CuSO4-d-glucose, an inexpensive and eco-efficient catalytic system: Direct access to diverse quinolines through modified Friedl??nder approach involving SNAr/reduction/annulation cascade in one pot

Article abstract of DOI:10.1039/c4ra14138e

A highly efficient and scalable multicomponent domino reaction for the synthesis of functionalized/annulated quinolines is devised directly from 2-bromoaromatic aldehydes/ketones in H₂O-EtOH mixture for the first time. The key to this reaction is the use of an air-stable, eco-efficient and inexpensive CuSO₄-d-glucose catalyst system, which is able to catalyze multiple transformations in one pot. The approach is carbon-economic and relies on sequential S_NAr/reduction/Friedl??nder annulation steps, forming C-C and C-N bonds by cleavage of the Csp²-Br bond in a single synthetic operation. The reaction has a broad substrate scope and affords products in good to excellent yields.

Full text of DOI:10.1039/c4ra14138e

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ARTICLE TYPE
CuSO -D-glucose an inexpensive and eco-efficient catalytic system:
4
direct access to diverse quinolines through modified Friedländer
approach involving S Ar/reduction/annulation cascade in one-pot
N
Namrata Anand, Tanmoy Chanda, Suvajit Koley, Sushobhan Chowdhury and Maya Shankar Singh*
5
Received (in XXX, XXX) Xth XXXXXXXXX 20XX, Accepted Xth XXXXXXXXX 20XX
DOI: 10.1039/b000000x
A
highly efficient and scalable multicomponent domino reaction for the synthesis of
1
0
functionalized/annulated quinolines is devised directly from 2ꢀbromoaromatic aldehydes/ketones in H Oꢀ
2
EtOH mixture for the first time. The key to this reaction is the use of an airꢀstable, ecoꢀefficient and
inexpensive CuSO ꢀDꢀglucose catalyst system, which is able to catalyze multiple transformations in oneꢀ
4
pot. The approach is carbonꢀeconomic and relies on sequential S Ar/reduction/Friedländer annulation
N
2
steps forming C−C and C−N bonds by cleavage of Csp −Br bond in a single synthetic operation. The
1
5
reaction has a broad substrate scope and affords products in good to excellent yields.
anticonvulsant, antiꢀinflammatory, anticardiovascular, antifungal,
6
Introduction
and HIVꢀ1 integrase inhibitory activities. A number of quinoline
derivatives have been successfully commercialized as drugs such
as Singulair, Tafenoquine, Aldara, and hydroxychloroquine.
Also, they are valuable synthons for the preparation of materials
with unique electronic and optical properties.
Generation of structural diversity and molecular complexity from
easily available and inexpensive starting materials in
operationally simple and pot, atom, and cost economic manner is
one of the most promising challenges for synthetic chemists. The
core strategies to minimize the environmental impact of a
reaction involves the use of greener solvents and recyclable ecoꢀ
7
4
4
5
5
0
5
0
5
8
1
2
2
3
3
0
5
0
5
Due to their vast applications, several strategies for the
9
synthesis of quinolines have been reported. The most common
10
11
12
ones include Skraup,
Friedländer,
Pfitzinger,
Conradꢀ
1
e,f
friendly catalysts. The copperꢀmediated transformations have
emerged as a powerful method for the construction of C−C and
C−heteroatom bonds because of its abundance, lowꢀcost, and ecoꢀ
13
14
15
Limpach, Combes and Doebnerꢀvon Miller synthesis. All
these routes access the quinoline synthesis through
inter/intramolecular annulation of aniline or its derivatives with
carbonyl compounds. Friedländer reaction still being an
“evergreen” method of choice, an array of conditional/structural
2
efficient nature.
Nitrogenꢀcontaining heterocycles are omnipresent in natural
products and pharmaceutical substances. Consequently, the
development of methods for the introduction of nitrogen in
simple organic compounds is an intense focus of modern
research. Quinolines are present as a core structural unit in a
wide range of pharmaceuticals and natural products. They have
been recognized as a privileged structure in the field of natural
alkaloids, material and medicinal chemistry as well as in bioꢀ
organic/bioꢀorganometallic processes. Furthermore, they show
16
modifications have been reported. Nevertheless, many existing
methods are inefficient and require multiple steps, highly
functionalized substrates and complicated operational procedures
producing large quantities of waste. Most relevant limitation is
the use of the 2ꢀaminobenzaldehyde as a substrate, which is
highly prone to self condensation.
3
4
17
Therefore, 2ꢀ
11b
11c
aminobenzylalcohols,
nitrobenzyl alcohols
2ꢀnitrobenzaldehyde,
are frequently utilized as 2ꢀ
and
2ꢀ
5
16a
antimalarial, tumoricidal, antimycobacterial, antimicrobial,
17b
aminobenzaldehyde counterpart.
The privileged status of
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a
quinolines still demands the more economical and ecoꢀefficient
strategies for their synthesis.
Table 1 Optimization studies for the synthesis of quinoline 3aa
9
a,18
To achieve this goal, two main approaches have been taken into
consideration: 1) The development of suitable catalytic system
and 2) the use of greener solvents instead of toxic organic
solvents. The direct use of 2ꢀbromoaromatic aldehydes/ketones
with active methylene for the synthesis of quinolines has not been
explored. Herein, we report an ecoꢀefficient oneꢀpot protocol for
the direct synthesis of diverse quinolines from commercially
available 2ꢀbromoaromatic aldehydes/ketones as a mimic of 2ꢀ
5
0
5
60
Entry
Catalyst
mmol)
Ligand (mmol)
Base (mmol)
Solvent
(5 mL)
Time
(h)
Yield
b
(
(%)
1
1
2
3
4
Cu
2
O (0.3)
Proline (1.2)
Proline (1.2)
Proline (1.2)
Acetic acid
DMSO
DMSO
8
8
50
55
52
21
aminobenzaldehyde in the presence of inexpensive CuSO ꢀDꢀ
4
CuI (0.3)
CuI (0.3)
CuI (0.3)
glucose catalyst system in green waterꢀethanol solvent. This type
of operationally simple and ecoꢀfriendly CuSO ꢀDꢀglucose
4
PEGꢀ400
DMSO
8
catalysed oneꢀpot S Ar/reduction/heteroannulation cascade for
N
24
1
the synthesis of quinolines is not explored previously to the best
of our knowledge.
(1.2)
5
6
7
8
CuI (0.3)
Proline (1.2)
DMSO
DMSO
DMSO
DMSO
8
24
24
8
62
+
K
2
CO (1)
3
Results and discussion
c
c
Cu(OAc)
0.3)
2
Proline (1.2)
+ K CO (1)
n.r.
n.r.
69
(
2
3
With a view to construct quinoline framework, we selected 2ꢀ
bromobenzaldehyde (1a) as a model substrate. In our initial
study, the reaction of 1a (1.0 mmol) with sodium azide (2.0
CuSO (0.3)
4
Proline (1.2)
CO (1)
+
K
2
3
20
25
30
35
40
45
50
55
mmol) and acetyl acetone (2a, 1.1 mmol) in the presence of Cu O
CuSO
NaꢀLꢀascorbate
0.3)
CuSO (0.3) +
4
(0.3) +
Proline (1.2)
+ K CO (1)
2
2
3
(0.3 mmol), proline (1.2 mmol) in DMSO at 90 ºC in the open
(
atmosphere afforded the desired product 3ꢀacetylꢀ2ꢀ
methylquinoline 3aa in 50% yield within 8 h (Table 1, entry 1).
Encouraged by this result, we turned our attention to find the
optimized reaction conditions by screening various catalysts,
ligands and solvents. The results are listed in Table 1. The use of
9
4
Proline (0.2)
+ K CO (1)
DMSO
EtOH
EtOH
24
6
21
82
NaꢀLꢀascorbate
(0.3)
2
3
10
CuSO
NaꢀLꢀascorbate
0.3)
CuSO (0.3) +
DꢀGlucose (0.3)
4
(0.3) +
Proline (0.2)
+ K CO (1)
2
3
(
CuI (0.3 mmol) in place of Cu O in the above reaction afforded
2
1
1
1
1
1
2
3
4
4
Proline (0.2)
+ K CO (1)
5
5
87
72
91
95
57
3
aa in 55% yield (Table 1, entry 2). Change of the solvent from
2
3
DMSO to PEGꢀ400 could not offer the better result (Table 1,
entry 3). Acetic acid in place of proline was also found to be
ineffective (Table 1, entry 4). Next, we assumed that the use of
CuSO (0.3) +
4
Proline (0.2)
+ K CO (1)
2
H O
DꢀGlucose (0.3)
2
3
CuSO (0.3) +
4
Proline (0.2)
+ K CO (1)
H
2
O+
4
19
base may improve the efficiency of this transformation.
Consequently, the use of K CO in the above reaction furnished
DꢀGlucose (0.3)
EtOH(3:2)
2
3
2
3
CuSO (0.3) +
4
Proline (0.2)
+ KOH (1)
H
2
O+
3
the desired product 3aa in 62% yield (Table 1, entry 5). Further
screening of other Cu salts such as Cu(OAc)2 and CuSO4
DꢀGlucose (0.3)
EtOH(3:2)
15
CuSO (0.1) +
4
Proline (0.2)
+ KOH (1)
H O+
2
15
5
separately was found to be completely ineffective (Table 1,
entries 6 and 7).
On the basis of above observations, we thought to generate
DꢀGlucose (0.1)
EtOH(3:2)
d
1
6
CuSO
4
(0.3) +
Proline(0.2)
+ KOH (1)
PEGꢀ400
ꢀ
DꢀGlucose (0.3)
Cu(I) in situ by the reduction of highly economical CuSO salt.
a
4
3
Reaction conditions: 1a (1.0 mmol), 2a (1.1 mmol), NaN (2.0 mmol),
The use of sodium Lꢀascorbate with CuSO noticeably increased
CuSO
4
(0.3 mmol), Dꢀglucose (0.3 mmol), proline (0.2 mmol), KOH (1
OꢀEtOH (3:2, 5 mL), 90 ºC. Isolated pure yields. n.r. = no
4
b
c
mmol), Hd
2
the yield of 3aa to 69% (Table 1, entry 8). The reaction did not
proceed to completion when lesser amount of proline (0.2 equiv)
was used under similar conditions (Table 1, entry 9). This may be
due to dual role of proline as ligand and a proton source.
Therefore, DMSO was replaced with ethanol to provide the direct
proton source. Notably, the use of EtOH as a solvent in the
presence of 0.2 equiv of proline increased the yield to 82% (Table
reaction. Partial conversion with several overlapping spots.
6
7
7
5
0
5
In an attempt to find the green solvent, the above reaction was
performed in water. Although the desired product 3aa was
obtained in 72% yield, the starting substrates were not completely
soluble in water and remained unconsumed (Table 1, entry 12).
We deemed to add ethanol to boost the worth of the reaction.
After several attempt, the better result was obtained by carrying
out the reaction in waterꢀethanol (3:2) mixture (Table 1, entry
3). We envisioned that the use of stronger base like KOH in
place of K CO3 may further improve the efficiency of the
reaction by promoting dehydrative cyclization. As expected, the
use of KOH increased the yield from 91% to 95% as well as
reduced the reaction time from 4 h to 3 h (Table 1, entry 14). On
lowering the catalytic loading, the conversion was drastically
1
, entry 10). We presume that this protocol undergoes copperꢀ
promoted Ullmannꢀtype coupling of 1a with NaN followed by
3
reduction to give 2ꢀaminobenzaldehyde in situ. The subsequent
reaction of 2ꢀaminobenzaldehyde with acetyl acetone 2a via
Friedländer annulation afforded the desired quinoline 3aa.
The success of this protocol prompted us to investigate about
the use of reducing carbohydrate Dꢀglucose. To our pleasure, the
use of Dꢀglucose in place of sodium Lꢀascorbate increased the
yield to 87% (Table 1, entry 11).
1
2
2
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diminished (Table 1, entry 15). Finally, when the model reaction
was carried out in PEGꢀ400 at 90 C, only partial conversion with
diketones affording the corresponding quinolines 3 in excellent
yields.
º
several overlapping spots was observed (Table 1, entry 16). Thus,
To illustrate the broad synthetic utility and generality of our
the optimum reaction conditions for the synthesis of quinoline 25 developed oneꢀpot domino methodology, we further treated 2ꢀ
5
3aa was achieved by employing 1a (1 mmol), NaN (2 mmol), 2a
bromoaromatic aldehydes/ketone (1aꢀc) with various monocyclic
and bicyclic ketones (2eꢀg) separately under the above optimized
conditions. Both mono and bicyclic ketones were tolerated well
and furnished the corresponding quinolines 3 in 76ꢀ86% yields
(Table 3). Notably, the bicyclic ketone 2g also worked efficiently
and afforded the tetracyclic quinoline 3ag in 79% yield. It seems
that the ring size of the cyclic ketones has no effect on the tandem
process.
3
(
1.1 mmol), CuSO (0.3 mmol), Dꢀglucose (0.3 mmol), proline
4
(
9
0.2 mmol) and KOH (1 mmol) in waterꢀethanol (3:2) mixture at
0 C.
º
30
Table 2 Reaction of 2ꢀbromobenzaldehydes/2ꢀbromobenzophenone
with 1,3ꢀdiketones
1
0
Table 4 Reaction of 2ꢀbromobenzaldehyde/2ꢀbromobenzophenone with
35
acyclic ketones
O
R1
O
R1
CuSO4-D-glucose
+
NaN3
+
R2
Me
Br
= H
c: R = Ph
proline, KOH
H2O-EtOH
N
R2
1
1
2h-2t
1
1
a
: R
3 (time (h)
isolated yields)
Substrate
Product
N
Substrate
Product
O
O
Cl
Me
Me
1
a +
1
a +
N
2
h
3ah, 8 h, 84%
Cl
3ai, 9 h, 76%
2i
O
O
Me
N
Me
1
a +
N
1
a +
3
aj (9 h, 81%)
Cl
3ak (8 h, 85%)
Cl
Cl
Cl
2k
2
j
O
O
Me
Me
N
1a +
OMe
N
1
a +
Me
3al (7 h, 83%)
3am (9 h, 80%)
Me
OMe
2l
2m
O
O
Me
1
a +
MeO
N
Me
1
a +
N
Table 3 Reaction of 2ꢀbromobenzaldehydes/2ꢀbromobenzophenone with
3an (10 h, 83%)
OMe
3ao (12 h, 52%)
2n
2o
cyclic ketones
O
O
Me
Me
O
Me
1
a +
N
1a +
S
N
O
S
3
ap (7 h, 78%)
2
p
2q
3aq (7 h, 75%)
Ph
O
O
N
Me
1
a +
N
1
c +
N
N
3
ar (10 h, 73%)
2
r
2h
2t
3ch (9 h, 79%)
O
O
Me
Me
1
a +
1a +
Me
N
N
Me
3
as (7 h, 87%)
3at (7 h, 84%)
2s
After the successful synthesis of 2,3ꢀdisubstituted/annulated
quinolines, we turned our attention toward the synthesis of 2ꢀ
substituted quinolines. Consequently, we utilized various
acetophenones (2hꢀo) and heteroaromatic ketones (2pꢀr) under
previously described oneꢀpot optimized conditions. The workup
of the reactions afforded the desired 2ꢀsubstituted quinolines 3 in
good yields. Notably, a series of substituted acetophenones such
as oꢀCl, mꢀCl, pꢀCl, pꢀMe, mꢀOMe, pꢀOMe groups on the phenyl
ring are well tolerated and the corresponding 2ꢀsubstituted
quinolines (3ahꢀ3an) are obtained in 76ꢀ85% yields (Table 4).
The protocol worked nicely with both electronꢀdonating and
electronꢀwithdrawing groups at orthoꢀ, metaꢀ, and paraꢀpositions
of the phenyl ring. The bulky naphthyl ethanone (2o) also reacted
under similar conditions to produce quinoline 3ao in moderate
yield. In addition, the reaction of propiophenone (2s) and
4
4
5
0
5
0
1
5
Under the optimal reaction conditions, the protocol scope and
generality for the direct construction of quinolines 3 was explored
Table 2). The oneꢀpot cascade process serves as a general
approach to access valuable substituted/annulated quinolines in
excellent yields (86ꢀ95%) with a broad substrate scope. 2ꢀ
Bromobenzaldehydes (1aꢀb) and 2ꢀbromobenzophenone (1c)
reacted smoothly with both acyclic (2aꢀb) and cyclic (2cꢀd) 1,3ꢀ
(
2
0
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butyrophenone (2t) separately with 2ꢀbromobenzaldeyde (1a)
was successfully performed to afford the respective quinolines
as and 3at in good yields. The structure of all the compounds
showed full agreement with spectroscopic data and previous
Experimental section
50
General experimental details
3
1
13
H and C NMR spectra were recorded at 300 and 75 MHz,
9
a,20
5
0
5
0
5
reports.
respectively. Chemical shift (δ) values are given in parts per
million (ppm) with reference to tetramethylsilane (TMS) as the
internal standard. Coupling constant (J) values are given in Hertz
To demonstrate the usefulness of this novel oneꢀpot domino
protocol, a gramꢀscale experiment was carried out under the
standard
reaction
conditions. The reaction
of 2ꢀ 55 (Hz). The IR spectra were recorded on Varian 3100 FTꢀIR
bromobenzaldehyde 1a (4 mL, 20 mmol) proceeded smoothly
providing 6.76 g of product 3aa (92%), which is comparable to
the small scale experiment. Thus, this new methodology could be
useful for the facile synthesis of quinoline scaffolds on an
spectrophotometer. Melting points were determined with Buchi
Bꢀ540 melting point apparatus and are uncorrected.
Commercially obtained reagents were used after further
purification when needed. All the reactions were monitored by
1
1
2
2
industrial scale. The use of inexpensive and easily prepared 60 TLC with silica gel coated plates. Column chromatography was
CuSO ꢀDꢀglucose as an ideal catalytic system offers an attractive
prospect in terms of industrial applications and sustainable
developments.
carried out whenever needed, using silica gel of 100/200 mesh.
Mixture of hexane/ethyl acetate in appropriate proportion
(determined by TLC analysis) was used as eluent.
4
Based on the entire experimental outcomes, a tentative
mechanism is proposed in scheme 1. Initially, Cu(I) (generated in
General procedure for the synthesis of compound 3
situ by the reduction of CuSO in presence of Dꢀglucose, base 65 A mixture of 2ꢀbromobenzaldehyde/2ꢀbromoacetophenone 1 (1
4
and proline) undergoes oxidative addition with substrate 1 to give
copper complex A. The nucleophilic substitution of Br with
sodium azide gives the azido Cu complex B followed by
reductive elimination to give complex C, which readily converts
to orthoꢀaminoaldehyde/ketone D under the reaction conditions.
Intermediate D undergoes dehydrative coupling with ketone 2 to
afford intermediate E followed by baseꢀcatalyzed dehydrative
cyclocondensation to produce the desired quinoline 3.
mmol), NaN
in H O + EtOH (3:2, 5 mL) was placed in a 50 mL round bottom
flask. To a stirring solution of above mixture added CuSO (0.3
3
(2 mmol) and cyclic/acyclic ketones 2 (1.1 mmol)
2
4
mmol),
Dꢀglucose (0.3 mmol), proline (0.2 mmol) and KOH (1
7
0
mmol). The reaction mixture was allowed to stir at 90 ºC for 3ꢀ10
h. After completion of reaction (monitored on TLC), solvent was
removed under reduced pressure and extracted with ethyl acetate.
The combined organic layer was dried over anhydrous sodium
sulphate, filtered and the solvent was removed under reduced
pressure. The crude residue thus obtained was purified by column
chromatography to give the desired quinolines 3.
75
2
0a
3
7
-Acetyl-2-methyl quinoline (3aa). Pale yellow solid, mp 74ꢀ
ꢀ
1
1
5 ˚C; IR (KBr) cm : 3053, 1788, 1624, 1579, 1456, 818; H
NMR (300 MHz, CDCl ) δ 8.48 (s, 1H, ArH), 8.05 (d, J = 8.4 Hz,
3
80
1H, ArH), 7.87ꢀ7.76 (m, 2H, ArH), 7.57ꢀ7.52 (m, 1H, ArH), 2.91
13
(
s, 3H, COCH ) 2.72 (s, 3H, CH ); C NMR (75 MHz, CDCl ) δ
3
3
3
Scheme 1 Plausible mechanism for the synthesis of quinolines 3.
1
1
99.9, 157.5, 138.2, 138.1, 131.6, 131.1, 128.5, 128.2, 126.6,
25.5, 29.2, 25.6.
30
Conclusions
20b
Phenyl(2-phenylquinolin-3-yl)methanone (3ab).
solid, mp 135ꢀ137 ºC; IR (KBr) cm : 3163, 2960, 1756, 1684,
1
8
Yellow
ꢀ
1
85
In summary, we have successfully designed and developed an
operationally simple, highly efficient oneꢀpot practical and
convenient method for the synthesis of diverse quinolines directly
1
562; H NMR (300 MHz, CDCl ) δ 8.23ꢀ8.15 (m, 5H, ArH),
3
.00 (d, J = 6.9 Hz, 1H, ArH), 7.89ꢀ7.81 (m, 2H, ArH), 7.75ꢀ7.70
13
(m, 1H, ArH), 7.55ꢀ7.43 (m, 6H, ArH); C NMR (75 MHz,
from
2ꢀbromobenzaldehydes/2ꢀbromobenzophenone.
An
CDCl ) δ 175.7, 157.3, 148.2, 139.6 (2C), 136.7, 132.4, 129.6,
3
35
40
45
inexpensive and easily prepared ecoꢀefficient CuSO ꢀDꢀglucose
4
90 129.2 (2C), 128.8 (3C), 128.6 (3C), 127.4 (2C), 127.1 (2C),
126.2, 118.9.
catalyst system and aqueous ethanol as the green solvent are the
key features of this novel method with promising synthetic
applications. The scope and diversity of the tolerated substrates in
this work is rather much broad in comparison to the reported
ones. The salient features of this domino protocol are its 95 1H, ArH), 7.94 (d, J = 8.1 Hz, 1H, ArH), 7.83ꢀ7.78 (m, 1H, ArH),
methodical simplicity, structural diversity, perfect carbonꢀ
economy, high product yields, readily available substrates and
20a
3,4-Dihydroacridin-1(2H)-one (3ac).
White solid, mp 103ꢀ
ꢀ
1
1
105 ºC; IR (KBr) cm : 3463, 2926, 1737, 1452, 1230, 835; H
NMR (300 MHz, CDCl ) δ 8.85 (s, 1H, ArH), 8.06 (d, J = 8.4 Hz,
3
7.57 (t, J = 7.2 Hz, 1H, ArH), 3.34 (t, J = 6.0 Hz, 2H, CH
), 2.82
2
(
t, J = 6.0 Hz, 2H, CH ), 2.32 (dd, J = 6.0 Hz, J = 12.6 Hz, 2H,
2
1
2
13
CH2); C NMR (75 MHz, CDCl ) δ 197.8, 161.9, 137.1, 132.3,
formation of three new bonds (one C
–
C and two C
–
N) and one
3
1
29.7, 128.4, 126.7, 126.6, 126.2, 39.0, 33.3, 21.7.
ring in a single operation. In addition, the present oneꢀpot process
is amenable to gram scale synthesis. Further investigations for the
synthetic utility of this catalyst system for the synthesis of
different heterocyclic rings are currently underway in our
laboratory.
20a
1
00 3,3-Dimethyl-3,4-dihydroacridin-1(2H)-one (3ad). White
solid, mp 116ꢀ118 ºC; IR (KBr) cm : 3062, 1768, 1594, 1488,
1
ꢀ
1
1
231; H NMR (300 MHz, CDCl ) δ 8.82 (s, 1H, ArH), 8.06 (d, J
3
=
8.7 Hz, 1H, ArH), 7.94 (d, J = 8.1 Hz, 1H, ArH), 7.82ꢀ7.77 (m,
1
H, ArH), 7.57ꢀ7.52 (m, 1H, ArH), 3.20 (s, 2H, CH ), 2.65 (s,
2
4
| Journal Name, [year], [vol], 00–00
This journal is © The Royal Society of Chemistry [year]

Page 5 of 7
RSC Advances
View Article Online
DOI: 10.1039/C4RA14138E
1
3
13
2
1
1
7
H, CH ), 1.15 (s, 6H, 2xCH ); C NMR (75 MHz, CDCl ) δ
CH2); C NMR (75 MHz, CDCl ) δ 165.2, 157.0, 143.3, 135.9,
3
2
3
3
97.9, 160.7, 149.9, 136.4, 132.1, 129.7, 128.5, 126.6 (2C), 60 129.7, 129.3, 128.2, 120.4, 105.5, 55.4, 34.2, 30.5, 23.6.
2
0d
25.2, 52.4, 47.1, 32.7, 28.3(2C).
9-Phenyl-2,3-diydro-1-cyclopenta[b]quinoline (3ce). Yellow
solid, mp 133ꢀ135 ºC; IR (KBr) cm : 3053, 1625, 1586, 1230,
1033, 836; H NMR (300 MHz, CDCl ) δ 8.09 (d, J = 8.4 Hz, 1H,
ArH), 7.63 (m, 2H, ArH), 7.51ꢀ7.45 (m, 3H, ArH), 7.37ꢀ7.34 (m,
ꢀ
1
-Methoxy-3,3-dimethyl-3,4-dihydroacridin-1(2H)-one
(3bd). Yellow solid, mp 98ꢀ100 ºC; IR (KBr) cm : 3062, 1768,
594, 1488, 1231; H NMR (300 MHz, CDCl ) δ 8.73 (s, 1H,
20c
ꢀ1
1
5
3
1
1
3
ArH), 7.97 (d, J = 9.0 Hz, 1H, ArH), 7.47ꢀ7.43 (m, 1H, ArH), 65 3H, ArH), 3.24 (t, J = 7.5 Hz, 2H, CH ), 2.90 (t, J = 7.2 Hz, 2H,
2
13
7
.167 (s, 1H, ArH), 3.93 (s, 3H, OCH ), 3.16 (s, 2H, CH ), 2.63
CH ), 2.21ꢀ2.11 (m, 2H, CH ); C NMR (75 MHz, CDCl ) δ
2 2 3
3
2
1
3
(s, 2H, CH ), 1.14 (s, 6H, 2xCH ); C NMR (75 MHz, CDCl ) δ
167.3, 147.7, 142.8, 136.7, 133.6, 129.2 (2C), 128.6, 128.4,
128.2, 127.9 (2C), 126.2, 125.6, 125.5, 35.1, 30.3, 23.5.
2
3
3
1
1
2
2
3
3
4
4
5
5
0
5
0
5
0
5
0
5
0
5
198.1, 158.2, 157.7, 146.1, 135.0, 129.8 (2C), 127.7, 125.3,
1
3
mp 112ꢀ114 ºC; IR (KBr) cm : 3053, 1788, 1624, 1579, 1456,
8
20e,f
06.3, 55.6, 52.4, 46.7, 32.8, 28.3(2C).
2-Phenylquinoline (3ah).
White solid, mp 85ꢀ87 ºC; IR (KBr)
2
0d
ꢀ1
1
-Acetyl-2-methyl-4-phenyl quinoline (3ca).
Yellow solid, 70 cm : 3056, 1612, 1598, 1557, 1478; H NMR (300 MHz, CDCl )
3
ꢀ
1
δ 8.21ꢀ8.14 (m, 3H, ArH), 7.88ꢀ7.80 (m, 2H, ArH), 7.74ꢀ7.69 (m,
1
13
18; H NMR (300 MHz, CDCl ) δ 8.08 (d, J = 8.4 Hz, 1H,
1H, ArH), 7.55ꢀ7.43 (m, 5H, ArH); C NMR (75 MHz, CDCl ) δ
3
3
ArH), 7.72ꢀ7.67 (m, 1H, ArH), 7.62 (d, J = 8.4 Hz, 1H, ArH),
.49ꢀ7.44 (m, 3H, ArH), 7.42ꢀ7.34 (m, 3H, ArH), 2.70 (s, 3H,
157.3, 148.2, 139.6, 129.6, 129.2 (2C), 128.8 (2C), 127.5 (2C),
7
127.4, 127.1, 126.2, 118.9.
1
3
9a
CH ), 2.00 (s, 3H, CH ); C NMR (75 MHz, CDCl ) δ 205.5, 75 2-(2-Chlorophenyl)quinoline (3ai). White solid, mp 72ꢀ75 ºC;
3
3
3
ꢀ
1
1
1
1
53.3, 147.3, 143.7, 135.0, 134.6, 129.9, 129.8 (2C), 128.8,
28.7, 128.5 (2C), 126.3, 126.0, 124.8, 31.8, 23.7.
IR (KBr) cm : 3063, 1614, 1574, 1512, 1423; H NMR (300
MHz, CDCl ) δ 8.20ꢀ8.17 (m, 2H, ArH), 8.13ꢀ8.08 (m, 2H, ArH),
3
2
0d
13
9-Phenyl-3,4-dihydroacridin-1(2H)-one (3cc).
solid, mp 153ꢀ156 ºC; IR (KBr) cm : 3407, 3048, 2924, 1737,
1
Pale yellow
7.81ꢀ7.69 (m, 2H, ArH), 7.54ꢀ7.45 (m, 3H, ArH); C NMR (75
ꢀ
1
MHz, CDCl ) δ 155.9, 148.1, 137.9, 136.9, 135.5, 129.9, 129.8,
3
1
498, 1230, 749; H NMR (300 MHz, CDCl ) δ 8.08 (d, J = 8.4 80 128.9 (2C), 128.7 (2C), 127.4, 127.1, 126.4, 118.6.
3
2
0h
Hz, 1H, ArH), 7.78 (m, 1H, ArH), 7.50ꢀ7.37 (m, 5H, ArH), 7.19ꢀ
2-(2-Chlorophenyl)quinoline (3aj).
White solid, mp 65ꢀ67
ꢀ
1
1
7
.16 (m, 2H, ArH), 3.40 (t, J = 6.3 Hz, 2H, CH ), 2.72 (t, J = 6.3
ºC; IR (KBr) cm : 3025, 2915, 1664, 1574, 1497, 1431, 815; H
2
13
Hz, 2H, CH ), 2.29 (dd, J = 6.6 Hz, J = 12.6 Hz, 2H, CH );
C
NMR (300 MHz, CDCl ) δ 8.24ꢀ8.16 (m, 3H, ArH), 8.03ꢀ7.97
2
1
2
2
3
NMR (75 MHz, CDCl ) δ 197.9, 162.2, 151.4, 148.5, 137.5,
(m, 1H, ArH), 7.85ꢀ7.71 (m, 3H, ArH), 7.56ꢀ7.51 (m, 2H, ArH);
3
13
1
1
2
31.7, 128.4 (2C), 128.1, 128.0 (2C), 127.9, 127.5 (2C), 126.4, 85 C NMR (75 MHz, CDCl ) δ 155.7, 137.0, 134.9, 132.6, 130.8,
3
23.8, 40.6, 34.5, 21.3.
,3-Dihydro-1H-cyclopenta[b]quinoline (3ae).
130.2, 129.9, 129.7, 129.3, 128.5, 127.7, 127.4, 126.6, 125.6,
2
0a
White solid,
118.6.
ꢀ
1
1
9a
mp 55ꢀ57 ºC; IR (KBr) cm : 3053, 1646, 1562, 1212; H NMR
300 MHz, CDCl ) δ 8.02 (d, J = 8.4 Hz, 1H, ArH), 7.70 (s, 1H,
2-(4-Chlorophenyl)quinoline (3ak). White solid, mp 110ꢀ113
ºC; IR (KBr) cm : 3065, 1610, 1553, 1525, 1412; H NMR (300
ꢀ
1
1
(
3
ArH), 7.67ꢀ7.64 (m, 1H, ArH), 7.60ꢀ7.55 (m, 1H, ArH), 7.43ꢀ 90 MHz, CDCl ) δ 8.20ꢀ8.08 (m, 4H, ArH), 7.81ꢀ7.69 (m, 3H, ArH),
3
13
7
.38 (m, 1H, ArH), 3.14 (t, J = 7.5 Hz, 2H, CH ), 3.02 (t, J = 7.2
7.54ꢀ7.46 (3H, ArH); C NMR (75 MHz, CDCl ) δ 155.9, 148.1,
2
3
Hz, 2H, CH ), 2.19ꢀ2.11 (dd, J = 7.5 Hz, J = 15.0 Hz, 2H, CH );
138.0, 136.9, 135.5, 129.7, 129.6, 128.9 (2C), 128.7 (2C), 127.4,
127.1, 126.4, 118.4.
2
1
2
2
13
C NMR (75 MHz, CDCl ) δ 157.6, 147.2, 135.3, 130.0, 128.3,
3
20f
1
1
28.2, 128.0, 127.1, 125.2, 34.3, 30.2, 23.3.
2-p-Tolylquinoline (3al). White solid, mp 80ꢀ82 ºC; IR (KBr)
2
0a,e
1
1
,2,3,4-Tetrahydroacridine (3af).
White solid, mp 85ꢀ87 ºC; 95 cm- : 3422, 2915, 1668, 1618, 1596, 1497, 815, 788; H NMR
ꢀ
1
1
IR (KBr) cm : 3058, 1624, 1557, 1453, 1214; H NMR (300
(300 MHz, CDCl ) δ 8.15 (d, J = 8.4 Hz, 2H, ArH), 8.06 (d, J =
3
MHz, CDCl ) δ 7.97 (d, J = 8.4 Hz, 1H, ArH), 7.70 (s, 1H, ArH),
8.1 Hz, 2H, ArH), 7.83ꢀ7.68 (m, 3H, ArH), 7.49ꢀ7.47 (m, 1H,
3
1
3
7.67ꢀ7.64 (m, 1H, ArH), 7.60ꢀ7.55 (m, 1H, ArH), 7.42ꢀ7.37 (m,
ArH), 7.32 (d, J = 7.8 Hz, 2H, ArH), 2.41 (s, 3H, CH3); C NMR
1
H, ArH), 3.13 (t, J = 6.3 Hz, 2H, CH ), 2.96 (t, J = 6.3 Hz, 2H,
(75 MHz, CDCl ) δ 157.2, 148.2, 139.3, 136.8, 136.5, 129.6 (2C),
2
3
13
CH ), 1.99ꢀ1.95 (m, 2H, CH ), 1.88ꢀ1.84 (m, 2H, CH ); C NMR 100 129.4 (2C), 127.3 (3C), 127.0, 126.0, 118.7, 21.2.
2
2
2
20h
(
75 MHz, CDCl ) δ 159.1, 146.4, 134.8, 130.8, 128.3, 128.1,
2-(3-Methoxyphenyl)quinoline (3am). Yellow oil, IR (Neat)
3
ꢀ
1
1
1
27.0, 126.7, 125.3, 33.4, 29.1, 23.1, 22.7.
cm : 3152, 1604, 1563, 1498; H NMR (300 MHz, CDCl ) δ
3
2
0f
5,6-Dihydrobenzo[a]acridine (3ag). Yellow solid, mp 63ꢀ65
ºC; IR (KBr) cm : 3417, 2929, 1498, 1278, 1033, 789; H NMR
8.17 (d, J = 8.4 Hz, 1H, ArH), 8.10 (d, J = 8.7 Hz, 1H, ArH),
7.78ꢀ7.65 (m, 5H, ArH), 7.47ꢀ7ꢀ35 (m, 2H, ArH), 6.99 (d, J = 8.1
ꢀ
1
1
13
(
300 MHz, CDCl ) δ 8.58 (d, J = 7.5 Hz, 1H, ArH), 8.13 (d, J = 105 Hz, 1H, ArH), 3.86 (s, 3H, OCH3); C NMR (75 MHz, CDCl ) δ
3
3
8
7
.4 Hz, 1H, ArH),7.84 (s, 1H, ArH), 7.69ꢀ7.59 (m, 2H, ArH),
160.0, 156.8, 148.0, 140.9, 136.5, 129.6, 129.5, 129.4, 127.3,
127.1, 126.1, 119.8, 118.8, 115.2, 112.6, 55.2.
.45ꢀ7.31 (m, 3H, ArH), 7.24 (d, J = 7.2 Hz, 1H, ArH), 3.08ꢀ3.04
1
3
20f
(m, 2H, CH ), 2.97ꢀ2.93 (m, 2H, CH ); C NMR (75 MHz,
2-(4-Methoxyphenyl)quinoline (3an). White solid, mp 117ꢀ
2
2
ꢀ
1
CDCl ) δ 153.2, 147.5, 139.3, 134.6, 133.6, 130.4, 129.5, 129.3,
120 ºC; IR (KBr) cm : 3039, 2921, 2840, 1604, 1499, 1251,
3
1
1
7
28.5, 127.8, 127.7, 127.2, 126.8, 126.0, 125.9, 28.7, 28.3.
110 1029, 818; H NMR (300 MHz, CDCl ) δ 8.14ꢀ8.11 (m, 4H,
3
20g
-Methoxy-2,3-dihydro-1H-cyclopenta[b]quinoline (3be).
ArH), 7.80ꢀ7.75 (m, 2H, ArH), 7.71ꢀ7.65 (m, 1H, ArH), 7.49ꢀ
ꢀ
1
White solid, mp 97ꢀ99 ºC; IR (KBr) cm : 3407, 3048, 2924,
1595, 1498, 1230, 749; H NMR (300 MHz, CDCl ) δ 7.91 (d, J
7.44 (m, 1H, ArH), 7.03 (d, J = 8.7 Hz, 2H, ArH), 3.85 (s, 3H,
1
13
OCH3); C NMR (75 MHz, CDCl ) δ 160.7, 156.8, 148.2, 136.5,
3
3
=
9.3 Hz, 1H, ArH), 7.77 (s, 1H, ArH), 7.28ꢀ7.24 (m, 1H, ArH),
132.1, 129.5, 129.4, 128.8, 127.3, 126.8, 125.8, 118.4, 114.1
7
.00 (d, J = 2.7 Hz, 1H, ArH), 3.90 (s, 3H, OCH ), 3.24 (t, J =7.5 115 (2C), 55.3.
3
20f
Hz, 2H, CH ), 3.14ꢀ3.02 (m, 4H, 2xCH ), 2.23ꢀ2.13 (m, 2H,
2-(Naphthalen-2-yl)quinoline (3ao). White solid, mp 163ꢀ165
2
2
This journal is © The Royal Society of Chemistry [year]
Journal Name, [year], [vol], 00–00 | 5

RSC Advances
Page 6 of 7
View Article Online
DOI: 10.1039/C4RA14138E
ꢀ
1
1
ºC; IR (KBr) cm : 3058, 1622, 1567, 1256; H NMR (300 MHz,
† Electronic Supplementary Information (ESI) available: [Elaborate
CDCl ) δ 8.59 (s, 1H, ArH), 8.37 (d, J = 8.7 Hz, 1H, ArH), 8.22
reaction procedure, characterization data, scanned spectra of all the
products]. See DOI: 10.1039/b000000x/
3
(d, J = 8.4 Hz, 2H, ArH), 8.00ꢀ7.96 (m, 3H, ArH), 7.89ꢀ7.86 (m,
1
H, ArH), 7.82 (d, J = 8.1 Hz, 1H, ArH), 7.75ꢀ7.70 (m, 1H, ArH),
1
3
5
0
5
0
5
0
5
0
5
7.53ꢀ7.49 (m, 2H, ArH); C NMR (75 MHz, CDCl ) δ 157.1, 60 References
1
1
2
3
48.3, 136.7, 133.8, 133.4, 129.6, 128.9, 128.7 (2C), 128.5,
27.6, 127.4, 127.2, 127.1, 126.6, 126.2 (2C), 125.0, 119.0.
1
(a) L. F. Tietze and U. Beifuss, Angew. Chem. Int. Ed. Engl, 1993,
2, 131ꢀ163; (b) L. F. Tietze, Chem. Rev., 1996, 96, 115–136; (c) T.
3
2
0f
-(Furan-2-yl)quinoline (3ap). White solid, mp 90ꢀ92 ºC; IR
Chanda, S. Chowdhury, B. J. Ramulu, S. Koley, R. C.F. Jones and
M. S. Singh, Tetrahedron, 2014, 70, 2190–2194; (d) S. Koley, S.
Chowdhury, T. Chanda, B. J. Ramulu and M. S. Singh,
Tetrahedron, 2013, 37, 8013–8018; (e) R. Martinez, D. J. Ramon and
M. Yus, Tetrahedron, 2006, 62, 8988–9001; (f) M. S. Singh, A.
Nagaraju, B. J. Ramulu, G. Shukla, A. Srivastava, G. K. Verma and
K. Raghuvanshi, Green Chem., 2014, DOI: 10.1039/C4GC01431F.
(a) C. Zhang, C. H. Tang and N. Jiao, Chem. Soc. Rev., 2012, 41,
3464–3484; (b) A. E. Wendlandt, A. M. Suess and S. S. Stahl,
Angew. Chem. Int. Ed., 2011, 50, 11062–11087; (c) W. Zhu, D.
Zhang, N. Yang and H. Liu, Chem. Commun., 2014, 50, 10634–
ꢀ
1
1
(KBr) cm : 3152, 1618, 1523, 1489; H NMR (300 MHz, CDCl )
3
6
5
1
1
2
2
3
3
4
4
δ 8.15ꢀ8.12 (m, 2H, ArH), 7.81ꢀ7.61 (m, 4H, ArH), 7.47 (t, J =
7
.5 Hz, 1H, ArH), 7.22ꢀ7.21 (m, 1H, ArH), 6.57 (bs, 1H, ArH);
1
3
C NMR (75 MHz, CDCl ) δ 153.6, 148.9, 148.0, 144.0, 136.6,
3
1
2
29.8, 129.3, 127.5, 127.1, 126.1, 117.4, 112.1, 110.0.
2
0f
-(Thiophen-2-yl)quinoline (3aq). White solid, mp 125ꢀ128
70
75
80
2
ꢀ
1
1
ºC; IR (KBr) cm : 3101, 3054, 1624, 1578, 1223; H NMR (300
MHz, CDCl ) δ 8.11ꢀ8.06 (m, 2H, ArH), 7.77ꢀ7.65 (m, 4H, ArH),
7
MHz, CDCl ) δ 152.2, 148.0, 145.3, 136.5, 129.7, 129.2, 128.5,
1
2-(Pyridin-3-yl)quinoline (3ar). White solid, mp 93ꢀ95 ºC; IR
3
1
3
.48ꢀ7.43 (m, 2H, ArH), 7.15ꢀ7.12 (m, 1H, ArH); C NMR (75
1
0636.
3
3
4
N. R. Candeias, L. C. Branco, P. M. P. Gois, C. A. M. Afonso and A.
F. Trindade, Chem. Rev., 2009, 109, 2703–2802.
28.0, 127.4, 127.1, 126.0, 125.7, 117.5.
2
0i
(a) J. P. Michael, Nat. Prod. Rep., 2008, 25, 166–187; (b) M.
Rouffet, C. A. F. de Oliveira, Y. Udi, A. Agrawal, I. Sagi, J. A.
McCammon and S. M. Cohen, J. Am. Chem. Soc., 2010, 132, 8232–
8233; (c) S. Andrews, S. J. Burgess, D. Skaalrud, J. X. Kelly and D.
H. Peyton, J. Med. Chem., 2010, 53, 916–919.
ꢀ
1
1
(KBr) cm : 3059, 2924, 1599, 1095, 787; H NMR (300 MHz,
CDCl ) δ 8.51 (d, J = 7.8 Hz, 1H, ArH), 8.25 (d, J = 8.7 Hz, 1H,
ArH), 8.18 (d, J = 8.4 Hz, 1H, ArH), 7.86ꢀ7.71 (m, 4H, ArH),
7
150.0, 148.6, 148.2, 137.0 (2C), 134.8, 129.9, 129.6, 127.4,
1
2
3
1
3
5
6
(a) V. R. Solomon and H. Lee, Curr. Med. Chem., 2011, 18, 1488–
.56ꢀ7.47 (m, 3H, ArH); C NMR (75 MHz, CDCl ) δ 154.5,
3
1
508; (b) K. Kaur, M. Jain, R. P. Reddy and R. Jain, Eur. J. Med.
Chem., 2010, 45, 3245–3264; (c) V. A. Mamedov, S. F. Kadyrova,
N. A. Zhukova, V. R. Galimullina, F. M. Polyancev and S. K.
Latypov, Tetrahedron, 2014, 70, 5934–5946.
(a) S. J. Benkovic, S. J. Baker, M. R. K. Alley, Y. H. Woo, Y. K.
Zhang, T. Akama, W. Mao, J. Baboval, P. T. R. Rajagopalan, M.
Wall, L. S. Kahng, A. Tavassoli and L. Shapiro, J. Med. Chem.,
2005, 48, 7468–7476; (b) H. Venkatesan, F. M. Hocutt, T. K. Jones,
M. H. Rabinowitz, J. Org. Chem., 2010, 75, 3488–3491.
27.2, 126.7 (2C), 118.4.
,4-Diphenylquinoline (3ch). White solid, mp 112ꢀ115 ºC; IR
8
9
5
0
1
6b
ꢀ
1
1
(KBr) cm : 3423, 3086, 2955, 1589, 1095, 846; H NMR (300
MHz, CDCl ) δ 7.81 (d, J = 7.2 Hz, 4H, ArH), 7.67ꢀ7.56 (m, 4H,
3
13
ArH), 7.51ꢀ7.38 (m 5H, ArH), 7.35ꢀ7.31 (m, 2H, ArH); C NMR
75 MHz, CDCl ) δ 163.1, 140.5, 137.5, 136.2, 136.0, 133.6,
(
3
1
1
3
33.0, 132.3, 131.8, 131.0, 130.0, 129.9, 129.0, 128.8, 128.5,
28.2, 128.1, 127.1, 119.4, 118.5, 118.5.
7
8
G. Shan, X. Sun, Q. Xia and Y. Rao, Org. Lett., 2011, 13, 5770–
5773.
2
0e,f
ꢀ
(a) V. Bhalla, V. Vij, M. Kumar, P. R. Sharma and T. Kaur, Org.
Lett., 2012, 14, 1012–1015; (b) M. Velusamy, C.ꢀH. Chen, Y. S.
Wen, J. T. Lin, C.ꢀC. Lin, C.ꢀH. Lai and P.ꢀT. Chou,
Organometallics, 2010, 29, 3912–3921; (c) Z.ꢀQ. Lei, H. Li, Y. Li,
X.ꢀS. Zhang, K. Chen, X. Wang, J. Sun and Z.ꢀJ. Shi, Angew. Chem.
Int. Ed., 2012, 51, 2690–2694.
(a) Z. Wang, S. Li, B. Yu, H. Wu, Y. Wang and X. Sun, J. Org.
Chem., 2012, 77, 8615−8620; (b) S. Khong and O. Kwon, J. Org.
Chem., 2012, 77, 8257−8267; (c) Y. Zhang, M. Wang, P. Li and W.
Lei, Org. Lett., 2012, 14, 2206–2209; (d) K. K. Toh, S. Sanjaya, S.
Sahnoun, S. Y. Chong and S. Chiba, Org. Lett., 2012, 14, 2290–
2292; (e) S. Cai, J. Zeng, Y. Bai and X.ꢀW. Liu, J. Org. Chem., 2012,
-Methyl-2-phenylquinoline (3as).
Yellow oil; IR (Neat) cm
1
1
95
00
05
: 3052, 1618, 1553, 1431, 1097, 756; H NMR (300 MHz,
CDCl ) δ 8.13 (d, J = 8.4 Hz, 1H, ArH), 7.96 (s, 1H, ArH), 7.74
3
(d, J = 8.1 Hz, 1H, ArH), 7.65ꢀ7.56 (m, 3H, ArH), 7.46ꢀ7.40 (m,
1
3
4
1
H, ArH), 2.43 (s, 3H, CH3); C NMR (75 MHz, CDCl ) δ160.4,
3
1
1
9
46.5, 140.8, 136.6, 129.2, 129.0, 128.7 (2C), 128.6, 128.1 (2C),
128.0, 127.5, 126.6, 126.2, 20.5.
3
3
2
0j
ꢀ1
-Ethyl-2-phenylquinoline (3at). Yellow oil. IR (Neat) cm :
1
048, 2924, 1595, 1432, 749; H NMR (300 MHz, CDCl ) δ 8.14
3
(
1
d, J = 8.4 Hz, 1H, ArH), 8.01 (s, 1H, ArH), 7.79 (d, J = 7.8 Hz,
H, ArH), 7.66ꢀ7.61 (m, 1H, ArH), 7.54ꢀ7.52 (m, 2H, ArH),
7.48ꢀ7.41 (m, 4H, ArH), 2.81ꢀ2.73 (m, 2H, CH ), 1.19 (t, J = 7.8
7
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Hz, 3H, CH3); C NMR (75 MHz, CDCl ) δ 160.5, 146.2, 140.8,
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930, 52, 3685–3688.
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Acknowledgements
115
50
We gratefully acknowledge the financial support from the
Science and Engineering Research Board (SB/S1/OCꢀ30/2013)
and the University Grant Commission, New Delhi, India.
Notes and references
120
Department of Chemistry, Faculty of Science, Banaras Hindu University,
Varanasiꢀ221005 (India); Fax: (+91) 542ꢀ2368127; Eꢀmail:
mssinghbhu@yahoo.co.in, Homepage: http:\\drmssinghchembhu.com
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