Cu(i)-catalyzed chemical fixation of CO2 with 2-alkynylaniline into 4-hydroxyquinolin-2(1H)-one

Article abstract of DOI:10.1039/c3cy00858d

A copper(i) catalyzed reaction of 2-alkynylaniline with CO₂ using DBU as base to produce 4-hydroxyquinolin-2(1H)-one derivatives in moderate to good yield is presented. In this reaction, a unique bond cleavage pattern for CO₂ was observed that one of the C-O double bonds of CO ₂ was totally broken and rearranged into two moieties in the absence of the reductive reagent. This efficient reaction system showed the wide generality of substrates including nitro, bromo, cyano and methoxylcarbonyl groups. A possible mechanism containing isocyanate intermediate is proposed. This journal is the Partner Organisations 2014.

Full text of DOI:10.1039/c3cy00858d

Catalysis
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Cu(I)-catalyzed chemical fixation of CO2 with
2-alkynylaniline into 4-hydroxyquinolin-2(1H)-one†
Cite this: Catal. Sci. Technol., 2014,
4, 1570
*
Chun-Xiao Guo, Wen-Zhen Zhang, Si Liu and Xiao-Bing Lu
A
copper(I) catalyzed reaction of 2-alkynylaniline with CO2 using DBU as base to produce
Received 29th October 2013,
Accepted 13th December 2013
4-hydroxyquinolin-2(1H)-one derivatives in moderate to good yield is presented. In this reaction, a
unique bond cleavage pattern for CO2 was observed that one of the C–O double bonds of CO2 was
totally broken and rearranged into two moieties in the absence of the reductive reagent. This efficient reac-
tion system showed the wide generality of substrates including nitro, bromo, cyano and methoxylcarbonyl
groups. A possible mechanism containing isocyanate intermediate is proposed.
DOI: 10.1039/c3cy00858d
www.rsc.org/catalysis
as basic structural elements in many natural products and
biologically active compounds,14 was found to be the main
Introduction
Catalytic transformation of carbon dioxide (CO2) has attracted
tremendous attention because CO2 is an abundant, inexpen-
sive and renewable carbon resource.1 Since CO2 is highly ther-
modynamically and kinetically stable, organic reactions
bearing CO2 usually use relatively high-energy reactant and
transition-metal catalysts. In this way, various organometallic
reagents,2–7 even C–H bonds8,9 and halide electrophiles10 suc-
cessfully conducted a reaction with CO2 to provide carboxylic
acids and derivatives containing a wide range of functional
groups in the last few decades. By far, the pursuit of an effi-
cient reaction system to convert CO2 into value-added fine
chemical is still a continuing effort of critical importance.
It is well known that the reaction of primary amines with
CO2 readily forms carbamic acids.11 Along with our efforts to
develop a new CO2 reaction system, we were interested in the
product in good yield (Scheme 1). In this reaction, one of the
C–O double bonds of CO2 was formally broken and
rearranged into two moieties in the absence of the reductive
reagent, which implied that the isocyanate intermediate
might be involved in the reaction sequence. A similar bond
cleavage pattern also appeared in the chemical fixation of
CO2 with 2-aminobenzonitrile to quinazoline-2,4(1H,3H)-
diones,15 in which organic base 1,8-diazabicyclo[5.4.0]undec-
7-ene (DBU) was found to be a suitable promoter. Herein, we
present our detailed study on the this copper-catalyzed
chemical fixation of CO2 with 2-alkynylaniline into
4-hydroxyquinolin-2(1H)-one derivatives.16
Results and discussion
Optimization of the reaction conditions
intramolecular
carboxylative
addition
reaction
of
Reactions of 2-phenylethynylaniline (1a) with CO2 were ini-
tially carried out to identify the optimized copper catalytic
system and reaction conditions (Table 1). Since copper(I) salts
generally served as effective π-acid catalysts to activate the
alkyne group, and DBU was used as a suitable base for the
reaction system containing amines and CO2, the combination
of Cu(I) salt with DBU was firstly tested as a catalytic system
2-alkynylaniline with CO2 to synthesize benzoxazine-2-one (A)
or benzoxazepin-2(1H)-one (B) derivatives at relatively higher
temperature (Scheme 1). Indeed, ruthenium-catalyzed inter-
molecular carboxylative addition reactions of amines, CO2
and unsaturated compounds were reported.12 More recently,
Yamada and co-workers also reported a silver-catalyzed intra-
molecular carboxylative addition reaction of 2-alkynylaniline
with CO2 to give benzoxazine-2-one derivatives.13 However,
neither benzoxazine-2-one nor benzoxazepin-2(1H)-one was
detected in our copper-catalyzed experiments, instead,
4-hydroxyquinolin-2(1H)-one (C), which are frequently found
State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian,
116024, PR China. E-mail: zhangwz@dlut.edu.cn; Fax: +86 411 8498 6256;
Tel: +86 411 8498 6257
† Electronic supplementary information (ESI) available: Copies of NMR spectra.
CCDC 967568 and 967567. For ESI and crystallographic data in CIF or other
electronic format see DOI: 10.1039/c3cy00858d
Scheme 1 Cu(I)-catalyzed reaction of 2-alkynylaniline with CO2.
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a
Table 1 Reaction of 2-phenylethynylaniline with CO2
of the copper salts (entry 16). When the reaction was carried
out in the absence of base, no carboxylative product was
isolated, which demonstrated the crucial role of DBU in this
reaction (entry 17).
The reaction system turned out to be relatively sensitive
to the temperature (entries 18–20). CO2 pressure also had a
profound effect on the reaction. When the reaction
proceeded at 0.5 MPa of CO2, 49% yield of 2a was obtained
(entry 21). The reaction at 1 atm of CO2 (CO2 balloon) almost
cannot be carried out (entry 22).
Therefore, on the basis of the above experiments, the opti-
mized reaction conditions for this reaction are: CuI (10 mol%),
DBU (1.5 equiv.), 1.0 MPa CO2, DMSO, 100 °C, 24 h.
Yield of
Entry
Cat. (mol%)
Base
Solvent
T (°C)
2ab (%)
1
2
3
4
5
6
7
8
CuCl (10)
CuBr(10)
CuI (10)
Cu(OAc)2 (10)
CuI (20)
CuI (5)
DBU
DBU
DBU
DBU
DBU
DBU
DBU
DBU
DBU
DBU
DBU
DBU
MTBD
DBN
DABCO
DBU
—
DMAc
DMAc
DMAc
DMAc
DMAc
DMAc
DMAc
DMSO
DMF
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
80
60
57
76
57
65
48
17
80
72
58
35
72
73
24
Trace
—
—
Substrate scope of the reaction
CuI (1)
CuI (10)
CuI (10)
CuI (10)
CuI (10)
CuI (10)
CuI (10)
CuI (10)
CuI (10)
—
CuI (10)
CuI (10)
CuI (10)
CuI (10)
CuI (10)
CuI (10)
With the optimized reaction conditions in hand, the substrate
scope regarding 2-alkynylaniline was investigated (Table 2). It
was found that the copper(I) catalytic systems showed a high
level of generality, and a variety of functional group including
electron-donating (alkyl, methoxy) and electron-withdrawing
(trifluoromethyl, fluoro, methoxylcarbonyl, nitro, cyano)
groups all tolerated. The nitro group in product 2g can be
readily and selectively reduced into an amino group, which
enabled a much wider synthetic application. The presence of
the bromo group in 2e, 2l and 2r provided the opportunity to
further functionalize the 4-hydroxyquinolin-2(1H)-one prod-
ucts using other convenient reactions such as the palladium-
catalyzed cross-coupling reaction.
It is reported that reaction of 2-aminobenzonitrile with CO2
in the presence of DBU underwent intramolecular carboxylative
addition reaction to yield quinazoline-2,4(1H,3H)-dione,15 while
the cyano which was located in the para position of the amino
group in 4-cyano-2-phenylethynylaniline (1p) proved to be com-
patible with our copper catalytic system. Importantly, the
4-hydroxyquinolin-2(1H)-one structure of products was clearly
confirmed by the X-ray crystallographic structures of 2q and 2s
(Fig. 1).17
9
10
11
12c
13
14
15
16
17
18
19
20
21d
22e
THF
Toluene
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DBU
DBU
DBU
DBU
DBU
78
53
45
49
50
25
100
100
Trace
a
Reaction conditions: unless otherwise noted, the reaction was
carried out with 1a (0.30 mmol), catalyst, base (0.45 mmol), solvent
(3 mL) at 100 °C for 24 h in 1.0 MPa of CO2, then reacted with
0.45 mmol nBuI for 5 h at 80 °C. Isolated yield. 1.0 equiv. base.
b
c
d
0.5 MPa CO2. e 1 atm CO2.
(entries 1–3). It turned out that copper(I) salts catalyzed the
reaction to produce 4-butoxy-3-phenyl-2(1H)-quinolinone (2a)
in moderate to good yield, and CuI showed higher catalytic
activity than CuBr and CuCl. The non-carboxylative byproduct
of this reaction was mainly 1-butyl-2-phenyl-indole 3a which
came from intramolecular hydroamination reaction of 1a.
The increase of catalyst loading from 10 mol% into 20 mol%
did not lead to a higher yield of 2a (entry 5), while the lower
catalyst loading gave a dramatically decreased yield of 2a
(entries 6 and 7). When the solvent was changed to DMSO, a
relatively higher yield of product was achieved (entry 8). Reac-
tion in other solvents such as DMF, THF, and toluene gave
inferior yields. (entries 9–11).
Possible mechanism
As mentioned above, the unique bond cleavage pattern for
CO2 in this reaction implied that the isocyanate intermediate
played a key role during the reaction. To explore whether the
reaction underwent in a stepwise way, the following experi-
ments were carried out.
It was recently reported by Yamada that in the presence of
silver(I) catalyst, the reaction of 2-phenylethynylaniline (1a with
CO2 at relatively lower temperature (20 °C) for 24 h formed
benzoxazine-2-one (4a), while this reaction was conducted
under our copper(I)-catalyzed standard conditions, no
benzoxazine-2-one product was detected (Scheme 2, a). When
2-aminophenylethanone (5a) reacted with CO2 under copper(I)-
catalyzed standard conditions, no 4-hydroxyquinolin-2(1H)-
one-type product 2t was formed (Scheme 2, a), which ruled out
the possible pathway that the alkyne moiety was firstly hydro-
lyzed into 2-aminophenylethanone derivative. The reaction of
The decrease of DBU quantity from 1.5 equiv. to 1.0 equiv.
had
a negative effect on the yield of 2a (entry 12).
7-Methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene (MTBD), which
was also established as a good organic base for the reaction
of the amines and CO2, exhibited a little lower efficiency in
this reaction system (entry 13). 1,5-Diazabicyclo[4.3.0]non-5-ene
(DBN) and 1,4-diazabicyclo[2.2.2]octane (DABCO) were found
to be unsuitable bases for this reaction (entries 14 and 15).
When the reaction was conducted without any metal catalyst,
no product 2a was detected, which testified the catalytic role
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a b
,
Table 2 CuI-catalyzed reaction of various 2-alkynylaniline with CO2
a
The reaction was carried out with 1 (0.30 mmol), CuI (0.03 mmol), DBU (0.45 mmol), DMSO (3 mL) at 100 °C for 24 h in 1.0 MPa of CO2,
then reacted with 0.45 mmol nBuI for 5 h at 80 °C. Isolated yield.
b
n
1a with CO2 in the presence of 1.5 equiv. of BuI did not pro-
duce 2a, instead, this reaction exclusively gave the non-
carboxylative product 3a, which came from intramolecular
hydroamination reaction of in situ formed N-butyl
2-phenylethynylaniline (Scheme 2, c). This also demonstrated
the vital role of the –NH2 group in this reaction system.
intermediate II bearing isocyanate and enolate groups, and
finally the reaction of those two groups produce the
4-hydroxyquinolin-2(1H)-one product.
Conclusions
Based on the above experiments, a possible reaction
mechanism is proposed (Scheme 3). Firstly, the reaction of
2-alkynylaniline with CO2 in the presence of DBU formed
carbamate, and the oxygen atom of the carbamate under-
went nucleophilic attack on CuI-activated alkyne moiety
to generate intermediate I, which then rearranged into
In conclusion, we have developed a copper(I) catalyzed reac-
tion of 2-alkynylaniline with CO2 in the presence of DBU to
produce synthetically important 4-hydroxyquinolin-2(1H)-one
derivatives in moderate to good yield, in which one of the
C–O double bond of CO2 was totally broken and rearranged
into two moieties in the absence of the reductive reagent. This
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Experimental section
General information
Unless otherwise stated, all manipulations were performed
using standard Schlenk techniques under a dry nitrogen or
CO2 atmosphere. DMF, DMAc and DMSO were distilled from
CaH2 at 60 °C under reduced pressure and stored over 4A
molecular sieves. 2-Alkynylanilines were prepared by
Sonogashira reaction of 2-bromoanilines or 2-iodoanilines
with terminal alkynes according to a reported procedure. Car-
bon dioxide (99.999%), commercially available silver(I) and
copper(I) salts, and all other reagents were used without fur-
ther purification.
General procedure for the reaction of 2-alkynylaniline with CO2
A 20 mL oven dried autoclave containing a stir bar was
charged with the CuI (0.03 mmol), DBU (0.45 mmol),
2-alkynylaniline (0.3 mmol), and 3 mL dry DMSO. After purg-
ing the autoclave with CO2 three times, the sealed autoclave
was pressurized to the appropriate pressure with CO2. The
reaction mixture was stirred at 100 °C for 24 h, then the auto-
clave was cooled to room temperature and the remaining
CO2 was vented slowly. Then nBuI (0.45 mmol) and K2CO3
(0.3 mmol) was added into the autoclave and the reaction
mixture was stirred at 80 °C for 5 h. The reaction mixture
was then diluted with water (30 mL) and extracted with ethyl
acetate (4× 30 mL). The combined organic layers were washed
with water and brine, dried over Na2SO4 and filtered. The sol-
vent was removed under vacuum. The product was isolated
as a white solid by column chromatography on silica gel
(CH2Cl2/CH3OH: 40 : 1).
Fig. 1 ORTEP plot of 2q (above) and 2s (below) shown with ellipsoids
at the 30% probability level, most hydrogen atoms were omitted
for clarity.
Product characterization
4-Butoxy-3-phenyl-2(1H)-quinolinone (2a). White solid. 1H
NMR (400 MHz, CDCl3): δ 10.46 (s, 1H), 7.93 (d, J = 8.0 Hz,
1H), 7.55 (d, J = 4.0 Hz, 2H), 7.43–7.54 (m, 3H), 7.37 (t, J =
4.2 Hz, 1H), 7.22 (t, J = 8.0 Hz, 2H), 3.59 (t, J = 6.0 Hz, 2H),
1.49–1.54 (m, 2H), 1.23–1.32 (m, 2H), 0.80 (t, J = 8.0 Hz, 3H).
13C NMR (100 MHz, CDCl3): δ 165.4, 162.0, 138.0, 133.4,
131.1, 130.8, 128.5, 127.8, 123.5, 122.3, 119.8, 118.1, 116.2,
73.4, 32.3, 19.2, 13.8. IR (KBr): 555, 698, 763, 910, 1097, 1349,
1398, 1495, 1598, 1653, 2872, 2932, 2959. HRMS (ESI, m/z)
calcd. for C19H19NO2Na [M + Na]+: 316.1313, found: 316.1319.
4-Butoxy-3-(4-methylphenyl)-2(1H)-quinolinone (2b). White
solid. 1H NMR (400 MHz, CDCl3): δ 10.79 (s, 1H), 7.91 (d, J = 4.0,
1H), 7.43–7.49 (m, 3H), 7.19–7.27 (m, 5H), 3.60 (t, J = 8.0 Hz,
2H), 2.42 (s, 3H), 1.50–1.57 (m, 2H), 1.25–1.34 (m, 2H), 0.81
(t, J = 8.0 Hz, 3H). 13C NMR (100 MHz, CDCl3): δ 165.4, 161.8,
137.8, 137.5, 130.9, 130.7, 130.3, 128.9, 123.5, 122.3, 119.7,
118.2, 116.0, 73.2, 32.3, 21.6, 19.2, 13.8. IR (KBr): 523, 647,
897, 1103, 1345, 1494, 1603, 1655, 2860, 2956, 3008, 3446.
HRMS (ESI, m/z) calcd. for C20H22NO2 [M + H]+: 308.1651,
found: 308.1646.
Scheme 2
Scheme 3 Possible mechanism.
efficient reaction system showed wide functional group
compatibility, and nitro, bromo, cyano and other groups were
successfully tolerated, which provided the opportunity to
further functionalize the 4-hydroxyquinolin-2(1H)-one products
using other convenient reactions. Based on the experimental
study, a possible mechanism containing isocyanate interme-
diate is proposed.
4-Butoxy-3-(4-tert-butylphenyl)-2(1H)-quinolinone (2c). White
solid. 1H NMR (400 MHz, CDCl3): δ 10.12 (s, 1H), 7.92
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(d, J = 8.0 Hz, 1H), 7.43–7.52 (m, 5H), 7.19–7.24 (m, 2H), 3.58
(t, J = 6.0 Hz, 2H), 1.48–1.55 (m, 2H), 1.37 (s, 9H), 1.21–1.29
(m, 2H), 0.77 (t, J = 8.2 Hz, 3H). 13C NMR (100 MHz, CDCl3):
δ 165.5, 162.0, 150.6, 130.6, 130.1, 125.1, 124.9, 123.5, 122.3,
120.0, 118.2, 116.1, 73.2, 34.8, 32.2, 31.6, 19.1, 13.8. IR (KBr):
528, 566, 620, 729, 750, 829, 908, 1091, 1283, 1347, 1495,
1602, 1650, 2744, 2871, 2960, 3166. HRMS (ESI, m/z) calcd.
for C23H28NO2 [M + H]+: 350.2120, found: 350.2116.
4-Butoxy-3-(4-methoxyphenyl)-2(1H)-quinolinone (2d). White
solid. 1H NMR (400 MHz, CDCl3): δ 10.23 (s, 1H), 7.92
(d, J = 8.0 Hz, 1H), 7.46–7.51 (m, 3H), 7.19–7.24 (m, 2H), 6.99
(d, J = 8.0 Hz, 2H), 3.87 (s, 3H), 3.59 (t, J = 4.2 Hz, 2H), 1.51–1.56
(m, 2H), 1.26–1.36 (m, 2H), 0.82 (t, J = 8.0 Hz, 3H). 13C NMR
(100 MHz, CDCl3): δ 165.27, 161.57, 159.09, 137.61, 132.09,
130.51, 125.31, 123.39, 122.17, 119.30, 118.12, 115.80,
113.55, 73.02, 55.30, 32.11, 19.06, 13.68. IR (KBr): 541, 648,
758, 833, 1095, 1177, 1253, 1343, 1514, 1601, 1647, 2840,
2938, 2961, 3418. HRMS (ESI, m/z) calcd. for C20H22NO3
[M + H]+: 324.1600, found: 324.1596.
130.9, 128.0, 127.6, 122.9, 119.8, 117.9, 115.8, 73.2, 32.1,
19.0, 13.6. IR (KBr): 561, 654, 704, 818, 916, 1094, 1312,
1351, 1598, 1606, 1652, 2870, 2927, 2957, 3053. HRMS
(ESI, m/z) calcd. for C20H21NO2Na [M + Na]+: 330.1470, found:
330.1476.
4-Butoxy-6-chloro-3-phenyl-2(1H)-quinolinone (2i). White
1
solid. H NMR (400 MHz, CDCl3): δ 12.33 (s, 1H), 7.84 (d, J =
4.0 Hz, 1H), 7.54 (t, J = 8.0, 2H), 7.45–7.48 (m, 2H), 7.33–7.42
(m, 1H), 7.32–7.34 (m, 1H), 7.17 (d, J = 8.0 Hz, 1H), 3.56
(t, J = 8.0 Hz, 2H), 1.48–1.55 (m, 2H), 1.25–1.29 (m, 2H),
0.80 (t, J = 8.0 Hz, 3H). 13C NMR (100 MHz, CDCl3): δ 165.2,
160.9, 136.4, 131.0, 130.9, 128.3, 128.1, 127.8, 122.9, 120.3,
119.2, 117.7, 73.5, 32.1, 19.1, 13.8. IR (KBr): 559, 701, 818,
1112, 1269, 1386, 1484, 1597, 1651, 2872, 2930, 2959, 3162.
HRMS (ESI, m/z) calcd. for C19H18NO2Cl [M + H]+: 327.1026,
found: 327.1029.
4-Butoxy-6,8-dichloro-3-phenyl-2(1H)-quinolinone (2j). White
solid. 1H NMR (400 MHz, CDCl3): δ 8.99 (s, 1H), 7.83
(d, J = 2.0 Hz, 1H), 7.56 (d, J = 4.0 Hz, 1H), 7.45–7.49 (m, 4H),
7.36–7.43 (m, 1H), 3.56 (t, J = 8.0 Hz, 2H), 1.49–1.56 (m, 2H),
1.21–1.28 (m, 2H), 0.80 (t, J = 8.0 Hz, 3H). 13C NMR (100 MHz,
CDCl3): δ 162.9, 160.0, 132.5, 132.3, 130.8, 130.4, 128.5, 128.4,
127.6, 122.6, 121.0, 120.4, 119.7, 73.8, 32.1, 19.1, 13.7. IR
(KBr): 556, 648, 700, 818, 1108, 1267, 1345, 1595, 1650, 2929,
2959, 3164. HRMS (ESI, m/z) calcd. for C19H17NO2NaCl2
[M + Na]+: 384.0534, found: 384.0542.
3-(4-Bromophenyl)-4-butoxy-2(1H)-quinolinone (2e). White
1
solid. H NMR (400 MHz, CDCl3): δ 11.67 (s, 1H), 7.61 (t, J =
2.0 Hz, 1H), 7.58 (t, J = 2.0 Hz, 1H), 7.46–7.51 (m, 3H), 7.28
(s, 1H), 7.20–7.24 (m, 1H), 3.62 (t, J = 8.0 Hz, 2H), 1.52–1.59
(m, 2H), 1.27–1.36 (m, 2H), 0.83 (t, J = 8.0 Hz, 3H). 13C NMR
(100 MHz, CDCl3): δ 165.0, 162.3, 138.1, 132.8, 132.3, 131.3,
131.1, 123.6, 122.5, 121.9, 118.8, 117.9, 116.1, 73.7, 32.3, 19.2,
13.8. IR (KBr): 572, 720, 755, 821, 1091, 1347, 1495, 1605,
1649, 2871, 2953, 3019. HRMS (ESI, m/z) calcd. for
C19H18NO2Br [M + H]+: 371.0521, found: 371.0529.
4-Butoxy-6-chloro-8-fluoro-3-phenyl-2(1H)-quinolinone
1
(2k). White solid. H NMR (400 MHz, CDCl3): δ 8.85 (s, 1H),
7.68 (t, J = 4.0 Hz, 1H), 7.44–7.49 (m, 4H), 7.36–7.40 (m, 1H),
7.28–7.31 (m, 1H), 3.56 (t, J = 4.0 Hz, 2H), 1.49–1.54 (m, 2H),
1.21–1.30 (m, 2H), 0.80 (t, J = 8.0 Hz, 3H). 13C NMR (100 MHz,
CDCl3): δ 162.9, 159.9, 150.1, 147.6, 132.2, 130.7, 128.2, 126.8,
125.1, 121.2, 120.6, 119.1, 116.6, 116.4, 73.5, 31.9, 18.9, 13.6.
IR (KBr): 520, 573, 703, 792, 908, 1065, 1345, 1502, 1644, 2872,
2960, 3140, 3423. HRMS (ESI, m/z) calcd. for C19H18ClFNO2
[M + H]+: 346.1010, found: 346.1006.
6-Bromo-4-butoxy-3-phenyl-2(1H)-quinolinone (2l). White
solid. 1H NMR (400 MHz, CDCl3): δ 11.69 (s, 1H), 8.01
(d, J = 4.0 Hz, 1 H), 7.50–7.54 (m, 3H), 7.46 (t, J = 8.0 Hz, 2H),
7.38–7.42 (m, 1H), 7.12 (d, J = 8.0 Hz, 1H), 3.56 (t, J = 8.0 Hz, 2H),
1.49–1.56 (m, 2H), 1.23–1.30 (m, 2H), 0.82 (t, J = 8.0 Hz,
3H). 13C NMR (100 MHz, CDCl3): δ 165.2, 160.8, 136.8,
133.7, 133.0, 131.0, 128.3, 128.1, 125.9, 120.2, 119.7, 118.0,
115.19, 73.5, 32.1, 19.1, 13.8. IR (KBr): 564, 701, 848, 1149,
1245, 1339, 1433, 1639, 2926, 2958, 3156, 3379. HRMS
(ESI, m/z) calcd. for C19H18NO2Br [M + H]+: 371.0521, found:
371.0527.
4-Butoxy-6-fluoro-3-phenyl-2(1H)-quinolinone (2m). White
solid. 1H NMR (400 MHz, CDCl3): δ 12.18 (s, 1H), 7.53–7.57
(m, 3H), 7.45–7.49 (m, 2H), 7.33–7.42 (m, 1H), 7.22–7.25
(m, 1H), 7.14–7.19 (m, 1H), 3.56 (t, J = 6.0 Hz, 2H), 1.48–1.55
(m, 2H), 1.22–1.31 (m, 2H), 0.80 (t, J = 8.0 Hz, 3H). 13C NMR
(100 MHz, CDCl3): δ 164.9, 161.1, 159.6, 157.2, 134.3, 133.1,
131.0, 128.3, 128.1, 120.2, 119.4, 119.1, 117.6, 109.0, 108.8,
73.5, 32.2, 19.2, 13.8. IR (KBr): 557, 649, 705, 1090, 1181,
1270, 1349, 1446, 1496, 1652, 2871, 2932, 2957, 3159. HRMS
4-Butoxy-3-(4-trifluoromethylphenyl)-2(1H)-quinolinone (2f).
1
White solid. H NMR (400 MHz, CDCl3): δ 10.31 (s, 1H), 7.93
(d, J = 8.0 Hz, 1H), 7.71 (t, J = 8.0 Hz, 3H), 7.53 (t, J = 8.0 Hz,
1H), 7.21–7.27 (m, 3H), 3.60 (t, J = 4.0 Hz, 2H), 1.51–1.55
(m, 2H), 1.24–1.33 (m, 2H), 0.80 (t, J = 8.0 Hz, 3H). 13C NMR
(100 MHz, CDCl3): δ 164.9, 162.7, 138.2, 137.2, 131.5, 131.4,
129.9, 129.6, 125.0, 123.6, 122.6, 118.8, 117.8, 116.3, 74.0,
32.2, 19.1, 13.7. IR (KBr): 569, 698, 754, 839, 1138, 1155,
1326, 1608, 1651, 2739, 2877, 2945. HRMS (ESI, m/z) calcd.
for C20H19F3NO2 [M + H]+: 362.1368, found: 362.1360.
4-Butoxy-3-(4-nitrophenyl)-2(1H)-quinolinone (2g). White
solid. 1H NMR (400 MHz, CDCl3): δ 11.92 (s, 1H), 8.33
(d, J = 12.0 Hz), 7.93 (d, J = 8.0 Hz, 1H), 7.81–7.84 (m, 2H),
7.52–7.56 (m, 1H), 7.28 (d, J = 12.0 Hz, 1H), 7.24 (d, J = 4.0 Hz,
1H), 3.63 (t, J = 8.0 Hz, 2H), 1.53–1.60 (m, 2H), 1.25–1.33
(m, 2H), 0.82 (t, J = 8.0 Hz, 3H). 13C NMR (100 MHz, CDCl3):
δ 164.3, 163.1, 147.2, 140.5, 138.3, 132.1, 131.8, 123.9, 123.3,
122.9, 118.1, 117.6, 116.1, 74.4, 32.2, 19.1, 13.8. IR (KBr):
597, 669, 754, 839, 955, 1024, 1285, 1344, 1518, 1650, 2869,
2952, 3396. HRMS (ESI, m/z) calcd. for C19H18N2O4 [M + H]+:
338.1267, found: 338.1277.
4-Butoxy-6-methyl-3-phenyl-2(1H)-quinolinone (2h). White
solid. 1H NMR (400 MHz, CDCl3): δ 10.19 (s, 1H), 7.69 (s,
1H), 7.53 (t, J = 4.0 Hz, 2H), 7.42–7.46 (m, 2H), 7.30–7.38 (m,
2H), 7.11 (d, J = 8.0 Hz, 1H), 3.57 (t, J = 8.0 Hz, 2H), 1.49–1.54
(m, 2H), 1.23–1.31 (m, 2H), 0.80 (t, J = 8.0 Hz, 3H). 13C NMR
(100 MHz, CDCl3): δ 164.9, 161.7, 135.8, 133.3, 132.11, 131.7,
1574 | Catal. Sci. Technol., 2014, 4, 1570–1577
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(ESI, m/z) calcd. for C19H18FNO2 [M + H]+: 311.1322, found:
311.1328.
HRMS (ESI, m/z) calcd. for C20H20NO2BrNa [M +
Na]+:
408.0575, found: 408.0568.
4-Butoxy-3-phenyl-6-trifluoromethyl-2(1H)-quinolinone (2n).
White solid. 1H NMR (400 MHz, CDCl3): δ 12.40 (s, 1H),
8.18 (s, 1H), 7.58–7.60 (m, 1H), 7.54 (t, J = 4.0 Hz, 2H), 7.48
(t, J = 8.0 Hz, 2H), 7.40–7.44 (m, 1H), 7.29 (d, J = 8.0 Hz, 1H),
3.59 (t, J = 8.1 Hz, 2H), 1.50–1.56 (m, 2H), 1.23–1.32 (m, 2H),
0.81 (t, J = 8.0 Hz, 3H). 13C NMR (100 MHz, CDCl3): δ 165.6,
161.4, 139.8, 132.9, 132.2, 131.0, 128.4, 128.3, 127.2, 125.7,
125.0, 124.8, 124.1, 123.0, 121.4, 120.2, 117.8, 116.8, 73.7,
32.1, 19.1, 13.7. IR (KBr): 556, 698, 832, 910, 1121, 1269,
1323, 1349, 1629, 1662, 2875, 2934, 2961, 3167. HRMS
(ESI, m/z) calcd. for C20H19F3NO2 [M + H]+: 362.1368, found:
362.1367.
4-Butoxy-6-methyl-3-(4-trifluoromethylphenyl)-2(1H)-
quinolinone (2s). White solid. 1H NMR (400 MHz, CDCl3): δ
10.72 (s, 1H), 7.71 (s, 4H), 7.68 (s, 1H), 7.33–7.35 (m, 1H),
7.14 (d, J = 8.0 Hz, 1H), 3.59 (t, J = 4.2 Hz, 2H), 2.44 (s, 3H),
1.51–1.57 (m, 2H), 1.23–1.32 (m, 2H), 0.79 (t, J = 8.0 Hz, 3H).
13C NMR (100 MHz, CDCl3): δ 164.2, 162.4, 137.1, 136.0,
132.7, 132.2, 131.4, 129.8, 129.5, 124.87, 123.1, 117.6, 115.8,
73.7, 32.0, 30.9, 21.2, 18.9, 13.5. IR (KBr): 655, 703, 815, 1069,
1126, 1162, 1323, 1349, 1604, 1653, 2873, 2956, 3418. HRMS
(ESI, m/z) calcd. for C21H21NO2F3 [M + H]+: 376.1524, found:
376.1521.
4-Butoxy-6-methoxycarbonyl-3-phenyl-2(1H)-quinolinone (2o).
White solid. 1H NMR (400 MHz, CDCl3): δ 11.29 (s, 1H),
8.63 (s, 1H), 8.15 (d, J = 12.0 Hz, 1H), 7.53 (d, J = 4.0, 2H),
7.47 (t, J = 8.0 Hz, 2H), 7.41 (t, J = 8.0 Hz, 1H), 7.25 (d, J =
12.0 Hz, 1H), 3.95 (s, 3H), 3.61 (t, J = 4.5 Hz, 2H), 1.52–1.59
(m, 2H), 1.26–1.33 (m, 2H), 0.81 (t, J = 8.0 Hz, 3H). 13C NMR
(100 MHz, CDCl3): δ 166.6, 165.5, 161.8, 140.7, 132.8, 131.4,
130.9, 128.1, 128.0, 126.2, 124.1, 119.9, 117.6, 115.9, 73.5,
52.2, 31.9, 18.9, 13.6. IR (KBr): 562, 652, 699, 760, 1124, 1241,
1264, 1437, 1624, 1646, 1716, 2873, 2932, 2959, 3413. HRMS
(ESI, m/z) calcd. for C21H22NO4 [M + H]+: 352.1549, found:
352.1546.
Crystallography
Single crystals of 2q and 2s suitable for X-ray structural analy-
sis were obtained from an ethyl acetate–heptane solution at
room temperature. A suitable crystal for X-ray diffraction was
mounted on a glass fiber. Data collection was performed on a
Bruker Smart APEX CCD diffractometer using graphite mono-
chromated Mo-Kα radiation (λ = 0.71073 Å) at 296 K. The dif-
fraction frames were integrated using the SAINT package.
The structure was solved by direct methods using the pro-
gram SHELXS97. Structure refinement by the full-matrix
least-squares on F2 was carried out with the program
SHELXL97. All non-hydrogen atoms of the complex were
assigned anisotropic displacement parameters. The hydrogen
atoms were constrained to idealized geometries and assigned
isotropic displacement parameters equal to 1.2 times the Uiso
values of their respective parent atoms. Details of the crystal
data, data collections, and structure refinements are summa-
rized in Table S1 (see ESI†).
4-Butoxy-6-cyano-3-phenyl-2(1H)-quinolinone (2p). White
1
solid. H NMR (400 MHz, CDCl3): δ 11.32 (s, 1H), 8.24 (d, J =
4.0 Hz, 1H), 7.64–7.67 (m, 1H), 7.46–7.52 (m, 4H), 7.41–7.45
(m, 1H), 7.24 (s, 1H), 3.58 (t, J = 8.0 Hz, 2H), 1.51–1.55 (m,
2H), 1.22–1.31 (m, 2H), 0.82 (t, J = 8.0 Hz, 3H). 13C NMR (100
MHz, CDCl3): δ 165.3, 160.5, 140.1, 133.0, 132.4, 130.8, 129.0,
128.3, 128.2, 120.0, 118.9, 118.2, 116.9, 105.7, 73.7, 31.9, 18.9,
13.6. IR (KBr): 545, 651, 706, 825, 909, 1097, 1256, 1280,
1350, 1596, 1621, 1653, 2228, 2869, 2960, 3151, 3423. HRMS
(ESI, m/z) calcd. for C21H22NO4 [M + H]+: 352.1549, found:
352.1546.
4-Butoxy-6-methyl-3-(4-methylphenyl)-2(1H)-quinolinone (2q).
White solid. 1H NMR (400 MHz, CDCl3): δ 12.13 (s, 1H),
7.66 (s, 1H), 7.46 (d, J = 8.0 Hz, 2H), 7.27 (s, 3H), 7.21 (d, J =
8.0 Hz, 1H), 3.58 (t, J = 8.0 Hz, 2H), 2.42 (s, 6H), 1.49–1.56
(m, 2H), 1.24–1.33 (m, 2H), 0.80 (t, J = 8.0 Hz, 3H). 13C NMR
(100 MHz, CDCl3): δ 165.4, 161.6, 137.2, 136.0, 131.6, 130.9,
130.4, 128.8, 122.8, 119.8, 118.0, 116.2, 73.0, 32.2, 21.54,
21.35, 19.1, 13.8. IR (KBr): 520, 606, 799, 823, 1093, 1261,
1451, 1573, 1597, 1731, 2854, 2922, 2962. HRMS (ESI, m/z)
calcd. for C21H23NO2Na [M + Na]+: 344.1626, found: 344.1623.
3-(4-Bromophenyl)-4-butoxy-6-methyl-2(1H)-quinolinone (2r).
White solid. 1H NMR (400 MHz, CDCl3): δ 10.15 (s, 1H),
7.68 (s, 1H), 7.58 (d, J = 8.0 Hz, 2H), 7.44 (d, J = 8.0 Hz, 2H),
7.32–7.34 (m, 1H), 7.10 (d, J = 8.0 Hz, 1H), 3.60 (t, J = 8.0 Hz,
2H), 2.44 (s, 1H), 1.52–1.60 (m, 2H), 1.25–1.34 (m, 2H), 0.83
(t, J = 8.0 Hz, 3H). 13C NMR (100 MHz, CDCl3): δ 164.6, 162.0,
135.9, 132.7, 132.4, 132.0, 131.2, 122.9, 121.8, 118.7, 117.7,
115.9, 73.5, 32.1, 21.2, 19.0, 13.7. IR (KBr): 652, 723, 815,
1011, 1188, 1281, 1346, 1489, 1603, 1651, 2852, 2921, 2953.
Acknowledgements
This work was supported by National Natural Science Foun-
dation of China (21172026), the Fundamental Research
Funds for the Central Universities (DUT12LK47), and Scien-
tific Research Fund of Liaoning Provincial Education Depart-
ment (no. L2012024). X.-B. L. gratefully acknowledges the
Chang Jiang Scholars Program (no. T2011056) from Ministry
of Education of the People's Republic of China.
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