow solid. Yield:
80% (92 mg). mp 151−153 °C. 1H NMR (500 MHz, Chloroform-d) δ 8.02 (s, 1H), 7.82
(d, J = 8.9 Hz, 2H), 6.95 (d, J = 8.9 Hz, 2H), 6.43 (s, 1H), 3.87 (s, 3H), 3.10 (s, 3H).
13C{1H} NMR (126 MHz, Chloroform-d) δ 163.4, 162.3, 129.3, 128.6, 128.5, 125.1,
114.1, 55.5, 42.3. HRMS: calcd.for C9H13N2O3S [M+H]+ 229.06414; found 229.0640.
(Z)-2,4-dichloro-N'-tosylbenzimidamide(5n). A Light yellow solid. Yield: 84%
(144mg). mp 153−154 °C. 1H NMR (500 MHz, Chloroform-d) δ 8.49 (s, 1H), 7.86 (s,
1H), 7.82 (d, J = 8.3 Hz, 1H), 7.56 (d, J = 8.4 Hz, 1H), 7.41 (d, J = 2.0 Hz, 1H), 7.32
(d, J = 2.3 Hz, 1H), 7.32 – 7.29 (m, 2H), 6.48 (s, 1H), 2.44 (s, 3H). 13C{1H} NMR (126
MHz, Chloroform-d) δ 143.5, 137.6, 132.2, 131.5, 130.3, 129.7, 129.4, 127.6, 126.6,
126.4, 21.5 .HRMS: calcd. for C14H13Cl2N2O2S [M+H]+ 343.0069; found 343.0070.
(Z)-2,4-dichloro-N'-(phenylsulfonyl)benzimidamide(5o). A Light yellow solid. Yield:
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83% (136 mg). mp 155−157 °C. H NMR (500 MHz, Chloroform-d) δ 8.46 (s, 1H),
7.97 (d, J = 7.4 Hz, 1H), 7.92 (d, J = 7.3 Hz, 1H), 7.58 (t, J = 7.4 Hz, 1H), 7.54 – 7.49
(m, 3H), 7.39 (d, J = 1.9 Hz, 1H), 7.29 – 7.26 (m, 1H), 6.66 (s, 1H). 13C{1H} NMR (126
MHz, Chloroform-d) δ 161.7, 141.4, 132.7, 132.2, 131.7, 131.5, 130.3, 129.1, 128.8,
127.6, 126.5, 126.3. HRMS: calcd. For C13H11Cl2N2O2S[M+H]+ 328.9912; found
328.9915.
(Z)-2,4-dichloro-N'-((4-nitrophenyl)sulfonyl)benzimidamide(5p). A Light yellow
1
solid. Yield: 68% (127 mg). mp 139−141 °C. H NMR (500 MHz, Chloroform-d) δ
8.52 (s, 1H), 8.39 – 8.36 (m, 1H), 8.34 – 8.31 (m, 1H), 8.20 – 8.18 (m, 1H), 8.08 (d, J
= 8.9 Hz, 1H), 7.61 (d, J = 8.4 Hz, 1H), 7.47 (d, J = 2.0 Hz, 1H), 7.35 (dd, J = 8.4, 2.0
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Hz, 1H), 6.68 (s, 1H). C{1H} NMR (126 MHz, DMSO-d6) δ 167.7, 136.42 134.7,
131.4, 130.5, 129.6, 128.2, 127.7, 124.7. HRMS: calcd. for C13H10Cl2N3O4S [M+H]+
373.9763; found 373.9762.
(Z)-2,4-dichloro-N'-(methylsulfonyl)benzimidamide(5q). A Light yellow solid. Yield:
72% (96 mg). mp 133−135 °C. 1H NMR (500 MHz, Chloroform-d) δ 8.23 (s, 1H), 7.63
(d, J = 8.4 Hz, 1H), 7.49 (d, J = 2.0 Hz, 1H), 7.36 (dd, J = 8.3, 2.0 Hz, 1H), 6.42 (s, 1H),
13
3.10 (s, 3H). C{1H} NMR (126 MHz, Chloroform-d) δ 161.4, 137.9, 132.2, 131.8,
131.7, 131.5, 130.5, 130.2, 127.7, 127.6, 42.2. HRMS: calcd. for C8H9Cl2N2O2S
[M+H]+ 266.9756; found 266.9758.
(Z)-4-chloro-N'-tosylbenzimidamide(5r). A Light yellow solid. Yield: 91% (141 mg).
mp 151−153 °C. 1H NMR (500 MHz, Chloroform-d) δ 8.30 (s, 1H), 7.86 (s, 1H), 7.84
(s, 1H), 7.75 (s, 1H), 7.74 (s, 1H), 7.34 (s, 1H), 7.32 (s, 1H), 7.28 (d, J = 8.0 Hz, 2H),
13
6.97 (s, 1H), 2.42 (s, 3H). C{1H} NMR (126 MHz, Chloroform-d) δ 161.9, 143.3,
139.1, 131.6, 129.7, 129.47, 129.0, 128.9, 126.4, 21.5. HRMS: calcd. for
C14H14ClN2O2S [M+H]+ 309.0459; found 309.0460.
(Z)-4-chloro-N'-(phenylsulfonyl)benzimidamide(5s). A Light yellow solid. Yield: 89%
(131 mg). mp 161−163 °C. 1H NMR (500 MHz, Chloroform-d) δ 8.32 (s, 1H), 7.99 –
7.94 (m, 2H), 7.77 – 7.73 (m, 2H), 7.59 – 7.54 (m, 1H), 7.52 – 7.47 (m, 2H), 7.32 (d, J
= 8.7 Hz, 2H), 7.17 (s, 1H). 13C{1H} NMR (126 MHz, Chloroform-d) δ 162.2, 141.8,
139.2, 132.5, 131.4, 129.1, 129.0, 128.9, 126.3. HRMS: calcd. for C13H12ClN2O2S
[M+H]+ 295.0302; found 295.0304.
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(Z)-4-chloro-N'-((4-nitrophenyl)sulfonyl)benzimidamide(5t). A Light yellow solid.
Yield: 85% (145 mg). mp 160−162 °C. 1H NMR (500 MHz, DMSO-d6) δ 9.36 (s, 1H),
8.50 (s, 1H), 8.41 (ddd, J = 9.4, 7.0, 1.9 Hz, 2H), 8.21 – 8.19 (m, 1H), 8.11 – 8.05 (m,
2H), 7.90 – 7.87 (m, 1H), 7.75 (s, 2H), 7.56 (d, J = 8.6 Hz, 1H). 13C{1H} NMR (126
MHz, DMSO-d6) δ 162.7, 149.9, 149.87, 149.6, 132.1, 130.4, 129.0, 128.1, 127.7,
124.9, 124.8. HRMS: calcd. for C13H11ClN3O4S [M+H]+ 340.0153; found 340.0153.
(Z)-4-chloro-N'-(methylsulfonyl)benzimidamide(5u). A Light yellow solid. Yield: 88%
(103 mg). mp 140−142 °C. 1H NMR (500 MHz, Chloroform-d) δ 8.06 (s, 1H), 7.80 (d,
J = 8.6 Hz, 2H), 7.44 (d, J = 8.6 Hz, 2H), 6.63 (s, 1H), 3.11 (s, 3H). 13C{1H} NMR (126
MHz, Chloroform-d) δ 161.8, 139.20 131.6, 129.1, 128.8, 42.3. HRMS: calcd. for
C8H10ClN2O2S [M+H]+ 233.0146; found 233.0145.
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(Z)-4-bromo-N'-tosylbenzimidamide(5v). A Light yellow solid. Yield: 92% (162 mg).
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mp 159−161 °C. H NMR (500 MHz, Chloroform-d) δ 8.30 (s, 1H), 7.85 (d, J = 8.3
Hz, 1H), 7.80 (d, J = 8.3 Hz, 1H), 7.68 (s, 1H), 7.66 (d, J = 2.0 Hz, 1H), 7.50 (s, 1H),
7.48 (d, J = 2.0 Hz, 1H), 7.29 (s, 1H), 7.27 (s, 1H), 6.96 (s, 1H), 2.42 (s, 3H). 13C{1H}
NMR (126 MHz, Chloroform-d) δ 161.9, 143.2, 138.9, 131.9, 129.6, 129.4, 129.1,
127.6, 126.4, 126.3, 21.5. HRMS: calcd. for C14H14BrN2O2S [M+H]+ 352.9953, found
352.9957.
(Z)-4-bromo-N'-(phenylsulfonyl)benzimidamide(5w). A Light yellow solid. Yield: 90%
(153mg). mp 169−171 °C. 1H NMR (500 MHz, DMSO-d6) δ 9.18 (s, 1H), 8.34 (s, 1H),
7.97 – 7.95 (m, 1H), 7.86 (dd, J = 7.8, 1.6 Hz, 1H), 7.82 – 7.80 (m, 1H), 7.70 (d, J =
1.8 Hz, 1H), 7.68 (s, 1H), 7.65 – 7.60 (m, 1H), 7.59 – 7.56 (m, 2H), 7.38 (s, 1H). 13C{1H}
NMR (126 MHz, DMSO-d6) δ 162.2, 142.8, 132.9, 132.7, 132.2, 131.9, 130.4, 129.4,
129.3, 126.8, 126.5, 126.0. HRMS: calcd. for C13H12BrN2O2S [M+H]+ 338.9797; found
338.9799.
(Z)-4-bromo-N'-((4-nitrophenyl)sulfonyl)benzimidamide(5x). A Light yellow solid.
Yield: 88% (169 mg). mp 164−166 °C. 1H NMR (500 MHz, DMSO-d6) δ 9.36 (s, 1H),
8.50 (s, 1H), 8.44 – 8.41 (m, 1H), 8.40 – 8.38 (m, 1H), 8.21 – 8.19 (m, 1H), 8.08 (d, J
= 8.8 Hz, 1H), 7.81 (d, J = 8.6 Hz, 1H), 7.75 (s, 1H), 7.70 (d, J = 8.6 Hz, 2H). 13C{1H}
NMR (126 MHz, DMSO-d6) δ 162.8, 149.9, 149.6, 148.2, 132.5, 132.0, 130.5, 128.1,
127.7, 127.0, 124.9, 124.8. HRMS: calcd. for C13H11BrN3O4S [M+H]+ 383.9648; found
383.9643.
(Z)-4-bromo-N'-(methylsulfonyl)benzimidamide(5y). A Light yellow solid. Yield: 86%
(119 mg). mp 149−151 °C. 1H NMR (500 MHz, Chloroform-d) δ 8.06 (s, 1H), 7.74 –
7.69 (m, 2H), 7.63 – 7.59 (m, 2H), 6.58 (s, 1H), 3.11 (s, 3H). 13C{1H} NMR (126
MHz, Chloroform-d) δ 161.9, 132.1, 132.1, 128.9, 127.7, 42.3. HRMS: calcd. for
C8H10BrN2O2S [M+H]+ 276.9640; found 276.9644.
(Z)-3-chloro-N'-tosylbenzimidamide(5z). A Light yellow solid. Yield: 88% (136 mg).
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mp 150−152 °C. H NMR (500 MHz, DMSO-d6) δ 9.19 (s, 1H), 8.32 (s, 1H), 7.90 –
7.83 (m, 2H), 7.74 (d, J = 8.1 Hz, 1H), 7.64 (d, J = 7.9 Hz, 1H), 7.50 (t, J = 7.9 Hz,
13
1H), 7.36 (d, J = 7.8 Hz, 2H), 7.31 (s, 1H), 2.36 (s, 3H). C{1H} NMR (126 MHz,
DMSO-d6) δ 161.5, 143.0, 139.8, 135.7, 133.7, 132.6, 130.8, 129.8, 129.7, 128.0, 127.0,
126.6, 126.1, 21.4, 21.3. HRMS: calcd. for C14H14ClN2O2S [M+H]+ 309.0459; found
309.0459.
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(Z)-3-chloro-N'-(phenylsulfonyl)benzimidamide(5ab). A yellow solid. Yield: 87%
(128 mg). mp 137−139 °C. 1H NMR (500 MHz, Chloroform-d) δ 8.35 (s, 1H), 7.99 (d,
J = 7.5 Hz, 2H), 7.81 (s, 1H), 7.68 (d, J = 7.9 Hz, 1H), 7.57 (t, J = 7.4 Hz, 2H), 7.50 (s,
2H), 7.33 (t, J = 7.9 Hz, 1H), 7.02 (s, 1H). 13C{1H} NMR (126 MHz, Chloroform-d) δ
161.8, 141.7, 134.96, 134.9, 132.7, 132.5, 130.0, 129.1, 128.8, 127.8, 126.4, 126.3,
125.5. HRMS: calcd. for C13H12ClN2O2S [M+H]+ 295.0302; found 295.0305.
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(Z)-3-chloro-N'-((4-nitrophenyl)sulfonyl)benzimidamide(5ac). A yellow solid. Yield:
77% (131 mg). mp 163−164 °C. 1H NMR (500 MHz, Chloroform-d) δ 8.36 (d, J = 8.9
Hz, 2H), 8.20 (d, J = 8.9 Hz, 2H), 7.85 (t, J = 1.9 Hz, 1H), 7.74 (d, J = 7.9 Hz, 1H),
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7.54 (dd, J = 8.0, 1.1 Hz, 1H), 7.40 (t, J = 7.9 Hz, 1H), 7.13 (s, 1H). C{1H} NMR
(126 MHz, Chloroform-d) δ 162.3, 149.9, 147.5, 135.1, 134.4, 133.1, 130.2, 127.9,
127.8, 125.5, 124.5. HRMS: calcd. for C13H11ClN3O4S [M+H]+ 340.0153; found
340.0154.
(Z)-3-chloro-N'-(methylsulfonyl)benzimidamide(5ad). A Light yellow solid. Yield:
84% (98 mg). mp 135−137 °C. 1H NMR (500 MHz, Chloroform-d) δ 8.07 (s, 1H), 7.86
(t, J = 1.9 Hz, 1H), 7.70 (d, J = 7.8 Hz, 1H), 7.54 (d, J = 8.0 Hz, 1H), 7.41 (t, J = 7.9
Hz, 1H), 6.63 (s, 1H), 3.12 (s, 3H). 13C{1H} NMR (126 MHz, Chloroform-d) δ 161.5,
135.1, 132.7, 132.1, 130.1, 129.9, 127.8, 127.7, 125.4, 125.3, 42.3. HRMS: calcd. for
C8H10ClN2O2S [M+H]+ 233.0146; found 233.0145.
(Z)-3-bromo-N'-tosylbenzimidamide(5ae). A Light yellow solid. Yield: 81% (143 mg).
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mp 157−159 °C. H NMR (500 MHz, DMSO-d6) δ 8.97 (s, 1H), 8.46 (s, 0.5H), 7.73
(d, J = 8.2 Hz, 2H), 7.37 (t, J = 7.7 Hz, 4H), 7.29 (s, 2H), 2.38 (s, 3H). 13C{1H} NMR
(126 MHz, DMSO-d6) δ 164.5, 142.7, 142.3, 141.8, 139.9, 137.1, 133.0, 131.8, 129.7,
129.6, 129.6, 127.9, 126.8, 126.1, 119.8, 21.4. HRMS: calcd. for C14H14BrN2O2S
[M+H]+ 352.9953; found 352.9959.
(Z)-3-bromo-N'-(phenylsulfonyl)benzimidamide(5af). A yellow solid. Yield: 82%
(139 mg). mp 138−140 °C. 1H NMR (500 MHz, DMSO-d6) δ 9.00 (s, 1H), 8.49 (s, 1H),
7.83 (s, 2H), 7.58 (d, J = 7.5 Hz, 4H), 7.38 (s, 3H). 13C{1H} NMR (126 MHz, DMSO-
d6) δ 169.8, 164.9, 144.4, 142.4, 136.9, 133.2, 133.1, 132.7, 132.4, 131.9, 131.2, 129.5,
129.4, 129.3, 128.9, 128.0, 127.9, 126.7, 126.0. HRMS: calcd. for C13H12BrN2O2S
[M+H]+ 338.9797; found 338.9799.
(Z)-3-bromo-N'-((4-nitrophenyl)sulfonyl)benzimidamide(5ag). A Light yellow solid.
Yield: 73% (140 mg). mp 111−113 °C. 1H NMR (500 MHz, DMSO-d6) δ 9.19 (s, 1H),
8.80 (s, 1H), 8.38 (d, J = 8.9 Hz, 2H), 8.06 (d, J = 8.8 Hz, 2H), 7.64 (dd, J = 7.9, 3.4
13
Hz, 1H), 7.46 – 7.37 (m, 3H). C{1H} NMR (126 MHz, DMSO-d6) δ 169.5, 165.7,
149.8, 148.2, 136.7, 133.2, 133.0, 131.9, 131.1, 129.6, 129.0, 128.3, 127.9, 127.9, 124.7,
119.8. HRMS: calcd. for C13H11BrN3O4S [M+H]+ 383.9648; found 383.9648.
ASSOCIATED CONTENT
Supporting Information
The Supporting Information is available free of charge on the ACS Publications
website at DOI: 10.1021/acs.joc.
1H NMR, 13C NMR and X-ray spectra of final products (PDF)
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AUTHOR INFORMATION
Corresponding Authors
*E-mail for W. Y.: yiwy@sit.edu.cn
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ORCID
Weiyin Yi: 0000-0003-4480-7407
Notes
The authors declare no competing financial interest.
Additional supporting research data, CCDC-1855635 (5a), containing the
supplementary crystallographic data for this article may be accessed free of charge from
the Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_
request/cif.
ACKNOWLEDGMENTS
This research was supported by the Horizontal Projects of Shanghai Institute of
Technology (J2017-150, J2017-202).
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