Fe-mediated synthesis of: N -aryl amides from nitroarenes and acyl chlorides

Article abstract of DOI:10.1039/d0ra10868e

Amides are prevalent in nature and valuable functional compounds in agrochemical, pharmaceutical, and materials industries. In this work, we developed a selective and mild method for the synthesis of N-aryl amides. Starting from commercially available nitroarenes and acyl halides, N-aryl amides with good yields can be obtained in water. Especially in the process of transformation, Fe dust is the only reductant and additive, and the reaction can be easily performed on a large scale.

Full text of DOI:10.1039/d0ra10868e

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Fe-mediated synthesis of N-aryl amides from
nitroarenes and acyl chlorides†
Cite this: RSC Adv., 2021, 11, 15290
a
b
b
c
Yundong Wu,a Lei Guo,
*
*
Yuxuan Liu, Jiannan Xiang and Jun Jiang
Amides are prevalent in nature and valuable functional compounds in agrochemical, pharmaceutical, and
materials industries. In this work, we developed a selective and mild method for the synthesis of N-aryl
amides. Starting from commercially available nitroarenes and acyl halides, N-aryl amides with good
yields can be obtained in water. Especially in the process of transformation, Fe dust is the only reductant
and additive, and the reaction can be easily performed on a large scale.
Received 27th December 2020
Accepted 19th April 2021
DOI: 10.1039/d0ra10868e
rsc.li/rsc-advances
widely used in organic synthesis. In addition, Fe dust is a cheap
and safe reducing agent and can be used in many organic
reactions.23,24 We are interested in Fe-promoted organic reac-
tions performed in water. Therefore, we developed a mild Fe-
promoted reaction of nitroarenes with acyl chloride (uoride)
using water as solvent in this work. Using the Fe-mediated
synthetic method, a series of N-aryl amides can be produced
in moderate to good yields, showing its fascinating application
prospects (Scheme 1d).
1. Introduction
Amides are synthetically important intermediates and usually
serve as useful building blocks for drugs, ne chemicals, and
bioactive molecules such as peptides and proteins.1–8 The ami-
dation reaction with anilines or amines as amino sources is
used to construct amide motifs.9–13 It is more efficient to start
directly from the nitrocompounds which are readily available
industrial chemicals rather than to start from the correspond-
ing amines or isocyanates.14,15 In general, the classical two-step
approach should be oen proposed when someone is asked to
prepare an amide from a nitro compound, namely reduction to
amine with subsequent acylation (Scheme 1a). More impor-
tantly, several methods for direct conversion of nitroarenes to
acetanilides are carried out by Pt nanoparticle ZrO2 and acetic
anhydride, molybdenum hexacarbonyl/acetic acid, and also
anilides have been obtained either via nickel or rhodium or
platinum catalyzed carbonylation of nitroarenes.16–18 However,
50–100 atm CO is required in each case. In 2018, Hu and co-
workers described Mn-catalyzed reductive transamidation of
tertiary amides with nitroarenes (Scheme 1b).19 Recently, the
reductive amidation between esters and nitroarenes can be
achieved by nickel catalysis by cleavage of acyl C–O bonds,
wherein metallic zinc serves as efficient reductant (Scheme
1c).20–22 However, these methods have some obvious short-
comings such as the use of organic solvents and additives which
are difficult to recover. To overcome the difficulties in the
transformation of N-aryl amides, we need to nd an efficient
and improved synthesis route. Water, as a green solvent, is
aSchool of Material and Chemical Engineering, Tongren University, Tongren 554300,
China. E-mail: cqglei@163.com
bCollege of Chemistry and Chemical Engineering, Hunan University, Changsha
410082, China
cSchool of Chemistry and Chemical Engineering, Hunan University of Science and
Technology, Xiangtan 411201, China. E-mail: jiangjunhust@163.com
† Electronic supplementary information (ESI) available: 1H NMR and 13C NMR
spectra of new compounds. See DOI: 10.1039/d0ra10868e
Scheme 1 Different approaches for amidation using nitroarenes as
amino sources.
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Table 2 Substrate scope with respect to acyl chloride a,b
2. Results and discussion
We used the reaction of nitrobenzene (1a) with benzoyl chloride
(2a, 2 equiv.) as test reaction (Table 1). Using the conditions of
benzoyl chloride (0.5 mmol) with nitrobenzenes (0.25 mmol),
iron dust (4 equiv.) as reductant, and water (1 mL) as solvent,
the transamidation was actually successful, giving the desired
amide product N-phenyl benzamide (3aa), in 88% yield (Table 1,
entry1). We optimized the Fe-mediated transamidation of 1a
with 2a. Other metal reductants such as zinc, aluminium, and
magnesium were not effective (Table 1, entries 2–4). By
changing the temperature to 80 ꢀC or 40 ꢀC, the yield of 3aa was
reduced (Table 1, entries 5 and 6). We believe that weak
hydrolysis reaction may occur for acyl chlorides at elevated
temperature, resulting in diminished yield of target product.
The use of other solvent instead of water all led to a great
reduction of yields (Table 1, entries 7–11). More loading of Fe (5
equiv.) or PhCOCl (2.5 equiv.) have no effect on yield, but lower
loading of Fe (3 equiv.) or PhCOCl (1.5 equiv.) led to a modest
reduction of yields (Table 1, entries 12–16).
The optimized reaction conditions were employed for the
transamidation of nitroarenes (1a) with acyl chloride (2) (shown
in Table 2). The reaction of nitrobenzene (1a) and benzoyl
chloride (2a) efficiently offered 88% yield of 3aa in 36 h at 60 ꢀC.
Various acyl chlorides reacted smoothly with nitrobenzene to
give the N-aryl amide products in medium to excellent yields. It
was observed that benzoyl chlorides with electron donating
substituents afforded the higher yields of corresponding prod-
ucts (3ab–3ad, 3ak). However, the yield of anilides with electron
withdrawing substituents were reduced (3ae, 3ag–3aj). Notably,
a
Conditions: 1a (0.25 mmol), 2 (0.5 mmol), Fe (1 mmol) and H2O (1
b
c
mL), 60 ꢀC, 36 h. Aer column chromatography. Use BzF as 2.
both isobutyryl chloride and cyclohexanecarbonyl chloride were
proven to be effective to produce the desired products in
medium yield (3af, 3al). However, when we used 4-nitrobenzoyl
chloride (2n) or 2-nitrobenzoyl chloride (2m), no obvious reac-
tions were observed. Moreover, benzoyl uoride reacted with
nitrobenzene to give 3aa in 56% yield (3aa).
Subsequently, various nitroarenes were reacted with benzoyl
chloride (2a) as shown in Table 3. The reaction of 2a with 1-
methyl-4-nitrobenzene, 1-methyl-3-nitrobenzene and 1-chloro-
4-methyl-2-nitrobenzene gave the corresponding products,
3ba, 3ca and 3ga in good yields. The 1-chloro-4-nitrobenzene
and 1-bromo-4-nitrobenzene also participated well in this
reaction (3ea, 3fa). Meanwhile, this reaction is also tolerant of 1-
Table 1 Screening optimal conditionsa
Entry
Variations from standard conditions
Yieldb
1
No variation
88
45
17
18
68
78
30
22
11
14
45
88
55
Trace
87
59
2
3
4
5
6
7
8
Zn (4 equiv.) instead of Fe
Al (4 equiv.) instead of Fe
Mg (4 equiv.) instead of Fe
80 ꢀC instead of 60 ꢀ
40 ꢀC instead of 60 ꢀ
NMP instead of H2O
DMF instead of H2O
C
C
9
Toluene instead of H2O
10
11
12
13
14
15
16
PhCl instead of H2O
EtOH instead of H2O
chloro-4-methoxy-2-nitrobenzene
and
1,4-dichloro-2-
Fe (5 equiv.) instead of (4 equiv.)
Fe (3 equiv.) instead of (4 equiv.)
Absence of Fe
PhCOCl (2.5 equiv.) instead of (2 equiv.)
PhCOCl (1.5 equiv.) instead of (2 equiv.)
nitrobenzene, and the desired products 3ha and 3ia were
produced in 78% and 64% yields. However, it was observed that
nitromethane (1j) failed to produce desired N-methylbenzamide
in practical yields.
To verify the practicality of the reaction, a scale–up reaction
were carried out. Nitrobenzene (1a, 10 mmol) reacted with
benzoyl chloride and Fe under standard conditions, and the
expected product 3aa was obtained in 80% yield (Scheme 2).
A series of control experiments were carried out to gain some
insights into the possible mechanism. When radical trapping
reagents (TEMPO) was added to the reaction mixture, the
a
All reactions were performed with nitrobenzene (1a, 0.25 mmol), acyl
chloride (2a, 0.5 mmol), reductant (1 mmol) and solvent (1 mL), 36 h.
Isolated yield.
b
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Table 3 Substrate scope with respect to nitroarenesa,b
Scheme 4 Proposed reaction mechanism.
3c), but N-phenyl-hydroxylamine or azobenzene or N,N0-diphe-
nylhydrazine could not react with benzoyl chloride to generate
3aa (Scheme 3d) suggesting that nitrosobenzene might be
involved as an intermediate in the transformation. Finally,
when the reaction was conducted under a nitrogen atmosphere,
we got the product 3aa in 86% yield (Scheme 3e). We observed
that the color of the mixtures changed from colourless to pale
brown and some brown solid was generated. We added 1 mL
HCl (1 M) to the reaction mixtures and the precipitation was
a
Conditions: 1 (0.25 mmol), 2a (0.5 mmol), Fe (1 mmol) and H2O (1 disappeared followed by color changing from pale brown to pale
b
mL), 60 ꢀC, 36 h. Aer column chromatography.
yellow. So we speculated that ferric hydroxide was generated in
the transformation. Finally, the reaction of 1a with carboxylic
acid anhydride Bz2O could not produce 3aa under the standard
conditions (Scheme 3f).
transformation was inhibited, implying that the transformation
might proceed via radical process (Scheme 3a). Lacking of BzCl
in the reaction, there was no PhNH2 generated (Scheme 3b).
Then, we usedsd nitrosobenzene as the reactant under the
standard conditions and the product 3aa was obtained (Scheme
According to the aforementioned experimental results and
literature reports,25 PhCOCl or PhCOF was activated by ferrous
powder to produce a benzoyl radical (Scheme 4a). Then, the
benzoyl radical reacted with nitrosoarene originating from the
reduction of nitroarene by ferrous powder to form the N–C
bond. Finally, the generated radical further transforms into the
desired product 3 in the presence of Ferrous ion and water
(Scheme 4b).
3. Conclusions
Scheme 2 Gram scale synthesis.
In conclusion, we have developed a step-economic amidation of
PhCOX using nitroarenes as amino sources promoted by Fe.
Broad scope and functional group compatibility have been
demonstrated. The direct use of nitroarenes in place of anilines
would provide potential advantages in cost and step economy.
4. Experimental details
NMR spectroscopy was performed on a Bruker advanced spec-
trometer operating at 400 MHz (1H NMR) and 100 MHz (13C
NMR). Melting point was measured with a XRC-1 melting point
apparatus. FT infrared (IR) spectra was recorded using FD-5DX
spectrometer. Mass spectrometric analysis was performed on
MAT 95 XP (Thermo Finnigan).
General procedure for synthesis of N-phenylacetamides (3)
A mixture of nitroarenes (0.25 mmol) and acyl chloride (uo-
ꢀ
Scheme 3 Control experiments.
ride) (0.5 mmol) and H2O (1 mL) was stirred at 60 C for 36 h
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under air. Aer cooling to room temperature, water (10 mL) was
added and the aqueous phase was extracted by EtOAc (3 ꢁ 10
mL). The combined organic phases were dried over Na2SO4, and
concentrated in vacuum. The residue was puried by chroma-
tography on silica gel with petroleum ether/ethyl acetate as
eluent to afford the corresponding product.
N-Phenylisobutyramide (3af)
12
ꢀ
ꢀ
Shallow brown solid. Mp: 101–102 C (lit 102–103 C). Yield
25 mg (62%) at 0.25 mmol scale.
1H NMR (400 MHz, DMSO-d6) d 9.86 (s, 1H), 7.63 (d, J ¼
8.0 Hz, 2H), 7.30 (t, J ¼ 7.4 Hz, 2H), 7.04 (t, J ¼ 7.2 Hz, 1H), 2.65–
2.58 (m, 1H), 1.12 (d, J ¼ 6.8 Hz, 6H).
13C NMR (100 MHz, DMSO-d6) d 175.7, 139.9, 129.1, 123.4,
119.5, 35.4, 20.0.
N-Phenylbenzamide (3aa)
Pale brown solid. Mp: 162–163 ꢀC (lit12 164–165 ꢀC). Yield 45 mg
(88%) at 0.25 mmol scale.
4-Fluoro-N-phenylbenzamide (3ag)
1H NMR (400 MHz, DMSO-d6) d 10.31 (s, 1H), 8.01 (d, J ¼
7.2 Hz, 2H), 7.84 (d, J ¼ 7.8 Hz, 2H), 7.62 (t, J ¼ 7.2 Hz, 1H), 7.56
(t, J ¼ 7.2 Hz, 2H), 7.39 (t, J ¼ 7.2 Hz, 2H), 7.14 (t, J ¼ 7.3 Hz, 1H).
13C NMR (100 MHz, DMSO-d6) d 166.1, 139.7, 135.5, 132.4,
129.1, 128.9, 128.1, 124.1, 120.9.
Pale brown solid. Mp: 182–184 ꢀC (lit12 183–184 ꢀC). Yield 33 mg
(63%) at 0.25 mmol scale.
1H NMR (400 MHz, DMSO-d6) d 10.31 (s, 1H), 8.07 (t, J ¼
6.6 Hz, 2H), 7.80 (t, J ¼ 8.0 Hz, 2H), 7.40 (t, J ¼ 8.0 Hz, 4H), 7.13
(t, J ¼ 7.2 Hz, 1H).
13C NMR (100 MHz, DMSO-d6) d 164.9, 164.5 (d, JC–F ¼ 247
Hz), 139.5, 131.9 (d, JC–F ¼ 3 Hz), 130.9 (d, JC–F ¼ 9 Hz), 129.1,
124.2, 120.9, 115.8 (d, JC–F ¼ 22 Hz).
4-Methyl-N-phenylbenzamide (3ab)
White solid. Mp: 142–143 ꢀC (lit12 145–146 ꢀC). Yield 39 mg
(91%) at 0.25 mmol scale.
1H NMR (400 MHz, DMSO-d6) d 10.22 (s, 1H), 7.92 (d, J ¼
7.6 Hz, 2H), 7.83 (d, J ¼ 7.6 Hz, 2H), 7.38 (t, J ¼ 8.0 Hz, 4H), 7.12
(t, J ¼ 7.0 Hz, 1H), 2.41 (s, 3H).
3-Bromo-N-phenylbenzamide (3ah)
White solid. Mp: 146–148 ꢀC (lit12 145–147 ꢀC). Yield 44 mg
(64%) at 0.25 mmol scale.
13C NMR (100 MHz, DMSO-d6) d 165.8, 142.0, 139.7, 132.6,
129.4, 129.0, 128.2, 124.0, 120.8, 21.5.
1H NMR (400 MHz, DMSO-d6) d 10.39 (s, 1H), 8.18 (s, 1H),
7.99 (d, J ¼ 7.8 Hz, 1H), 7.83–7.79 (m, 3H), 7.52 (t, J ¼ 7.8 Hz,
1H), 7.39 (t, J ¼ 7.8 Hz, 2H), 7.14 (t, J ¼ 7.4 Hz, 1H).
13C NMR (100 MHz, DMSO-d6) d 164.4, 139.4, 137.6, 134.7,
131.1, 130.7, 129.1, 127.3, 124.4, 122.2, 120.9.
3-Methyl-N-phenylbenzamide (3ac)
White solid. Mp: 125–127 ꢀC (lit12 125–126 ꢀC). Yield 35 mg
(67%) at 0.25 mmol scale.
1H NMR (400 MHz, DMSO-d6) d 10.28 (s, 1H), 7.86–7.78 (m,
4H), 7.44 (t, J ¼ 7.2 Hz, 2H), 7.39 (t, J ¼ 8.0 Hz, 2H), 7.13 (t, J ¼
7.2 Hz, 1H), 2.43 (s, 3H).
4-Chloro-N-phenylbenzamide (3ai)
White solid. Mp: 197–198 ꢀC (lit12 199–200 ꢀC). Yield 41 mg
(71%) at 0.25 mmol scale.
13C NMR (100 MHz, DMSO-d6) d 166.2, 139.7, 138.2, 135.5,
132.6, 129.1, 128.7, 128.6, 125.3, 124.1, 120.8, 21.4.
1H NMR (400 MHz, DMSO-d6) d 10.36 (s, 1H), 8.02 (d, J ¼
7.8 Hz, 2H), 7.81 (d, J ¼ 7.8 Hz, 2H), 7.63 (t, J ¼ 7.8 Hz, 2H), 7.38
(t, J ¼ 7.2 Hz, 2H), 7.14 (t, J ¼ 7.0 Hz, 1H).
13C NMR (100 MHz, DMSO-d6) d 164.9, 139.4, 136.9, 134.1,
130.1, 129.1, 128.9, 124.3, 120.9.
2-Methyl-N-phenylbenzamide (3ad)
White solid. Mp: 125–126 ꢀC (lit12 125–126 ꢀC). Yield 45 mg
(86%) at 0.25 mmol scale.
1H NMR (400 MHz, DMSO-d6) d 10.34 (s, 1H), 7.78 (d, J ¼
8.0 Hz, 2H), 7.48 (d, J ¼ 7.4 Hz, 1H), 7.42 (t, J ¼ 7.2 Hz, 1H), 7.38–
7.31 (m, 4H), 7.12 (t, J ¼ 7.2 Hz, 1H), 2.41 (s, 3H).
13C NMR (100 MHz, DMSO-d6) d 168.3, 139.8, 137.7, 135.6,
131.0, 130.1, 129.2, 127.7, 126.1, 124.0, 120.1, 19.8.
N-Phenyl-4-(triuoromethyl)benzamide (3aj)
Brown solid. Mp: 196–197 ꢀC (lit12 196–197 ꢀC). Yield 41 mg
(73%) at 0.25 mmol scale.
1H NMR (400 MHz, DMSO-d6) d 10.58 (s, 1H), 8.00 (d, J ¼
6.8 Hz, 2H), 7.92 (d, J ¼ 7.8 Hz, 2H), 7.25 (t, J ¼ 7.2 Hz, 2H), 7.15
(t, J ¼ 7.8 Hz, 2H), 7.05 (t, J ¼ 7.0 Hz, 1H).
13C NMR (100 MHz, DMSO-d6) d 160.0, 143.8, 137.6, 133.0
(q, JC–F ¼ 26 Hz),129.7, 128.1, 126.9 (q, JC–F ¼ 3 Hz), 125.0, 123.8
(q, JC–F ¼ 271 Hz), 121.0.
3,5-Dichloro-N-phenylbenzamide (3ae)
ꢀ
White solid. Mp: 148–149 C. Yield 47 mg (71%) at 0.25 mmol
scale.
1H NMR (400 MHz, DMSO-d6) d 10.46 (s, 1H), 8.00 (s, 2H),
7.86 (s, 1H), 7.79 (d, J ¼ 7.8 Hz, 2H), 7.39 (t, J ¼ 7.2 Hz, 2H), 7.15
(t, J ¼ 7.2 Hz, 1H).
N-Phenylfuran-2-carboxamide (3ak)
ꢀ
White solid. Mp: 178–179 C. Yield 36 mg (78%) at 0.25 mmol
13C NMR (100 MHz, DMSO-d6) d 163.1, 139.1, 138.5, 134.7, scale.
131.3, 129.1, 127.0, 124.6, 120.9.
1H NMR (400 MHz, DMSO-d6) d ¼ 10.17 (s, 1H), 7.93 (s, 1H),
HRMS (ESI) m/z calcd for C13H10Cl2NO [M + H]+: 266.0134, 7.75 (d, J ¼ 7.6 Hz, 2H), 7.40–7.27 (m, 3H), 7.09 (t, J ¼ 7.6 Hz,
found 266.0135.
1H), 6.70 (dd, J ¼ 3.4, 1.8 Hz, 1H).
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13C NMR (101 MHz, DMSO-d6) d 156.7, 148.0, 146.1, 139.0,
129.1, 124.2, 120.8, 115.2, 112.6.
N-(4-Bromophenyl)benzamide (3fa)
White solid. Mp: 205–207 ꢀC (lit12 205–206 ꢀC). Yield 48 mg
(70%) at 0.25 mmol scale.
HRMS (ESI) m/z calcd for C11H10NO2 [M + H]+: 188.0712,
found 188.0716.
1H NMR (400 MHz, DMSO-d6) d 10.46 (s, 1H), 8.03 (d, J ¼
7.2 Hz, 2H), 7.87 (d, J ¼ 8.8 Hz, 2H), 7.65 (t, J ¼ 7.2 Hz, 1H), 7.62–
7.56 (m, 4H).
N-Phenylcyclohexanecarboxamide (3al)
13C NMR (100 MHz, DMSO-d6) d 166.1, 139.1, 135.2, 132.2,
131.9, 128.9, 128.2, 122.7, 115.8.
ꢀ
White solid. Mp: 133–135 C. Yield 34 mg (67%) at 0.25 mmol
scale.
1H NMR (400 MHz, DMSO-d6) d ¼ 9.78 (s, 1H), 7.61 (d, J ¼
8.0 Hz, 2H), 7.27 (t, J ¼ 7.8 Hz, 2H), 7.00 (t, J ¼ 7.5 Hz, 1H), 2.32
(t, J ¼ 11.6 Hz, 1H), 1.78–1.73 (m, 4H), 1.67–1.63 (m, 1H), 1.45–
1.38 (m, 2H), 1.27–1.23 (m, 3H).
N-(2-Chloro-5-methylphenyl)benzamide (3ga)
ꢀ
White solid. Mp: 121–122 C. Yield 49 mg (80%) at 0.25 mmol
13C NMR (101 MHz, DMSO-d6) d 174.7, 140.0, 129.0, 123.3,
119.5, 45.3, 29.6, 25.7.
scale.
1H NMR (400 MHz, DMSO-d6) d 10.46 (s, 1H), 8.04 (d, J ¼
7.8 Hz, 2H), 7.67–7.62 (m, 1H), 7.57 (t, J ¼ 6.8 Hz, 2H), 7.46 (t, J ¼
8.4 Hz, 2H), 7.14 (d, J ¼ 8.2 Hz, 1H), 2.35 (s, 3H).
13C NMR (100 MHz, DMSO-d6) d 165.8, 137.5, 135.2, 134.5,
132.3, 129.6, 129.4, 129.0, 128.6, 128.1, 126.9, 20.9.
HRMS (ESI) m/z calcd for C14H13ClNO [M + H]+: 246.0680,
found 246.0682.
HRMS (ESI) m/z calcd for C13H18NO [M + H]+: 204.1388,
found 204.1385.
N-(p-Tolyl)benzamide (3ba)
White solid. Mp: 158–159 ꢀC (lit12 156–157 ꢀC). Yield 50 mg
(95%) at 0.25 mmol scale.
1H NMR (400 MHz, DMSO-d6) d10.23 (s, 1H), 7.99 (d, J ¼
7.2 Hz, 2H), 7.72 (d, J ¼ 8.0 Hz, 2H), 7.60 (d, J ¼ 7.0 Hz, 1H), 7.55
(t, J ¼ 7.4 Hz, 2H), 7.19 (d, J ¼ 8 Hz, 2H), 2.31 (s, 3H).
13C NMR (100 MHz, DMSO-d6) d 165.8, 137.1, 135.5, 133.1,
131.9, 129.5, 128.8, 128.1, 120.9, 21.0.
N-(2-Chloro-5-methoxyphenyl)benzamide (3ha)
ꢀ
White solid. Mp: 124–125 C. Yield 50 mg (78%) at 0.25 mmol
scale.
1H NMR (400 MHz, DMSO-d6) d 10.03 (s, 1H), 8.03 (d, J ¼
7.8 Hz, 2H), 7.64 (t, J ¼ 7.0 Hz, 1H), 7.57 (t, J ¼ 7.2 Hz, 2H), 7.48
(d, J ¼ 8.8 Hz, 1H), 7.29 (s, 1H), 6.92 (d, J ¼ 8.8 Hz, 1H),3.81 (s,
3H).
N-(m-Tolyl)benzamide (3ca)
White solid. Mp: 125–126 ꢀC (lit12 124–125 ꢀC). Yield 45 mg
(85%) at 0.25 mmol scale.
13C NMR (100 MHz, DMSO-d6) d 165.8, 158.7, 136.3, 134.4,
132.4, 130.3, 129.0, 128.2, 120.9, 113.9, 113.5, 56.1.
HRMS (ESI) m/z calcd for C14H13ClNO2 [M + H]+: 262.0629,
found 262.0626.
1H NMR (400 MHz, DMSO-d6) d 10.23 (s, 1H), 7.99 (d, J ¼
7.2 Hz, 2H), 7.68 (s, 1H), 7.61 (t, J ¼ 7.4 Hz, 2H), 7.55 (t, J ¼
7.4 Hz, 2H), 7.29–7.23 (m, 1H), 6.95 (d, J ¼ 7.2 Hz, 1H), 2.34 (s,
3H).
13C NMR (100 MHz, DMSO-d6) d 166.0, 139.6, 138.2, 135.5,
132.0, 128.9, 128.8, 128.1, 124.8, 121.4, 118.0, 21.7.
N-(2,5-Dichlorophenyl)benzamide (3ia)
White solid. Mp: 122–123 ꢀC (lit12 123–124 ꢀC). Yield 42 mg
(64%) at 0.25 mmol scale.
N-(o-Tolyl)benzamide (3da)
1H NMR (400 MHz, DMSO-d6) d 10.19 (s, 1H), 8.02 (d, J ¼
7.5 Hz, 2H), 7.80 (s, 1H), 7.67–7.62 (m, 2H), 7.58 (t, J ¼ 7.2 Hz,
2H), 7.41 (d, J ¼ 8.4 Hz, 1H).
White solid. Mp: 145–146 ꢀC (lit12 143–145 ꢀC). Yield 42 mg
(79%) at 0.25 mmol scale.
1H NMR (400 MHz, DMSO-d6) d 9.96 (s, 1H), 8.05 (d, J ¼
7.0 Hz, 2H), 7.64 (d, J ¼ 6.8 Hz, 1H), 7.59 (d, J ¼ 7.0 Hz, 2H), 7.41
(d, J ¼ 6.8 Hz, 1H), 7.34 (t, J ¼ 7.0 Hz, 1H), 7.28–7.23 (m, 2H),
2.30 (s, 3H).
13C NMR (100 MHz, DMSO-d6) d 165.9, 136.9, 134.1, 132.6,
131.9, 131.4, 129.0, 128.4, 128.2, 128.1, 127.6.
13C NMR (100 MHz, DMSO-d6) d 165.8, 136.9, 135.0, 134.2,
132.0, 130.8, 128.9, 128.1, 127.1, 126.5, 18.4.
Author contributions
Conceptualization: J. N. Xiang; data curation: Y. X. Liu and Y. D.
Wu; formal analysis: Y. D. Wu. and J. Jiang; investigation: Y. D.
N-(4-Chlorophenyl)benzamide (3ea)
White solid. Mp: 195–196 ꢀC (lit12 199–200 ꢀC). Yield 42 mg Wu and L. Guo; methodology: Y. X. Liu and L. Guo; resources:
(71%) at 0.25 mmol scale.
J. N. Xiang; visualization: Y. D. Wu and Y. X. Liu; writing –
1H NMR (400 MHz, DMSO-d6) d 10.44 (s, 1H), 8.00 (d, J ¼ original dra preparation: Y. D. Wu and L. Guo; writing – review
7.2 Hz, 2H), 7.88 (d, J ¼ 8.2 Hz, 2H), 7.63–7.59 (m, 1H), 7.56 (t, J and editing: Y. D. Wu, L. Guo, Y. X. Liu, J. N. Xiang; supervision:
¼ 7.2 Hz, 2H), 7.44 (d, J ¼ 8.0 Hz, 2H).
J. Jiang; project administration: L. Guo and J. N. Xiang; funding
13C NMR (100 MHz, DMSO-d6) d 166.1, 138.7, 135.2, 132.2, acquisition: L. Guo. All authors have read and agreed to the
129.0, 128.9, 128.2, 127.8, 122.3.
published version of the manuscript.
15294 | RSC Adv., 2021, 11, 15290–15295
© 2021 The Author(s). Published by the Royal Society of Chemistry

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Paper
RSC Advances
10 M. Sun, J. Jiang, J. Chen, Q. Yang and X. Yu, Tetrahedron,
2019, 75, 130456.
Conflicts of interest
11 C. L. Allen and J. M. Williams, Chem. Soc. Rev., 2011, 40,
3405–3415.
The authors have declared that no conicting interests exist.
12 R. Takise, K. Muto and J. Yamaguchi, Chem. Soc. Rev., 2017,
46, 5864–5888.
Acknowledgements
13 A. S. Santos, A. M. S. Silva and M. M. B. Marques, Eur. J. Org.
Chem., 2020, 2020, 2501–2516.
14 E. M. Nahmed and G. Jenner, Tetrahedron Lett., 1991, 32,
4917–4920.
15 B. N. Atkinson, A. R. Chhatwal, H. V. Lomax, J. W. Walton
and J. M. Williams, Chem. Commun., 2012, 48, 11626–11628.
16 M. L. Kantam, R. S. Reddy, K. Srinivas, R. Chakravarti,
B. Sreedhar, F. Figueras and C. Venkat Reddy, J. Mol.
Catal. A: Chem., 2012, 355, 96–101.
This work was supported by the Guizhou Provincial Department
of Education Foundation (QJHKY2020-067), the National
Natural Science Foundation of China (21502049, 22062022),
and the Foundation of the Department of Education of Guizhou
Province (KY[2018]030).
References
1 C. W. Cheung, M. L. Ploeger and X. Hu, Nat. Commun., 2017,
8, 14878.
2 R. M. de Figueiredo, J. S. Suppo and J. M. Campagne, Chem.
Rev., 2016, 116, 12029–12122.
3 U. Manna and G. Das, Coord. Chem. Rev., 2021, 427, 213547.
4 J. M. Humphrey and A. R. Chamberlin, Chem. Rev., 1997, 97,
2243–2266.
17 T. L. Ho, J. Org. Chem., 1977, 42, 3755.
18 Y. Watanabe, Y. Tsuji, T. Kondo and R. Takeuchi, J. Org.
Chem., 1984, 49, 4451–4455.
19 C. W. Cheung, J. A. Ma and X. Hu, J. Am. Chem. Soc., 2018,
140, 6789–6792.
20 C. W. Cheung, M. Leendert Ploeger and X. Hu, Chem. Sci.,
2018, 9, 655–659.
5 J. Jiang, S. Zeng, D. Chen, C. Cheng, W. Deng and J. Xiang,
Org. Biomol. Chem., 2018, 16, 5016–5020.
6 C. W. Cheung, M. L. Ploeger and X. Hu, ACS Catal., 2017, 7,
7092–7096.
7 B. L. Korbad and S. H. Lee, Chem. Commun., 2014, 50, 8985–
8988.
21 L. Hie, N. F. Fine Nathel, T. K. Shah, E. L. Baker, X. Hong,
Y. F. Yang, P. Liu, K. N. Houk and N. K. Garg, Nature,
2015, 524, 79–83.
22 C. W. Cheung, N. Shen, S.-P. Wang, A. Ullah, X. Hu and
J.-A. Ma, Org. Chem. Front., 2019, 6, 756–761.
23 L. N. de Paula, L. A. dos Reis Giusto, J. D. Ardisson and
8 C. L. Allen, B. N. Atkinson and J. M. Williams, Angew. Chem.,
Int. Ed. Engl., 2012, 51, 1383–1386.
9 H. Lundberg, F. Tinnis, N. Selander and H. Adolfsson, Chem.
Soc. Rev., 2014, 43, 2714–2742.
˜
F. Magalhaes, Environ. Chem. Lett., 2015, 13, 347–351.
24 M. Zhang, J. Li, Q. Zeng and Q. Mou, Appl. Sci., 2019, 9, 3604.
25 C. W. Cheung and X. Hu, Nat. Commun., 2016, 7, 13776.
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