FeCl3?6H2O-catalyzed intramolecular allylic amination: Synthesis of substituted dihydroquinolines and quinolines

Article abstract of DOI:10.1021/jo301560w

A facile and efficient method to synthesize 2- or 4-substituted 1,2-dihydroquinolines and quinolines catalyzed by FeCl₃?6H ₂O (2 mol %) was described. The iron-catalyzed intramolecular allylic amination of 2-aminophenyl-1-en-3-ols proceeded smoothly to afford 13 1,2-dihydroquinoline and 8 quinoline derivatives under mild reaction conditions with good to excellent yields (up to 96%).

Full text of DOI:10.1021/jo301560w

Article
pubs.acs.org/joc
FeCl3·6H2O‑Catalyzed Intramolecular Allylic Amination: Synthesis of
Substituted Dihydroquinolines and Quinolines
Zhiming Wang,* Shen Li, Bin Yu, Haibo Wu, Yurong Wang, and Xiaoqiang Sun*
School of Petrochemical Engineering, Changzhou University, Changzhou, Jiangsu 213164, China
S
* Supporting Information
ABSTRACT: A facile and efficient method to synthesize 2- or 4-substituted 1,2-dihydroquinolines and quinolines catalyzed by
FeCl3·6H2O (2 mol %) was described. The iron-catalyzed intramolecular allylic amination of 2-aminophenyl-1-en-3-ols
proceeded smoothly to afford 13 1,2-dihydroquinoline and 8 quinoline derivatives under mild reaction conditions with good to
excellent yields (up to 96%).
intramolecular allylic amination of N-protected 2-amino-
phenyl-1-en-3-ols catalyzed by FeCl3·6H2O at room temper-
ature. Unlike other methods that also utilize alcohol pro-
electrophiles in 1,2-dihydroquinoline synthesis,17 our reaction
could be performed with the reaction vessel open to ambient
air. Furthermore, with the same reaction setup and with the
subsequent treatment of NaOH, substituted quinolines could
be achieved instead.
INTRODUCTION
■
Heterocyclic compounds, especially nitrogen-containing het-
erocycles, are ubiquitous in natural products and pharmaceut-
icals and represent the most important class of key structural
units in a large number of bioactive molecules.1 In particular,
quinolines and their derivatives play an important role in the
fields of natural products, medicinal chemistry, and materials
chemistry.2 In consequence, several significant methods for the
quinoline framework constructions are well-known, such as the
Skraup reaction,3 Combes synthesis,4 Gould−Jacobs reaction,5
RESULTS AND DISCUSSION
■
Friedlander synthesis,6 and Doebner−von Miller reaction.7
̈
Initially, we chose (E)-1-phenyl-3-(2-tosylaminophenyl)prop-1-
en-3-ol (1a) to optimize the reaction conditions by varying the
catalysts, solvents, and reaction temperature. The results are
summarized in Table 1. Although 2-phenyl-1-tosyl-1,2-dihy-
droquinoline was barely detected in the absence of metal
catalyst, a reaction yield of 96% was achieved in the presence of
2 mol % of FeCl3·6H2O at room temperature (rt) in CH2Cl2
(entries 1 and 2). It indicated that the catalyst FeCl3·6H2O was
essential and efficient for the cyclization reaction. Increasing the
catalyst loading to 5 mol % could not benefit the reaction time
or the yield (entry 3). However, lowering the catalyst loading to
1 mol % led to a sluggish reaction and a moderate yield of 50%
and longer reaction time (entry 4). Surprisingly, the reaction
provided lower yield at elevated temperature, albeit shorter
reaction time (entry 5). Among the solvents screened, the
intramolecular allylic amination took place in toluene or
benzene at rt (entries 6 and 8), but higher reaction temperature
was needed to improve the reaction efficiency by using toluene,
benzene, CHCl3, CH3NO2, or ClCH2CH2Cl as a reaction
medium (entries 7 and 9−12). When BF3·Et2O, CF3COOH,
and TsOH were applied as the catalyst, 58−70% yields of 2a
were achieved (entries 13−15). It was noteworthy that other
Because of their importance, the development of new synthetic
methodologies of quinolines with high efficiency and mild
reaction conditions is still an active research area.8 Selected
recent examples include reductive cyclizations of Baylis−
Hillman adducts,9 cascade reactions of alkynes,8b metal-
catalyzed cyclizations with anilines,10 and aza-Diels−Alder
reactions with N-arylaldimines.11
In recent years, iron-catalyzed carbon−carbon and carbon−
heteroatom bond formation processes have attracted consid-
erable attention because iron is one of the most inexpensive
and environmentally benign metals on earth.12 Among the
known methods in the literature,13,14 the iron-catalyzed
substitution reaction of alcohols with various nucleophiles has
become one of the most efficient and environmentally friendly
synthetic strategies for C- and N-alkylation.15 Although the
iron-catalyzed intermolecular allylic amination has been
extensively studied, examples of iron-catalyzed intramolecular
allylic amination between allylic alcohols and nitrogen
nucleophiles are relatively limited.15b During the course of
our ongoing study on the development of transition-metal-
mediated heterocyclic compound formations,16 we found that
dihydroquinolines and quinolines could be efficiently prepared
using iron catalyst under mild reaction conditions. Herein, we
would like to report an efficient synthetic pathway to 2- or 4-
substituted 1,2-dihydroquinolines and quinolines involving
Received: July 27, 2012
Published: August 30, 2012
© 2012 American Chemical Society
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Article
a
catalyzed intramolecular allylic amination of (E)-1-phenyl-3-
(2-tosylamino-phenyl)prop-1-en-3-ol is proposed in Scheme 2.
The coordination of catalyst FeCl3 to the hydroxyl group of 1a
leads to intermediate I, and the carbocation II is formed by
dehydration of intermediate I. Cyclization of the newly formed
carbocation II follows to generate dihydroquinoline 2a.15b
Although we have failed to isolate the intermediate I or II, it
was found that the carbocation species II could be trapped by
EtOH under the standard reaction conditions.20
Encouraged by the results above, we decided to apply this
new methodology to the one-pot synthesis of substituted
quinolines. As shown in Table 3, the corresponding substituted
quinolines could be synthesized from the same N-protected 2-
aminophenyl-1-en-3-ols in 66−93% yields using the iron-
catalyzed intramolecular allylic amination followed by basic
deprotection and aromatization. Both N-tosyl and N-mesyl
protected 2-aminophenyl-1-en-3-ols gave the desired final
quinoline derivatives with excellent reaction yields (entries 1
and 3). Surprisingly, when N-benzoyl protected 2-amino-
phenyl-1-en-3-ol was used as the starting material, only
dihydroquinoline intermediate 2c was detected (entry 4).
Methyl group, C−F bond, C−Cl bond, C−Br bond, and CC
bond at the terminal position of the allylic alcohol moiety were
suitable for this reaction (entries 5−11). It was also noteworthy
that the presence of small amount of ethanol in the reaction
system could improve the efficiency of the detosylation-
aromatization reaction (entries 1 and 2).21
Table 1. Optimization of Reaction Conditions
entry
catalyst
solvent
CH2Cl2
temp (°C) time (h) yield (%)
b
1
rt
24
1
trace
96
2
FeCl3·6H2O
FeCl3·6H2O
FeCl3·6H2O
FeCl3·6H2O
FeCl3·6H2O
FeCl3·6H2O
FeCl3·6H2O
FeCl3·6H2O
FeCl3·6H2O
FeCl3·6H2O
FeCl3·6H2O
BF3·Et2O
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
toluene
toluene
benzene
benzene
CHCl3
rt
c
3
rt
1
95
d
4
rt
12
50
5
40
rt
0.5
72
e
6
24
6
40
7
110
rt
85
e
8
24
6
45
9
80
70
100
90
rt
90
10
11
12
13
14
15
16
17
18
19
20
6
86
CH3NO2
ClCH2CH2Cl
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
8
83
5
83
12
12
1
70
CF3COOH
TsOH
rt
65
rt
58
b
b
b
b
b
CuCl
rt
24
24
24
24
24
trace
trace
trace
trace
CuCl2
rt
PdCl2
rt
HCl
rt
CH3COOH
rt
trace
a
b
CONCLUSION
0.5 mmol of 1a, 0.01 mmol of catalyst, and 2 mL of solvent. Little
■
desired product was detected, and up to 95% starting material was
recovered. 5 mol % of catalyst was used. 1 mol % of catalyst was
used. Up to 50% starting material was recovered.
In conclusion, a new method to synthesize the substituted 1,2-
dihydroquinolines via an iron-catalyzed intramolecular allylic
amination of N-protected 2-aminophenyl-1-en-3-ols under mild
conditions has been developed. The advantages of our
approach are the use of inexpensive and environmentally
friendly FeCl3·6H2O as the catalyst, as well as the tolerance for
the presence of water and air in the reaction system. In
addition, the synthetic application of this new method to the
one-pot synthesis of substituted quinolines has also been
demonstrated. The methodology is highly facile and efficient
and can be a useful tool for the synthesis of biologically and
photochemically active molecules.
c
d
e
catalyst, such as CuCl, CuCl2, PdCl2, HCl, and CH3COOH,
gave little desired product (entries 16−20).
With the optimized reaction conditions in hand, the reaction
scope was explored with a variety of N-protected 2-amino-
phenyl-1-en-3-ols. The results are summarized in Table 2. It
was found that N-mesyl and N-benzoyl 2-aminophenyl-1-en-3-
ols also worked for the cyclization reactions, albeit lower
reaction yield (entries 1 vs entries 3 and 4). The regioisomer of
1a (1a′) could lead to the same product 2a despite longer
reaction time and lower yield (entry 2). The iron-catalyzed
synthesis of substituted dihydroquinolines could tolerate a
methyl group, C−F bond, C−Cl bond, and C−Br at the
terminal position of the allylic alcohol moiety, giving 2d−2h
with 86−96% yields (entries 5−9). Low reaction yield was
obtained when furanyl-substituted allylic alcohol 1i was used as
a substrate (entry 10). The cyclization of alcohol with trans-
diene gave an acceptable yield of the product 2j (entry 11).
Interestingly, 4-methyl and 4-phenyl substituted 1,2-dihydro-
quinoline products 2k−2m were achieved by using the
standard catalyzed conditions; however, the reaction yields
greatly improved in benzene at 80 °C (entries 12−17).
To probe the reaction mechanism of the FeCl3·6H2O-
catalyzed intramolecular allylic amination, (S,E)-1-phenyl-3-(2-
tosylamino-phenyl)prop-1-en-3-ol and (R,E)-1-phenyl-3-(2-to-
sylamino-phenyl)prop-1-en-3-ol were subjected to the reac-
tion.18 In each case, dihydroquinoline 2a was obtained in 93−
95% yield as a racemic mixture,19 and no chirality transfer was
observed (Scheme 1).
EXPERIMENTAL SECTION
■
All reagents and solvents were obtained from commercial suppliers
and used without further purification. All H NMR and 13C MNR
1
spectra were recorded in CDCl3 or DMSO-d6 using TMS as an
internal standard. The starting materials protected 2-aminophenyl-1-
en-3-ols were prepared according to the literature procedures.17a
General Procedure for the Synthesis of Substituted 1,2-
dihydroquinolines 2. To a solution of protected 2-aminophenyl-1-
en-3-ol (0.5 mmol) in CH2Cl2 was added FeCl3·6H2O (0.01 mmol).
The reaction mixture was stirred at rt for 1 h (TLC monitored). The
resulting mixture was purified by flash column chromatography on
silical gel (petroleum ether/ethyl acetate) to give the desired pure
product (2a−m).
2-Phenyl-1-tosyl-1,2-dihydroquinoline (2a).17a 173 mg, 96% yield;
white solid; 1H NMR (400 MHz, CDCl3): δ 7.64 (d, J = 8.0 Hz, 1H),
7.34−7.33 (m, 4H), 7.24−7.18 (m, 4H), 7.14−7.08 (m, 3H), 6.96 (d, J
= 7.2 Hz, 1H), 6.28 (d, J = 9.6 Hz, 1H), 6.02 (d, J = 6.0 Hz, 1H), 5.88
(dd, J = 9.6, 6.0 Hz, 1H), 2.35 (s, 3H); 13C NMR (125 MHz, CDCl3)
δ 21.5, 57.0, 125.5, 126.3, 126.4, 126.5, 127.2, 127.4, 127.6, 127.9,
128.2, 128.4, 128.6, 129.1, 132.9, 136.1, 138.4, 143.4; IR (neat) 3061,
2922, 1347, 1168, 687 cm−1; MS (70 eV, EI) m/z = 361 [M+].
1-(Mesyl)-2-phenyl-1,2-dihydroquinoline (2b).21 128 mg, 90%
According to the literature15,17a and the results of our
experiments, a possible mechanism for the FeCl3·6H2O-
1
yield; white solid; H NMR (400 MHz, CDCl3) δ 7.53 (d, J = 7.6
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a
Table 2. FeCl3·6H2O-Catalyzed Intramolecular Allylic Amination for the Synthesis of Substituted Dihydroquinolines
a
b
c
0.5 mmol of 1, 0.01 mmol of FeCl3·6H2O, and 2 mL of CH2Cl2 at rt. Reaction time of 8 h. Benzene was used as a solvent instead of CH2Cl2 and
at 80 °C.
Scheme 1. Intramolecular Allylic Amination of (S)-1a and
(R)-1a
Scheme 2. Possible Mechanism for Iron-Catalyzed
Intramolecular Allylic Amination of (E)-1-Phenyl-3-(2-
tosylamino-phenyl)prop-1-en-3-ol
Hz, 1H), 7.34−7.32 (m, 2H), 7.25−7.17 (m, 6H), 6.81 (d, J = 9.6 Hz,
1H), 6.30 (dd, J = 9.6, 6.0 Hz, 1H), 6.00 (d, J = 6.0 Hz, 1H), 2.76 (s, 3
H); 13C NMR (125 MHz, CDCl3) δ 37.8, 56.9, 126.4, 126.6, 126.7,
127.0, 127.2, 127.3, 128.0, 128.4, 128.7, 132.9, 138.1; IR (neat) 3029,
2929, 1343, 1153, 760 cm−1; MS (70 eV, EI) m/z = 285 [M+].
1-(Benzoyl)-2-phenyl-1,2-dihydroquinoline (2c).22 135 mg, 87%
130.4, 135.4, 135.5, 139.2, 169.4; IR (neat) 3060, 2928, 1647, 1337,
698 cm−1; MS (70 eV, EI) m/z = 311 [M+].
2-(p-Tolyl)-1-tosyl-1,2-dihydroquinoline (2d).17a 161 mg, 86%
1
1
yield; white solid; H NMR (400 MHz, DMSO-d6) δ 7.41 (t, J = 7.2
yield; white solid; H NMR (400 MHz, CDCl3) δ 7.63 (d, J = 8.0
Hz, 1H), 7.33−7.21 (m, 10H), 7.01 (t, J = 7.2 Hz, 1H), 6.89−6.82 (m,
2H), 6.58 (dd, J = 9.2, 6.0 Hz, 1H), 6.52 (d, J = 7.6 Hz, 1H), 6.23 (d, J
= 6.0 Hz, 1H); 13C NMR (125 MHz, DMSO-d6) δ 54.3, 124.9, 125.0,
125.6, 126.4, 126.7, 127.0, 127.2, 127.5, 128.2, 128.4, 128.6, 129.9,
Hz, 1H), 7.33 (d, J = 8.0 Hz, 2H), 7.23−7.18 (m, 3H), 7.14−7.08 (m,
3H), 7.04 (d, J = 8.0 Hz, 2H), 6.96 (d, J = 7.6 Hz, 1H), 6.26 (d, J = 9.6
Hz, 1H), 5.98 (d, J = 6.0 Hz, 1H), 5.87 (dd, J = 9.6, 6.0 Hz, 1H), 2.35
(s, 3H), 2.26 (s, 3H); 13C NMR (125 MHz, CDCl3) δ 21.1, 21.6, 56.8,
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Hz, 1H), 7.18−7.09 (m, 5H), 7.01 (t, J = 7.6 Hz, 1H), 6.95 (d, J = 7.6
Hz, 1H), 6.45 (d, J = 5.6 Hz, 1H), 6.15 (d, J = 9.6 Hz, 1H), 6.01 (dd, J
= 9.6, 5.6 Hz, 1H), 2.35 (s, 3H); 13C NMR (125 MHz, CDCl3) δ 21.6,
55.2, 124.6, 126.0, 126.5, 126.6, 127.1, 127.5, 128.1,128.3, 128.6, 129.0,
129.1, 129.9, 131.3, 134.0, 135.8, 137.3, 143.6; IR (neat) 3065, 2924,
1598, 1353, 1168, 685 cm−1; HRMS (TOF, EI) [M]+ calculated for
C22H18ClNO2S 395.0747, found 395.0748.
Table 3. FeCl3·6H2O-Catalyzed Intramolecular Allylic
Amination for the Synthesis of Substituted Quinolines
a
2-(4-Fluorophenyl)-1-tosyl-1,2-dihydroquinoline (2g).17a 182 mg,
96% yield; white solid; 1H NMR (400 MHz, CDCl3) δ 7.63 (d, J = 8.0
Hz, 1H), 7.33−7.29 (m, 4H), 7.21 (t, J = 7.6 Hz, 1H), 7.16−7.08 (m,
3H), 6.98 (d, J = 7.6 Hz, 1H), 6.91 (t, J = 8.6 Hz, 2H), 6.29 (d, J = 9.6
Hz, 1H), 5.99 (d, J = 5.6 Hz, 1H), 5.85 (dd, J = 9.6, 5.6 Hz, 1H), 2.35
2
(s, 3H); 13C NMR (125 MHz, CDCl3) δ 21.6, 56.3, 115.3 (d, JFC
=
22.1 Hz), 125.8, 126.2, 126.3, 126.6, 127.2, 127.6, 128.4, 128.5, 129.1,
129.2 (d, 3JFC = 8.2 Hz), 132.7, 134.0 (d, 4JFC = 2.9 Hz), 136.0, 143.5,
1
162.4 (d, JFC = 244.5 Hz); IR (neat) 3066, 2925, 1601, 1346, 1167,
687 cm−1; MS (70 eV, EI) m/z = 379 [M+].
2-(4-Bromophenyl)-1-tosyl-1,2-dihydroquinoline (2h).17a 193 mg,
88% yield; white solid; 1H NMR (400 MHz, CDCl3) δ 7.64 (d, J = 8.0
Hz, 1H), 7.36 (d, J = 8.4 Hz, 2H), 7.32 (d, J = 8.0 Hz, 2H), 7.24−7.20
(m, 3H), 7.16−7.08 (m, 3H), 6.97 (d, J = 7.2 Hz, 1H), 6.29 (d, J = 9.6
Hz, 1H), 5.96 (d, J = 5.6 Hz, 1H), 5.85 (dd, J = 9.6, 5.6 Hz, 1H), 2.35
(s, 3H); 13C NMR (125 MHz, CDCl3) δ 21.6, 56.3, 122.0, 125.8,
126.0, 126.4, 126.7, 127.2,127.6, 128.4, 128.5, 129.1, 129.2, 131.5,
132.6, 135.9, 137.4, 143.6; IR (neat) 3047, 2923, 1598, 1348, 1167,
687 cm−1; MS (70 eV, EI) m/z = 439 [M+].
(E)-2-Styryl-1-tosyl-1,2-dihydroquinoline (2j).17a 132 mg, 68%
1
yield; white solid; H NMR (400 MHz, CDCl3) δ 7.74 (d, J = 8.0
Hz, 1H), 7.32 (d, J = 8.4 Hz, 2H), 7.28−7.26 (m, 1H), 7.26−7.13 (m,
6H), 7.08 (d, J = 8.0 Hz, 2H), 6.96 (dd, J = 7.6, 1.2 Hz, 1H), 6.52 (dd,
J = 15.6, 1.2 Hz, 1H), 6.16 (d, J = 9.2 Hz, 1H), 6.04 (dd, J = 16.0, 6.0
Hz, 1H), 5.72 (dd, J = 9.2, 6.0 Hz, 1H), 5.57 (t, J = 5.2 Hz, 1H), 2.34
(s, 3H); 13C NMR (125 MHz, CDCl3) δ 21.6, 56.0, 125.3, 125.4,
126.0, 126.5, 126.6, 127.2, 127.5, 127.8, 128.2, 128.4, 129.1, 132.1,
133.0, 136.1, 136.3, 143.4; IR (neat) 3027, 2924, 1598, 1349, 1168,
687 cm−1; MS (70 eV, EI) m/z = 387 [M+].
4-Methyl-1-tosyl-1,2-dihydroquinoline (2k).17a 103 mg, 69% yield;
white solid; 1H NMR (400 MHz, CDCl3) δ 7.70 (d, J = 8.0 Hz, 1H),
7.32−7.28 (m, 1H), 7.26−7.16 (m, 3H), 7.11 (d, J = 7.6 Hz, 1H), 7.05
(d, J = 8.0 Hz, 2H), 5.32 (br, 1H), 4.34−4.33 (m, 2H), 2.33 (s, 3H),
1.58 (s, 3H); 13C NMR (125 MHz, CDCl3) δ 17.7, 21.4, 45.3, 120.3,
123.3, 126.7, 127.2, 127.4, 127.8, 128.8, 131.4, 131.6, 135.2, 136.1,
143.2; IR (neat) 3064, 2924, 1350, 1164, 682 cm−1; MS (70 eV, EI)
m/z = 299 [M+].
4-Phenyl-1-tosyl-1,2-dihydroquinoline (2l).17a 141 mg, 78% yield;
white solid; 1H NMR (400 MHz, CDCl3) δ 7.80 (d, J = 8.0 Hz, 1H),
7.35−7.32 (m, 3H), 7.25−7.22 (m, 3H), 7.14 (t, J = 7.6 Hz, 1H), 7.03
(d, J = 8.0 Hz, 2H), 6.87 (d, J = 7.6 Hz, 1H), 6.71 (d, J = 7.0 Hz, 2H),
5.58 (t, J = 4.4 Hz, 1H), 4.54 (d, J = 4.4 Hz, 2H), 2.27 (s, 3H); 13C
NMR (125 MHz, CDCl3) δ 21.3, 45.5, 121.6, 126.0, 126.6, 127.57,
127.61, 127.64, 127.9, 128.3, 128.5, 129.1, 131.0, 135.5, 136.1, 138.1,
138.7, 143.4; IR (neat) 3030, 2924, 1351, 1165, 681 cm−1; MS (70 eV,
EI) m/z = 361 [M+].
a
0.5 mmol of 1, 0.01 mmol of FeCl3·6H2O, and 2 mL of CH2Cl2 at rt
for 1 h; then 2.5 mmol of NaOH and 0.1 mL EtOH were added to the
reaction mixture, and the reaction was continued for 12 h under reflux.
b
Without EtOH and 50% dihydroquinoline intermediate 2a was
c
recovered. Only 86% of dihydroquinoline intermediate 2c was
isolated. Benzene was used as a solvent instead of CH2Cl2 and at 80
°C.
d
6-Chloro-4-phenyl-1-tosyl-1,2-dihydroquinoline (2m).17a 152 mg,
77% yield; white solid; 1H NMR (300 MHz, CDCl3) δ 7.73 (d, J = 8.8
Hz, 1H), 7.34 (d, J = 8.4 Hz, 2H), 7.31−7.23 (m, 4H), 7.06 (d, J = 7.8
Hz, 2H), 6.84 (d, J = 2.4 Hz, 1H), 6.71−6.68 (m, 2H), 5.61 (t, J = 4.5
Hz, 1H), 4.53 (d, J = 4.5 Hz, 2H), 2.28 (s, 3 H); 13C NMR (75 MHz,
CDCl3) δ 21.4, 45.4, 122.9, 125.8, 127.5, 127.9, 128.1, 128.2, 128.4,
129.0, 129.2, 132.3, 132.4, 134.0, 135.8, 137.3, 137.9, 143.7; IR (neat)
3028, 2920, 1354, 1163, 676 cm−1; MS (70 eV, EI) m/z = 395 [M+].
General Procedure for the Synthesis of Substituted Quino-
lines 3. To a solution of protected 2-aminophenyl-1-en-3-ol (0.5
mmol) in CH2Cl2 was added FeCl3·6H2O (0.01 mmol). After the
reaction mixture was stirred at rt for 1 h (TLC monitored), NaOH
(2.5 mmol) and EtOH (0.1 mL) were added, and the reaction was
continued for 12 h under reflux (TLC monitored). The resulting
mixture was purified by flash column chromatography on silical gel
(petroleum ether/ethyl acetate) to give the desired pure product (3a−
h).
125.4, 126.2, 126.4, 126.7, 127.3, 127.4, 127.7, 128.2, 128.7, 129.1,
129.2, 132.9, 135.3, 136.2, 137.7, 143.3; IR (neat) 3028, 2923, 1598,
1347, 1346, 1167, 687 cm−1; MS (70 eV, EI) m/z = 375 [M+].
2-(4-Chlorophenyl)-1-tosyl-1,2-dihydroquinoline (2e).17a 172 mg,
87% yield; white solid; 1H NMR (400 MHz, CDCl3) δ 7.64 (d, J = 8.0
Hz, 1H), 7.32 (d, J = 8.0 Hz, 2 H), 7.27 (d, J = 8.0 Hz, 2H), 7.24−7.19
(m, 3H), 7.16−7.08 (m, 3H), 6.97 (d, J = 7.6 Hz, 1H), 6.28 (d, J = 9.6
Hz, 1H), 5.98 (d, J = 6.0, 1H), 5.85 (dd, J = 9.6, 6.0 Hz, 1H), 2.35 (s,
3H); 13C NMR (125 MHz, CDCl3) δ 21.6, 56.2, 125.9, 126.0, 126.4,
126.6, 127.2, 127.6, 128.5, 128.6, 128.9, 129.2, 132.7, 133.8, 136.0,
136.9, 143.6; IR (neat) 3063, 2923, 1597, 1347, 1168, 687 cm−1; MS
(70 eV, EI) m/z = 395 [M+].
2-(2-Chlorophenyl)-1-tosyl-1,2-dihydroquinoline (2f). 186 mg,
94% yield; white solid; mp 85−86 °C; 1H NMR (400 MHz,
CDCl3) δ 7.79 (d, J = 8.0 Hz, 1H), 7.39−7.34 (m, 3H), 7.30 (t, J = 7.6
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Article
2-Phenylquinoline (3a).23 95 mg, 93% yield; white solid; 1H NMR
(400 MHz, CDCl3) δ 8.22−8.16 (m, 4H), 7.87 (d, J = 8.8 Hz, 1H),
7.82 (d, J = 8.4 Hz, 1H), 7.72 (t, J = 8.4 Hz, 1H), 7.55−7.51 (m, 3H),
7.46 (t, J = 7.6 Hz, 1H); 13C NMR (125 MHz, CDCl3) δ 119.0, 126.3,
127.2, 127.5, 127.6, 128.9, 129.3, 129.6, 129.7, 136.8, 139.7, 148.3,
157.4; IR (neat) 3058, 2926, 1597, 1491, 772 cm−1; MS (70 eV, EI)
m/z = 205 [M+].
136.7, 143.5; HRMS (TOF, EI) [M]+ calculated for C24H25NO3S
407.1555, found 407.1556.
ASSOCIATED CONTENT
■
S
* Supporting Information
1H NMR and 13C NMR spectra of compounds 2a−m and 3a−
h. This material is available free of charge via the Internet at
http://pubs.acs.org.
2-(p-Tolyl)quinoline (3b).23 94 mg, 86% yield; white solid; 1H
NMR (400 MHz, CDCl3) δ 8.19 (d, J = 8.8 Hz, 1H), 8.16 (d, J = 8.4
Hz, 1H), 8.07 (d, J = 8.0 Hz, 2H), 7.85 (d, J = 8.8 Hz, 1H), 7.81 (d, J
= 8.0 Hz, 1H), 7.71 (td, J = 8.0, 1.2 Hz, 1H), 7.50 (t, J = 7.6 Hz, 1H),
7.33 (d, J = 8.0 Hz, 2H), 2.43 (s, 3H); 13C NMR (125 MHz, CDCl3) δ
21.4, 118.8, 126.6, 127.06, 127.08, 127.4, 129.5, 129.6, 136.6, 136.8,
139.4, 148.3, 157.3; IR (neat) 3039, 2925, 1596, 1432, 814 cm−1; MS
(70 eV, EI) m/z = 219 [M+].
AUTHOR INFORMATION
Corresponding Author
*E-mail: wzmmol@hotmail.com; xqsun@cczu.edu.cn.
■
Notes
2-(4-Chlorophenyl)quinoline (3c).23 104 mg, 87% yield; white
The authors declare no competing financial interest.
1
solid; H NMR (400 MHz, CDCl3) δ 8.22 (d, J = 8.4 Hz, 1H), 8.16
(d, J = 8.4 Hz, 1H), 8.15−8.10 (m, 2H), 7.84−7.82 (m, 2H), 7.75−
7.71 (m, 1H), 7.55−7.47 (m, 3H); 13C NMR (100 MHz, CDCl3) δ
118.6, 126.5, 127.2, 127.5, 128.8, 129.0, 129.7, 129.9, 135.6, 137.0,
138.0, 148.2, 156.0; IR (neat) 3055, 2924, 1594, 1486, 817 cm−1; MS
(70 eV, EI) m/z = 239 [M+].
ACKNOWLEDGMENTS
■
This work was financially supported by the Natural Science
Foundation of China (no. 21102009), the Priority Academic
Program Development of Jiangsu Higher Education Institu-
tions, and Natural Science Foundation of Jiangsu Province (no.
BK2011230).
2-(2-Chlorophenyl)quinoline (3d).23 110 mg, 92% yield; white
1
solid; H NMR (400 MHz, CDCl3) δ 8.21 (d, J = 8.8 Hz, 1H), 8.18
(d, J = 8.4 Hz, 1H), 7.87 (d, J = 8.4 Hz, 1H), 7.76−7.72 (m, 2H), 7.70
(dd, J = 7.2, 2.0 Hz, 1H), 7.59−7.55 (m, 1H), 7.51 (dd, J = 7.6, 1.6 Hz,
1H), 7.43−7.35 (m, 2 H); 13C NMR (100 MHz, CDCl3) δ 122.8,
126.8, 127.1, 127.2, 127.6, 129.6, 129.7, 129.9, 130.1, 131.7, 132.4,
135.7, 139.7, 148.1, 157.4; IR (neat) 3058, 2922, 1598, 1504, 1037,
760 cm−1; MS (70 eV, EI) m/z = 239 [M+].
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■
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chez-Rosello,
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2-(4-Fluorophenyl)quinoline (3e).23 104 mg, 93% yield; white
solid; 1H NMR (400 MHz, CDCl3) δ 8.22 (d, J = 8.4 Hz, 1H), 8.18−
8.15 (m, 3H), 7.83 (d, J = 8.8 Hz, 2H), 7.75−7.71 (m, 1H), 7.55−7.51
(m, 1H), 7.23−7.19 (m, 2H); 13C NMR (125 MHz, CDCl3) δ 115.8
3
2
(d, JFC = 7.8 Hz), 118.6, 126.4, 127.1, 127.5, 129.4 (d, JFC = 22.1
4
Hz), 129.6, 129.8, 135.8 (d, JFC = 2.0 Hz), 137.0, 148.2, 156.2, 163.8
1
(d, JFC = 246.9 Hz); IR (neat) 3066, 2926, 1593, 1498, 1432, 821
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cm−1; MS (70 eV, EI) m/z = 223 [M+].
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2-(4-Bromophenyl)quinoline (3f).23 126 mg, 89% yield; white
2812.
1
solid; H NMR (400 MHz, CDCl3) δ 8.22 (d, J = 8.8 Hz, 1H), 8.15
́
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7.54 (t, J = 7.2 Hz, 1H); 13C NMR (125 MHz, CDCl3) δ 118.5, 123.9,
126.5, 127.2, 127.5, 129.1, 129.7, 129.9, 132.0, 137.0, 138.5, 148.2,
156.0; IR (neat) 3060, 2924, 1594, 1550, 1429 cm−1; MS (70 eV, EI)
m/z = 283 [M+].
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(E)-2-Styrylquinoline (3g).24 77 mg, 67% yield; white solid; 1H
NMR (300 MHz, CDCl3) δ 8.14 (d, J = 8.4 Hz, 1H), 8.08 (d, J = 8.4
Hz, 1H), 7.80 (d, J = 8.1 Hz, 1H), 7.72−7.64 (m, 5H), 7.50 (t, J = 7.8
Hz, 1H), 7.44−7.33 (m, 4H); 13C NMR (125 MHz, CDCl3) δ 119.3,
126.2, 127.3, 127.5, 128.7, 128.8, 129.0, 129.2, 129.8, 134.4, 136.4,
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2-Phenyl-4-vinylquinoline (3h). 83 mg, 72% yield; white solid; mp
1
108−110 °C; H NMR (400 MHz, CDCl3) δ 8.20−8.17 (m, 2H),
8.10 (d, J = 8.4 Hz, 1H), 7.95 (s, 1H), 7.80−7.69 (m, 1H), 7.57−7.45
(m, 4H), 7.34−7.28 (m, 1H), 7.25−7.19 (m, 1H), 6.05 (d, J = 17.2
Hz, 1H), 5.71 (d, J = 11.2 Hz, 1H); 13C NMR (125 MHz, CDCl3) δ
115.5, 120.6, 123.4, 125.2, 126.3, 127.5, 128.8, 129.3, 129.5, 130.3,
132.6, 139.8, 144.2, 148.6, 157.3; IR (neat) 3062, 2925, 1592, 1348,
764 cm−1; HRMS (TOF, EI) [M]+ calculated for C17H13N 231.1048,
found 231.1045.
̃
(E)-N-(2-(1-Ethoxy-3-phenylallyl)phenyl)-4-methylbenz-ene-
sulfonamide (4). 187 mg, 92% yield; semisolid; 1H NMR (300 MHz,
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7.25−7.23 (m, 3H), 7.11−7.00 (m, 4H), 6.41 (dd, J = 15.9, 1.2 Hz,
1H), 6.08 (dd, J = 15.9, 6.0 Hz, 1H), 4.89 (dd, J = 6.0, 1.2 Hz, 1H),
3.62−3.48 (m, 2H), 2.28 (s, 3 H), 1.34 (t, J = 7.2 Hz, 3H); 13C NMR
(75 MHz, CDCl3) δ 15.2, 21.5, 64.7, 83.1, 119.7, 123.8, 126.8, 127.2,
127.7, 128.0, 128.3, 128.5, 129.0, 129.1, 129.5, 131.9, 136.1, 136.2,
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