Sulfuric acid-modified PEG-6000 (PEG-OSO3H): An efficient, bio-degradable and reusable polymeric catalyst for the solvent-free synthesis of poly-substituted quinolines under microwave irradiation

Article abstract of DOI:10.1039/c0gc00953a

Sulfuric acid-modified polyethylene glycol 6000 (PEG-OSO₃H) is applied as an efficient and eco-friendly polymeric catalyst for Friedlaender synthesis of poly-substituted quinolines from 2-aminoaryl ketones (or anthranilonitrile) and carbonyl compounds possessing a reactive methylene group under microwave irradiation and solvent-free conditions. The reactions are completed in short times, and the products are obtained in good to excellent yields. The Royal Society of Chemistry.

Full text of DOI:10.1039/c0gc00953a

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PAPER
Sulfuric acid-modified PEG-6000 (PEG-OSO3H): an efficient,
bio-degradable and reusable polymeric catalyst for the solvent-free synthesis
of poly-substituted quinolines under microwave irradiation
Alireza Hasaninejad,*a Abdolkarim Zare,*b Mohsen Shekouhya and Javad Ameri-Rada
Received 26th December 2010, Accepted 14th January 2011
DOI: 10.1039/c0gc00953a
Sulfuric acid-modified polyethylene glycol 6000 (PEG-OSO3H) is applied as an efficient and
eco-friendly polymeric catalyst for Friedla¨nder synthesis of poly-substituted quinolines from
2-aminoaryl ketones (or anthranilonitrile) and carbonyl compounds possessing a reactive
methylene group under microwave irradiation and solvent-free conditions. The reactions are
completed in short times, and the products are obtained in good to excellent yields.
as well as solid phase methods.8 Moreover, due to their low
Introduction
melting points (<100 ◦C), these compounds can be used as a
Nowadays, green chemistry has attained the status of a major
solvent for high temperature reactions.9 Sulfuric acid-modified
scientific discipline.1,2 Cleaner and more benign processes in
PEG-6000 (PEG-OSO3H) is an example of polyethylene glycol-
organic synthesis have been developed in parallel with the
supported catalyst that is functionalized by acidic groups and is a
development of new technologies each year. For many chemical
processes, a major adverse effect to environment is the consump-
mild, non-volatile and non-corrosive organic acid. This catalyst
has been used for the synthesis of 3,4-dihydropyrimidones via the
tion of energy for heating and cooling. Genesis of microwave
Biginelli reaction under microwave and solvent-free conditions,9
irradiation as a method of heating was a great revolution in
regioselective ring opening of epoxides with thiocyanate anion in
green chemistry. A recent study comparing the energy efficiency
water,10 Beckmann rearrangement and dehydration of oximes.11
of conventional oil-bath synthesis and microwave-assisted syn-
Quinolines are nitrogen-containing heterocycles with wide
thesis has indicated that for most chemical transformations, a
range of medicinal properties which have been used as an-
significant energy savings, up to 85-fold, can be expected using
timalarial, antiasthmatic, antihypertensive, antibacterial and
microwaves as an energy source on a laboratory scale.3 Rapid
tyrosine kinase inhibiting agents.12–16 These compounds have
uncontrolled heating of organic solvents under microwave irra-
been also applied for the preparation of nano- and mesostruc-
diation has made several hazardous situations. Hence, the first
tures having enhanced electronic and photonic properties.17 4-
attempts at solvent-free microwave chemistry, which eliminated
the danger of explosions, were made in 1990s.4–6
Aminoquinolines are an important group of quinoline deriva-
tives, and have been found to be a potent acetylcholinesterase
The utility of polymer-supported catalysts is now well-
inhibitors18 and an even stronger inhibitor of the butyryl-
recognized because of their ease of workup and separation of
cholinesterase family of enzymes.19 Moreover, these compounds
products and catalysts, from the economical point of view, and
have been shown to possess a much broader pharmacological
in application to industrial processes.7 Most polymers of this
profile than cholinesterase inhibition: blockage of potassium
type have high molecular weights and unique solubility profile.
channels,20 inhibition of the neuronal monoamine uptake
Between them, PEGs with Mw > 2000 Da are mostly soluble in
many polar solvents and insoluble in a few nonpolar solvents.
Because of this solubility profile, PEG-based supports combine
the advantageous features of homogeneous catalysis such as high
reactivity, lack of diffusion phenomena and analytical simplicity,
processes,21 and inhibition of monamine oxidase.22 Two biolog-
ical active quinolines are shown in Scheme 1.
A straightforward synthesis of quinolines is Friedla¨nder an-
nulation reaction.23–28 In this method, quinoline derivatives have
been prepared by condensation of 2-aminoaryl ketones with
carbonyl compounds possessing a reactive methylene group fol-
lowed by cyclodehydration.23–28 This reaction has been generally
carried out either by refluxing an aqueous or alcoholic solution
of reactants in the presence of a base at high temperature, 150–
220 ◦C.23 However, under basic or thermal-catalysis conditions,
2-aminobenzophenone does not react with simple ketones such
aDepartment of Chemistry, Faculty of Sciences, Persian Gulf University,
Bushehr, 75169, Iran. E-mail: ahassaninejad@yahoo.com;
Fax: +98(771)4541494; Tel: +98(771)4222319
bDepartment of Chemistry, Payame Noor University (PNU), Iran.
E-mail: abdolkarimzare@yahoo.com; Fax: +98(771)5559489;
Tel: +98(771)559486
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Scheme 2 The condensation of 2-aminobenzophenone (1a) with dime-
done (2a) using PEG-OSO3H under microwave irradiation.
yield of the product was very low (28% after 20 min). These
observations established the crucial rule of PEG-OSO3H for the
expedition of the reaction time and the product yield.
To realize the efficiency and the scope of PEG-OSO3H for the
synthesis of quinolines, 2-aminoarylketones were reacted with
various carbonyl compounds including cyclic and acyclic 1,3-
diketones, b-ketoesters and cyclic ketones under the optimized
reaction conditions (Scheme 3). The results are displayed in
Table 1.
Scheme 1 Two biologically active quinolines.
as cyclohexanone and b-ketoesters.24 In order of improve the
generality of Friedla¨nder method, some catalytic systems have
been reported.23–28 The common procedure for the synthesis of 4-
aminoquinolines is the acid-catalyzed condensation reaction be-
tween 2-aminonitriles (such as anthranilonitrile) with carbonyl
compounds possessing a reactive methylene group followed by
cyclodehydration.29 Some of the catalytic systems which◦have
been used include zinc chloride in nitrobenzene at 120 C,29a
aluminium trichloride in 1,2-dichloroethane at reflux,29b boron
trifluoride diethyl etherate in toluene at reflux,29c or titanium
tetrachloride in methylene chloride.29d Most of the reported
procedures for the synthesis of poly-substituted quinolines and
4-aminoquinolines suffer from drawbacks such as low yields of
the products, long reaction times, the use of hazardous and often
expensive catalysts, the use of volatile and hazardous organic
solvents, harsh reaction conditions, tedious work-up, and no
compliance with the green chemistry protocols. Consequently,
development of the efficient, inexpensive and environmentally
benign methods for the synthesis of quinolines is in demand.
In this paper, we wish to report a convenient and rapid method
for the Friedla¨nder synthesis of poly-substituted quinolines and
4-aminoquinolines via the condensation of 2-aminoaryl ketones
or anthranilonitrile with carbonyl compounds in the presence
of PEG-OSO3H as an efficient, green, inexpensive, reusable and
biodegradable polymeric catalyst under microwave irradiation
and solvent-free conditions.
As can be seen in Table 1, cyclic and acyclic 1,3-diketones
as well as b-ketoesters were efficiently condensed with 2-
aminoaryl ketones, and the corresponding quinolines were
obtained in good to excellent yields and in short reaction times
(Table 1, compounds 3a–g and 3k–q). Interestingly, cyclic
mono-functionalized ketones were successfully reacted with 2-
aminoarylketones to afford the respective tricyclic quinolines
in reasonable yields and in short reaction times (Table 1,
compounds 3h–j and 3r–t). Moreover, the catalyst was applied
for the synthesis of a sterically hindered quinoline, by the
condensation of 1,3-diphenyl-1,3-propandione with 5-chloro-2-
aminobenzophenone (Table 1, compound 3q). In the next step,
the efficiency of PEG-OSO3H were examined for the synthesis
of 4-aminoquinolines via the condensation of anthranilonitrile
with carbonyl compounds (Scheme 3, compound 3u–z). As
Table 1 indicates, anthranilonitrile was efficiently condensed
with dimedone, 1,3-cyclohexanedione or mono-functionalized
cyclic ketones in the presence of 3 mol% of PEG-OSO3H
◦
under microwave irradiation (600 W, 130 C) and solvent-free
conditions to provide the products 3u–z in high yields and in
short reaction times.
Results and discussions
After completion of each reaction, H2O was added to the
reaction mixture and was shaken for a few minutes to dissolve
PEG-OSO3H. The crude product (insoluble in water) was fil-
tered and recrystallized from hot ethanol for more purification.
In order to recover the catalyst, H2O was evaporated under
reduced pressure, and the resulting solid was washed with t-
butylmethyl ether, and dried. The recovered catalyst was reused
ten times in the condensation of 2-aminobenzophenone (1a)
with dimedone (2a), and smooth loss of catalytic activity was
observed from the 7th time of reuse (Fig. 1).
In order to find the best reaction conditions for the synthesis
of quinoline derivatives, the microwave-assisted condensation
of 2-aminobenzophenone (1a) (1 mmol) with dimedone (2a)
(1.5 mmol) was examined in the presence of different amounts
of PEG-OSO3H at range of 100–800 W of microwave power and
100–140 ◦C in the absence of solvent (Scheme 2).
The best results were obtained in the presence of 3 mol%
of PEG-OSO3H at 600 W (130 ◦C) of microwave irradiation.
The reaction was also checked without the catalyst in which the
Scheme 3 The condensation of 2-aminobenzophenones or 2-aminobenzonitrile with carbonyl compounds using PEG-OSO3H as catalyst under
solvent-free and microwave conditions.
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Table 1 Friedla¨nder synthesis of poly-substituted quinolines and 4-
aminoquinolines in the presence of PEG-OSO3H under microwave and
solvent-free conditions (Scheme 3)
Table 1 (Contd.)
Entry R
Y
Ketone
Product
Time/min Yielda (%)
Entry R
Y
Ketone
Product
Time/min Yielda (%)
3t
Cl
H
H
COPh
10
80
91
94
3a
H
COPh
4
91
3u
3v
CN
CN
4
3b
3c
3d
3e
3f
H
H
H
H
H
COPh
COPh
COPh
COPh
COPh
6
8
4
7
4
93
75
90
83
90
9
3w
3x
H
H
CN
CN
12
8
91
93
3y
3z
H
H
CN
CN
9
90
91
12
3g
3h
H
H
COPh
COPh
5
7
88
84
a Yields refer to isolated pure products.
3i
3j
H
H
COPh
COPh
8
79
81
12
3k
3l
Cl
Cl
Cl
COPh
COPh
COPh
3
4
5
94
92
90
3m
Fig. 1 The catalytic activity of PEG-OSO3H in ten cycles for the
reaction of 2-aminobenzophenone (1a) with dimedone (2a).
3n
3o
3p
Cl
Cl
Cl
COPh
COPh
COPh
6
6
4
89
91
87
To assess the capability and efficiency of our catalyst with
respect to the reported catalysts for Friedla¨nder synthesis of
quinoline derivatives, the results of the application of these
catalysts for the preparation of some quinolines are tabulated
in Table 2. As is clear from Table 2, PEG-OSO3H was more
efficient.
In another study, to recognize the applicability of our method
at large scales, we examined some reactions in scales of 100 and
300 mmol. The results are summarized in Table 3. As shown in
Table 3, the reactions were successfully performed at large scales
without significant loss of the yields.
The microwave-enhanced chemistry in this reaction is based
on the efficient heating of materials by “microwave dielectric
heating” effects. This phenomenon refers to the ability of PEG-
OSO3H to absorb microwave energy and convert it into heat
because of polar skeleton.30 Traditionally, organic synthesis is
carried out by conductive heating with an oil bath. This is a
3q
Cl
COPh
10
83
3r
3s
Cl
Cl
COPh
COPh
6
9
85
82
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Table 2 Comparison of the condensation of 2-aminobenzophenone (1a) or anthralinonitrile (4) with cyclopentanone using the reported catalysts
versus PEG-OSO3H
Reagents and conditions
Y
Time/min
Yield (%)
Ref.
NH2SO3H (5 mol%), solvent-free, 70 ◦
C
COPh
COPh
COPh
COPh
COPh
CN
50
50
180
360
120
720
12
87
60
92
90
90
41
81
91
27d
27c
36
28c
37
29c
Our catalyst
Our catalyst
Cellulose sulfuric acid, solvent-free, 100 ◦
Amberlyst-15, EtOH, reflux
C
Zr(DS)4 (5 mol%), EtOH–H2O (1 : 2), reflux
HClO4-SiO2, CH3CN, 60 ◦
C
BF3·(Et2O)2 (200 mol), toluene, reflux
PEG-OSO3H (3 mol%), solvent-free, MW
PEG-OSO3H (3 mol%), solvent-free, MW
COPh
CN
12
Table 3 The large scale synthesis of poly-substituted quinolines and 4-
aminoquinolines using PEG-OSO3H under microwave and solvent-free
conditions
Experimental
All chemicals were purchased from Merck or Fluka chemical
companies. All reactions were carried out using a laboratory
microwave oven (MicroSYNTH, Milestone Company, Italy).
2-Aminoarylketone (or nitrile)
amount/mmol
Product
Time/min
Yield (%)
1
The H NMR (500 MHz) and 13C NMR (125 MHz) were run
1
3a
3a
3a
3j
4
5
10
12
15
20
4
91
89
84
81
78
71
87
86
82
91
87
76
on a Bruker Avance DPX-250, FT-NMR spectrometer (d in
ppm). Microanalysis was performed on a Perkin–Elmer 240-B
microanalyzer. Melting points were recorded on a Bu¨chi B-545
apparatus in open capillary tubes. All known compounds were
identified by comparison of their melting points, 1H NMR and
13C NMR data with those reported in the literature.
100
300
1
100
300
1
100
300
1
100
300
3j
3j
3p
3p
3p
3w
3w
3w
6
10
12
16
22
Preparation of PEG-OSO3H
At 0 ◦C, chlorosulfonic acid (10 mmol) was added to a solution
of PEG-6000 (1 mmol) in CH2Cl2 (10 mL), and the resulting
solution was stirred at room temperature overnight. Then, the
solution was concentrated under vacuum, and ether was added
to it. The resulting precipitate was filtered and washed with ether
three times to afford PEG-OSO3H as a gummy solid.9 1H NMR
(CDCl3, 500 MHz): d (ppm) 3.40–3.54 (m, PEG), 4.18 (s, 2H,
CH2OSO3H), 12.69 (s, 1H, SO3H).
a Yields refer to isolated pure products.
comparatively slow and inefficient method for transferring en-
ergy into the system, since it depends on the thermal conductivity
of the various materials that must be penetrated, and results in
the temperature of the reaction vessel being higher than that
of the reaction mixture. In contrast, microwave irradiation pro-
duces efficient internal heating (in-core volumetric heating) by
direct coupling of microwave energy with the molecules that are
present in the reaction mixture. These effects should be termed
“specific microwave effects” and the formation of “molecular
radiators” or microscopic hotspots,31 and the elimination of wall
effects caused by inverted temperature gradients.32 Furthermore,
at the initial moments of microwave irradiation, PEG-OSO3H
melts and works as solvent as well as catalyst for these reactions.
So, these dual activation modes lead to reduce the reaction times
and improve the yield of the products.
General procedure for the synthesis of poly-substituted quinolines
and 4-aminoquinolines
A
well-ground mixture of 2-aminoarylketone or 2-
aminobenzonitrile (1 mmol), carbonyl compound (1.5 mmol)
and PEG-OSO3H (0.18 g, 0.03 mmol) in a test tube was
irradiated and stirred in a microwave oven at 600 W. The
microwave oven was programmed to enhance the internal
reaction temperature to 130 ◦C within 1.5 min, and then
continue suitable irradiation (0–600 W) at this temperature,
for the appropriate time. The combined times are showed in
Tables 1 and 2. Afterward, the reaction mixture was cooled
to room temperature, and H2O (5 mL) was added to it, and
shaken for 3 min to dissolve PEG-OSO3H. The crude product
(insoluble in water) was filtered and recrystallized from hot
ethanol (3 mL) to afford the pure product. In order to recover
the catalyst, H2O was evaporated under reduced pressure, the
resulting solid was washed with t-butylmethyl ether (2 mL) and
dried. The recovered PEG-OSO3H was reused for another time
without loss of its activity.
Conclusions
In conclusion, we have reported a highly efficient and green
method for Friedla¨nder synthesis of poly-substituted quinolines
and 4-aminoquinolines using PEG-OSO3H as an inexpensive,
biodegradable and reusable catalyst. This method not only offers
substantial improvements in the reaction rates and yields, but
also avoids the use of hazardous catalysts or solvents. Moreover,
the uses of microwave irradiation for direct heating of the
reaction mixture and solvent-free conditions have marked our
work as a green and economically benign methodology.
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General procedure for the synthesis of poly-substituted quinolines
and 4-aminoquinolines in large scale
Ethyl
2-methyl-4-phenylquinoline-3-carboxylate
(3e).
Yield = 83% (0.241 g), m.p. = 102–103 C (lit.33 99 ◦C),
1H NMR (CDCl3, 500 MHz): d (ppm) 0.99 (t, 3H, J = 6.6 Hz),
2.83 (s, 3H), 4.08–4.12 (q, 2H, J = 5.3 Hz), 7.40–7.41 (m, 2H),
7.45–7.48 (t, 1H, J = 7.5 Hz), 7.49–7.54 (m, 3H), 7.62 (d, 1H,
J = 8.3 Hz), 7.74–7.77 (t, 1H, J = 7.6 Hz), 8.12 (d, 1H, J =
8.4 Hz); 13C NMR (DMSO d6, 125 MHz): d (ppm) 13.8, 23.7,
61.4, 124.7, 126.4, 127.3, 128.8, 129.0, 129.5, 130.9, 135.4,
145.9, 147.5, 154.3, 167.9. Anal. calcd for C19H17NO2: C, 78.33;
H, 5.88; N, 4.81%. Found: C, 78.39; H, 5.84; N, 4.90%.
◦
A
well-ground mixture of 2-aminoarylketone or 2-
aminobenzonitrile (300 mmol), carbonyl compound (330 mmol)
and PEG-OSO3H (54 g, 9 mmol) in a round-bottomed flask
connected to a reflux condenser, was irradiated and stirred in a
microwave oven at 600 W. The microwave oven was programmed
◦
to enhance the internal reaction temperature to 130 C within
4 min, and then continue suitable irradiation (0–600 W) at this
temperature, for the appropriate time. The combined times are
showed in Table 3. Afterward, the reaction mixture was cooled
to room temperature, H2O (600 mL) was added to it, and it was
shaken for 5 min to dissolve PEG-OSO3H. The crude product
(insoluble in water) was filtered and recrystallized from hot
ethanol (400 mL) to afford the pure product. In order to recover
the catalyst, H2O was evaporated under reduced pressure, the
resulting solid was washed with t-butylmethyl ether (150 mL)
and dried. The recovered PEG-OSO3H was reused for another
time without loss of its activity.
Methyl
2-methyl-4-phenylquinoline-3-carboxylate ◦ (3f).
◦
Yield = 90% (0.249 g), m.p. = 105–107 C (lit.33 107 C), H
NMR (CDCl3, 500 MHz): d (ppm) 2.77 (s, 3H), 3.56 (s, 3H),
7.34–7.35 (m, 2H), 7.41 (t, 1H, J = 7.5 Hz), 7.43–7.49 (m, 3H),
7.57 (d, 1H, J = 8.0 Hz), 7.70 (t, 1H, J = 7.2 Hz), 8.07 (d, 1H,
J = 8.5 Hz). Anal. calcd for C18H15NO2: C, 77.96; H, 5.45; N,
5.05%. Found: C, 77.98; H, 5.48; N, 5.02%.
1
(2-Methyl-4-phenylquinolin-3-yl)(phenyl)methanone
(3g).
Yield = 88% (0.284 g), m.p. = 135–138 C (lit.25 133–134 ◦C),
1H NMR (CDCl3, 500 MHz): d (ppm) 2.48 (s, 3H), 7.29 (m,
7H), 7.31 (m, 2H), 7.57 (m, 3H), 7.67 (m, 1H), 8.05 (d, 1H, J =
8.5 Hz); 13C NMR (CDCl3, 125 MHz): d (ppm) 24.1, 125.0,
126.0, 126.3, 127.7, 128.0, 128.3, 128.7, 129.0, 129.8, 129.9,
132.3, 133.3, 134.4, 136.9, 145.4, 147.6, 154.3, 197.4. Anal.
calcd for C23H17NO: C, 85.42; H, 5.30; N, 4.33%. Found: C,
85.39; H, 5.33; N, 4.35%.
◦
Physical and spectral data of the products
3,3-Dimethyl-9-phenyl-3,4-dihydroacrid◦in-1(2H)-one
(3a).
◦
Yield = 91% (0.274 g), m.p. = 193–194 C (lit.33 192 C), H
NMR (CDCl3, 500 MHz): d (ppm) 1.16 (s, 6H), 2.56 (s, 2H),
3.27 (s, 2H), 7.17 (d, 2H, J = 6.5 Hz), 7.40 (t, 1H, J = 7.5 Hz),
7.47–7.50 (m, 4H), 7.75 (t, 1H, J = 7.0 Hz), 8.06 (d, 1H, J =
8.5 Hz); 13C-NMR (DMSO-d6, 125 MHz): d (ppm) 28.3, 32.8,
47.8, 53.8, 126.0, 127.1, 127.7, 127.9, 128.3, 128.6, 128.7, 128.9,
131.3, 132.1, 134.6, 137.8, 148.7, 150.1, 161.6, 197.7. Anal.
calcd for C21H19NO: C, 83.69; H, 6.35; N, 4.65%. Found: C,
83.64; H, 6.39; N, 4.71%.
1
9-Phenyl-1,2,3,4-tetrahydroacridine (3h). Yield
=
84%
◦
◦
(0.217 g), m.p. = 143–145 C (lit.33 139 C), H NMR (CDCl3,
500 MHz): d (ppm) 1.83–1.85 (m, 2H), 2.00–2.01 (m, 2H), 2.65
(t, 2H, J = 6.2 Hz), 3.25 (t, 2H, J = 6.2 Hz), 7.27 (d, 2H, J =
7.0 Hz), 7.36 (s, 2H), 7.49– 7.52 (m, 1H), 7.55– 7.58 (m, 2H),
7.64– 7.65 (m, 1H), 8.07 (d, 1H, J = 8.2 Hz); 13C NMR (DMSO
d6, 125 MHz): d (ppm) 22.7, 22.8, 27.9, 34.0, 125.6, 126.0, 126.4,
127.7, 128.3, 128.4, 128.5, 128.6, 128.7, 129.3, 136.8, 146.2,
159.0. Anal. calcd for C19H17N: C, 87.99; H, 6.61; N, 5.40%.
Found: C, 87.89; H, 6.63; N, 5.38%.
1
9-Phenyl-3,4-dihydroacridi◦n-1(2H)-one (3b). Yield = 93%
(0.254 g), m.p. = 157–159 C (lit.33 151–153 ◦C), 1H NMR
(CDCl3, 500 MHz): d (ppm) 2.62–2.65 (t, 2H, J = 6.5 Hz),
3.22 (t, 2H, J = 6.5 Hz), 3.75–3.78 (m, 2H), 7.25–7.26 (m, 2H),
7.32 (d, 1H, J = 2.2 Hz), 7.51–7.66 (m, 5H), 8.00 (d, 1H, J =
8.7 Hz); 13C NMR (DMSO d6, 125 MHz): d (ppm) 21.6, 34.6,
40.9, 127.7, 127.5, 127.5, 128.1, 128.2, 128.7, 129.0, 129.1, 132.5,
138.2, 148.7, 150.8, 163.2, 198.3. Anal. calcd for C19H15NO: C,
83.49; H, 5.53; N, 5.12%. Found: C, 83.53; H, 5.49; N, 5.17%.
2-tert-Butyl-9-phenyl-1,2,3,4-tetrahydroacridine (3i). Yield =
79% (0.249 g), m.p. = 133–135 ◦C (lit.35 132–133 ◦C), 1H NMR
(CDCl3, 500 MHz): d (ppm) 0.90 (s, 9H), 1.47–1.58 (m, 2H),
2.08–2.10 (m, 1H), 2.22–2.27 (m, 1H), 2.63–2.65 (m, 1H), 3.09–
3.15 (m 1H), 3.23–3.27 (m, 1H), 7.32–7.37 (m, 3H), 7.43–7.46
(m, 1H), 7.49–7.52 (m, 2H), 7.61–7.65 (m, 2H), 8.06 (d, 1H, J =
8.4 Hz). Anal. calcd for C23H25N: C, 87.57; H, 7.99; N, 4.44%.
Found: C, 87.67; H, 8.06; N, 4.39%.
9-Phenyl-2,3-dihydro-1H-cyclopenta[b]quinolin-1-one
(3c).
Yield = 75% (0.194 g), m.p. = 170–173 C (lit.34 171–175 ◦C),
1H NMR (CDCl3, 500 MHz): d (ppm) 2.71 (m, 2H), 3.42
(m, 2H), 7.31 (m, 2H), 7.58 (m, 4H), 7.64 (m, 2H), 8.07 (d,
1H, J = 8.5 Hz); 13C NMR (CDCl3, 125 MHz): d (ppm) 28.3,
36.6, 123.4, 126.3, 126.4, 127.7, 128.1, 128.5, 128.8, 129.2,
130.4, 131.8, 132.9, 148.7, 151.0, 170.6, 203.3. Anal. calcd for
C18H13NO: C, 83.37; H, 5.05; N, 5.40%. Found: C, 83.33; H,
5.09; N, 5.49%.
◦
9-Phenyl-2,3-dihydro-1H-cyclopenta[b]quinoline
(3j).
Yield = 81% (0.198 g), m.p. = 142–143 C (lit.35 140–142 ◦C),
1H NMR (CDCl3, 500 MHz): d (ppm) 2.18–2.24 (m, 2H), 2.95
(t, 2H, J = 7.3 Hz), 3.29 (t, 2H, J = 7.6 Hz), 7.40–7.44 (m, 3H),
7.49–7.52 (m, 1H), 7.55–7.58 (m, 2H), 7.65–7.68 (m, 2H), 8.12
(d, 1H, J = 8.5 Hz). Anal. calcd for C18H15N: C, 88.13; H, 6.16;
N, 5.71%. Found: C, 88.10; H, 6.13; N, 5.77%.
◦
1-(2-Methyl-4-phenylquinolin-3-yl)ethanone (3d). Yield
=
90% (0.235 g), m.p. = 109–110 ◦C (lit.28c 105–106 ◦C), 1H NMR
(CDCl3, 500 MHz): d (ppm) 2.04 (s, 3H), 2.74 (s, 3H), 7.39–7.41
(m, 2H), 7.48 (t, 1H, J = 7.5 Hz), 7.55–7.56 (m, 3H), 7.66 (d, 1H,
J = 8.3 Hz), 7.76 (t, 1H, J = 7.4 Hz), 8.12 (d, 1H, J = 8.3 Hz).
Anal. calcd for C18H15NO: C, 82.73; H, 5.79; N, 5.36%. Found:
C, 82.70; H, 5.72; N, 5.44%.
7-Chloro-3,3-dimethyl-9-phenyl-3,4-dihydroacridin-1(2H)-one
(3k). Yield = 94% (0.315 g), m.p. = 211–212 ◦C, (lit.33 211 ◦C),
1H NMR (CDCl3, 500 MHz): d (ppm) 1.15 (s, 6H), 2.56 (m,
2H), 3.25 (s, 2H), 7.14–7.16 (m, 2H), 7.42 (d, 1H, J = 2.5 Hz),
7.50–7.51 (m, 3H), 7.66–7.68 (dd, 1H, J = 2.5, 8.9 Hz), 7.99 (d,
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1H, J = 9.0 Hz); 13C NMR (CDCl3, 125 MHz): d (ppm) 28.4,
32.3, 48.1, 54.3, 124.0, 126.5, 127.9, 128.4, 130.5, 132.3, 136.7,
147.9, 150.1, 162.0, 196.9. Anal. calcd for C21H18ClNO: C,
75.11; H, 5.40; N, 4.17%. Found: C, 75.17; H, 5.38; N, 4.21%.
125 MHz): d 121.2, 125.5, 125.9, 126.3, 126.7, 128.2, 128.6,
129.5, 131.0, 131.5, 132.0, 132.3, 132.4, 133.10, 133.18, 133.6,
134.3, 140.2, 142.9, 152.8, 201.2. Anal. calcd for C28H18ClNO:
C, 80.09; H, 4.32; N, 3.34%. Found: C, 80.16; H, 4.30; N, 3.32%.
7-Chloro-9-phenyl-3,4-dihydroacridin-1(2H)-one
(3l).
7-Chloro-9-phenyl-1,2,3,4-tetrahydroacridine (3r). Yield =
◦
◦
Yield = 92% (0.283 g), m.p. = 187–188 C (lit.33 185 C), H
NMR (CDCl3, 500 MHz): d (ppm) 2.23–2.26 (m, 2H), 2.70
(t, 2H, J = 6.6 Hz), 3.35 (t, 2H, J = 6.3 Hz), 7.14–7.16 (m,
2H), 7.41 (d, 1H, J = 2.5 Hz), 7.49–7.51 (m, 3H), 7.67–7.69
(dd, 1H, J = 2.5, 8.9 Hz), 7.99 (d, 1H, J = 9.0 Hz); 13C NMR
(CDCl3, 125 MHz): d (ppm) 20.8, 34.1, 40.2, 124.1, 126.1,
127.8, 129.9, 132.0, 136.5, 146.6, 149.9, 162.1, 196.8. Anal.
calcd for C19H14ClNO: C, 74.15; H, 4.58; N, 4.55%. Found: C,
74.17; H, 4.55; N, 4.63%.
1
◦
◦
85% (0.249 g), m.p. = 166–167 C (lit.33 165 C), H NMR
(CDCl3, 500 MHz): d (ppm) 1.77 (m, 2H), 1.94–1.95 (m, 2H),
2.57–2.59 (m, 2H), 3.15–3.18 (m, 2H), 7.20 (d, 2H, J = 7.0 Hz),
7.26–7.27 (m, 1H), 7.47–7.52 (m, 4H), 7.93 (d, 1H, J = 8.5 Hz);
13C NMR (CDCl3, 125 MHz): d (ppm) 23.0, 23.1, 28.4, 34.4,
124.5, 127.6, 129.1, 129.7, 129.8, 130.2, 130.8, 131.4, 136.4,
145.0, 145.7, 160.4. Anal. calcd for C19H16ClN: C, 77.68; H,
5.49; N, 4.77%. Found: C, 77.75; H, 5.51; N, 4.85%.
1
2-tert-Butyl-7-chloro-9-phenyl-1,2,3,4-tetrahydroacridine (3s).
1-(6-Chloro-2-methyl-4-phenylquinolin-3-yl)ethanone
(3m).
◦
1
Yield = 82% (0.286 g), m.p. = 154–155 C, H NMR (CDCl3,
500 MHz): d (ppm) 0.83 (s, 9H), 1.45–1.57 (m, 2H), 2.11–2.13
(m, 1H), 2.26–2.32 (m, 1H), 2.64–2.67 (m, 1H), 3.06–3.13 (m
1H), 3.27–3.31 (m, 1H), 7.20–7.21 (m, 2H), 7.27–7.28 (m, 1H),
7.46–7.53 (m, 4H), 7.93 (d, 1H, J = 9.0 Hz); 13C NMR (CDCl3,
125 MHz): d (ppm) 25.1, 30.7, 33.5, 45.2, 125.1, 125.8, 126.7,
126.8, 128.4, 128.9, 129.6, 131.3, 131.7, 132.0, 142.7, 145.8,
146.9, 160.4. Anal. calcd. for C23H24ClN: C, 78.95; H, 6.91; N,
4.00%. Found: C, 78.74; H, 6.81; N, 4.13%.
◦
◦
Yield = 90% (0.266 g), m.p. = 157–158 C (lit.33 157 C), H
NMR (CDCl3, 500 MHz): d (ppm) 1.98 (s, 3H), 2.66 (s, 3H),
7.31–7.33 (m, 2H), 7.51–7.52 (m, 3H), 7.55 (d, 1H, J = 2.0 Hz),
1
7.62–7.64 (dd, 1H, J = 2.0, 8.9 Hz), 7.99 (d, 1H, J = 8.5 Hz); 13
C
NMR (DMSO-d6, 125 MHz): d (ppm) 24.1, 53.2, 125.3, 126.0,
128.5, 129.4, 129.8, 129.8, 131.8, 131.9, 132.3, 135.0, 145.6,
146.4, 155.4, 169.6. Anal. calcd for C18H14ClNO: C, 73.10; H,
4.77; N, 4.74%. Found: C, 73.16; H, 4.80; N, 4.86%.
Ethyl 6-chloro-2-methyl-4-phenylquinoline-3-carboxylate (3n).
Yield = 89% (0.289 g), m.p. = 99–100 ◦C (lit.33 101 ◦C), 1H NMR
(CDCl3, 500 MHz): d (ppm) 0.92 (t, 3H, J = 7.0 Hz), 2.75 (s, 3H),
4.02–4.06 (q, 2H, J = 5.2 Hz), 7.32 (m, 2H), 7.46–7.51 (m, 4H),
7.60–7.62 (m, 1H), 7.97 (d, 1H, J = 9.0 Hz); 13C NMR (DMSO
d6, 125 MHz): d (ppm) 13.8, 23.7, 61.6, 124.9, 125.7, 129.1,
129.3, 129.4, 129.5, 131.3, 131.4, 131.8, 134.6, 145.1, 145.9,
155.0, 167.5. Anal. calcd for C19H16ClNO2: C, 70.05; H, 4.95;
N, 4.30%. Found: C, 70.07; H, 4.92; N, 4.38%.
7-Chloro-9-phenyl-2,3-dihydro-1H -cyclopenta[b]quinoline
(3t). Yield = 80% (0.223 g), m.p. = 106–108 ◦C (lit.25 105 ◦C), 1H
NMR (CDCl3, 500 MHz): d (ppm) 2.21–2.32 (m, 2H), 2.98 (m,
2H), 2.28 (t, 2H, J = 7.0 Hz), 7.38 (m, 2H), 7.44–7.56 (m, 5H),
8.22 (d, 1H, J = 8.5 Hz); 13C NMR (CDCl3, 125 MHz): d (ppm)
23.3, 30.4, 35.0, 124.1, 126.7, 128.3, 128.7, 129.2, 130.3, 131.4,
134.1, 135.6, 141.8, 146.3, 167.5. Anal. calcd. for C18H14ClN: C,
77.28; H, 5.04; N, 5.01%. Found: C, 77.21; H, 5.12; N, 5.17%.
9-Amino-3,3-dimethyl-3,4-dihydroacridin-1(2H)-one
(3u).
Methyl
6-chloro-2-methyl-4-phenylquinol◦ine-3-carboxylate
◦
1
Yield = 91% (0.218 g), m.p. = 173–175 C, H NMR (CDCl3,
500 MHz): d (ppm) 1.12 (s, 6H), 2.25 (s, 2H), 2.37 (s, 2H),
5.53 (s, 1H), 6.88–7.38 (m, 4H), 8.74 (s, 1H); 13C NMR
(CDCl3, 125 MHz): d (ppm) 28.12, 29.38, 32.51, 43.18, 50.25,
100.54, 125.72, 133.84, 141.38, 159.84, 198.39. Anal. Calcd for
C15H16N2O: C, 74.97; H, 6.71; N, 11.66%. Found: C, 75.07; H,
6.76; N, 11.73%.
(3o). Yield = 91% (0.283 g), m.p. = 136–137 C (lit.33 135 ◦C),
1H NMR (CDCl3, 500 MHz): d (ppm) 2.75 (s, 3H), 3.57 (s, 3H),
7.32–7.34 (m, 2H), 7.49–7.54 (m, 4H), 7.46–7.66 (dd, 1H, J =
2.5, 9.0 Hz), 8.00 (d, 1H, J = 9.0 Hz); 13C NMR (DMSO d6,
125 MHz): d (ppm) 24.1, 53.2, 125.3, 126.0, 128.5, 129.4, 129.8,
131.8, 131.9, 132.3, 135.0, 145.6, 146.4, 155.4, 168.6. Anal.
calcd for C18H14ClNO2: C, 69.35; H, 4.53; N, 4.49%. Found: C,
69.42; H, 4.59; N, 4.58%.
9-Amino-3,4-dihydroacridin-1(2H)-one (3v). Yield = 94%
(0.199 g), m.p. = 208–210 ◦C (dec.), 1H NMR (CDCl3, 500 MHz):
d (ppm) 1.91–1.96 (m, 2H), 2.33–2.36 (t, J = 6.0 Hz, 2H), 2.65–
2.67 (t, J = 6.0 Hz, 2H), 5.23 (s, 1H), 7.50–7.53 (t, J = 7.0 Hz,
2H), 7.78–7.81 (t, J = 7.5 Hz, 1H), 7.94–7.96 (d, J = 7.5 Hz,
1H), 8.53 (s, 1H); 13C NMR (CDCl3, 125 MHz): d (ppm) 21.93,
28.71, 34.73, 40.88, 98.98, 110.00, 117.14, 128.29, 128.61, 134.89,
135.46, 141.01, 195.51. Anal. calcd for C13H12N2O: C, 73.56; H,
5.70; N, 13.20%. Found: C, 74.01; H, 5.65; N, 13.29%.
(6-Chloro-2-methyl-4-phenylquinolin-3-yl)(phenyl)methanone
◦
(3p).◦ Yield = 87% (0.311 g), m.p. = 214–216 C (lit.25 209–
1
211 C), H NMR (CDCl3, 500 MHz): d (ppm) 2.68 (s, 3H),
7.22 (s, 1H), 7.30–7.35 (m, 5H), 7.50 (t, 1H, J = 7.3 Hz),
7.59–7.62 (m, 3H), 7.71–7.73 (dd, 1H, J = 2.15, 8.9 Hz), 8.11 (d,
1H, J = 8.9 Hz); 13C NMR (CDCl3, 125 MHz): d (ppm) 24.4,
125.4, 126.5, 128.9, 129.0, 129.6, 130.3, 131.0, 131.4, 132.9,
133.6, 134.1, 134.5, 137.3, 145.2, 146.6, 155.5, 197.7. Anal.
calcd for C23H16ClNO: C, 77.20; H, 4.51; N, 3.91%. Found: C,
77.16; H, 4.53; N, 4.03%.
2,3-Dihydro-1H-cyclopenta[b]quinolin-9-amine (3w). Yield =
91% (0.167 g), m.p. = 181–183 ◦C (lit.29c 180–182 ◦C), 1H NMR
(CDCl3, 500 MHz): d (ppm) 2.17 (m, 2H), 2.79 (t, J = 7.6 Hz,
2H), 3.09 (t, J = 7.5 Hz, 2H), 4.66 (s, 2H), 7.35 (t, J = 8.0 Hz,
1H), 7.61 (t, J = 8.0 Hz, 1H), 7.63 (d, J = 8.5 Hz, 1H), 7.77 (d,
J = 8.5 Hz, 1H). Anal. calcd for C12H12N2: C, 78.23; H, 6.57; N,
15.21%. Found: C, 78.26; H, 6.53; N, 15.26%.
(6-Chloro-2,4-diphenylquinolin-3-yl)(phenyl)methanone (3q).
◦
1
Yield = 83% (0.348 g), m.p. = 170–172 C, H NMR (CDCl3,
500 MHz): d 7.16–7.19 (t, J = 7.7 Hz, 3H), 7.25–7.34 (m, 8H),
7.46 (d, J = 7.0 Hz, 2H), 7.58–7.60 (m, 3H), 7.73 (dd, J =
2.5, 9.0 Hz, 1H), 8.22 (d, J = 8.9 Hz, 1H); 13C NMR (CDCl3,
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1,2,3,4-Tetrahydroacridin-◦9-amine (3x). Yield
=
93%
16 D. Doube, M. Blouin, C. Brideau, C. Chan, S. Desmarais, D. Eithier,
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and R. N. Young, Bioorg. Med. Chem. Lett., 1998, 8, 1255–1260.
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6808.
18 (a) F. H. Shaw and G. Bentley, Aust. J. Exp. Biol. Med. Sci., 1953, 31,
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Biochem. Pharmacol., 1974, 23, 1263–1281.
(0.184 g), m.p. = 177–179 C (lit.29c 178–180 ◦C), 1H NMR
(CDCl3, 500 MHz): d (ppm) 1.88–1.93 (m, 4H), 2.51 (t, J =
6.5 Hz, 2H), 3.11 (t, J = 5.5 Hz, 2H), 4.71 (s, 2H), 7.18 (m, 1H),
7.56 (m, 1H), 7.61 (dd, J = 8.5, 1.0 Hz, 1H), 7.88 (d, J = 8.5 Hz,
1H). Anal. calcd for C13H14N2: C, 78.75; H, 7.12; N, 14.13%.
Found: C, 78.77; H, 7.15; N, 14.08%.
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191–197.
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Neilsen, E. E. Mena, I. H. Williams, M. R. Nocerini and D. Liston,
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7,8,9,10-Tetrahydro-6H-cyclohepta[b]quinolin-11-amine (3y).
◦
◦
Yield = 90% (0.191 g), m.p. = 169–170 C (lit.29c 167–171 C),
1H NMR (CDCl3, 500 MHz): d (ppm) 1.67– 1.90 (m, 6H), 2.71
(m, 2H), 3.22 (m, 2H), 4.63 (s, 2H), 7.43 (m, 1H), 7.65 (m, 1H),
7.71 (dd, J = 8.3, 0.8 Hz, 1H), 7.97 (dd, J = 8.3, 0.60 Hz, 1H).
Anal. calcd for C14H16N2: C, 79.21; H, 7.60; N, 13.20%. Found:
C, 79.27; H, 7.52; N, 13.12%.
6,7,8,9,10,11-Hexahydrocycloocta[b]quinolin-12-amine (3z).
◦
◦
Yield = 91% (0.205 g), m.p. = 197–199 C (lit.29c 198–200 C),
1H NMR (CDCl3, 500 MHz): d (ppm) 1.27–1.59 (m, 4H),
1.62–1.96 (m, 4H), 2.89 (m, 2H), 3.07 (m, 2H), 4.82 (s, 2H),
7.44 (m, 1H), 7.67 (m, 1H), 7.76 (dd, J = 8.5, 0.6 Hz, 1H), 7.96
(dd, J = 8.5, 0.6 Hz, 1H). Anal. calcd for C15H18N2: C, 79.61; H,
8.02; N, 12.38%. Found: C, 79.56; H, 8.04; N, 12.41%.
24 E. A. Fehnel, J. Heterocycl. Chem., 1967, 4, 565–570.
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Acknowledgements
The authors thank the Research Committee of Persian Gulf
University and Payame Noor University (PNU) for financial
support of this work.
Notes and references
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