Synthesis of N-Sulfonylformamidines by tert-butyl Hydroperoxide–Promoted, metal-free, direct oxidative dehydrogenation of aliphatic amines

Article abstract of DOI:10.1016/j.tet.2018.03.074

A direct and convenient metal-free method to prepare sulfonyl amidines in the presence of aqueous tert-butyl hydroperoxide (T-HYDRO) has been developed. Different tertiary and secondary amines were tested for compatibility with the oxidative conditions and could be coupled with sulfonyl azides to form the corresponding amidines in moderate to good yields.

Full text of DOI:10.1016/j.tet.2018.03.074

Accepted Manuscript
Synthesis of N-Sulfonylformamidines by tert-butyl Hydroperoxide–Promoted, metal-
free, direct oxidative dehydrogenation of aliphatic amines
Ayijiamali Rouzi, Ruzeahong Hudabaierdi, Abudureheman Wusiman
PII:
S0040-4020(18)30367-3
10.1016/j.tet.2018.03.074
TET 29414
DOI:
Reference:
To appear in: Tetrahedron
Received Date: 18 January 2018
Revised Date: 27 March 2018
Accepted Date: 31 March 2018
Please cite this article as: Rouzi A, Hudabaierdi R, Wusiman A, Synthesis of N-Sulfonylformamidines
by tert-butyl Hydroperoxide–Promoted, metal-free, direct oxidative dehydrogenation of aliphatic amines,
Tetrahedron (2018), doi: 10.1016/j.tet.2018.03.074.
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Synthesis of N-Sulfonylformamidines by tert-
Butyl Hydroperoxide–Promoted, Metal-Free,
Direct Oxidative Dehydrogenation of
Aliphatic Amines
Leave this area blank for abstract info.
Ayijiamali Rouzi, Ruzeahong Hudabaierdi, Abudureheman Wusiman*
School of Chemistry and Chemical Engineering, Xinjiang Normal University, Urumqi, Xinjiang, P. R China
830054.
A mild and simple, inexpensive oxidant T-HYDRO® (70 wt.-% aqueous tert-butyl hydroperoxide)-promoted, metal-free
synthetic method to prepare N-sulfonyl formamidines has been developed.

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Tetrahedron
journal homepage: www.elsevier.com
Synthesis of N-Sulfonylformamidines by tert-Butyl Hydroperoxide–Promoted, Metal-
Free, Direct Oxidative Dehydrogenation of Aliphatic Amines
Ayijiamali Rouzi, Ruzeahong Hudabaierdi, Abudureheman Wusiman
School of Chemistry and Chemical Engineering, Xinjiang Normal University, Urumqi, Xinjiang, P. R China 830054.
ARTICLE INFO
ABSTRACT
Article history:
Received
Received in revised form
Accepted
A direct and convenient metal-free method to prepare sulfonyl amidines in the presence of
aqueous tert-butyl hydroperoxide (T-HYDRO) has been developed. Different tertiary and
secondary amines were tested for compatibility with the oxidative conditions and could be
coupled with sulfonyl azides to form the corresponding amidines in moderate to good yields.
Available online
2009 Elsevier Ltd. All rights reserved
.
Keywords:
sulfonyl amidine
aliphatic amine
oxidative dehydrogenation
tert-butyl hydroperoxide
1. Introduction
Various synthetic methodologies have been developed for
activation/ functionalization of the α, β-C(sp3)-H bonds of amines.
However, most of these procedures need a transition metal as the
active catalyst.8 Thus, the development of a new and efficient
Amidines are interesting compounds because they have a
unique structural motif, and are regarded as organic superbases,1
as well as being key intermediates in the synthesis of heterocyclic
compounds,2 and versatile nitrogen ligands in metallocyclic
complexes.3 Amidines are also important in medicinal chemistry
because they are found in many bioactive natural products4 and
have been identified as important pharmacophores.5
metal-free
method
for
the
simultaneous
oxidative
dehydrogenation and functionalization of amines remains a
significant challenge. Based on our previous work on oxidation
using tert-butyl hydroperoxide (TBHP) as the terminal oxidant,9
we investigated the use of TBHP for the oxidative
dehydrogenation of amines. Herein, we describe a mild and
simple T-HYDRO (TBHP 70 wt% in water)-promoted, catalyst-
free direct functionalization of aliphatic amines with sulfonyl
azides to produce sulfonyl formamidines (Scheme 1, eq d).
There are several well-known practical methods for the
synthesis of N-sulfonyl formamidines6 and recent efforts have
been dedicated to the improvement of traditional protocols.7
Among selected elegant examples, the Li group have reported
two types of dehydrogenation of aliphatic tertiary amines: using
sulfonyl azides in the presence of stoichiometric diethyl
azodicarboxylate (DEAD)7a and CuCl-CCl4 catalytic systems
7b
(Scheme 1, eq a). He and co-workers have also reported the
CuCl-catalyzed imidation of a tertiary amine using sulfonyl
azides as the nitrogen source in the presence of
benzyltriethylammonium chloride (TEBA)7c (Scheme 1, eq b).
Wang and co-workers have developed a synthesis of sulfonyl
amidines from tertiary amines and sulfonyl azides in the presence
7d
of
a
stoichiometric amount of FeCl3
,
as well as an
electrochemical approach7e (Scheme 1, eq c). Although
tremendous efforts have been made,6g a milder and metal-free
method for the synthesis of sulfonyl amidines is still in demand.
Scheme 1. Representative approaches for synthesis of N-
sulfonylformamidines
———
Corresponding author. Tel.: +86-158-991-27270; fax: +86-0991-433-4683; e-mail: arahman@xjnu.edu.cn

2
Tetrahedron
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2. Results and Discussion
5 h (entry 8). Surprisingly, when treated with 3.0 equiv. of T-
HYDRO, 1a was consumed in 2 h and the yield of 3a decreased
to 60% (entry 9). In contrast, the use of 1.0 equiv. of T-HYDRO
generated a 77% yield of product (entry 10). The use of TBHP in
decane instead of T-HYDRO gave a similar yield of the product
(entry 11). Leaving the other conditions unchanged and
decreasing the loading of TsN3 to 2.0 equiv. resulted in the
highest yield of 78% (entry 12). Further screening of different
oxidants revealed no better results (entries 13–16). Moreover, the
yield of 3a showed an obvious decline when the amount of TsN3
was decreased (entry 17). When the molar ratio of 1a : 2a was
changed to from 2:1 to 1:3, the yield decreased (entry 18).
Interestingly, a 6.0% yield of the desired sulfonyl amidine 3a
could be isolated in the absence of T-HYDRO (entry 19).
Therefore, the optimal reaction conditions were determined to be
treatment of sulfonylazide (1) with tertiary amine (2) in a 2:1
molar ratio, with T-HYDRO (1.0 equiv.) as the oxidant, in DCE
at 80 °C.
Initially, we chose tosylazide (TsN3) 1a and triethylamine 2a
as standard substrates to optimize suitable conditions for this
reaction (Table 1). To our delight, the reaction of 1a (1.2 equiv.)
with 2a (1.0 equiv.) was performed smoothly in the presence of
2.0 equiv. of T-HYDRO in ethyl acetate (EtOAc) at 60 °C, and
generated the desired sulfonyl formamidine 3a in 40% yield,
while the tosylamide 4a was also isolated as a byproduct in
approximately 20% yield (entry 1). Therefore, we investigated
the use of an excess of TsN3. As expected, when the amount 1a
was increased from 1.2 to 2.0 and 2.5 equiv. the yield of 3a was
gradually increased to 55% and 60%, respectively and the yield
of the isolated tosylamide 4a to 40% (entries 2–3). Various
solvents, including acetonitrile (MeCN), chloroform (CHCl3),
dichloromethane (DCM), and 1,2-dichloroethane (DCE) were
screened (entries 4–7). The highest yield was observed with DCE
(entry 7). A 75% yield was also obtained by raising the reaction
temperature to 80 °C and shortening the reaction time from 24 to
Table 1. Optimizing the condition for the formation of 3a a
Entry
1
1a: 2a
1.2 : 1
2.0 : 1
2.5 : 1
2.5 : 1
2.5 : 1
2.5 : 1
2.5 : 1
2.5 : 1
2.5 : 1
2.5 : 1
2.5 : 1
2.0 : 1
2.0 : 1
2.0 : 1
2.0 : 1
2.0 : 1
1.5 : 1
1 : 3.0
2.0 : 1
Oxidant (eq.)
T-HYDRO (2)
T-HYDRO (2)
T-HYDRO (2)
T-HYDRO (2)
T-HYDRO (2)
T-HYDRO (2)
T-HYDRO (2)
T-HYDRO (2)
T-HYDRO (3)
T-HYDRO (1)
TBHP (1)
Solvent
EtOAc
EtOAc
EtOAc
MeCN
CHCl3
DCM
DCE
Temp. (oC)
60
Time (h)
Yield of 3a (%)b
2
4
40
55
60
55
20
56
65
75
60
77
77
78
8
2
60
3
60
24
24
24
24
24
5
4
60
5
60
6
60
7
60
8
DCE
80
9
DCE
80
2
10
11c
12
13
14
15
16
17
18
19
DCE
80
5
DCE
80
5
T-HYDRO (1)
DTBP (1)
DCE
DCE
80
2.5
8
80
CHP (1)
DCE
80
5
63
30
48
55
30
6
TBPB (1)
DCE
80
8
BPO (1)
DCE
80
8
T-HYDRO (1)
T-HYDRO (1)
-
DCE
80
1
DCE
80
1
DCE
80
12
a
Reactions were performed in 2 mL of solvent in a sealed tube unless otherwise noted. [T-HYDRO]: TBHP, 70 wt% in water. [DTBP]: Di-tert-butylperoxide.
[CHP]: Cumyl hydroperoxide. [TBPB]: tert-Butyl peroxybenzoate. [BPO]: Benzoyl peroxide. b Isolated yield after column chromatography. c TBHP 5.5 M in
decane.
With the optimized conditions in hand, the scope of the
reaction was investigated as shown in Table 2. A wide range of
sulfonyl azides and tertiary amines could be used in this reaction
system under the optimized conditions. The phenylsulfonyl
azides bearing electron-donating and electron-withdrawing
groups reacted with triethylamine to afford the corresponding
sulfonyl amidines in good to excellent yields (Table 2, 3a−3j).
Moreover, having the substituted group at different positions on
the phenyl ring had no obvious effect on the reaction. However,
the strong electron-withdrawing nitro group gave a comparably
lower yield of 3i. 2-Naphthalenesulfonyl azide reacted slowly,
but the desired product 3k was obtained in a relatively high yield.
Notably, the aliphatic sulfonylazides, benzylsulfonyl azide and
butylsulfonyl azide, afforded the products 3l and 3m in nearly
40% isolated yields. In addition, the five membered
heteroaromatic sulfonyl azide derivatives with one or two
heteroatoms provided the corresponding amidines in good yields
(Table 2, 3n−3q). Furthermore, the reaction of 3-pyridinesulfonyl
azide with tri-propyl amine allowed the formation of the 3r in
75% yield. To our satisfaction, an array of tertiary amines proved
to be suitable reaction partners and afforded the corresponding
coupling

Table 2. Scope of sulfonyl azides and tertiary aminesa,b
diethylethenamine was synthesized via the reaction of
ACCEPTED MANUSCRIPT
diethylamine with acetaldehyde using K2CO3 as the dehydrating
agent,11 followed by reaction with 1a without further purification
to give 3a isolated in 45% yield (Scheme 2, eq. 3). Furthermore,
the enamine intermediate was also successfully captured using
Scheme 2. Control experiments
(2,4-dinitrophenyl)hydrazine
[see
Electronic
Supporting
Information (ESI)]. However, the sulfonyl amidine could not be
converted to the sulfonamide under the standard conditions
(Scheme 2, eq. 4).
Combined with literature reports7a–d and the aforementioned
experimental results, a plausible mechanism for this coupling
reaction is proposed in Scheme 3. The sulfonyl azide and tert-
butyl hydroperoxide system exhibits mutually-induced
decomposition12 and homolytic cleavage of TBHP produces the
alkoxyl and hydroxyl radicals.13 The decomposition of sulfonyl
azide gives sulfonylnitrene and nitrogen.14 We envisioned that
the enamine may be the key intermediate in this system and two
possible pathways may be involved: a) an alkoxy radical-
promoted mechanism; and b) a sulfonyl nitrene-promoted
mechanism. In path a, the initial step begins with the alkoxyl
radical then hydrogen is abstracted from the tertiary amine to
generate radical A, this is followed by an electron transfer to
form the iminium ion B.15 Subsequently, B is converted into
enamine C by further deprotonation. The nitrene promoted
pathway (path b) is also possible for this reaction.16 First, the
cation radical A’ is formed from the tertiary amine and sulfonyl
a
Reactions were performed with 2.0 mmol of sulfonyl azide
1 (2.0
equiv.), 1.0 mmol of tertiary amine
HYDRO (1.0 equiv.) in 2 mL of DCE, unless otherwise noted.
2 (1.0 equiv.) and 1.0 mmol of T-
b
c
Isolated yield after column chromatography. Gram scale reaction in 5
h. d N,N-diisopropylethylamine was used. e The ratio of E/Z isomers was
f
g
4:3. The ratio of E/Z isomers was 4:3. 2.0 Equiv. of T-HYDRO was
used. h The ratio of E/Z isomers was 4:1.
products 3s–3w in good to moderate yields. For tri-n-octylamine,
the yield of corresponding sulfonyl amidine 3u was 47%,
probably because of steric hindrance from the long alkyl group.
Tertiary amines with different alkyl groups, N,N-
diethylpropylamine and N,N-diethylbutylamine, were also
investigated and two products (3v/3a and 3w/3a) were obtained
for each tertiary amine in good yields, and it was found that the
reaction was more selective for the ethyl group giving a ratio for
the two products of nearly 2:1. Cyclic amines were also used as
substrates and N-ethyl piperidine produced the corresponding
amidine 3x in 45% isolated yield with a trace amount of product
resulting from hydrogen abstraction from the cyclic α-carbon.
Interestingly, when using N-methylpyrrolidine, the cyclic
sulfonyl amidine 3y was obtained predominantly. The aromatic
tertiary amine N,N-diethyl aniline gave a relatively poor yield of
3z with a mixture of E and Z configurations.
To gain further insight into the mechanism of the reaction, a
series of control experiments were carried out (Scheme 2). First,
tosylazide and T-HYDRO were reacted under the standard
reaction conditions; however, neither sulfonamide nor 1,2-
ditosyldiazene (TsN=NTs)7c were observed (Scheme 2, eq. 1).
Then, butylated hydroxytoluene (BHT) as a radical scavenger10
was added to the reaction mixture. When 1.0 or 2.0 equiv. BHT
was used, the yields of product and sulfonamide decreased
dramatically, and no products were obtained when 3.0 equiv. of
BHT were used and the starting material 1a was almost
completely recovered (Scheme 2, eq. 2). From these results, we
believe that a radical pathway is involved in the reaction process.
In addition, we considered that the enamine may be the
intermediate product, and to confirm this hypothesis, N,N-
Scheme 3. Possible reaction mechanism

4
Tetrahedron
ACCEPTED MANUSCRIPT
4. Experimental Section
nitrene, while a nitrene radical anion is also formed by a SET,
which is followed by sequential H-atom transfer and
deprotonation to form the iminium ion B and enamine C, while
the sulfonamide 4a is formed as a byproduct. Finally, The
triazoline intermediate D is produced from enamine C and TsN3
through a 1,3-dipolar cycloaddition reaction, and the subsequent
release of one molecule of diazomethane17 affords the final
product 3a.
4.1. General information
Substituted sulfonyl azides were prepared according to the
literature.19 (Caution: Azides may be hazardous and/or explosive.)
Et3N was distilled from sodium/benzophenone. Other reagents
and solvents were obtained from commercial available and used
directly without further purification. T-HYDRO was purchased
from Alfa as a 70 wt% aqueous solution. Purification of the
reaction products was carried out by flash column
chromatography using 200–300 mesh silica gel. Visualization on
TLC (analytical thin layer chromatography) was achieved by the
use of UV light (254 nm) and treatment with phosphomolybdic
The current direct dehydrogenative functionalization was
further extended to secondary amines using the developed
reaction conditions. Interestingly, we observed that a wide array
of sulfonyl azides and secondary amine derivatives were well
tolerated and the same products were obtained as found for the
tertiary amines (Table 3). Aromatic sulfonyl azides reacted with
diethylamine smoothly and afforded the corresponding products
(3a–c, 3h and 3n) in 45%–74% yields. It is noteworthy that di-n-
propylamine and di-n-butylamine can be transformed into their
corresponding amidines 3s and 3aa in 53- 65% yield respectively.
When N-ethylbutylamine was used as reaction partner, two
products (3w and 3aa) were isolated in a 4:1 ratio. These results
indicate that secondary amine is oxidized to form secondary
enamine through the same route as tertiary amine, then enamine
exchanges with one molecule of secondary amine to give tertiary
enamine.18 Surprisingly, when diisopropylamine was used as a
reactant, a different type of sulfonyl amidine 3ab was isolated in
48% yield as a mixture of Z and E isomers. This result revealed
that the sterically hindered diisopropylamine is directly oxidized
to form the secondary enamine, and then the reaction follows the
same route as for tertiary amines, (details are provided in the
ESI).
acid or anisaldehyde stain followed by heating. H and 13C NMR
1
spectra were recorded on a Varian spectrometer in deuterated
chloroform (CDCl3) or dimethyl sulfoxide (DMSO-d6) with the
solvent residual peak as an internal reference unless otherwise
stated (CDCl3: 1H = 7.26 ppm, 13C = 77.16 ppm; DMSO-d6: 1H =
2.50 ppm, 13C = 39.52 ppm). 1H NMR data are reported as
follows: chemical shifts, multiplicity (s = singlet, d = doublet, t =
triplet, dd = doublet of doublet, m = multiplet), coupling
constant(s) in Hz, integration. High-resolution mass spectra were
recorded on a Bruker BIO TOF Q mass spectrometer.
4.2. General procedure for the synthesis of compounds 3
To a 5-mL screw-cap vial containing sulfonyl azide (2.0 mmol)
and tertiary amine or secondary amine (1.0 mmol) in 2.0 mL of
DCE, was added T-HYDRO (70 wt% in H2O, 1.0 equiv.) in a
single delivery via syringe. The vial was tightly capped and the
reaction mixture was stirred at 80 °C for the indicated time
(monitored by TLC). After the reaction was completed, the
solvent was removed under reduced pressure. The crude residue
was purified via silica gel column chromatography with an
appropriate eluting solvent system (ethyl acetate- petroleum
ether).
Table 3. Reaction of sulfonyl azides with secondary aminesa,b
4.2.1. (E)-N,N-diethyl-N'-tosylformimidamide (3a):7a White solid,
mp: 71–72 °C. 1H NMR (400 MHz, CDCl3): δ = 8.14 (s, 1H),
7.76 (d, J = 8.0 Hz, 2H), 7.25 (d, J = 8.0 Hz, 2H), 3.46 (q, J = 7.2
Hz, 2H), 3.37 (q, J = 7.2 Hz, 2H), 2.39 (s, 3H), 1.25 (t, J = 7.2
Hz, 3H), 1.13 (t, J = 7.2 Hz, 3H); 13C NMR (100 MHz, CDCl3): δ
= 158.1, 142.3, 139.9, 129.3, 126.4, 47.1, 41.0, 21.5, 14.6, 12.2.
4.2.2. (E)-N,N-diethyl-N'-(phenylsulfonyl)formimidamide (3b):7a
White solid, mp: 76–77 °C. H NMR (400 MHz, CDCl3): δ =
1
a
Reactions were performed with 2.0 mmol of sulfonyl azide
1 (1.0
8.14 (s, 1H), 7.87 (d, J = 8.0 Hz, 2H), 7.48-7.42 (m, 3H), 3.46(q,
J = 7.2 Hz, 2H), 3.36 (q, J = 7.2 Hz, 2H), 1.24 (t, J = 7.2 Hz,
3H), 1.12 (t, J = 7.2 Hz, 3H); 13C NMR (100 MHz, CDCl3): δ =
158.2, 142.7, 131.7, 128.7, 126.4, 47.2, 41.0, 14.5, 12.18.
equiv.), 1.0 mmol of secondary amine
HYDRO (1.0 equiv.) in 2 mL of DCE, unless otherwise noted.
Isolated yield after column chromatography. The ratio of E/Z isomers
was 4:3. d The ratio of E/Z isomers was 2:1.
2
(1.0 equiv.) and 1.0 mmol of T-
b
c
Then, we investigated whether primary amines could tolerate
this transformation; however, the application of primary amines
was not successful.
4.2.3ꢀ(E)-N,N-diethyl-N'-((4-methoxyphenyl)sulfonyl)formimid-
1
amide (3c):7a White solid, mp: 64–65 °C. H NMR (400MHz,
CDCl3): δ = 8.11 (s, 1H), 7.79 (d, J = 8.8 Hz, 2H), 6.91 (d, J =
8.8 Hz, 2H), 3.82 (s, 3 H), 3.44 (q, J = 7.2 Hz, 2H), 3.35 (q, J =
3. Conclusions
7.2 Hz, 2H), 1.23 (t, J = 7.2 Hz, 3H), 1.11 (t, J = 7.2 Hz, 3H); 13
C
We have developed a novel metal-free protocol for the
synthesis of sulfonyl amidines from aliphatic amines and sulfonyl
azides in the presence of aqueous tert-butyl hydroperoxide. This
method was employed for different tertiary and secondary amines
and the corresponding amidines were generated in moderate to
high yield. Several control experiments were conducted and
potential mechanisms were proposed. The oxidative
dehydrogenation of the α, β-C(sp3)-H bond of an aliphatic amine
to form an enamine is a key step to give the desired products.
Further research on elucidating the oxidative mechanism of
TBHP with tertiary amines and synthetic applications of the
strategy are in progress in our lab.
NMR (100 MHz, CDCl3): δ = 162.2, 157.9, 134.7, 128.4, 113.9,
55.6, 47.1, 40.9, 14.5, 12.1.
4.2.4. (E)-N'-((4-(tert-butyl)phenyl)sulfonyl)-N,N-diethylformimid
1
amide (3d): White solid, mp: 95–96 °C. H NMR (400 MHz,
CDCl3): δ = 8.14 (s, 1H), 7.79 (d, J = 8.4 Hz, 2H), 7.45 (d, J =
8.4 Hz, 2H) , 3.47 (q, J = 7.2 Hz, 2H), 3.37 (q, J = 7.2 Hz, 2H),
1.31 (s, 9H), 1.24 (t, J = 7.2 Hz, 3H), 1.14 (t, J = 7.2 Hz, 3H); 13
C
NMR (100 MHz, CDCl3): δ = 158.2, 155.3, 139.7, 126.2, 125.7,
47.1, 41.0, 35.1, 31.2, 29.7, 14.6, 12.2. HRMS calcd. for
C15H24N2NaO2S [M+Na]+; 319.1456; found 319.1461.

4.2.5. (E)-N,N-diethyl-N'-(mesitylsulfonyl)formimidamide (3e):7a
White solid, mp: 77–78 °C. H NMR (400 MHz, CDCl3): δ =
Hz, 2H), 1.79-171 (m, 2H), 1.46-1.40 (m, 2H), 1.26 (q, J = 7.2
ACCEPTED MANUSCRIPT
1
Hz, 3H), 1.19 (d, J = 7.2 Hz, 3H), 0.92(t, J = 7.2 Hz, 3H); 13
C
8.12 (s, 1H), 6.90 (s, 1H) , 3.45 (q, J = 7.2 Hz, 2H), 2.67 (s, 6H),
NMR (100 MHz, CDCl3): δ = 158.4, 53.7, 47.1, 40.9, 25.8, 21.7,
14.6, 13.7, 12.1.
2.27 (s, 3H), 1.23 (t, J = 7.2 Hz, 3H), 1.14(t, J = 7.2 Hz, 3 H); 13
C
NMR (100 MHz, CDCl3): δ =157.5, 141.2, 138.5, 136.7, 131.5,
46.9, 40.9, 23.1, 21.0, 14.7, 14.2.
4.2.14. (E)-N,N-diethyl-N'-(thiophen-2-ylsulfonyl)formimidamide
(3n):7a White solid, mp: 56–57 °C.1H NMR (400 MHz, DMSO-
d6): δ = 8.21 (s, 1H), 7.82 (d, J = 4.0 Hz, 1H), 7.50 (d, J = 4.0 Hz,
1H), 7.10 (t, J = 4.0 Hz, 1H) , 3.49 (q, J = 7.2 Hz, 2H), 3.38 (q, J
= 7.2 Hz, 2H), 1.15 (t, J = 7.2 Hz, 3H), 1.07 (t, J = 7.2 Hz, 3H);
13C NMR (100 MHz, DMSO-d6): δ = 158.8, 144.7, 131.4, 129.9,
127.3, 46.5, 14.2, 11.9.
4.2.6.
(E)-N'-((4-chlorophenyl)sulfonyl)-N,N-diethylformimid-
1
amide (3f):7a White solid, mp: 86–87 °C. H NMR (400MHz,
CDCl3): δ = 8.12 (s, 1H), 7.80 (d, J = 8.4 Hz, 2H),7.41 (d, J = 8.4
Hz, 2H), 3.46 (q, J = 7.2 Hz, 2H), 3.38 (q, J = 7.2 Hz, 2H), 1.25
(t, J = 7.2 Hz, 3H), 1.13 (t, J = 7.2 Hz, 3H); 13C NMR (100 MHz,
CDCl3): δ = 158.2, 141.3, 138.1,129.0, 127.9, 47.3, 41.1, 14.5,
12.1.
4.2.15.
(E)-N,N-diethyl-N'-((5-methylfuran-2-yl)sulfonyl)form-
imidamide (3o): Viscous liquid. 1H NMR (400 MHz, CDCl3): δ =
8.05 (s, 1H), 8.51 (d, J = 3.2 Hz, 1H), 6.03 (d, J = 3.2 Hz, 1H),
3.50(q, J = 7.2 Hz, 2H), 3.40 (q, J = 7.2 Hz, 2H), 2.32 (s, 3H),
1.27 (t, J = 7.2 Hz, 3H), 1.16 (t, J = 7.2 Hz, 3H); 13C NMR (100
MHz, CDCl3): δ = 159.1, 156.1, 148.8, 115.5, 107.3, 47.3, 41.2,
14.5, 13.9, 12.1; HRMS calcd. for C10H16N2NaO3S [M+Na]+;
267.0779; found 267. 0774.
4.2.7.
(E)-N'-((2-chlorophenyl)sulfonyl)-N,N-diethylformimid-
amide (3g): White solid, mp: 82–83 °C. 1H NMR (400MHz,
DMSO-d6): δ = 8.28 (s, 1H), 8.04 (dd, J = 7.6, 1.2 Hz, 1H), 7.60
(dd, J = 4.8, 0.6 Hz, 2H), 7.53-7.49 (m, 1H), 3.53 (q, J = 7.2 Hz,
2H), 3.36 (q, J = 7.2 Hz, 2H), 1.17 (t, J = 7.2 Hz, 3H), 1.04 (t, J =
7.2 Hz, 3H); 13C NMR (100 MHz, DMSO-d6): δ = 160.0, 139.4,
133.5, 131.5, 130.5, 129.4, 127.5, 46.4, 40.5, 14.4, 11.7; HRMS
calcd. for C11H15ClN2NaO2S [M+Na]+; 297.0440; found
297.0438.
4.2.16. (E)-N'-((3,5-dimethylisoxazol-4-yl)sulfonyl)-N,N-diethyl-
formimidamide (3p): Waxy solid. 1H NMR (400 MHz, CDCl3): δ
= 8.09 (s, 1H), 3.46 (q, J = 7.2 Hz, 2H), 3.39 (q, J = 7.2 Hz, 2H),
2.60 (s, 3H), 2.37 (s, 3H), 1.26 (t , J = 7.2 Hz, 3H), 1.15 (t, J =
7.2 Hz, 3H); 13C NMR (100 MHz, CDCl3): δ = 170.8, 157.8,
157.7, 118.7, 47.2, 41.1, 14.5, 12.6, 12.0, 11.0; HRMS calcd. for
C10H17N3NaO3S [M+Na]+; 282.0888; found 282. 0885.
4.2.8.
(E)-N'-((3-bromophenyl)sulfonyl)-N,N-diethylformimid-
amide (3h): White solid, mp: 79–80 °C. 1H NMR (400MHz,
DMSO-d6): δ = 8.24 (s, 1H), 7.90 (s, 1H), 7.89-7.76 (m, 2H),
7.50 (t, J = 8.0 Hz, 1H), 3.49 (q, J = 7.2 Hz, 2H), 3.36 (q, J = 7.2
Hz, 2H), 1.16 (t, J = 7.2 Hz, 3H), 1.04 (t, J = 7.2 Hz, 3H); 13C
NMR (100 MHz, DMSO-d6): δ = 159.2, 145.1, 134.5, 131.3,
128.2, 124.9, 121.8, 46.4, 40.4, 14.1, 11.8; HRMS calcd. for
C11H15BrN2NaO2S [M+Na]+; 340.9935; found 340.9939.
4.2.17. (E)-N,N-diethyl-N'-((1-methyl-1H-imidazol-4-yl)sulfonyl)-
formimidamide (3q): White solid, mp: 91–92 °C. 1H NMR (400
MHz, CDCl3): δ = 8.30 (s, 1H), 7.49 (s, 1H), 7.48 (s, 1H), 3.72
(s, 3H), 3.48 (q, J = 7.2 Hz, 2H), 3.41 (q, J = 7.2 Hz, 2H), 1.27 (t,
J = 7.2 Hz, 3H), 1.15 (t, J = 7.2 Hz, 3H); 13C NMR (100 MHz,
CDCl3): δ = 159.7, 142.5, 138.6, 122.9, 47.2, 40.9, 34.1, 14.5,
12.1; HRMS calcd. for C9H16N4NaO2S [M+Na]+; 267.0892;
found 267. 0889.
4.2.9.
(E)-N,N-diethyl-N'-((4-nitrophenyl)sulfonyl)formimid-
amide (3i):7d 1H NMR (400MHz, CDCl3): δ = 8.29 (d, J = 8.8 Hz
2H), 8.15 (s, 1H) 8.05 (d, J = 9.2 Hz, 2H), 3.49 (q, J = 7.2 Hz,
2H), 3.42 (q, J = 7.2 Hz, 2H), 1.28 (t, J = 7.2 Hz, 3H), 1.15 (t, J
= 7.2 Hz, 3H); 13C NMR (100 MHz, CDCl3): δ = 158.4, 149.6,
148.5,127.8, 124.4, 47.5, 41.4, 14.5, 12.2.
4.2.18.
(E)-N,N-dipropyl-N'-(pyridin-3-ylsulfonyl)formimid-
1
amide (3r): White solid, mp: 93–94 °C. H NMR (600 MHz,
CDCl3): δ = 9.06 (s, 1H), 8.72 (d, J = 4.8 Hz, 1H), 8.18-8.16 (m,
2H), 7.40(dd, J = 4.8, 3.0 Hz, 1H), 3.38 (t, J = 7.8 Hz, 2H), 3.29
(t, J = 7.2 Hz, 2H), 1.67-1.57 (m, 4H), 0.92 (t, J = 7.2 Hz, 3H),
0.87(t, J = 7.2 Hz, 3H); 13C NMR (125 MHz, CDCl3): δ = 159.2,
152.4, 147.6, 139.3, 134.1, 123.5, 54.6, 48.2, 22.0, 20.1, 11.3,
11.0; HRMS calcd. for C12H19N3NaO2S [M+Na]+; 292.1096;
found 292.1094.
4.2.10. (E)-N-(4-(N-((diethylamino)methylene)sulfamoyl)phenyl)-
1
acetamide (3j): White solid, mp: 101–102 °C. H NMR (400
MHz, DMSO-d6): δ = 10.53 (bs, 1H), 8.17(s, 1H), 7.75 (d, J =
8.8 Hz, 2H), 7.66 (d, J = 8.8 Hz, 2H) , 3.46 (q, J = 7.2 Hz, 2H),
3.35 (q, J = 7.2 Hz, 2H), 2.08 (s, 3H),1.14 (t, J = 7.2 Hz, 3H),
1.03 (t, J = 7.2 Hz, 3H); 13C NMR (100 MHz, DMSO-d6): δ =
168.9, 158.5, 142.2, 136.8, 126.7, 118.3, 46.2, 24.1, 24.0, 14.3,
11.8; HRMS calcd. for C13H19N3NaO3S [M+Na]+; 320.1045;
found 320.1049.
4.2.19. (E)-N,N-dipropyl-N'-tosylformimidamide (3s)ꢁ7d White
1
solid, mp: 43–44 °C. H NMR (400 MHz, CDCl3): δ = 8.14 (s,
4.2.11.
(E)-N,N-diethyl-N'-(naphthalen-2-ylsulfonyl)formimid-
1H), 7.74 (d, J = 8.4 Hz, 2H), 7.25 (d, J = 8.0 Hz, 2H), 3.35 (t, J
= 7.6 Hz, 2H), 3.22 (t, J = 7.2 Hz, 2H), 2.39 (s, 3H), 1.65-1.54
(m, 4H), 0.90 (t, J = 7.2 Hz, 3H), 0.85 (t, J = 7.2 Hz, 3H),; 13C
NMR (100 MHz, CDCl3): δ = 159.0, 142.3, 139.9, 129.3, 126.4,
54.3, 47.9, 22.0, 21.6, 20.1, 11.3, 10.9.
1
amide (3k):7a White solid, mp: 99–100 °C. H NMR (400 MHz,
CDCl3): δ = 8.46 (s, 1H), 8.20 (s, 1H), 7.95-7.85 (m, 4H), 7.60-
7.56 (m, 2H) , 3.48(q, J = 7.2 Hz, 2H), 3.39 (q, J = 7.2 Hz, 2H),
1.27 (t, J = 7.2 Hz, 3H), 1.14 (t, J = 7.2 Hz, 3H); 13C NMR (100
MHz, CDCl3): δ = 158.3, 139.6, 134.6, 132.3, 129.3, 129.0,
128.3, 127.9, 127.2, 127.0, 122.6, 47.2, 41.1, 14.6, 12.2.
7b
4.2.20. (E)-N,N-diisopropyl-N'-tosylformimidamide (3t) ꢁ
1
White solid, mp: 110–111 °C. H NMR (400 MHz, CDCl3): δ =
4.2.12. (E)-N'-(benzylsulfonyl)-N,N-diethylformimidamide (3l) :
White solid, mp: 80–81 °C. H NMR (400 MHz, DMSO-d6): δ =
8.23 (s, 1H), 7.73 (d, J = 8.4 Hz, 2H), 7.23(d, J = 8.4 Hz, 2H),
4.55-4.48 (m, 1H), 3.70-3.63 (m, 1H), 2.38 (s, 3H), 1.30 (d, J =
6.8 Hz,6H), 1.20 (d, J = 6.8 Hz, 6H); 13C NMR (100 MHz,
CDCl3): δ =156.2, 142.0, 139.9, 129.2, 126.2, 48.4, 47.8, 23.5,
21.4, 19.6.
1
7.56 (s, 1H), 7.31 (m, 5H), 4.26(s, 2H), 3.35(q, J = 7.2 Hz, 2H),
3.28 (q, J = 7.2 Hz, 2H), 1.08 (t, J = 7.2 Hz, 3H), 1.00 (t, J = 7.2
Hz, 3H); 13C NMR (100 MHz, DMSO-d6): δ = 159.3, 130.9,
130.8, 128.0, 127.7, 59.0, 46.0, 14.2, 11.6; HRMS calcd. for
C12H18N2NaO2S [M+Na]+; 277.0987; found 277.0984.
4.2.21. (E)-N,N-dioctyl-N'-tosylformimidamide (3u)ꢁviscous oil.
1H NMR (400 MHz, DMSO-d6): δ = 8.19 (s, 1H), 7.61 (d, J = 8.4
Hz, 2H), 7.31 (d, J = 7.6 Hz, 2H), 3.41 (t, J = 7.2 Hz, 2H), 3.29
(t, J = 7.2 Hz, 2H), 2.35 (s, 3H), 1.53-1.42 (m, 4H), 1.27-1.15 (m,
20H), 0.87-0.82 (m, 6H); 13C NMR (100 MHz, DMSO-d6): δ =
4.2.13. (E)-N'-(butylsulfonyl)-N,N-diethylformimidamide (3m):7a
1
Light yellow oil. H NMR (400 MHz, CDCl3): δ = 8.03 (s, 1 H),
3.48 (q, J = 7.2 Hz, 2H), 3.37 (q, J = 7.2 Hz, 2H), 3.00 (t, J = 8.0

6
Tetrahedron
ACCEPTED MANUSCRIPT
159.5, 141.8, 140.3, 129.2, 125.7, 51.3, 31.1, 28.59, 28.54,
Acknowledgements
28.46, 25.98, 22.04, 13.92; HRMS calcd. for C24H42N2NaO2S
This work was supported by the National Natural Science
Foundation of China (No. 21762044, 21362038), and Xinjiang
Normal University Graduate Research and Innovation Fund (No:
XSY201702014).
[M+Na]+; 445.2865; found 445.2864.
4.2.22. (E/Z) N-ethyl-N-propyl-N'-tosylformimidamide (3v):
White solid, mp: 62–63 °C. H NMR (400 MHz, CDCl3): δ =
1
8.16 (s, 0.4H), 8.10 (s, 0.6H), 7.74 (d, J = 8.0 Hz, 2H), 7.23 (d, J
= 8.0 Hz, 2H), 3.44 (q, J = 7.2 Hz, 1.2H), 3.35 (q, J = 7.2 Hz,
1.7H), 3.25 (t, J = 7.2 Hz, 1H), 2.38 (s, 3H), 1.64-1.53 (m, 2H),
1.23(t, J = 7.2 Hz, 1.4H), 1.12(t, J = 7.2 Hz, 1.6H), 0.91 (t, J =
7.2 Hz, 1.7H), 0.86 (t, J = 7.2 Hz, 1.3H),; 13C NMR (100 MHz,
CDCl3): δ = 158.6, 158.5, 142.33, 142.31, 139.9, 129.36, 129.34,
126.4, 54.0, 47.6, 47.4, 41.3, 22.0, 21.5, 20.1, 14.6, 12.1, 11.3,
10.9; HRMS calcd. for C13H20N2NaO2S [M+Na]+; 291.1143;
found 291.1144.
Appendix A. Supplementary data
Supplementary data related to this article can be found at t
http:// dx.doi.org/
References and notes
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4.2.23. (E/Z) N-butyl-N-ethyl-N'-tosylformimidamide (3w): White
1
solid, mp: 54–55 °C. H NMR (400 MHz, CDCl3): δ = 8.14 (s,
0.4H), 8.09 (s, 0.6H), 7.73 (d, J = 8.0 Hz, 2H), 7.22 (d, J = 8.0
Hz, 2H), 3.45-3.31 (m, 3H), 3.27 (q, J = 7.2 Hz, 1H), 2.37 (s,
3H), 1.57-1.47 (m, 2H), 1.31-1.20(m, 3.5), 1.23(t, J = 7.2 Hz,
1.4H), 1.10(t, J = 7.2 Hz, 1.5H), 0.91 (t, J = 7.2 Hz, 1.7H), 0.84
(t, J = 7.2 Hz, 1.3H),; 13C NMR (100 MHz, CDCl3): δ = 158.48,
158.45, 142.26, 142.23, 139.8, 129.30, 129.26, 126.3, 52.1, 47.2,
45.4, 41.2, 30.7, 28.7, 21.4, 19.9, 19.6, 14.5, 13.7, 13.6, 12.0;
HRMS calcd. for C14H22N2NaO2S [M+Na]+; 305.1300; found
305.1304.
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4.2.24. (E)-4-methyl-N-(piperidin-1-ylmethylene)benzenesulfon-
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amide (3x):7a White solid, mp: 139–141 °C. H NMR (400 MHz,
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Hz, 2H), 3.45 (t, J = 7.2 Hz, 2H), 2.86 (s, 3H), 2.81 (d, J = 7.6
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18.5.
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4.2.26. (E/Z)-N-ethyl-N-phenyl-N'-tosylformimidamide (3z):7a
.
1
White solid, mp: 96–97 °C. H NMR (400 MHz, DMSO-d6): δ =
.
8.55 (s, 0.2H), 8.35 (s, 0.8H), 7.73 (d, J = 8.0 Hz, 1.6H), 7.59(d,
J = 8.0 Hz, 0.4H), 7.48-7.24 (m, 7H), 3.90 (q, J = 7.2 Hz, 2H),
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129.7, 129.5, 129.4, 129.2, 127.8, 127.4, 126.4, 126.2, 125.9,
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4.2.27. (E)-N,N-dibutyl-N'-tosylformimidamide (3aa):7a viscous
,
1
oil. H NMR (400 MHz, CDCl3): δ = 8.12 (s, 1H), 7.74 (d, J =
.
8.4 Hz, 2H), 7.24 (d, J = 8.4 Hz, 2H), 3.39 (t, J = 7.6 Hz, 2H),
3.28 (t, J = 7.6 Hz, 2H), 2.39 (s, 3H), 1.57-1.49 (m, 4H), 1.33-
1.27 (m, 4H), 0.93 (t, J = 7.2 Hz, 3H), 0.86(t, J = 7.2 Hz, 3H) ;
13C NMR (100 MHz, CDCl3): δ = 158.8, 142.3, 139.9, 129.3,
126.4, 52.4, 46.1, 30.8, 28.8, 21.6, 20.0, 19.8, 13.8, 13.7.
,
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4.2.28. (E/Z)- N-isopropyl-N'-tosylacetimidamide (3ab): White
1
solid, mp: 83–84 °C. H NMR (600 MHz, CDCl3): δ =7.81 (m,
2H), 7.26 (m, 2H), 5.29 (bs, 1H), 4.17- 4.11 (m, 0.7H), 3.74 -
3.68 (m, 0.3H), 2.40 (s, 3H), 2.37 (s, 2H), 2.10 (s, 1H), 1.25 (d, J
= 6.6 Hz, 2H), 1.15 (d, J = 6.6 Hz, 4H); 13C NMR (125 MHz,
CDCl3): δ = 164.4, 142.8, 142.1, 140.9, 129.4, 129.2, 126.5,
126.4, 46.7, 44.0, 23.5, 22.0, 21.8, 21.65, 21.61. HRMS calcd.
for C12H18N2NaO2S [M+Na]+; 277.0987; found 277.0985.
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