Palladium-catalyzed direct ortho -acylation through an oxidative coupling of acetanilides with toluene derivatives

Article abstract of DOI:10.1021/jo302125h

A facile ortho-acylation of acetanilides by a Pd-catalyzed oxidative C-H activation was developed in which low toxic, stable, and commercially available toluene derivatives were first used as acylation reagents by a tandem reaction to form o-acylacetanili

Full text of DOI:10.1021/jo302125h

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Note
Palladium Catalyzed Direct ortho-Acylation through an
Oxidative Coupling of Acetanilides with Toluene Derivatives
Zhangwei Yin, and Peipei Sun
J. Org. Chem., Just Accepted Manuscript • DOI: 10.1021/jo302125h • Publication Date (Web): 26 Nov 2012
Downloaded from http://pubs.acs.org on November 26, 2012
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Palladium Catalyzed Direct ortho-Acylation through an Oxidative
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Coupling of Acetanilides with Toluene Derivatives
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Zhangwei Yina and Peipei Suna,b,c
*
a Jiangsu Key Laboratory of Biofunctional Materials, College of Chemistry and Materials Science,
Nanjing Normal University, Nanjing 210097, China
b Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical
Engineering and Materials Science, Soochow University, Suzhou 215123, China
c Key Laboratory of Applied Photochemistry, Nanjing Normal University, Nanjing 210097, China
sunpeipei@njnu.edu.cn
A facile orthoꢀacylation of acetanilides by a Pdꢀcatalyzed oxidative C−H activation was developed,
in which low toxic, stable and commercially available toluene derivatives were firstly used as
acylation reagents by a tandem reaction to form orthoꢀacylacetanilides with moderate to good
yields. Inexpensive, safe, and environmentally benign TBHP was proved to be an effective
oxidant for these transformations.
In the last decade, transitionꢀmetalꢀcatalyzed C−H bond functionalization protocols have
emerged as a valuable and atomꢀeconomical alternative to traditional crossꢀcouplings in the
construction of carbon−carbon and carbon−heteroatom bonds and thus have profoundly changed
the landscape of organic synthesis.1 In this strategy, directing groups that are commonly employed
in C−H activation processes have a dual role of assisting chelation and subsequently promoting
further functionalization. In numerous strongly or weakly coordinating directing groups,
acylamino group was noticeable. Using acylamino as a directing group, ortho C−H bond of
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acetanilide could be highly regioselectively functionalized. Some pioneering works such as
alkylation,2 arylation,3 halogenation,4 olefination,5 alkoxylation,6 and acylation7 were reported in
succession. Further studies on the acylamino group directed C−H bond functionalization would be
desirable to construct polyfunctional acetanilide derivatives.
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orthoꢀAcylacetanilides are important structural motifs and resourceful intermediates for
preparing natural products, dyes and pharmaceutically useful compounds.8 For the synthesis of
this kind of compounds, except traditional methods such as Friedel–Crafts acylation and oxidation
of the corresponding secondary alcohols by various oxidants,9 the palladiumꢀcatalyzed directed
acylations were developed in recent years (Scheme 1). Ge and coꢀworkers developed a
Pdꢀcatalyzed decarboxylative orthoꢀacylation of acetanilides with αꢀoxocarboxylic acids;7a using
arylaldehydes as coupling partners, Wang and Li reported orthoꢀacylation of acetanilides
respectively;7b,c considering benzylic alcohols can be oxidized to be benzaldehydes, Yuan using
benzylic alcohols as starting materials, TBHP as the oxidant, successfully developed the acylation
reaction of acetanilides via oxidative crossꢀcoupling.7d Even so, in all of these procedures,
relatively expensive and unstable prefunctionalized reagents should be employed as the acyl
sources. Our continuous interest in metalꢀcatalyzed C−H bond activation prompted us to explore
the reaction of Pdꢀcatalyzed ortho directed multiple C−H bond activation using substrates without
prefunctionalization. It is well known that toluene derivatives are low toxic, stable, commercially
available and easy to handle and thus may be potentially used as ideal acylation reagents to
achieve aryl ketones. Herein, we present a facile palladiumꢀcatalyzed regioselective acylation
reaction of acetanilides with no prefunctionalized toluene derivatives as acylation reagents to
afford orthoꢀacylacetanilides.
Scheme 1. Strategies toward Syntheses of orthoꢀAcylacetanilides
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We initially used acetanilide (1a) and toluene (2a) as the substrates to optimize the reaction
conditions. The results of this transitionꢀmetalꢀcatalyzed oxidative coupling reaction were
summarized in Table 1. Pd(OAc)2 was firstly chosen as a catalyst for this transformation, and
toluene was used as both reactant and solvent. The presence of an oxidant was requisite for this
reaction. Therefore the oxidant screening was investigated. Some generally used oxidants, such as
H2O2, TBHP, DTBP, BPO, O2 and K2S2O8 were tested, in which TBHP was found to be the best
one, while others showed little effect (entries 9ꢀ13). To gain the ideal yield, the amount of TBHP
was also examined and it turned out that 4 eq TBHP could bring the highest yield of 78%.
Increasing the amount of TBHP to 5 eq could not raise the yield evidently, while decreasing that to
3 eq led to the reduction of the yield (entries 1~3). Considering the requirement for enlarging the
applicability of this reaction, it was essential to select a suitable solvent. It was delightfully found
that the reaction could proceed in the solvent such as dioxane, DMF, DCE, DMSO, and even in
H2O (entries 4~8). In DMSO, it gave the highest yield, which would be significant when other
toluene derivatives, except toluene, were employed as acylation regents. So DMSO was chosen as
the general solvent for this acylation reaction. Furthermore, different transitionꢀmetal catalysts
were also tested, in which Pd(OAc)2 was proved to have the highest catalytic activity for this
transformation, and the appropriate amount of Pd(OAc)2 was 5 mol %, but PdCl2 and
PdCl2(PPh3)2 were less effective (entries 15, 16). Some Ru catalysts such as RuCl3 and
Ru[Cp(PPh3)2Cl] revealed no catalytic activity to this reaction (entries 17, 18). Besides, when the
mole ratio of 1a and 2a was changed from 1/2 to 1/1, the yield decreased obviously to 47% (entry
14). At 100 oC, the reaction proceeded smoothly and finished in 20 h with the highest yield of 81%.
o
Increasing the temperature to 110 C didn’t lead to the obvious rise of the yield. But at the
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temperature of 80 oC, the yield decreased sharply (entry 7).
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Table 1. Optimization of the Reaction Conditionsa
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entry
1
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3
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catalyst
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
PdCl2
oxidant (eq)
TBHP (4)
TBHP (5)
TBHP (3)
TBHP (4)
TBHP (4)
TBHP (4)
TBHP (4)
TBHP (4)
H2O2 (4)
solvent
toluene
toluene
toluene
dioxane
DMF
DCE
DMSO
H2O
toluene
toluene
toluene
toluene
toluene
DMSO
DMSO
DMSO
DMSO
DMSO
yield (%)b
78
77
65
70
76
64
81 (80, 62)c
62
0
trace
0
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16
17
18
DTBP (4)
BPO (4)
K2S2O8 (4)
O2 (1 atm)
TBHP (4)
TBHP (4)
TBHP (4)
TBHP (4)
TBHP (4)
0
0
47d
57
24
0
PdCl2(PPh3)2
RuCl3
Ru[Cp(PPh3)2Cl]
0
a
Unless otherwise specified, all reactions were carried out with acetanilide (1a, 0.5 mmol), toluene (2a, 1.0
mmol), catalyst (5 mol %), oxidant (2.0 mmol) in 1.0 mL solvent under air atmosphere at 100 oC for 20 h.
b
Isolated yields. c At 110 and 80 oC, respectively. d The mole ratio of 1a and 2a was 1/1.
Under the optimized reaction conditions, the substrate scope was studied. As summarized in
Table 2, a number of toluene derivatives were employed as acylation regents to react with
acetanilide (1a) to generate the desired ortho C−H bond acylation products. In general, the
reactions of acetanilide with the toluene derivatives with electronꢀdonating groups (such as CH3,
OCH3) or weakly electronꢀwithdrawing groups (such as Cl, Br) on the aromatic ring gave
moderate to good yields. But the presence of strongly electronꢀwithdrawing group such as nitro
and acetyl restrained the reaction. It is worth noting that to the toluene derivatives with more than
one methyl group such as xylene, mesitylene and 1,2,4,5ꢀtetramethylbenzene, the reaction only
took place on one methyl group and the others remained (3ab-3af). This result was attributable to
that one of the methyl groups on the aromatic ring was preꢀoxidized to carbonyl group and its
electronꢀwithdrawing property was unfavorable to the subsequent oxidation. αꢀMethylnaphthalene
and βꢀmethylnaphthalene also could be employed as acylation reagents to react with acetanilide
giving moderate yields (3ao, 3ap). Furthermore, haloꢀgroup (e. g. Br, Cl) on aromatic rings could
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remain in the products (3ag-3al). The tolerance of the reaction to these functional groups in
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substrates provided the possibility for the further useful transformation of the products.
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Table 2. The ortho-Acylation of Toluene Derivatives to Acetanilidea
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O
O
O
O
NH
O
NH
O
NH
O
NH
O
3aa, 81%b (89%c)
O
3ab, 83% (90%)
O
3ac, 77% (85%)
O
3ad, 70% (73%)
O
NH
O
NH
O
NH O
NH
O
Cl
Br
3ag, 71% (80%)
3ah, 73% (79%)
3ae, 75% (81%)
O
3af, 62% (67%)
O
O
O
NH
O
NH
O
NH
O
NH
O
Cl
O
Br
Cl
Cl
Cl
3ai, 78% (87%)
3aj, 70% (81%)
3ak, 60% (65%)
O
3al, 67% (70%)
O
O
O
NH
O
NH
O
NH
O
NH
O
Ph
3am, 71% (77%)
3ao, 57% (61%)
3ap, 65% (70%)
3an, 43% (53%)
a All the reactions were carried out using acetanilide (1a, 0.50 mmol), toluene derivatives (2, 1.0 mmol), Pd(OAc)2
(5 mol %), TBHP (2.0 mmol), DMSO (1.0 mL) at 100 oC in air atmosphere for 20 h. Isolated yields.
b
c
Conversions.
The orthoꢀacylation of a series of substituted acetanilides under the optimized reaction
conditions were performed as well, and the results are showed in Table 3. For the most substrates
we used, the reaction gave moderate to good yields. The reaction of acetanilides with a methyl
group at the metaꢀ or paraꢀposition of amido group gave comparable orthoꢀacylation yields to that
of unsubstituted acetanilides (3ba, 3ca). An interesting regioselectivity could be found that when a
metaꢀsubstituent existed at acetanilide, in which only acylation at the paraꢀposition of this
substituent took placed because of the sterically hinderance (3ca, 3ea, 3ha). Unfortunately, to
orthoꢀsubstituted acetanilide, only trace desired product was detected (3ia), which could also be
attributed to the steric effect.10 It seems that this method was not favorable to the acetanilides with
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strongly electronꢀwithdrawing groups. For example, when a nitro group existed, almost no
orthoꢀacylation product was obtained (3ja), and some hydrolyzed product of acetanilide was
found in the reaction mixture. Furthermore, the orthoꢀacylations of Nꢀphenylpropionamide,
Nꢀphenylisobutyramide and Nꢀphenylbenzamide also gave good yields (3ka-3ma).
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Table 3. The ortho-Acylation of Toluene to Acetanilidesa
O
O
O
O
NH
O
NH
O
O
NH
O
NH
O
Ph
Ph
Ph
Ph
O
3ca, 79% (86%)
3ea, 78% (83%)
3ba, 77%b (85%c)
3da, 52% (60%)
O
O
O
O
NH
Cl
O
NH
NH
O
NH O
O
Cl
Ph
Ph
Ph
Ph
Cl
3ia, trace (9%)
Br
3ha, 75% (82%)
3fa, 71% (78%)
3ga, 80% (87%)
O
O
O
O
NH
O
Et
NH
O
i-Pr
NH
O
Ph
NH O
Ph
Ph
Ph
Ph
3ka, 85% (93%)
3la, 81% (89%)
3ma, 83% (90%)
NO2
3ja, trace (77%)
a All the reactions were carried out using acetanilide (1, 0.50 mmol), toluene (2a, 1.0 mmol), Pd(OAc)2 (5 mol %),
TBHP (2.0 mmol), DMSO (1.0 mL) at 100 oC in air atmosphere for 20 h. b Isolated yields. c Conversions.
Based on the above results and previous researches, a plausible reaction pathway was
suggested (Scheme 2). Our experiment showed that the presence of ascorbic acid (radical
scavenger) could inhibit this reaction, which suggested that a radical was generated in this
procedure. Furthermore, without acetanilide, the toluene was oxidized to benzaldehyde by TBHP
with a low yield regardless of palladium catalyst. Thus, the possible mechanism of this acylation
reaction may be as follows. Firstly, the palladium catalyst reacted with acetanilide by
chelationꢀdirected C−H activation to form a cyclopalladated intermediate (A), which was
confirmed by many previous reports.7 Secondly, the palladacycle (A) reacted with the acyl radical
which was in situ formed from benzaldehyde (by the oxidation of toluene) to generate either
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reactive Pd(IV)11 or the dimeric Pd(III)12 species B. Finally, the intermediate B underwent
reductive elimination to afford the acylation product C, at the same time, the Pd (II) was
regenerated for the next catalytic cycle.
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Scheme 2. Proposed Mechanism for the PdꢀCatalyzed orthoꢀAcylation Reaction
O
O
HN
Pd(OAc)2
NH O
C
H
N
H
N
O
O
O
Pd
(III/IV)
A
Pd
OAc
B
tBuO
O
CHO
TBHP
tBuOH
In summary, we have developed an efficient method for the direct orthoꢀacylation of
acetanilides via a Pdꢀcatalyzed directed sp2 C−H bond activation. Low toxic, stable and
commercially available toluene derivatives were used as acyl sources, and inexpensive, safe, and
environmentally benign TBHP was employed to be an effective oxidant in these transformations.
The reaction exhibited good functional group tolerance. The mild reaction conditions provide
future opportunities to apply this methodology in the synthesis of natural products and other useful
compounds.
Experimental Section
General
All reactions were run in a sealed tube with a Teflon lined cap under air atmosphere. All
reagents were commercially available and were used without purification. 1H NMR and 13C NMR
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spectra were recorded in CDCl3 [using (CH3)4Si (for H, δ = 0.00; for 13C, δ = 77.00) as internal
standard]. The following abbreviations were used to explain the multiplicities: s = singlet, d =
doublet, t = triplet, q = quartet, m = multiplet. Melting points are uncorrected. For the HRMS
measurements, QꢀTOF was used.
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General Experimental Procedures and Characterizations
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Acetanilide (0.5 mmol), toluene derivative (1.0 mmol), Pd(OAc)2 (0.025 mmol), TBHP (2.0
mmol, 70% aq.) and DMSO (1.0 mL) were added in a 25 mL sealed tube with a Teflon lined cap.
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temperature, the volatiles were removed under reduced pressure, and the residue was purified by a
flash column chromatography on silica gel using hexane/ethyl acetate as eluent to give the
corresponding product.
N-(2-benzoylphenyl)acetamide (3aa)7a Yield: 81% (97 mg). 1H NMR (CDCl3, 400 MHz): δ 10.83
(s, 1H), 8.64 (d, J = 8.3 Hz, 1H), 7.71 (t, J = 4.2 Hz, 2H), 7.62ꢀ7.56 (m, 3H), 7.52ꢀ7.48 (m, 2H),
7.10 (s, 1H), 2.25 (s, 3H). 13C NMR (CDCl3, 100 MHz): δ 199.8, 169.2, 140.5, 138.6, 134.3,
133.5, 132.5, 129.9, 128.3, 123.3, 122.1, 121.5, 25.3. ESIꢀMS [MꢀH]ꢀ: 237.7.
1
N-(2-(4-methylbenzoyl)phenyl)acetamide (3ab)7a Yield: 83% (105 mg). H NMR (CDCl3, 400
MHz): δ 10.74 (s, 1H), 8.60 (d, J = 8.6 Hz, 1H), 7.63 (d, J = 8.1 Hz, 2H), 7.59ꢀ7.55 (m, 2H),
7.31ꢀ7.25 (m, 2H), 7.11ꢀ7.07 (m, 1H), 2.46 (s, 3H), 2.23(s, 3H). 13C NMR (CDCl3, 100 MHz): δ
199.3, 169.1, 143.5, 140.2, 135.8, 133.9, 133.3, 130.2, 129.0, 123.7, 122.0, 121.6, 25.2, 21.7.
ESIꢀMS [MꢀH]ꢀ: 251.7.
1
N-(2-(3-methylbenzoyl)phenyl)acetamide (3ac)7b Yield: 77% (97 mg). H NMR (CDCl3, 400
MHz): δ 10.82 (s, 1H), 8.63 (d, J = 8.2 Hz, 1H), 7.60ꢀ7.54 (m, 3H), 7.49 (d, J = 7.4 Hz, 1H),
7.44ꢀ7.36 (m, 2H), 7.12ꢀ7.08 (m, 1H), 2.44 (s, 3H), 2.24 (s, 3H). 13C NMR (CDCl3, 100 MHz): δ
200.0, 169.2, 140.4, 138.7, 138.3, 134.2, 133.5, 133.3, 130.3, 128.1, 127.2, 123.4, 122.0, 121.5,
25.3, 21.3. ESIꢀMS [MꢀH]ꢀ: 251.7.
1
N-(2-(2-methylbenzoyl)phenyl)acetamide (3ad)7a Yield: 70% (88 mg). H NMR (CDCl3, 400
MHz): δ 11.57 (s, 1H), 8.77 (d, J = 8.4 Hz, 1H), 7.60ꢀ7.56 (m, 1H), 7.40 (d, J = 7.8 Hz, 2H),
7.32ꢀ7.24 (m, 3H), 7.04ꢀ6.99 (m, 1H), 2.31 (s, 3H), 2.30 (s, 3H). 13C NMR (CDCl3, 100 MHz): δ
202.9, 169.6, 141.6, 139.3, 135.9, 135.3, 134.5, 130.9, 130.2, 127.9, 125.4, 122.5, 122.2, 120.8,
25.6, 19.7. ESIꢀMS [MꢀH]ꢀ: 251.7.
N-(2-(3,5-dimethylbenzoyl)phenyl)acetamide (3ae) Yield: 75% (100 mg). Pale yellow solid. Mp:
83ꢀ85 oC. 1H NMR (CDCl3, 400 MHz): δ 10.81 (s, 1H), 8.62 (d, J = 8.6 Hz, 1H), 7.58 (t, J = 7.4
Hz, 2H), 7.31 (s, 2H), 7.24 (s, 1H), 7.12ꢀ7.08 (m, 1H), 2.39 (s, 6H), 2.24 (s, 3H). 13C NMR
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(CDCl3, 100 MHz): δ 200.2, 169.2, 140.3, 138.7, 138.1, 134.2, 134.1, 133.5, 127.6, 123.6, 122.1,
121.5, 25.3, 21.2. HRMS (ESI): calcd for C17H17NO2[Na] 290.1157, found 290.1154.
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N-(2-(2,4,5-trimethylbenzoyl)phenyl)acetamide (3af) Yield: 62% (87 mg). Pale yellow solid. Mp:
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o
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76ꢀ78 C. H NMR (CDCl3, 400 MHz): δ 11.49 (s, 1H), 8.73 (d, J = 8.4 Hz, 1H), 7.59ꢀ7.54 (m,
1H), 7.45ꢀ7.43 (m, 1H), 7.07 (s, 1H), 7.05ꢀ7.00 (m, 2H), 2.31 (s, 3H), 2.29 (s, 3H), 2.25(s, 6H).
13C NMR (CDCl3, 100 MHz): δ 202.9, 169.5, 141.2, 139.3, 136.8, 134.9, 134.4, 133.6, 133.5,
132.3, 129.5, 123.1, 122.1, 120.8, 25.5, 19.7, 19.3, 19.2. HRMS (ESI): calcd for C18H19NO2[Na]
304.1313, found 304.1332.
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N-(2-(4-chlorobenzoyl)phenyl)acetamide (3ag)7a Yield: 71% (97 mg). H NMR (CDCl3, 400
1
MHz): δ 10.72 (s, 1H), 8.63 (d, J = 8.4 Hz, 1H), 7.68ꢀ7.66 (m, 2H), 7.60 (s, 1H), 7.53ꢀ7.48 (m,
3H), 7.12 (t, J = 4.0 Hz, 1H), 2.25 (s, 3H). 13C NMR (CDCl3, 100 MHz): δ 198.3, 169.2, 140.5,
139.1, 136.9, 134.5, 133.2, 131.3, 128.7, 123.0, 122.2, 121.7, 25.3. ESIꢀMS [MꢀH]ꢀ: 271.6.
N-(2-(4-bromobenzoyl)phenyl)acetamide (3ah)7a Yield: 73% (116 mg). H NMR (CDCl3, 400
1
MHz): δ 10.73 (s, 1H), 8.63 (d, J = 8.3 Hz, 1H), 7.66ꢀ7.64 (m, 2H), 7.61ꢀ7.58 (t, J = 7.7 Hz, 3H),
7.53ꢀ7.51 (m, 1H), 7.12ꢀ7.09 (m, 1H), 2.24 (s, 3H). 13C NMR (CDCl3, 100 MHz): δ 198.5, 169.2,
140.5, 137.3, 134.5, 133.2, 131.7, 131.4, 127.6, 122.9, 122.2, 121.7, 25.3. ESIꢀMS [MꢀH]ꢀ: 315.4.
N-(2-(3-chlorobenzoyl)phenyl)acetamide (3ai)7b Yield: 78% (107 mg). H NMR (CDCl3, 400
1
MHz): δ 10.77 (s, 1H), 8.65 (d, J = 8.4 Hz, 1H), 7.70 (t, J = 1.8 Hz, 1H), 7.61ꢀ7.52 (m, 4H), 7.45
(d, J = 7.8 Hz, 1H), 7.12 (s, 1H), 2.25 (s, 3H). 13C NMR (CDCl3, 100 MHz): δ 198.2, 169.2, 140.7,
140.3, 134.7, 134.6, 133.4, 132.4, 129.7, 129.6, 127.9, 122.7, 122.2, 121.7, 25.3. ESIꢀMS [MꢀH]ꢀ:
272.8.
N-(2-(3-bromobenzoyl)phenyl)acetamide (3aj)7b Yield: 70% (111 mg). H NMR (CDCl3, 400
1
MHz): δ 10.77 (s, 1H), 8.65 (d, J = 8.4 Hz, 1H), 7.85 (t, J = 1.6 Hz, 1H), 7.73 (t, J = 4.4 Hz, 1H),
7.62 (t, J = 3.9 Hz, 2H), 7.40ꢀ7.36 (t, J = 8.4 Hz, 1H), 7.12 (s, 1H), 2.25 (s, 3H). 13C NMR (CDCl3,
100 MHz): δ 198.1, 169.2, 140.7, 140.5, 135.3, 134.8, 133.4, 132.6, 129.9, 128.4, 122.6, 122.2,
121.27 121.7, 25.3. ESIꢀMS [MꢀH]ꢀ: 315.4.
N-(2-(2-chlorobenzoyl)phenyl)acetamide (3ak)7a Yield: 60% (82 mg). H NMR (CDCl3, 400
1
MHz): δ 11.56 (s, 1H), 8.81 (d, J = 8.4 Hz, 1H), 7.61 (s, 1H), 7.49ꢀ7.47 (m, 2H), 7.40ꢀ7.33 (m,
3H), 7.03 (s, 1H), 2.25 (s, 3H). 13C NMR (CDCl3, 100 MHz): δ 199.3, 169.6, 141.9, 138.8, 135.9,
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N-(2-(3,4-dichlorobenzoyl)phenyl)acetamide (3al) Yield: 67% (104 mg). Pale yellow solid. Mp:
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108ꢀ110 C. H NMR (CDCl3, 400 MHz): δ 10.66 (s, 1H), 8.61 (d, J = 8.4 Hz, 1H), 7.81 (d, J =
1.8 Hz, 1H), 7.61ꢀ7.47 (m, 4H), 7.13 (d, J = 8.0 Hz, 1H), 2.24 (s, 3H). 13C NMR (CDCl3, 100
MHz): δ 196.9, 169.2, 140.5, 138.2, 134.9, 133.1, 133.0, 131.6, 130.5, 130.5, 128.9, 126.0, 122.4,
25.3. HRMS (ESI): calcd for C15H11NO2Cl2[Na] 330.0065, found 330.0059.
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N-(2-(3-methoxybenzoyl)phenyl)acetamide (3am)7d Yield: 71% (96 mg). H NMR (CDCl3, 400
1
MHz): δ 10.80 (s, 1H), 8.63 (d, J = 8.7 Hz, 1H), 7.60ꢀ7.57 (m, 2H), 7.39 (d, J = 8.2 Hz, 1H),
7.28ꢀ7.25 (m, 2H), 7.15 (s, 1H), 7.10 (s, 1H), 3.87 (s, 3H), 2.25 (s, 3H). 13C NMR (CDCl3, 100
MHz): δ 199.5, 169.2, 159.5, 140.5, 139.9, 134.3, 133.5, 129.3, 123.3, 122.6, 122.1, 121.5, 118.9,
114.3, 55.5, 25.3. ESIꢀMS [MꢀH]ꢀ: 267.6.
N-(2-(4-phenylbenzoyl)phenyl)acetamide (3an) Yield: 43% (68 mg). White solid. Mp: 130ꢀ131 oC.
1H NMR (CDCl3, 400 MHz): δ 10.79 (s, 1H), 8.65 (d, J = 8.4 Hz, 1H), 7.81 (d, J = 8.3 Hz, 2H),
7.74 (t, J = 4.2 Hz, 2H), 7.69ꢀ7.63 (m, 4H), 7.53ꢀ7.44 (m, 3H), 7.14(s, 1H), 2.26 (s, 3H). 13C NMR
(CDCl3, 100 MHz): δ 199.2, 169.2, 145.4, 140.4, 139.8, 137.2, 134.2, 133.4, 130.6, 129.0, 128.3,
127.3, 127.0, 123.5, 122.1, 121.6, 25.3. HRMS (ESI): calcd for C21H17NO2[Na] 338.1157, found
338.1187.
N-(2-(2-naphthoyl)phenyl)acetamide (3ap)7a Yield: 65% (94 mg). 1H NMR (CDCl3, 400 MHz): δ
10.79 (s, 1H), 8.66 (d, J = 8.3 Hz, 1H), 8.20 (s, 1H), 7.99ꢀ7.93 (m, 3H), 7.86ꢀ7.84 (m, 1H),
7.65ꢀ7.59 (m, 4H), 7.13(s, 1H), 2.26 (s, 3H). 13C NMR (CDCl3, 100 MHz): δ 199.6, 169.2, 140.4,
135.8, 135.2, 134.2, 133.5, 132.1, 131.8, 129.4, 128.5, 128.4, 127.8, 127.0, 125.6, 123.7, 122.2,
121.7, 25.3. ESIꢀMS [MꢀH]ꢀ: 287.7.
N-(2-(1-naphthoyl)phenyl)acetamide (3ao)7a Yield: 57% (83 mg). 1H NMR (CDCl3, 400 MHz): δ
11.60 (s, 1H), 8.80 (d, J = 7.8 Hz, 1H), 8.03 (d, J = 9.3 Hz, 1H), 7.97ꢀ7.94 (m, 2H), 7.60ꢀ7.51 (m,
5H), 7.45ꢀ7.43 (m, 1H), 6.97 (s, 1H), 2.33 (s, 3H). 13C NMR (CDCl3, 100 MHz): δ 202.2, 169.6,
141.6, 137.0, 135.4, 134.8, 133.6, 131.2, 130.6, 128.5, 127.4, 127.2, 126.6, 125.3, 124.4, 123.2,
122.2, 120.9, 25.6. ESIꢀMS [MꢀH]ꢀ: 287.7.
N-(2-benzoyl-4-methylphenyl)acetamide (3ba)7a Yield: 77% (98 mg). 1H NMR (CDCl3, 400 MHz):
δ 10.65 (s, 1H), 8.50 (d, J = 8.5 Hz, 1H), 7.71 (t, J = 4.2 Hz, 2H), 7.64ꢀ7.61 (m, 1H), 7.53ꢀ7.49 (t,
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J = 7.6 Hz, 2H), 7.39 (d, J = 8.1 Hz, 1H), 7.35 (s, 1H), 2.31 (s, 3H), 2.22 (s, 3H). 13C NMR
(CDCl3, 100 MHz): δ 199.7, 169.1, 138.7, 138.0, 134.9, 133.5, 132.5, 131.7, 129.9, 128.3, 121.6,
25.2, 20.8. ESIꢀMS [MꢀH]ꢀ: 251.7.
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N-(2-benzoyl-5-methylphenyl)acetamide (3ca)7a Yield: 79% (100 mg). H NMR (CDCl3, 400
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MHz): δ 11.03 (s, 1H), 8.51 (s, 1H), 7.67 (t, J = 4.2 Hz, 2H), 7.62ꢀ7.58 (m, 1H), 7.51ꢀ7.45 (m, 3H),
6.89 (d, J = 8.0 Hz, 1H), 2.44 (s, 3H), 2.24 (s, 3H). 13C NMR (CDCl3, 100 MHz): δ 199.7, 169.3,
145.9, 140.8, 139.0, 133.9, 132.2, 129.7, 128.3, 122.9, 121.7, 120.5, 25.4, 22.2. ESIꢀMS [MꢀH]ꢀ:
251.5.
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N-(2-benzoyl-4-methoxyphenyl)acetamide (3da)7d Yield: 52% (70 mg). H NMR (CDCl3, 400
MHz): δ 10.33 (s, 1H), 8.49 (d, J = 9.1 Hz, 1H), 7.75 (t, J = 4.3 Hz, 2H), 7.64ꢀ7.61 (m, 1H),
7.53ꢀ7.49 (t, J = 7.6 Hz, 2H), 7.15 (d, J = 9.1 Hz, 1H), 7.06 (d, J = 3.0 Hz, 1H), 3.77 (s, 3H), 2.21
(s, 3H). 13C NMR (CDCl3, 100 MHz): δ 199.1, 168.8, 154.2, 138.3, 133.5, 132.7, 130.0, 128.4,
125.1, 123.5, 119.3, 118.2, 55.7, 25.0. ESIꢀMS [MꢀH]ꢀ: 267.7.
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N-(2-benzoyl-5-methoxyphenyl)acetamide (3ea)7d Yield: 78% (105 mg). H NMR (CDCl3, 400
MHz): δ 11.57 (s, 1H), 8.38 (d, J = 2.6 Hz, 1H), 7.59 (t, J = 4.2 Hz, 2H), 7.57ꢀ7.51 (m, 1H),
7.49ꢀ7.44 (m, 3H), 6.53 (d, J = 8.9 Hz, 1H), 3.88 (s, 3H), 2.24 (s, 3H). 13C NMR (CDCl3, 100
MHz): δ 198.9, 169.6, 164.6, 143.8, 139.5, 136.3, 131.7, 129.3, 128.2, 115.5, 108.9, 104.8, 55.6,
25.5. ESIꢀMS [MꢀH]ꢀ: 267.7.
N-(2-benzoyl-4-chlorophenyl)acetamide (3fa)7d Yield: 71% (97 mg). 1H NMR (CDCl3, 400 MHz):
δ 10.63 (s, 1H), 8.60 (d, J = 8.6 Hz, 1H), 7.70 (t, J = 4.2 Hz, 2H), 7.66ꢀ7.62 (m, 1H), 7.54ꢀ7.51 (m,
4H), 2.22 (s, 3H). 13C NMR (CDCl3, 100 MHz): δ 198.4, 169.1, 138.9, 137.8, 133.9, 133.0, 132.6,
129.9, 128.6, 127.2, 124.6, 123.1, 25.2. ESIꢀMS [MꢀH]ꢀ: 271.5.
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N-(2-benzoyl-4-bromophenyl)acetamide (3ga)13 Yield: 80% (127 mg). H NMR (CDCl3, 400
MHz): δ 10.63 (s, 1H), 8.55 (d, J = 9.6 Hz, 1H), 7.72ꢀ7.68 (m, 2H), 7.67ꢀ7.63 (m, 3H), 7.53 (t, J =
7.6 Hz, 2H), 2.22 (s, 3H). 13C NMR (CDCl3, 100 MHz): δ 198.3, 169.1, 139.4, 137.8, 136.8, 135.5,
133.0, 129.9, 128.6, 124.9, 123.3, 114.6, 25.3. ESIꢀMS [MꢀH]ꢀ: 315.5.
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N-(2-benzoyl-5-chlorophenyl)acetamide (3ha)7a Yield: 75% (103 mg). H NMR (CDCl3, 400
MHz): δ 10.97 (s, 1H), 8.74 (d, J = 1.9 Hz, 1H), 7.67ꢀ7.59 (m, 3H), 7.52ꢀ7.47 (m, 3H), 7.05 (d, J
= 8.5 Hz, 1H), 2.23 (s, 3H). 13C NMR (CDCl3, 100 MHz): δ 199.0, 169.4, 141.6, 140.7, 138.4,
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134.7, 132.7, 129.7, 128.5, 122.3, 121.3, 121.1, 25.8. ESIꢀMS [MꢀH]ꢀ: 271.5.
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N-(2-benzoylphenyl)propionamide (3ka)14 Yield: 85% (108 mg). H NMR (CDCl3, 400 MHz): δ
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10.88 (s, 1H), 8.65 (d, J = 8.1 Hz, 1H), 7.67 (t, J = 4.2 Hz, 2H), 7.62ꢀ7.56 (m, 3H), 7.57ꢀ7.52 (m,
3H), 7.46 (t, J = 7.6 Hz, 2H), 7.07ꢀ7.03 (m, 1H), 2.44 (q, J = 7.6 Hz, 2H) 1.26 (t, J = 7.6 Hz, 3H).
13C NMR (CDCl3, 100 MHz): δ 199.7, 173.0, 140.6, 138.7, 134.3, 133.6, 132.4, 129.9, 128.3,
123.1, 121.9, 121.5, 31.4, 9.6. ESIꢀMS [MꢀH]ꢀ: 251.7.
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N-(2-benzoylphenyl)isobutyramide (3la)7a Yield: 81% (108 mg). H NMR (CDCl3, 400 MHz): δ
10.99 (s, 1H), 8.69 (d, J = 7.8 Hz, 1H), 7.68 (t, J = 4.1 Hz, 2H), 7.58ꢀ7.54 (m, 3H), 7.49ꢀ7.45 (m,
2H), 7.04 (d, J = 7.6 Hz, 1H), 2.63ꢀ2.58 (m, 1H), 1.28 (d, J = 7.0 Hz, 6H). 13C NMR (CDCl3, 100
MHz): δ 199.8, 176.3, 140.9, 138.7, 134.4, 133.7, 132.4, 129.8, 128.3, 123.1, 121.9, 121.4, 37.3,
19.5. ESIꢀMS [MꢀH]ꢀ: 265.7.
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N-(2-benzoylphenyl)benzamide (3ma)7d Yield: 83% (125 mg). H NMR (CDCl3, 400 MHz): δ
12.00 (s, 1H), 8.92 (d, J = 8.2 Hz, 1H), 8.11ꢀ8.08 (m, 2H), 7.74 (t, J = 4.3 Hz, 2H), 7.66ꢀ7.59 (m,
3H), 7.56ꢀ7.49 (m, 5H), 7.14 (s, 1H). 13C NMR (CDCl3, 100 MHz): δ 200.4, 165.9, 141.2, 138.8,
134.7, 134.6, 134.1, 132.4, 132.1, 129.8, 128.9, 128.4, 127.4, 123.1, 122.2, 121.5. ESIꢀMS [MꢀH]ꢀ:
299.6.
Acknowledgment
This work was supported by the National Natural Science Foundation of China (Project 21272117
and 20972068) and the Priority Academic Program Development of Jiangsu Higher Education
Institutions.
Supporting Information
1H NMR and 13C NMR spectra for all compounds. This material is available free of charge via the
internet at http://pubs.acs.org.
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