Microwave-assisted heteropolyanion-based ionic liquids catalyzed transamidation of non-activated carboxamides with amines under solvent-free conditions

Article abstract of DOI:10.1016/j.tet.2014.10.066

An environmentally benign and highly efficient protocol for the transamidation of non-activated carboxamides with amines using heteropolyanion-based ionic liquids as catalysts under microwave-assisted and solvent-free conditions has been developed. As evaluated by the reactions of a structurally diverse set of amides and amines, the scope and utility of the transamidation proved to be quite general. Operational simplicity, solvent-free media, the potential reusability of catalysts and wide functional group tolerance are attractive features. This method provides a much improved protocol over the existing methods.

Full text of DOI:10.1016/j.tet.2014.10.066

Tetrahedron 70 (2014) 9492e9499
Contents lists available at ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Microwave-assisted heteropolyanion-based ionic liquids catalyzed
transamidation of non-activated carboxamides with amines under
solvent-free conditions
*
*
Renzhong Fu, Yang Yang , Zhikai Chen, Wenchen Lai, Yongfeng Ma, Quan Wang ,
Rongxin Yuan
Jiangsu Laboratory of Advanced Functional Material, School of Chemistry and Materials Engineering, Changshu Institute of Technology,
Changshu 215500, PR China
a r t i c l e i n f o
a b s t r a c t
Article history:
An environmentally benign and highly efficient protocol for the transamidation of non-activated car-
boxamides with amines using heteropolyanion-based ionic liquids as catalysts under microwave-assisted
and solvent-free conditions has been developed. As evaluated by the reactions of a structurally diverse
set of amides and amines, the scope and utility of the transamidation proved to be quite general. Op-
erational simplicity, solvent-free media, the potential reusability of catalysts and wide functional group
tolerance are attractive features. This method provides a much improved protocol over the existing
methods.
Received 20 September 2014
Received in revised form 21 October 2014
Accepted 27 October 2014
Available online 30 October 2014
Keywords:
Amide
Ionic liquid
Ó 2014 Elsevier Ltd. All rights reserved.
Microwave-assisted
Solvent-free condition
Transamidation
1. Introduction
evolved enzymes and long reaction time.7 Moreover, great ad-
vances have recently been made to develop more convenient pro-
Amide bond is a widely prevalent linkage in numerous bioactive
cedures to achieve transformation at relatively lower temperatures
by using activating reagents or catalysts. Several metal species
1
8,9
products, as well as biological and synthetic polymers (i.e., pro-
2
teins and nylons). Amides also act as fundamental building blocks
have been reported to promote transamidation reactions in the last
8
a
8b
8c
for the synthesis of pharmaceuticals, agrochemicals, polymers and
materials.3 Traditional amide formation relies on activation of
a carboxylic acid derivative (acyl halide, anhydride, ester or acid)
using a coupling reagent and subsequent coupling of the activated
species with an amine, but there are limitations, such as using
stoichiometric amounts of coupling reagents, poor atom efficiency,
large quantities of potentially hazardous waste and difficulties in
two decades, including AlCl
3
,
Sc(OTf)
3
,
HfCl
,8g Cp
2 5
O , Mn(II) complex, and Fe(III)-salt.
4
,
lanthanide cat-
8d
8e
8f
8h
alysts,
Ti(NMe
2
)
4
,
Cu(OAc)
2
,
CeO
2
2
ZrCl
2
,
sulfated
In addi-
8
i
8j
8k
8l,m
tungstate, Nb
tion, very recently some metal-free catalysts, such as N,N-dia-
9
a
9b
lkylformamide dimethyl acetals,
imidazole,
hydroxylamine
9
c
9d
9e
9f,9g
hydrochloride, boric acid, ammonium-salt, borate esters,
-proline, hypervalent iodine and benzotriazole as well as
9
h
9i
9j
L
4
9k,l
purification. These drawbacks have promoted the development of
microwave irradiation
have come to the forefront offering
5
numerous alternative amide formation methods in recent years.
enough impetus to improvement. Although the existing methods
have their own advantages, the resulting transamidations suffer
from certain demerits, such as stoichiometric amount of the cata-
lysts, harsh reaction conditions, long reaction times, low
selectivities and limited substrate scopes. Moreover, some of the
catalysts have the difficulties in separation from the reaction mass
and recycling. Therefore there is a clear need for more efficient and
greener methods for transamidation with a broad substrate
suitability.
Amongst various catalytic methods, transamidation of amide with
amine is potentially an attractive alternative tool for the direct
amide bond formation. However, due to the relatively high in-
ertness of the amide bond in contrast with other acyl donors,
transamidation is hindered under thermal and noncatalytic con-
6
ditions. Although lipase-catalyzed transformation has been re-
ported, this protocol requires high substrate specificity, highly
Over the past decades, ionic liquids (ILs) have attracted much
interest as efficient and eco-friendly reaction media and/or cata-
lysts due to their excellent properties such as negligible vapour
*
Corresponding authors. Tel./fax: þ86 512 52251842; e-mail addresses:
yangyangirisjs@126.com (Y. Yang), wangquanlzu@163.com (Q. Wang).
http://dx.doi.org/10.1016/j.tet.2014.10.066
0
040-4020/Ó 2014 Elsevier Ltd. All rights reserved.

R. Fu et al. / Tetrahedron 70 (2014) 9492e9499
9493
pressure, ease of recovery and reuse.10 Amongst them a series of
heteropolyanion-based ILs (HPAILs) have been recently prepared as
hybrid materials by combining Keggin heteropolyanions with ‘task-
11
specific’ ILs (TSILs) cations containing special functional groups.
HPAILs usually have high melting points, thermal stability and
chemical stability owing to the large volume and high valence of
heteropolyanions and hydrogen bonding net-works existing in the
compounds, and that is consistent with the requirements of a solid
acid catalyst. So far, HPAILs have turned out to be an eco-benign,
12
high-efficient and recyclable catalyst for acid-catalyzed or oxi-
13
dative organic transformations due to their advantages, such as
operationally simplicity, no toxicity, easily isolation and reusability.
On the other hand, ‘non-classical’ methods have been developed
in organic synthesis to improve yields, selectivity and experimental
14
conditions during the last few years. Amongst them microwave
MW)-assisted technology has blossomed into a useful tool for
(
a variety of applications in organic synthesis due to their unique
advantages, such as the significant rate enhancements, yield and
selectivity improvements, very simplified ease of manipulation and
Fig. 1. N-Substituted imidazole, pyridine and triethylamine based HPAILs.
15
work-up as well as less environmental polluting processes. Al-
though MW-assisted reactions in organic solvents have developed
rapidly, the focus is now shifted to environmentally friendlier
methods, which explore the using of MW irradiation in conjunction
Table 1
Optimization of the reaction conditions for transamidation of acetamide with
a
aniline
16
with solvent-free conditions or benign reaction media.
Recently, our group has introduced HPAILs as eco-benign and
highly efficient catalysts for condensation between carboxylic acids
17
and amines to obtain amides. We envisioned that HPAILs could
potentially catalyze the transamidation reaction. To the best of our
knowledge, ILs promoted transamidation has not been reported to
date. In our continuing efforts in developing efficient and green
protocols for catalytic methods for amide bonds formation, we wish
to describe herein the first MW-assisted HPAILs catalyzed trans-
amidation of non-activated carboxamides with amines under
solvent-free conditions (Scheme 1).
ꢀ
Yieldb (%)
Entry
Catalyst
Temp (
C)
Time (min)
c
1
2
d
120
120
120
100
140
120
120
120
120
120
120
100
120
120
120
120
120
120
120
1440
1440
50
50
50
50
50
50
50
50
50
50
50
50
50
50
50
0
71
80
65
78
80
72
47
45
38
25
12
<5
75
83
78
72
65
75
c
[MIMPS]
[MIMPS]
[MIMPS]
[MIMPS]
[MIMPS]
[MIMPS]
[MIMPS]
[MIMPS]
[MIMPS]
[MIMPS]
[MIMPS]
[MIMPS]
[MIMPS]
3
3
3
3
3
3
3
3
3
3
3
3
3
PW12
PW12
PW12
PW12
PW12
PW12
PW12
PW12
PW12
PW12
PW12
PW12
O
O
O
O
O
O
O
O
O
O
O
O
40, 2 mol %
40, 2 mol %
40, 2 mol %
40, 2 mol %
40, 3 mol %
40, 1 mol %
40, 2 mol %
40, 2 mol %
40, 2 mol %
40, 2 mol %
40, 2 mol %
40, 2 mol %
3
4
5
6
7
d
8
9
e
1
1
1
1
1
1
1
1
1
1
0f
g
1
2
3
4
5
6
7
8
9
h
i
PMo12
40, 2 mol %
40, 2 mol %
40, 2 mol %
40, 2 mol %
40, 2 mol %
O
40, 2 mol %
[PyPS]
[PyPS]
3
PW12
O
O
3
PMo12
[TEAPS]
[TEAPS]
3
PW12
O
3
PMo12
O
50
50
H
3
PMo12
O
a
Unless otherwise noted, all reactions were carried out with acetamide (2 mmol),
Scheme 1. HPAILs catalyzed amidation reactions developed by our group.
aniline (2.6 mmol) and related catalyst under MW (700 W) and solvent-free
conditions.
b
Isolated yields.
Conventional heating.
Toluene (1.0 mL) was used as solvent.
Xylene (1.0 mL) was used as solvent.
Mesitylene (1.0 mL) was used as solvent.
DMSO (1.0 mL) was used as solvent.
2
. Results and discussions
c
d
e
Our study is mainly focused on N-substituted imidazole, pyri-
f
dine and triethylamine based HPAILs, which have already been
g
12,13,17
used as catalysts for many different organic transformations.
Thus, six structurally related HPAILs (Fig. 1) were prepared
h
H
2
O (1.0 mL) was used as solvent.
i
n-C OH (1.0 mL) was used as solvent.
5 9
H
12a
according to published procedure.
The obtained HPAILs were
characterized and the results were compared with the literature
data.
should be absolutely necessary for the catalyzed transamidation. To
our delight, it was shown that the rate and yield of the reaction
both increased dramatically when MW-assisted heating at 120 C
Initially, transamidation of acetamide with aniline was chosen
as a model system to optimize the catalytic parameters (Table 1).
Firstly, a control experiment was performed with conventional
ꢀ
was utilized in the catalyzed transamidation (Table 1, entry 3). In
ꢀ
ꢀ
ꢀ
heating at 120 C in the absence of any catalyst and additional
addition, lower or higher temperature (100 C or 140 C) was
harmful to the transamidation product (Table 1, entries 4 and 5).
Further, no improvement was observed in the present of more
amount of catalyst (Table 1, entry 6), but a decrease in the catalyst
diminished the yield of the product considerably (Table 1, entry 7).
In order to study the effect of the medium, reactions were carried
solvent and, as expected, the complete lack of reactivity was ob-
served even after a prolonged reaction time of 24 h (Table 1, entry
1
). Whereas addition of 2 mol % amount of [MIMPS]
reaction mixture resulted in the desired transformation product in
1% yield (Table 1, entry 2). The results revealed that the HPAILs
3
PW12O40 to the
7

9494
R. Fu et al. / Tetrahedron 70 (2014) 9492e9499
out in various solvents. It was observed that aromatic hydrocarbon
solvents such as toluene, xylene and mesitylene (Table 1, entries
Table 2
HPAIL catalyzed transamidation of 1 amides with aminesa
ꢀ
8
e10) were found to be better reaction media than polar aprotic
(
DMSO, Table 1, entry 11) or protic solvents (H O, n-C OH, Table
2
5 9
H
1, entries 12 and 13), but a decrease was found in the yield with any
solvent. Afterwards catalytic activities of other related catalysts
prepared before were screened under the same reaction condition
b
Product:temp (oC)/time (min)/yield (%)
(
Table 1, entry 3). It was shown that the catalytic activities of
MIMPS] 40 and [TEAPS] 40 were slightly lower than
PW12 40 (Table 1, entries 3, 15, 17). In the cases of
catalysts combining with different heteropolyanions, the results
demonstrated that PW12 40 was more active than PMo12
HPAILs (Table 1, entries 3, 14e18). Although pure HPA catalyst
40 gave a yield of 75%, its good solubility throughout or-
[
3
PW12
O
3
PW12O
that of [PyPS]
3
O
O
O
40
3a:120/50/83
3b:120/50/85
3c:120/50/90
3d:120/60/81
3
H PW12O
ganic solvents and water made its isolation from the reaction
mixture difficult (Table 1, entry 19). Finally, optimum result was
obtained when the reaction was performed using 2 mol % of
c
3e:120/80/56
3
f:120/60/78
3g:120/40/92
4a:120/50/81
3h:120/60/78
4b:120/50/86
[
PyPS]
3
PW12
O
40 under MW (700 W) and solvent-free condition at
20 C for 50 min affording N-phenylacetamide in 83% yield
Table 1, entry 15).
With the optimized conditions in hand, the substrate scope of
ꢀ
1
(
c
3
i:120/60/85
3j:120/60/75
this HPAILs catalyzed transamidation reaction was explored. As
shown in Table 2, reactions of aliphatic or aromatic primary am-
ides or formamide with a series of aromatic and aliphatic primary
or secondary amines proceeded smoothly and afforded the
desired products in reasonable to excellent yields. In general,
aromatic amines were less reactive than aliphatic amines and
afforded longer reaction times and lower yields (Table 2, 3ae3f vs
4e:120/40/87
5a:140/50/78
4c:120/40/91
4d:120/40/89
4f:120/60/76
5b:140/50/81
c
4
h:120/60/78
6a:140/70/75
4
g:120/50/87
3
8
g, 4a,4b vs 4ce4e, 5a,5b vs 5c, 6a,6b vs 6c,6d, 7a vs 7b, 8ae8g vs
he8j). Aromatic amines bearing substitution with an electron-
5
6
c:140/40/91
d:140/50/88
6c:140/50/86
6
b:140/70/78
donating group (methyl or methoxyl) exhibited higher reactivity
as compared to an electron-withdrawing group (chloro or nitro,
Table 2, 3b,3c vs 3d,3e, 8b,8c vs 8d,8e). Notably, heterocyclic ar-
omatic amines (Table 2, 3f, 8g) reacted well and gave the corre-
sponding product in good yields. Moreover, steric hindrance
appeared to play an important role in the results of the reactions.
The good conversions of benzylic amines (Table 2, 3g, 4c,4d, 6c,
c
c
6e:140/60/77
6f:140/60/78
8a:70/15/88
6g:140/50/76
8
b:70/15/92
8
h,8i) or linear chain amines (Table 2, 4e, 5c, 6d, 7b) to their
7a:140/60/79
c:70/15/90
7b:140/60/91
8d:70/30/84
8h:70/10/92
corresponding amides were observed, but in the case of hindered
primary aliphatic amines (Table 2, 3h, 4f, 6e,6f, 8j,8k) and sec-
ondary amines (Table 2, 3i,3j, 4g,4h, 6g, 8le8n), which are very
poor nucleophiles, longer reaction times and lower yields were
achieved.
8
8e:100/50/68
8i:70/15/89
8f:100/40/77
8j:100/90/80
With regards to the reactivities of the amides, aliphatic amides
(
acetamide, Table 2, 3ae3j, and phenylacetamide, Table 2, 4ae4h),
even the hindered aliphatic amides (isobutyramide, Table 2,
ae5c), were more reactive than aromatic amides (benzamide,
Table 2, 6ae6g) and heteroaromatic amides (nicotinamide, Table 2,
a,7b) in this procedure. Moreover, it was worth mentioning that
8g:100/40/85
5
c
c
8
k:100/45/82
8m:100/45/72
8n:100/45/78
8
l:100/90/75
7
a
the formamide showed high reactivities in this catalyzed trans-
amidation (Table 2, 8ae8n), which may be due to the high elec-
trophilicity of formamide.
In addition, in contrast to most other transamidation methods,
which are limited to primary amides, this HPAILs catalyzed trans-
amidation is applicable to substrate primary, secondary, and even
tertiary amides. As shown in Table 3, transamidation of the sec-
ondary (9ae9c) and tertiary (9de9e) amides.
Reaction condition : amide (2 mmol), amine (2.6 mmol) and
[PyPS] 40 (2 mol %) under MW (700 W) and solvent-free condition.
3
PW12O
Isolated yields.
Sealed tube.
b
c
A further advantage of this HPAILs catalytic system is its re-
usability. Thus, the recycling of the catalyst was examined based on
the optimal conditions for the transamidation of acetamide with
benzylamine (Table 2, 3g). The outstanding feature of the catalyst is
its excellent solubility in water or strong polar solvents but non-
miscibility with apolar esters. After completion of the reaction
(monitored by TLC), EtOAc was added to the reaction mixture. After
vigorous stirring the catalyst can be easily retrieved from the re-
action mixture by simple centrifugation or filtration and drying at
room temperature under reduced pressure. After removal of the
solvent, the pure product was obtained by recrystallization or
In order to further expand the substrate scope, the trans-
amidation of phthalimide was examined with various primary
amines (Table 4). We were delighted to see that all reactions
reacted smoothly to provide the corresponding N-substituted
phthalimides in good to excellent yields. In the cases of aliphatic
ꢀ
amines the reaction could be carried out at 120 C (Table 4, entries 3
and 4). For aromatic amine (Table 4, entries 1 and 2) or more hin-
dered aliphatic amines (Table 4, entry 5) higher temperature and
longer reaction times were required.

R. Fu et al. / Tetrahedron 70 (2014) 9492e9499
9495
Table 3
HPAIL catalyzed transamidation of 2 and 3 amides with aminesa
ꢀ
ꢀ
ꢀ
Yieldb (%)
Entry
Amide
Temp ( C)
Time (min)
1
2
3
4
5
6
7
HCONHMe, 9a
HCONHMe, 9a
HCONHMe, 9a
120
120
120
140
140
140
140
80
80
70
80
80
90
90
8a, 78
8c, 80
8h, 86
3g, 77
3g, 67
8h, 75
3g, 71
CH
CH
3
CONHMe, 9b
CONHPh, 9c
3
HCONMe
CH CONMe
3
2
, 9d
, 9e
2
a
Reaction condition: amide (2 mmol), amine (2.6 mmol) and [PyPS]
2 mol %) under MW (700 W) and solvent-free condition.
Isolated yields.
3 40
PW12O
(
b
Table 4
a
HPAIL catalyzed transamidation of phthalimide with amines
Fig. 2. Plausible mechanism of HPAIL promoted transamidation.
amides and phthalimide with aromatic, aliphatic, cyclic, acyclic,
primary and secondary amines. Considering the economic attrac-
tiveness, operational simplicity, solvent-free media, reusable cata-
lysts and wide functional group tolerance makes the present
protocol a green and efficient alternative for the existing reports on
the synthesis of amides.
ꢀ
Yieldb (%)
Entry
Amine
PhNH
p-MeOC
BnNH
BnCH
1-Phenethylamine
Temp ( C)
Time (min)
1
2
3
4
5
2
140
140
120
120
140
80
80
50
50
80
11a, 82
11b, 83
11c, 93
11d, 91
11e, 71
6 4 2
H NH
2
2
NH
2
a
4. Experimental section
Reaction condition: formamide (2 mmol), amine (2.6 mmol) and
PW12 40 (2 mol %) under MW (700 W) and solvent-free condition.
Isolated yields.
[
PyPS]
3
O
b
4.1. General
chromatography. After this treatment, the recovered catalyst was
Reagent grade solventswereusedforextraction, recrystallization
reused at least five times with a little loss of catalytic efficiency
and flash chromatography. All other commercial reagents were used
as received without additional purification. The progress of re-
actions was checked by analytical thin-layer chromatography (TLC,
silica gel 60 F-254 plates). The plates were visualized first with UV
illumination followed by iodine or phosphomolybdic acid hydrate.
Column chromatography was performed using silica gel (200e300
mesh). NMR spectra were obtained using BRUKER AVANCE III in-
(Table 5), demonstrating the robustness of the catalyst and its
reusability.
Table 5
a
Reusability studies of catalyst for the HPAILs catalyzed transamidation
Number of cycles
Yield (%)
1
92
2
91
3
89
4
87
5
85
1
b
strument. H NMR spectra were recorded at 300 MHz and are re-
ported in parts per million (ppm) on the
tetramethylsilane (TMS) as an internal standard. C NMR spectra
wererecorded at 75 MHz and are reported inparts per million (ppm)
d scale relative to
a
Reaction condition: acetamide (2 mmol), benzylamine (2.6 mmol) and
13
ꢀ
[
PyPS]
3
PW12
O40 (2 mol %) under MW (700 W) and solvent-free condition at 120 C.
b
Isolated yields.
on the
3 6
d scale relative to CDCl (d 77.16) and DMSO-d (d 39.52).
Multiplicities are indicated as the following: s, singlet; d, doublet; t,
triplet; q, quartet; m, multiplet; dd, doubled doublet; td, tripled
doublet; br, broad. Coupling constants (J values) where noted are
quotedin hertz(Hz). ESIhigh-resolution massspectrawereobtained
using Agilent 1260-6210 (TOF LC/MS) instrument. The melting point
was uncorrected.
Although the reaction mechanism has not yet been elucidated,
the nucleophilicities of amines appeared to play an important role
in the transamidation procedure based on the above discussions.
Thus a possible reaction mechanism of HPAILs catalyzed trans-
amidation is shown in Fig. 2. The catalytic cycle starts with the
activation of carbonyl of amide by the coordination with HPAIL.
Amide could be much more active when it is attacked by the nu-
cleophilic amine. The proton-exchange and subsequent de-
amination could produce amide and regenerate the catalyst.
4
.2. General procedure for the synthesis of HPAILs catalysts12a
Methylimidazole (0.11 mol) and 1,3-propane sulfone (0.10 mol)
ꢀ
were dissolved in toluene (30 mL) and stirred for 24 h at 50 C under
a nitrogen atmosphere. A white precipitate 3-(1-methyl)imidazo-
liumpropanesulfonate (MIMPS) formed, which was filtered, washed
with diethyl ether three times, then dried in a vacuum. MIMPS
3
. Conclusion
In summary, we have developed a novel catalytic system for the
transamidation of non-activated carboxamides with amines using
catalytic amounts of HPAILs under MW-assisted and solvent-free
conditions. The substrate scope of the methodology has been
demonstrated by the reactions of primary, secondary, tertiary
3 40
(0.09 mol) was added to an aqueous solution of H PW12O
(0.03mol), and thenthe mixturewasstirredatroomtemperaturefor
24 h. Water was removed in vacuum to give the product [MIM-
3 3 3 40
PS] PW12O40 as a solid. Thus [MIMPS] PMo12O40, [PyPS] PW12O ,

9496
R. Fu et al. / Tetrahedron 70 (2014) 9492e9499
þ
[
PyPS]
3
PMo12
O
40, [TEAPS]
3
PW12
O
40 and [TEAPS]
3
PMo12
O40 were
25.6, 25.0, 23.5; HRMS calcd for C
found: 142.1229.
8
H
16NO (MþH ): 142.1226;
prepared using according starting materials.
4
.3. General procedure for the synthesis of amides
4.3.9. 1-(Piperidin-1-yl)ethanone (3i). Yellow oil. 1H NMR
300 MHz, CDCl 3.55 (br s, 2H), 3.39 (br s, 2H), 2.08 (s, 3H), 1.64
(br s, 2H), 1.55 (br s, 4H); C NMR (75 MHz, CDCl
(
3
) d
13
To a mixture of amide (2 mmol) and amine (2.6 mmol) in
a 10 mL round bottomed flask was added [PyPS]
140 mg, 0.04 mmol). The reaction mixture was stirred at the
3
)
d
168.9, 47.6,
þ
3
PW12
O
40
42.6, 26.5, 25.6, 24.6, 21.6; HRMS calcd for C
128.1070; found: 128.1074.
7
H14NO (MþH ):
(
corresponding temperature under MW (700 W). The progress of
the reaction was monitored by TLC. On completion, the mixture
was diluted with ethyl acetate (20 mL) with stirring for 30 min.
The insoluble catalyst was recovered by filtration or centrifuga-
tion. The filtrate was evaporated and the residue in almost pure
form. Recrystallization or column chromatography could be used
for further purification.
4.3.10. N-Benzyl-N-methylacetamide (3j). The presence of two
rotamers (ratio 1:1.3) was observed in the NMR spectra. Yellow oil.
1
3
H NMR (300 MHz, CDCl ) d 7.40e7.23 (m, 8H), 7.18e7.16 (m, 2H),
4.59 (s, 2H), 4.53 (s, 2H), 2.94 (s, 3H), 2.92 (s, 3H), 2.16 (s, 3H), 2.15
13
3
(s, 3H); C NMR (75 MHz, CDCl ) d 171.0, 170.7, 137.4, 136.6, 129.0,
128.6, 128.0, 127.7, 127.4, 126.3, 54.3, 50.6, 35.5, 33.7, 21.9, 21.5;
þ
HRMS calcd for C10
H
14NO (MþH ): 164.1070; found: 164.1075.
ꢀ
4
.3.1. N-Phenylacetamide (3a). Yellow solid. Mp: 112.8e114.1 C; IR
(
1
CDCl
7
1
1
KBr): 3294, 3261, 3196, 3137, 1665, 1600, 1558, 1500, 1491, 1435,
369, 1324, 1266, 768, 760, 693, 534, 511 cm ; H NMR (300 MHz,
4.3.11. N-Phenyl-2-phenylacetamide (4a). Yellow solid. Mp:
ꢁ1
1
ꢀ
1
110.5e112.8 C; H NMR (300 MHz, CDCl
3
)
d
7.43e7.24 (m, 10H),
169.3,
13
3
)
d
7.83 (br s, 1H), 7.51e7.49 (m, 2H), 7.32e7.26 (m, 2H),
7.07 (t, J¼7.5 Hz, 1H), 3.72 (s, 2H); C NMR (75 MHz, CDCl
3
) d
13
.11e7.06 (m, 1H), 2.15 (s, 3H); C NMR (75 MHz, CDCl
38.1, 129.0, 124.4, 120.2, 24.6; HRMS calcd for C
36.0757; found: 136.0752.
3
)
d
168.9,
137.7, 134.6, 129.6, 129.3, 129.1, 127.8, 124.6, 120.0, 44.9; HRMS calcd
þ
þ
8
H
10NO (MþH ):
for C14H14NO (MþH ): 212.1070; found: 212.1074.
4
.3.12. N-(p-Tolyl)-2-phenylacetamide (4b). Yellow solid. Mp:
ꢀ
ꢀ
1
4
.3.2. N-(p-Tolyl)acetamide (3b). Yellow solid. Mp: 149.4e152.0 C;
124.5e126.0 C; HNMR(300MHz, CDCl )d7.41e7.25(m, 7H), 7.15(br
3
ꢁ1
1
13
IR (KBr): 3421, 1664, 1606, 1550, 1540, 1380, 768 cm
;
H NMR
s,1H), 7.07 (d, J¼8.1Hz, 2H), 3.71(s,2H),2.28(s,3H); CNMR(75MHz,
(
300 MHz, CDCl
3
)
d
7.68 (br s, 1H), 7.37 (d, J¼8.4 Hz, 2H), 7.09 (d,
CDCl
3
)
d
169.1, 135.2,134.7, 134.2,129.7, 129.5, 129.3,127.7, 120.1, 44.9,
13
þ
J¼8.1 Hz, 2H), 2.30 (s, 3H), 2.13 (s, 3H); C NMR (75 MHz, CDCl
3
)
21.0; HRMS calcd for C15
H16NO (MþH ): 226.1226; found: 226.1229.
d
168.7, 135.5, 134.0, 129.5, 120.3, 24.5, 21.0; HRMS calcd for
þ
C
9
H
12NO (MþH ): 150.0913; found: 150.0910.
4.3.13. N-Benzyl-2-phenylacetamide (4c). Yellow solid. Mp:
ꢀ
1
101.4e103.4 C; H NMR (300 MHz, CDCl ) d 7.29e7.14 (m, 8H),
3
4
.3.3. N-(4-Methoxyphenyl)acetamide (3c). Yellow solid. Mp:
7.11e7.08 (m, 2H), 5.74 (br s, 1H), 4.32 (d, J¼5.7 Hz, 2H), 3.54 (s, 2H);
ꢀ
1
13
126.5e128.9 C; H NMR (300 MHz, CDCl
3
)
d
7.68 (br s, 1H),
C NMR (75 MHz, CDCl
3
)
d
171.0, 138.2, 134.9, 129.7, 129.3, 128.9,
13
þ
7.41e7.36 (m, 2H), 6.85e6.80 (m, 2H), 3.77 (s, 3H), 2.12 (s, 3H);
C
128.5, 127.8, 127.4, 43.9, 43.7; HRMS calcd for C15
226.1226; found: 226.1230.
H
16NO (MþH ):
NMR (75 MHz, CDCl
HRMS calcd for C
3
)
d
168.7, 156.5, 131.2, 122.1, 114.2, 55.6, 24.3;
þ
9
H
12NO
2
(MþH ): 166.0863; found: 166.0866.
4
.3.14. N-(Furan-2-ylmethyl)-2-phenylacetamide (4d). Yellow solid.
ꢀ
1
4.3.4. N-(4-Chlorophenyl)acetamide (3d). Yellow solid. Mp:
Mp: 123.4e124.5 C; H NMR (300 MHz, CDCl
3
)
d
7.39e7.25 (m,
ꢀ
1
133.5e135.1 C; H NMR (300 MHz, DMSO-d
6
)
d
10.06 (s, 1H),
6H), 6.29 (dd, J¼3.0, 1.8 Hz, 1H), 6.14 (dd, J¼3.3, 0.6 Hz, 1H), 5.72 (br
13
13
7.63e7.58 (m, 2H), 7.35e7.30 (m, 2H), 2.104 (s, 3H); C NMR
s, 1H), 4.40 (d, J¼5.7 Hz, 2H), 3.61 (s, 2H); C NMR (75 MHz, CDCl
3
)
(
75 MHz, DMSO-d
6
)
d
168.4, 138.3, 128.6, 126.5, 120.5, 24.0; HRMS
d
170.8,151.3, 142.2,134.8,129.5,129.0,127.4, 110.5,107.3, 43.7, 36.7;
þ
þ
calcd for C
H
8 9
ClNO (MþH ): 170.0367; found: 170.0371.
HRMS calcd for C13
H14NO
2
(MþH ): 216.1019; found: 216.1014.
4
2
.3.5. N-(4-Nitrophenyl)acetamide
(3e). Yellow
solid.
Mp:
4.3.15. N-Octyl-2-phenylacetamide
(4e). Yellow
117.5e119.9 C; H NMR (300 MHz, CDCl 7.39e7.24 (m, 5H), 5.43
(br s, 1H), 3.57 (s, 2H), 3.19 (q, J¼6.9 Hz, 2H), 1.45e1.36 (m, 2H), 1.23
solid.
Mp:
ꢀ
ꢀ
1
07.8e208.9 C; IR (KBr): 3303, 1698, 1681, 1620, 1590, 1506, 1346,
3
) d
ꢁ
1 1
1333, 1312, 1301 cm ; H NMR (300 MHz, DMSO-d
6
) d 10.57 (br s,
13
13
1
H), 8.23e8.18 (m, 2H), 7.84e7.79 (m, 2H), 2.11 (s, 3H); C NMR
(m, 10H), 0.87 (t, J¼6.9 Hz, 3H); C NMR (75 MHz, CDCl
3
) d 171.0,
(
75 MHz, DMSO-d
6
)
d
169.4, 145.5, 142.0, 125.0, 118.6, 24.3; HRMS
135.2, 129.5, 129.0, 127.3, 44.0, 39.8, 31.8, 29.5, 29.3, 29.2, 26.9, 22.7,
þ
þ
calcd for C
H
8 9
N
2
O
3
(MþH ): 181.0608; found: 181.0603.
14.1;HRMScalcd for C16
H26NO(MþH ):248.2009;found:248.2010.
4
9
.3.6. N-(Pyridin-2-yl)acetamide
5.4e97.1 C; H NMR (300 MHz, CDCl
(3f). White
solid.
Mp:
4.3.16. N-(1-Phenylethyl)-2-phenylacetamide (4f). Yellow solid. Mp:
ꢀ
1
ꢀ
1
3
)
d
9.48 (s, 1H), 8.28e8.24
97.3e99.3 C; H NMR (300 MHz, CDCl ) d 7.38e7.15 (m, 10H), 5.62
3
1
3
(
m, 2H), 7.73 (td, J¼8.0, 1.8 Hz, 1H), 7.08e7.03 (m, 1H), 2.21 (s, 3H);
(br s, 1H), 5.17e5.07 (m, 1H), 3.58 (s, 2H), 1.39 (d, J¼6.9 Hz, 3H);
C
1
3
C NMR (75 MHz, CDCl
4.7; HRMS calcd for C
3
)
d
169.1, 151.9, 147.5, 138.7, 119.7, 114.6,
O (MþH ): 137.0709; found: 137.0711.
NMR (75 MHz, CDCl
3
)
d
170.4, 143.1, 135.0, 129.5, 129.1, 128.7, 128.6,
þ
þ
2
7
H
9
N
2
127.4, 126.1, 48.9, 43.9, 21.9; HRMS calcd for C16
40.1383; found: 240.1387.
H
18NO (MþH ):
2
.3.7. N-Benzylacetamide (3g). Yellow solid. Mp: 55.4e57.1 C; 1
7.35e7.25 (m, 5H), 6.05 (br s, 1H), 4.40 (d,
ꢀ
H
4
NMR (300 MHz, CDCl
3
)
d
4.3.17. 2-Phenyl-1-(piperidin-1-yl)ethanone (4g). Yellow oil. 1H
NMR (300 MHz, CDCl 7.34e7.20 (m, 5H), 3.73 (s, 2H), 3.59e3.55
(m, 2H), 3.39e3.35 (m, 2H), 1.62e1.48 (m, 4H), 1.38e1.30 (m, 2H);
13
J¼5.4 Hz, 2H), 1.99 (d, J¼0.9 Hz, 3H); C NMR (75 MHz, CDCl
3
)
3
) d
d
170.1, 138.3, 128.8, 127.9, 127.6, 43.8, 23.3; HRMS calcd for
þ
13
C
9
H
12NO (MþH ): 150.0913; found: 150.0910.
C NMR (75 MHz, CDCl
3
)
d
169.3, 135.5, 128.7, 128.6, 126.7, 47.3,
þ
42.9, 41.2, 26.2, 25.5, 24.5; HRMS calcd for C13
H18NO (MþH ):
1
4
.3.8. N-Cyclohexylacetamide (3h). Yellow oil. H NMR (300 MHz,
CDCl 5.83 (br s, 1H), 3.76e3.65 (m, 1H), 1.93 (s, 3H), 1.89e1.86
m, 2H), 1.69e1.66 (m, 2H), 1.60e1.57 (m, 1H), 1.37e1.23 (m, 2H),
.16e1.05 (m, 3H); 13C NMR (75 MHz, CDCl
169.3, 48.3, 33.2,
204.1383; found: 204.1387.
3
) d
(
1
4.3.18. N-Benzyl-N-methyl-2-phenylacetamide (4h). The presence
of two rotamers (ratio 1:1.3) was observed in the NMR spectra. Oil.
3
)
d

R. Fu et al. / Tetrahedron 70 (2014) 9492e9499
9497
1H NMR (300 MHz, CDCl
.61 (s, 2H), 4.53 (s, 2H), 3.79 (s, 2H), 3.76 (s, 2H), 2.95 (s, 3H), 2.90
s, 3H); 13C NMR (75 MHz, CDCl
171.5, 171.2, 137.3, 136.5, 135.1,
35.0, 129.0, 128.9, 128.8, 128.7, 128.6, 128.5, 128.1, 127.7, 127.4,
)
d
7.48e7.28 (m, 18H), 7.11e7.08 (m, 2H),
7.52e7.32 (m, 7H), 7.31e7.26 (m, 1H), 6.38 (br s, 1H), 5.39e5.29
3
13
4
(
1
(m, 1H), 1.61 (d, J¼6.9 Hz, 3H); C NMR (75 MHz, CDCl
3
) d 166.7,
3
)
d
143.3, 134.8, 131.6, 128.9, 128.7, 127.6, 127.1, 126.4, 49.4, 21.9; HRMS
þ
calcd for C15
H
16NO (MþH ): 226.1226; found: 226.1229.
1
C
26.9, 126.8, 126.4, 53.7, 51.0, 41.2, 41.0, 35.3, 34.1; HRMS calcd for
þ
16
H18NO (MþH ): 240.1383; found: 240.1385.
4.3.28. Phenyl(piperidin-1-yl)methanone (6g). Yellow solid. Mp:
ꢀ
1
1
08.3e109.5 C; H NMR (300 MHz, CDCl
3
) d 7.39 (br s, 5H), 3.71 (br
13
4
1
(
.3.19. N-Phenylisobutyramide
(5a). Yellow
15.3e117.5 C; H NMR (300 MHz, CDCl 7.55e7.53 (m, 2H), 7.47
br s, 1H), 7.33e7.27 (m, 2H), 7.11e7.06 (m, 1H), 7.59e7.45 (m, 1H),
solid.
Mp:
s, 2H), 3.34 (br s, 2H),1.67 (br s, 4H),1.51 (br s, 2H); C NMR (75 MHz,
ꢀ
1
3
)
d
CDCl
HRMS calcd for C12
3
)
d
170.3, 136.5, 129.3, 128.4, 126.8, 48.7, 43.1, 26.5, 25.6, 24.6;
þ
H16NO (MþH ): 190.1226; found: 190.1230.
13
1
1
1
.24 (d, J¼6.9 Hz, 6H); C NMR (75 MHz, CDCl
23.2, 119.0, 35.8, 18.7; HRMS calcd for C10
64.1070; found: 164.1073.
3
)
d
174.5,137.2,128.0,
þ
H14NO (MþH ):
4.3.29. N-(p-Tolyl)nicotinamide
(7a). Yellow
164.3e166.2 C; H NMR (300 MHz, CDCl
9.08 (d, J¼1.8 Hz, 1H),
.77 (dd, J¼4.8,1.5 Hz,1H), 8.21 (dt, J¼7.8, 1.8 Hz,1H), 7.89 (br s, 1H),
7.52 (d, J¼8.4 Hz, 2H), 7.44 (dd, J¼7.8, 0.9 Hz, 1H), 7.19 (d, J¼8.4 Hz,
solid.
Mp:
ꢀ
1
3
) d
8
4
1
7
.3.20. N-(p-Tolyl)isobutyramide
(5b). Yellow
09.3e110.1 C; H NMR (300 MHz, CDCl
7.41 (d, J¼8.4 Hz, 2H),
.26 (br s, 1H), 7.11 (d, J¼8.1 Hz, 2H), 2.56e2.43 (m, 1H), 2.31 (s, 3H),
solid.
Mp:
ꢀ
1
13
3
)
d
3
2H), 2.35 (s, 3H); C NMR (75 MHz, CDCl ) d 164.2, 152.2, 148.1,
135.5, 135.1, 134.8, 131.0, 129.7, 123.6, 120.9, 21.0; HRMS calcd for
13
þ
1
.24 (d, J¼6.6 Hz, 6H); C NMR (75 MHz, CDCl
3
)
d
175.3, 135.6,
C
13
H
13
N
2
O (MþH ): 213.1022; found: 213.1026.
133.8, 129.5, 120.0, 36.7, 21.0, 19.8; HRMS calcd for C11
H16NO
þ
(
MþH ): 178.1226; found: 178.1231.
4.3.30. N-Phenethylnicotinamide
1
(7b). Yellow
32.5e134.1 C; H NMR (300 MHz, CDCl
8.86 (d, J¼1.8 Hz, 1H),
8.65 (dd, J¼4.8, 1.5 Hz, 1H), 8.07 (dt, J¼8.1, 1.8 Hz, 1H), 7.38e7.21 (m,
solid.
Mp:
ꢀ
1
3
) d
4
8
.3.21. N-Phenethylisobutyramide
8.9e90.2 C; H NMR (300 MHz, CDCl
(5c). Yellow
solid.
Mp:
ꢀ
1
13
3
)
d
7.34e7.17 (m, 5H), 5.62
6H), 6.62 (br s, 1H), 3.72 (q, J¼6.9 Hz, 2H), 2.94 (t, J¼6.9 Hz, 2H);
NMR (75 MHz, CDCl
C
(
(
1
C
br s, 1H), 5.27 (q, J¼6.9 Hz, 2H), 2.81 (t, J¼6.9 Hz, 2H), 2.36e2.22
3
)
d
165.7, 152.0, 147.7, 138.7, 135.4, 130.5, 128.9,
13
þ
m, 1H), 1.11 (d, J¼6.9 Hz, 6H); C NMR (75 MHz, CDCl
3
)
d
177.0,
128.8, 126.8, 123.6, 41.4, 35.6; HRMS calcd for C14
227.1179; found: 227.1181.
H
15
N
2
O (MþH ):
39.1, 128.9, 128.7, 126.6, 40.5, 35.8, 35.7, 19.7; HRMS calcd for
þ
12
H
18NO (MþH ): 192.1383; found: 192.1384.
4.3.31. N-Phenylformamide (8a). The presence of two rotamers
ꢀ
4
.3.22. N-Phenylbenzamide (6a). Yellow solid. Mp: 164.2e166.6 C;
(ratio 1:1.1) was observed in the NMR spectra. White solid. Mp:
ꢀ
IR (KBr): 3346, 1657, 1601, 1579, 1536, 1493, 1449, 1440, 1329, 1301,
48.1e50.6 C; IR (KBr): 3300, 2877, 1650, 1540, 1438, 1403,
ꢁ1
1
1290 cm ; 1H NMR (300 MHz, CDCl
ꢁ1
1
262, 760, 716, 692, 683 cm ; H NMR (300 MHz, CDCl
3
)
d
7.93 (br
3
)
d
8.69 (br s, 2H), 8.36 (d,
s, 1H), 7.88e7.84 (m, 2H), 7.66e7.62 (m, 2H), 7.56e7.43 (m, 3H),
J¼1.5 Hz, 1H), 7.79 (br s, 1H), 7.55 (d, J¼7.5 Hz, 2H), 7.38e7.30 (m,
13
13
7
.39e7.33 (m, 2H), 7.18e7.12 (m, 1H); C NMR (75 MHz, CDCl
3
)
3
4H), 7.21e7.09 (m, 4H); C NMR (75 MHz, CDCl ) d 163.0, 159.4,
d
165.9, 138.0, 135.1, 132.0, 129.2, 128.9, 127.2, 124.7, 120.4; HRMS
137.0, 136.9, 129.8, 129.2, 125.4, 124.9, 120.2, 118.9; HRMS calcd for
þ
þ
calcd for C13
H12NO (MþH ): 198.0913; found: 198.0916.
C
7
H
8
NO (MþH ): 122.0600; found: 122.0603.
4
1
.3.23. N-(p-Tolyl)benzamide
(6b). Yellow
solid.
7.91 (br s, 1H),
Mp:
4.3.32. N-p-Tolylformamide (8b). The presence of two rotamers
(ratio 1:1) was observed in the NMR spectra. White solid. Mp:
52.2e153.5 C; 1H NMR (300 MHz, CDCl
ꢀ
)
d
3
ꢀ
ꢁ1 1
7
3
.87e7.82 (m, 2H), 7.55e7.42 (m, 5H), 7.15 (d, J¼8.4 Hz, 2H), 2.33 (s,
51.5e53.3 C; IR (KBr): 3030, 1688, 1615, 1519, 1303 cm ; H NMR
(300 MHz, CDCl
8.63 (d, J¼11.1 Hz, 1H), 8.52 (br s, 1H), 8.33 (d,
J¼1.5 Hz, 1H), 7.65 (br s, 1H), 7.42 (d, J¼8.4 Hz, 2H), 7.14 (t, J¼8.4 Hz,
13
H); C NMR (75 MHz, CDCl
3
)
d
165.8, 135.5, 135.2, 134.3, 131.8,
3
) d
þ
129.7, 128.8, 127.1, 120.5, 21.0; HRMS calcd for C14
H14NO (MþH ):
13
212.1070; found: 212.1075.
4H), 6.99 (d, J¼8.4 Hz, 2H); C NMR (75 MHz, CDCl
3
) d 163.0, 159.2,
1
35.2, 134.6, 134.5, 134.2, 130.3, 129.7, 120.2, 119.2, 21.0, 20.9; HRMS
ꢀ
þ
4
.3.24. N-Benzylbenzamide (6c). Yellow solid. Mp: 120.2e122.5 C;
calcd for C
8
H
10NO (MþH ): 136.0757; found: 136.0761.
1
H NMR (300 MHz, CDCl
3
) d 7.82e7.77 (m, 2H), 7.52e7.29 (m, 8H),
.53 (br s, 1H), 4.66e4.61 (m, 2H); C NMR (75 MHz, CDCl
13
6
3
)
d
167.5,
4.3.33. N-(4-Methoxyphenyl)formamide (8c). The presence of two
1
38.3, 134.5, 131.7, 128.9, 128.7, 128.0, 127.7, 127.1, 44.2; HRMS calcd
rotamers (ratio 1:1) was observed in the NMR spectra. Brown solid.
þ
ꢀ
for C14
H14NO (MþH ): 212.1070; found: 212.1074.
Mp: 76.5e79.4 C; IR (KBr): 3246, 3052, 2890, 2939, 2363, 1660,
ꢁ
1
1
1
511,1238 cm ; H NMR (300 MHz, CDCl
3
)
d
8.51 (d, J¼11.4 Hz,1H),
4.3.25. N-Phenethylbenzamide
(6d). Yellow
solid.
Mp:
8.31 (d, J¼1.8 Hz, 1H), 8.21 (br d, J¼10.5 Hz, 1H), 7.53 (br s 1H),
ꢀ
1
133.4e136.1 C; H NMR (300 MHz, CDCl
3
)
d
7.69 (d, J¼7.2 Hz, 2H),
7.47e7.42 (m, 2H), 7.07e7.02 (m, 2H), 6.91e6.83 (m, 4H), 3.80 (s,
13
7
.50e7.22 (m, 8H), 6.27 (br s, 1H), 3.71 (q, J¼6.9 Hz, 2H), 2.93 (t,
3
3H), 3.79 (s, 3H); C NMR (75 MHz, CDCl ) d 163.3, 159.1, 157.8,
13
J¼6.9 Hz, 2H); C NMR (75 MHz, CDCl
3
)
d
167.6, 139.0, 134.8, 131.5,
156.8, 130.1, 129.7, 121.9, 121.8, 115.0, 114.3, 55.7, 55.6; HRMS calcd
þ
128.9,128.8,128.6,126.9,126.7, 41.3, 35.8; HRMS calcd for C15
H16NO
for C
8
H10NO
2
(MþH ): 152.0706; found: 152.0709.
þ
(
MþH ): 226.1226; found: 226.1229.
4.3.34. N-(4-Chlorophenyl)formamide (8d). The presence of two
4
.3.26. N-Cyclohexylbenzamide
(6e). Yellow
solid.
Mp:
rotamers(ratio1:1.3) was observed in the NMR spectra. Yellowsolid.
ꢀ
1
ꢀ
ꢁ1 1
150.1e153.0 C; H NMR (300 MHz, CDCl
3
)
d
7.74 (d, J¼6.9 Hz, 2H),
Mp: 104.3e106.4 C; IR (KBr): 3258,1680,1671,1607,1543 cm ; H
NMR (300 MHz, CDCl
8.78 (br s, 1H), 8.66 (d, J¼11.4 Hz, 1H), 8.36
(br s, 1H), 7.89 (br s, 1H), 7.59 (br s, 1H), 7.50 (d, J¼8.7 Hz, 2H),
7.48e7.37 (m, 3H), 6.13 (br s, 1H), 4.02e3.91 (m, 1H), 2.02e1.98 (m,
3
) d
2
1
H), 1.76e1.71 (m, 2H), 1.67e1.61 (m, 1H), 1.49e1.34 (m, 2H),
166.7, 135.2, 131.3,
.27e1.16 (m, 3H); 13C NMR (75 MHz, CDCl
)
d
7.34e7.26 (m, 4H), 7.05 (d, J¼8.7 Hz, 2H); C NMR (75 MHz, CDCl
13
3
3
)
128.6, 126.9, 48.8, 33.3, 25.7, 25.0; HRMS calcd for C13
H
18NO
d
162.8, 159.3, 135.5, 135.4, 130.8, 130.0, 129.2, 126.0, 121.4, 120.2;
þ
þ
(
MþH ): 204.1383; found: 204.1386.
HRMS calcd for C
7
H
7
ClNO (MþH ): 156.0211; found: 156.0215.
4
.3.27. N-(1-Phenylethyl)benzamide
(6f). Yellow
solid.
Mp:
4.3.35. N-(4-Nitrophenyl)formamide (8e). The presence of two
rotamers(ratio3.3:1) was observed in the NMR spectra. Yellowsolid.
ꢀ
1
124.5e126.3 C; H NMR (300 MHz, CDCl
3
)
d
7.77 (d, J¼6.9 Hz, 2H),

9498
R. Fu et al. / Tetrahedron 70 (2014) 9492e9499
ꢀ
1H), 7.20e7.16 (m, 2H), 3.33 (s, 3H); 13C NMR (75 MHz, CDCl
)
3
Mp: 193.5e195.8 C; IR (KBr): 3248, 3050, 2941, 2367, 1660, 1541,
ꢁ1 1
1
235 cm ; H NMR (300 MHz, DMSO-d
6
)
d
10.82 (br s,1H),10.71 (d,
d
162.5, 142.3, 129.7, 126.5, 122.5, 32.2; HRMS calcd for C
8
H10NO
þ
J¼10.8 Hz, 1H), 9.05 (d, J¼10.5 Hz, 1H), 8.40 (br s, 1H), 8.23e8.17 (m,
(MþH ): 136.0757; found: 136.0755.
2
2
.5H), 7.93 (d, J¼8.7 Hz, 0.5H), 7.81 (d, J¼8.7 Hz, 2H), 7.41 (d, J¼8.7 Hz,
13
H), 6.73 (br s, 0.5H), 6.59 (d, J¼9.0 Hz, 0.5H); C NMR (75 MHz,
4.3.43. N-Benzyl-N-methylformamide (8m). The presence of two
1
DMSO-d
calcd for C
6
)
d
162.8,160.5,144.2,142.5,125.5,125.1,119.0,116.6; HRMS
rotamers (ratio 4:3) was observed in the NMR spectra. Yellow oil. H
þ
7
H
7
N
2
O
3
(MþH ): 167.0451; found: 167.0455.
NMR (300 MHz, CDCl
0H), 4.52 (s, 2H), 4.39 (s, 2H), 2.84 (s, 3H), 2.78 (s, 3H); C NMR
(75 MHz, CDCl 162.8, 162.6, 136.1, 135.9, 129.0, 128.8, 128.3,
3
) d 8.29 (s, 1H), 8.16 (s, 1H), 7.40e7.19 (m,
13
1
4
.3.36. N-(Naphthalen-1-yl)formamide (8f). The presence of two
3
) d
rotamers (ratio 5:2) was observed in the NMR spectra. White solid.
128.2, 127.7, 127.5, 53.5, 47.8, 34.1, 29.5; HRMS calcd for C
(MþH ): 150.0913; found: 150.0915.
9
H
12NO
ꢀ
þ
Mp: 125.8e127.3 C; IR (KBr): 3226, 1578, 1538, 1504, 1396, 1270,
ꢁ
1 1
7
90 cm ; H NMR (300 MHz, CDCl
J¼11.1 Hz,1H), 8.60 (br s,1H), 8.05 (d, J¼7.8 Hz,1H), 7.99 (d, J¼7.5 Hz,
H), 7.91e7.85 (m, 2H), 7.79 (d, J¼8.4 Hz, 1H), 7.71 (d, J¼8.1 Hz, 1H),
3
)
d
9.10 (d, J¼9.6 Hz,1H), 8.64 (d,
4.3.44. Piperidine-1-carbaldehyde (8n). Colourless oil. IR (KBr):
ꢁ
1 1
1
7
d
2940, 2860, 1588, 1441, 1400, 1369, 1348, 1328, 1280, 1118 cm ; H
NMR (300 MHz, CDCl
8.00 (br s, 1H), 3.48 (t, J¼5.7 Hz, 2H), 3.32
(t, J¼5.7 Hz, 2H), 1.74e1.66 (m, 2H), 1.62e1.51 (m, 4H); C NMR
(75 MHz, CDCl 160.8, 46.8, 40.7, 26.6, 25.1, 24.8; HRMS calcd for
1
3
.62e7.43 (m, 3H), 7.31 (d, J¼7.2 Hz, 1H); C NMR (75 MHz, CDCl
3
)
3
) d
13
164.5,160.0,134.3,134.1,132.4,131.1,128.9,128.6,127.8,127.1,127.0,
1
26.9, 126.9, 126.3, 126.2, 125.8, 125.6, 121.5, 121.0, 120.6, 119.0;
3
) d
þ
þ
HRMS calcd for C11
H10NO (MþH ): 172.0757; found: 172.0759.
C
6
H
12NO (MþH ): 114.0913; found: 114.0916.
4
.3.37. N-(Pyridin-2-yl)formamide (8g). The presence of two
4.3.45. 2-Phenylisoindoline-1,3-dione (11a). Yellow solid. Mp:
ꢀ
1
rotamers (ratio 1.2:1) was observed in the NMR spectra. Yellow
solid. Mp: 34.1e36.5 C; IR (KBr): 3197, 2852,1691,1595,1433,1303,
165.5e167.3 C; H NMR (300 MHz, CDCl
7.80e7.77 (m, 2H), 7.54e7.45 (m, 2H), 7.43e7.38 (m, 3H); C NMR
3
) d 7.97e7.94 (m, 2H),
ꢀ
13
ꢁ
1 1
7
(
8
78, 517 cm ; H NMR (300 MHz, CDCl
br s, 1H), 9.34 (d, J¼10.8 Hz, 1H), 8.32 (br s, 1H), 8.55 (s, 1H),
.36e8.33 (m, 1H), 8.28 (d, J¼8.4 Hz, 1H), 7.76 (td, J¼8.0, 1.8 Hz, 1H),
.69 (td, J¼7.8,1.8 Hz,1H), 7.137e7.06 (m, 2H), 6.96 (d, J¼8.1 Hz,1H);
3
)
d
10.40 (br s, 1H), 10.21
(75 MHz, CDCl
HRMS calcd for C14
3
)
d
167.4,134.5,131.9,131.8,129.2,128.2,126.7,123.9;
þ
H10NO
2
(MþH ): 224.0706; found: 224.0708.
7
4.3.46. 2-(4-Methoxyphenyl)isoindoline-1,3-dione
(11b). Yellow
7.96e7.93
(m, 2H), 7.80e7.77 (m, 2H), 7.36e7.31 (m, 2H), 7.05e7.00 (m, 2H),
1
3
ꢀ
1
C NMR (75 MHz, CDCl
3
)
d
163.2, 159.7, 151.2, 151.1, 148.6, 147.5,
solid. Mp: 156.5e158.3 C; H NMR (300 MHz, CDCl ) d
3
139.0, 138.8, 120.3, 119.9, 115.3, 110.6; HRMS calcd for C
6
H
7
N
2
O
þ
13
(
MþH ): 123.0553; found: 123.0556.
3.85 (s, 3H); C NMR (75 MHz, CDCl
1
3
)
d
167.7, 159.4, 134.5, 132.0,
þ
28.1, 124.4, 123.8, 114.6, 55.7; HRMS calcd for C15
254.0812; found: 254.0814.
H12NO
3
(MþH ):
4
.3.38. N-Benzylformamide (8h). The presence of two rotamers
(
ratio 5.5:1) was observed in the NMR spectra. White solid. Mp:
ꢀ
ꢁ1 1
6
d
2
CDCl
4
0.4e62.8 C; IR (KBr): 1650 (C]O) cm ; H NMR (300 MHz, CDCl
3
)
4.3.47. 2-Benzylisoindoline-1,3-dione (11c). Yellow solid. Mp:
ꢀ
1
8.19 (s, 1H), 8.11 (d, J¼12.0 Hz, 1H), 7.39e7.22 (m, 10H), 6.34 (br s,
138.4e139.9 C; H NMR (300 MHz, CDCl
3
) d 7.87e7.81 (m, 2H),
13
H), 4.43 (d, J¼6.0 Hz, 2H), 4.37 (d, J¼6.3 Hz, 2H); C NMR (75 MHz,
7.72e7.67 (m, 2H), 7.45e7.42 (m, 2H), 7.34e7.23 (m, 3H), 4.85 (s,
1
3
3
)
d
164.8,161.2,137.7,129.0,128.8,128.0,127.8,127.7,127.0, 45.7,
2H); C NMR (75 MHz, CDCl
3
)
d
168.2, 136.5, 134.1, 132.2, 128.8,
þ
þ
2.2; HRMS calcd for C
8
H10NO (MþH ): 136.0757; found: 136.0762.
128.7, 127.9, 123.5, 41.7; HRMS calcd for C15
38.0863; found: 238.0867.
H12NO
2
(MþH ):
2
4
.3.39. N-(Furan-2-ylmethyl)formamide (8i). The presence of two
1
rotamers (ratio 5:1) was observed in the NMR spectra. Yellow oil. H
NMR (300 MHz, CDCl
4.3.48. 2-Phenethylisoindoline-1,3-dione (11d). Yellow solid. Mp:
ꢀ
1
3
)
d
8.20 (s, 1H), 8.15 (d, J¼12.0 Hz, 1H), 7.39
126.4e128.6 C; H NMR (300 MHz, CDCl
3
) d 7.84e7.81 (m, 2H),
(
4
2
dd, J¼1.8, 0.6 Hz, 1H), 7.36 (dd, J¼1.8, 0.6 Hz, 1H), 6.45e6.32 (m,
7.71e7.68 (m, 2H), 7.31e7.19 (m, 5H), 3.92 (t, J¼7.8 Hz, 2H), 2.99 (t,
1
3
H), 6.25e6.24 (m, 2H), 4.47 (d, J¼6.0 Hz, 2H), 4.37 (d, J¼6.6 Hz,
J¼7.8 Hz, 2H); C NMR (75 MHz, CDCl
3
) d 168.3, 138.1, 134.0, 132.2,
1
3
H); C NMR (75 MHz, CDCl
3
)
d
164.8, 161.1, 150.9, 150.8, 142.9,
NO
129.0, 128.7, 126.8, 123.3, 39.4, 34.7; HRMS calcd for C16
(MþH ): 252.1019; found: 252.1022.
H14NO
2
þ
142.4, 110.6, 110.5, 107.7, 107.6, 39.0, 35.1; HRMS calcd for C
6
H
8
2
þ
(
MþH ): 126.0550; found: 126.0554.
4
.3.49. 2-(1-Phenylethyl)isoindoline-1,3-dione (11e). Yellow solid.
ꢀ
1
4
.3.40. N-(1-Phenylethyl)formamide (8j). The presence of two
Mp: 85.8e88.9 C; H NMR (300 MHz, CDCl
3
) d 7.82e7.77 (m,
1
rotamers (ratio 5:1) was observed in the NMR spectra. Yellow oil. H
NMR (300 MHz, CDCl
2H), 7.69e7.65 (m, 2H), 7.52e7.50 (m, 2H), 7.36e7.23 (m, 3H),
13
3
)
d
8.13 (d, J¼12.0 Hz, 1H), 8.12 (s, 1H),
5.57 (q, J¼7.5 Hz, 1H), 1.93 (d, J¼7.5 Hz, 3H); C NMR (75 MHz,
7.39e7.24 (m, 10H), 6.39 (br s, 1H), 6.17 (br s,1H), 5.24e5.14 (m, 1H),
CDCl
3
)
d
168.2, 140.4, 134.0, 132.1, 128.6, 127.8, 127.5, 123.2, 49.7,
1
3
þ
4
.72e4.62 (m, 1H), 1.55 (d, J¼6.9 Hz, 3H), 1.50 (d, J¼6.9 Hz, 3H);
C
17.6; HRMS calcd for C16
252.1023.
H
14NO
2
(MþH ): 252.1019; found:
3
NMR (75 MHz, CDCl ) d
164.3, 160.4, 142.9, 142.7, 129.0, 128.8, 127.9,
1
27.6, 126.2, 125.9, 51.8, 47.7, 29.8, 21.8; HRMS calcd for C
9
H12NO
þ
(
MþH ): 150.0913; found: 150.0918.
Acknowledgements
4
.3.41. N-tert-Butylformamide (8k). The presence of two rotamers
Financial support from the National Natural Science Foundation
of China (21302013, 51203013), the Natural Science Foundation of
Jiangsu Province (BK2012207), the Natural Science Foundation of
Jiangsu Educational Department (12KJB150001, 12KJB610001), the
Foundation of Jiangsu Laboratory of Advanced Functional Material
(12KFJJ008), the Key University Science Research Project of Jiangsu
Province (12KJA150001), the Prospective Joint Research Project of
Jiangsu Province (BY2013041), the China Postdoctoral Science
Foundation (20100480990).
1
(
(
6
(
ratio 1:1) was observed in the NMR spectra. Yellow oil. H NMR
300 MHz, CDCl
8.22 (d, J¼12.3 Hz, 1H), 7.98 (d, J¼1.5 Hz, 1H),
.51 (br s, 1H), 5.62 (br s, 1H), 1.34 (s, 9H), 1.30 (s, 9H); C NMR
75 MHz, CDCl 163.2, 160.7, 51.4, 50.4, 30.0, 29.0; HRMS calcd for
3
) d
13
3
) d
þ
C
5
H
12NO (MþH ): 102.0913; found: 102.0918.
4
(
.3.42. N-Methyl-N-phenylformamide (8l). Yellow oil. 1H NMR
300 MHz, CDCl 8.49 (s, 1H), 7.46e7.39 (m, 2H), 7.31e7.26 (m,
3
) d

R. Fu et al. / Tetrahedron 70 (2014) 9492e9499
9499
Supplementary data
M. A. H.; Kon, K.; Shimizu, K. Tetrahedron Lett. 2014, 55, 1316e1319; (m) Be-
cerra-Figueroa, L.; Ojeda-Porras, A.; Gamba-Sanchez, D. J. Org. Chem. 2014, 79,
4
544e4552.
Characterization data and copies of the 1H NMR and 13C NMR
spectra for all final products can be found. Supplementary data
associated with this article can be found in the online version, at
http://dx.doi.org/10.1016/j.tet.2014.10.066.
9
. For representative examples of metal-free catalyzed transamidation, see: (a)
Dineen, T. A.; Zajac, M. A.; Myers, A. G. J. Am. Chem. Soc. 2006, 128,
1
6406e16409; (b) Such yꢀ , M.; Elmehriki, A. A. H.; Hudson, R. H. E. Org. Lett. 2011,
13, 3952e3955; (c) Allen, C. L.; Atkinson, B. N.; Williams, J. M. J. Angew. Chem.,
Int. Ed. 2012, 51, 1383e1386; (d) Nguyen, T. B.; Sorres, J.; Tran, M. Q.; Ermolenko,
L.; Al-Mourabit, A. Org. Lett. 2012, 14, 3202e3205; (e) Shimizu, Y.; Morimoto,
H.; Zhang, M.; Ohshima, T. Angew. Chem., Int. Ed. 2012, 51, 8564e8567; (f)
Starkov, P.; Sheppard, T. D. Org. Biomol. Chem. 2011, 9, 1320e1323; (g) Lanigan,
R. M.; Starkov, P.; Sheppard, T. D. J. Org. Chem. 2013, 78, 4512e4523; (h) Rao, S.
N.; Mohan, D. C.; Adimurthy, S. Org. Lett. 2013, 15, 1496e1499; (i) Vanjari, R.;
Allam, B. K.; Singh, K. N. RSC Adv. 2013, 3, 1691e1694; (j) Nguyen, T. B.; Er-
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