A green protocol for the synthesis of conformationally rigid sulfur linked bisquinolines by double Friedlander reaction in water

Article abstract of DOI:10.1039/c1nj20539k

A series of bis(2-aryl-4-arylquinolin-3-yl)sulfanes and 1,2-bis(2-aryl-4-arylquinolin-3-yl)disulfanes were synthesised in good to excellent yields by double Friedlander reaction between 2-[(2-oxo-2-arylethyl) sulfanyl]-1-aryl-1-ethanones/2-[(2-oxo-2-aryle

Full text of DOI:10.1039/c1nj20539k

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PAPER
A green protocol for the synthesis of conformationally rigid sulfur linked
bisquinolines by double Friedlander reaction in waterw
Nidhin Paul,a Shanmugam Muthusubramanian*a and Nattamai Bhuvaneshb
Received (in Montpellier, France) 20th June 2011, Accepted 15th August 2011
DOI: 10.1039/c1nj20539k
A series of bis(2-aryl-4-arylquinolin-3-yl)sulfanes and 1,2-bis(2-aryl-4-arylquinolin-3-yl)disulfanes were
synthesised in good to excellent yields by double Friedlander reaction between 2-[(2-oxo-2-arylethyl)sulfanyl]-
1-aryl-1-ethanones/2-[(2-oxo-2-arylethyl)disulfanyl]-1-aryl-1-ethanones and 2-aminobenzophenone
with p-toluenesulfonic acid in water medium. An interesting restricted rotation of aryl rings has
been noticed in bis(2-aryl-4-arylquinolin-3-yl)sulfanes as revealed by NMR and crystal data.
Introduction
Although numerous biochemical organic reactions require the
making or breaking of chemical bonds in an aqueous environment,
water as a solvent was ruled out from organic reactions during the
preceding decades. From the standpoint of green chemistry
and its twelve principles,1 water is the solvent of choice, being
cheap, clean, inexpensive, non-toxic, non-polluting and non-
flammable.2 Due to hydrophobic effects,3 water can not only
Fig. 1 Structures of bisquinoline antimalarial drugs.
accelerate reaction rates but also enhance the reaction selectivity.
Polyquinoline derivatives have found application in the field
of electronics, optoelectronics and non-linear optics4 and
quinoline metal complexes are used in organic light emitting
diodes.5 Bisquinolines are well known heterocyclic compounds
that contain two quinoline nuclei combined through an aliphatic
or aromatic linker. Bisquinoline drugs such as Ro 47-7737,
piperaquine and hydroxypiperaquine (Fig. 1) are active against
chloroquine resistant strains of malaria and bisquinolines also
have potential as antibiotics and antitumor agents.6 In addition,
these compounds are useful for studying the role of chromophores
in natural compounds.7
In many of these procedures, the reaction is usually carried out
in polar and in aprotic solvents such as acetonitrile, THF,
DMSO and DMF. Though p-toluenesulfonic acid (p-TsOH)
has been used in a variety of reactions to produce several
heterocyclic compounds,17 its use in Friedlander reaction is
limited.18 Synthesis of quinoline derivatives by the Friedlander
method was reported in water, but requires stoichiometric
amounts of mineral acid, metal dodecyl sulfates, dodecyl
phosphonic acid, cyanuric chloride or Lewis acids.19 In this article,
we report a very efficient and environmentally benign strategy to
get a set of conformationally rigid novel sulfur linked bisquinolines
in excellent yields using p-toluenesulfonic acid in water.
Among the well-established methods for the preparation of
quinolines,8 the Friedlander approach is arguably the best
known. Even though the two step Friedlander condensation,
including enamine formation and cyclodehydration, has been
performed under neutral, basic and acidic conditions,9 subsequent
work showed that acid catalysts are more effective.10 Several
catalysts such as Bronsted acids,11 Lewis acids,12 solid supported
acids,13 molecular iodine,14 metals15 and ionic liquids mediated
catalysts16 have been reported to be effective for this reaction.
Results and discussion
In the present investigation, the preparation of a series of
bisquinoline derivatives [3a–n] has been achieved in excellent
yields by the reaction of 2-aminobenzophenone 1 with substituted
diphenacylsulfides20 2 in the presence of p-toluenesulfonic acid
as catalyst in water medium (Scheme 1).
The effect of solvent and catalyst has been investigated on the
formation of 3c and the results are tabulated (Table 1). The
reaction proceeds well in water with 10 mol% of p-toluenesulfonic
acid compared to other trials. Base catalysts failed to effect the
reaction even after prolonged heating. The reaction described
in Scheme 1 has been carried out under optimized conditions
(Table 2). It is to be noted that the formation of monoquinoline
has not been noticed, whatever be the ratio of aminobenzo-
phenone and diphenacyl sulfide, 1 : 1 or 2 : 1.
a Department of Organic Chemistry, School of Chemistry, Madurai
Kamaraj University, Madurai 625 021, India.
E-mail: muthumanian2001@yahoo.com
b Department of Chemistry, Texas A & M University, College Station,
TX 77843, USA
w Electronic supplementary information (ESI) available. CCDC reference
numbers 824667, 827881 and 827882. For ESI and crystallographic data
in CIF or other electronic format see DOI: 10.1039/c1nj20539k
c
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Scheme 2 Preparation of disulfide linked bisquinolines 5.
Scheme 1 Preparation of sulfur linked bisquinolines 3.
Table 1 Catalyst and solvent screening for the formation of 3c
Entry
Solvent
Catalyst
Mol%
Yielda,b (%)
1
2
3
4
5
6
7
8
9
10
H2O
H2O
H2O
H2O
AlCl3
ZnCl2
HCl
p-TsOH
AlCl3
p-TsOH
p-TsOH
p-TsOH
p-TsOH
NaOH
20
15
15
10
30
25
25
25
20
15
26
20
64
96
55
78
73
61
38
CH3OH
CH3OH
CH3CN
THF
Fig. 2 ORTEP diagram of 3c.
c
—
CH3OH
d
—
a
Recrystallised from the dichloromethane–ethyl acetate mixture.
c
Isolated yield after purification by column chromatography. No
b
d
solvent. No recognisable product can be isolated.
In order to broaden the scope of the proposed reaction, we
also carried out the reaction of 2-aminobenzophenone 1 with
diphenacyl disulfide21 4 under the above mentioned conditions
(Scheme 2) to give 5a–e and the results are encouraging
(Table 2). The reusability of the reaction medium is also tested
without much variation in conversion22 and the yields were
92 and 89% for consecutive trials for 3a.
Fig. 3 ORTEP diagram of 3h.
[M + 1]), respectively, in their mass spectra. The structure was
also confirmed from single crystal X-ray analysis of 3c, 3h and
5e (Fig. 2, 3 and 4).23
The structures of bisquinolines 3 and 5 have been established
unambiguously by NMR, mass and single crystal X-ray analyses.
The molecular mass for the compounds 3b, 3f, 5a and 5c was
obtained as m/e 621.2359 [M + 1] (calcd 621.2286 [M + 1]),
661.1266 [M + 1] (calcd 661.1194 [M + 1]), 725.0 [M + 1]
(calcd 725.2 [M + 1]) and m/e 693.0 [M + 1] (calcd 693.1
The NMR spectral data for 3 and 5 are very significant,
revealing interesting conformational features. The symmetrical
sulfide 3i is expected to exhibit seventeen carbon signals in the
aryl region of the 13C NMR spectrum, out of which eight are
to be methine carbons, rest being quaternary. But the 13C
NMR spectrum of 3i exhibits nineteen carbon signals in the
aryl region, ten of them being methine carbons. The quinoline
H-8 proton appears as doublet at 7.90 ppm (J = 9.0 Hz), H-7
as doublet of doublet at 7.53 ppm (J = 9.0, 2.1 Hz) and H-5 as
a doublet at 7.12 (J = 2.1 Hz). Two other doublets at
6.64 ppm (J = 7.5 Hz) and 6.95 ppm (J = 7.5 Hz) have
common HMBC contours with a quaternary carbon, indicating
them to be the non-equivalent ortho hydrogens of the aryl ring
either at C-2 or at C-4. It is very clear from the number of
methine carbons in DEPT-135 and the non-equivalence of the
ortho hydrogens of one aryl ring that one of the aryl rings has
Table 2 Yields of 3 and 5
Compound
Ar
R
Time/h
Yielda,b (%)
3a
3b
3c
3d
3e
3f
3g
3h
3i
3j
3k
3l
3m
3n
5a
5b
5c
5d
5e
C6H5
H
H
H
H
H
H
H
Cl
Cl
Cl
Cl
Cl
Cl
Cl
H
H
H
Cl
Cl
1.1
1.2
2
1.5
1.2
1.5
1.5
1.5
1.2
2
93
95
96
94
91
93
95
92
94
95
92
90
95
96
93
94
91
96
93
4-MeC6H4
4-ClC6H4
4-BrC6H4
2-Naphthyl
3-ClC6H4
3-BrC6H4
C6H5
4-MeC6H4
4-ClC6H4
4-BrC6H4
2-Naphthyl
3-ClC6H4
3-BrC6H4
2-Naphthyl
4-MeC6H4
4-ClC6H4
2-Naphthyl
4-ClC6H4
1.1
1.4
1.5
2
2
1.6
1.5
2
1.5
a
Isolated yield after recrystallisation from the dichloromethane–ethyl
b
acetate (8 : 2) mixture. All the compounds have melting points
above 280 1C.
Fig. 4 ORTEP diagram of 5e.
c
2608 New J. Chem., 2011, 35, 2607–2613
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Fig. 7 NMR chemical shifts and HMBCs of 5b.
Fig. 5 NMR chemical shifts and HMBCs of 3i.
all its six carbons non-equivalent. For a phenyl ring or a para
substituted phenyl ring this is unexpected, unless the rotation of
the C–C bond is slow enough to feel different chemical environ-
ment. A conformationally biased24 arrangement has to be
ascribed for this observation. It is confirmed that C-4 aryl and
not C-2 aryl has this restricted rotation by introducing a meta
substituted aryl ring in the C-2 position (3f, 3g, 3m and 3n), when
the number of carbon signals in the aryl region of the 13C NMR
spectrum is increased by two. The complete assignment of
hydrogen and carbon signals for 3i has been achieved by
analysing the two dimensional NMR spectral data (Fig. 5).
The upfield chemical shift values of the ortho hydrogens of
the aryl ring under discussion suggest that these two hydrogens
are under the influence of the ring current effect of the quinoline
ring, experiencing the shielding due to the near perpendicular
orientation of this ring with respect to the quinoline nucleus. It
must be mentioned that the crystal structure also supports this
proposed preferred conformation in solution. An energy
minimised structure for 3a predicted by semi-empirical AMI
calculation using ArgusLab software25 also has a similar
arrangement (Fig. 6).
Fig. 8 Energy minimized structure for di(2,4-diphenyl-3-quinolyl)
disulfide.
C-4 aryl ring hydrogens are not giving any HMBC contours
with any of the quaternary carbons preventing assignment of
the observed carbon signals. There is no appreciable change in
the NMR spectral pattern of these compounds, even when the
solvent was changed to DMSO-d6 or acetone-d6 from CDCl3.
Probably a dynamic conformational switching might have led
to the above observations in the NMR spectra.
An energy minimized structure for di(2,4-diphenyl-3-
quinolyl) disulfide (Fig. 8) is given for comparison.
The NMR spectral features of the bisquinoline linked by the
disulfide are still more interesting. In the 1H NMR spectrum of
5b, the quinoline ring hydrogens appear well resolved (Fig. 7).
Thus the C-8 hydrogen appears as a doublet at 8.19 ppm
(J = 8.1 Hz), C-7 hydrogen as a triplet at 7.77 ppm (J = 8.1 Hz),
C-6 hydrogen as another triplet at 7.41 ppm (J = 8.1 Hz) and
the C-5 hydrogen at 7.20 ppm as a doublet (J = 8.1 Hz). But
the C-2 and C-4 aryl ring hydrogens are not well resolved
appearing as broad peaks around 7.3 (8H) and 6.9 ppm
(10H). In the H,H-COSY spectrum of 5b, there is no contour
connecting 7.3 and 6.9 ppm peaks, indicating that the former is
exclusively for one aryl ring and the latter is for another ring.
In the 13C NMR spectrum, it is observed that (i) not all the
carbons are being picked up and (ii) a few carbons are
appearing unusually broad and less intense. The C-2 and
Conclusion
Mono- and di-sulfur linked bisquinolines have been synthesized
using p-toluenesulfonic acid in water through a green Friedlander
approach. The restricted rotation in the compounds has been
investigated using NMR, crystal and mass analysis. The
mono-sulfur linked bisquinolines exhibit conformational
rigidity with all the hydrogen and carbons of the C-4 aryl
being non-equivalent in their NMR spectra. The disulfur
linked compounds also have unusual NMR patterns.
Experimental section
All melting points reported in this work were measured in
open capillaries. The 1H, 13C NMR and 2D NMR spectra
have been measured at 300 and 75 MHz, respectively, using a
Bruker 300 MHz (Avance) instrument in CDCl3 and using
tetramethylsilane (TMS) as internal standard. Chemical shifts
are reported as d values (ppm). For compounds 5a–e, all the
carbon signals are not picked up. All one- and two-dimensional
NMR spectra were obtained using standard Bruker software
throughout. Silica gel-G plates (Merck) were used for TLC
analysis with a mixture of petroleum ether (60–80 1C) and
ethyl acetate as eluent. Elemental analyses were performed on
a Perkin Elmer 2400 Series II Elemental CHNS analyzer. IR
spectra were recorded on a JASCO FT IR instrument (KBr
pellet method). Crystals suitable for X-ray crystallographic
Fig. 6 Energy minimized structure for 3a.
c
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studies were obtained by crystallization from a 1 : 1 mixture of
dichloromethane and DMF.
C42H26Br2N2S: C, 67.21; H, 3.49; N, 3.73%. Found C,
67.17; H, 3.46; N, 3.77%.
Di[2-(2-naphthyl)-4-phenyl-3-quinolyl] sulfide (3e). Isolated
General procedure for quinoline derivatives (3/5)
as a colorless solid; IR (KBr): 3054 (C-H), 1560 (CQN) cmÀ1
;
2-[(2-Oxo-2-arylethyl)sulfanyl]-1-aryl-1-ethanone/2-[(2-oxo-2-
phenylethyl)disulfanyl]-1-aryl-1-ethanone 2/4 (0.1 mole) and
2-amino benzophenone 1 (0.2 mole) were taken in 15 mL
water followed by the addition of p-toluenesulfonic acid
(10 mol%) and refluxed for 1–2 h. After the completion of the
reaction (monitored by TLC), the mixture was cooled to room
temperature and the solid was filtered out and recrystallised from
the dichloromethane–ethyl acetate (8 : 2) mixture to yield a
pure product. Spectral data of all the compounds are
given below.
1H NMR (300 MHz, CDCl3) dH: 6.75 (d, 2H, J = 7.8 Hz,
Ar-H), 6.79 (d, 2H, J = 8.1 Hz, Ar-H), 7.08–7.17 (m, 4H,
Ar-H), 7.20 (d, 2H, J = 1.5 Hz, Ar-H), 7.26–7.32 (m, 4H,
Ar-H), 7.38 (t, 2H, J = 7.2 Hz, Ar-H), 7.45–7.63 (m, 12H,
Ar-H), 7.89 (t, 4H, J = 9.0 Hz, Ar-H); 13C NMR (75 MHz,
CDCl3) dC: 125.3, 125.8, 126.4 (2C), 127.0, 126.8, 127.4, 127.5,
127.8, 127.9, 128.0, 128.5, 128.7, 129.0, 129.2 (2C), 129.8,
130.2, 132.8, 133.0, 136.4, 137.8, 146.0, 150.6, 160.2. Anal.
calcd for C50H32N2S: C, 86.67; H, 4.66; N, 4.04%. Found C,
86.63; H, 4.63; N, 4.09%.
Di(2,4-diphenyl-3-quinolyl) sulfide (3a). Isolated as a colorless
solid; IR (KBr): 3057 (C-H), 1560 (CQN) cmÀ1 1H NMR
;
Di[2-(3-chlorophenyl)-4-phenyl-3-quinolyl]
sulfide
(3f).
Isolated as a colorless solid; IR (KBr): 3056 (C-H), 1560
1
(CQN) cmÀ1; H NMR (300 MHz, CDCl3) dH: 6.68 (d, 2H,
(300 MHz, CDCl3) dH: 6.67 (d, 2H, J = 7.5 Hz, Ar-H), 6.95
(d, 2H, J = 7.5 Hz, Ar-H), 7.12–7.18 (m, 4H, Ar-H), 7.24–7.35
(m, 16H, Ar-H), 7.59 (td, 2H, J = 8.4, 1.5 Hz, Ar-H), 7.98
(d, 2H, J = 8.4 Hz, Ar-H); 13C NMR (75 MHz, CDCl3) dC:
125.3, 126.4, 126.7, 127.6, 127.7, 127.8, 127.9, 128.0, 128.5,
129.0, 129.1, 129.2, 129.7, 129.9, 136.4, 140.2, 145.9, 150.3,
160.0. Anal. calcd for C42H28N2S: C, 85.10; H, 4.76; N, 4.73%.
Found C, 85.06; H, 4.73; N, 4.78%.
J = 7.2 Hz, Ar-H), 6.92 (d, 2H, J = 7.5 Hz, Ar-H), 7.09–7.17
(m, 4H, Ar-H), 7.19–7.40 (m, 14H, Ar-H), 7.64 (td, 2H,
J = 8.4, 1.5 Hz, Ar-H), 8.00 (d, 2H, J = 8.4 Hz, Ar-H);
13C NMR (75 MHz, CDCl3) dC: 125.3, 126.8, 126.9, 127.3,
128.0, 128.1, 128.2 (2C), 128.3, 129.0, 129.2, 129.3, 129.5,
129.8, 129.9, 133.8, 136.1, 141.9, 145.9, 150.9, 158.7; m/e
661.1266 [M + 1] (calcd 661.1194 [M + 1]); Anal. calcd for
C42H26Cl2N2S: C, 76.24; H, 3.96; N, 4.23%. Found C, 76.20;
H, 3.93; N, 4.27%.
Di[2-(4-methylphenyl)-4-phenyl-3-quinolyl]
sulfide
(3b).
Isolated as a colorless solid; IR (KBr): 3059 (C-H), 1560
1
(CQN) cmÀ1; H NMR (300 MHz, CDCl3) dH: 2.39 (s, 6H,
Di[2-(3-bromophenyl)-4-phenyl-3-quinolyl]
sulfide
(3g).
Isolated as a colorless solid; IR (KBr): 3054 (C-H), 1559
1
CH3), 6.62 (d, 2H, J = 7.5 Hz, Ar-H), 6.96 (d, 2H, J = 7.5 Hz,
Ar-H), 7.05 (d, 4H, J = 8.1 Hz, Ar-H), 7.13–7.21 (m, 8H,
Ar-H), 7.25–7.35 (m, 6H, Ar-H), 7.59 (td, 2H, J = 8.4, 1.5 Hz,
Ar-H), 7.96 (d, 2H, J = 8.4 Hz, Ar-H); 13C NMR (75 MHz,
CDCl3) dC: 21.4, 125.3, 126.2, 126.8, 127.6, 127.9, 128.1, 128.5,
128.7, 129.0, 129.1, 129.2, 129.6, 129.8, 136.6, 137.4, 137.9,
146.0, 150.1, 160.1; m/e 621.2359 [M + 1] (calcd 621.2286
[M + 1]); Anal. calcd for C44H32N2S: C, 85.13; H, 5.20; N,
4.51%. Found C, 85.10; H, 5.17; N, 4.55%.
(CQN) cmÀ1; H NMR (300 MHz, CDCl3) dH: 6.66 (d, 2H,
J = 7.8 Hz, Ar-H), 6.93 (d, 2H, J = 7.2 Hz, Ar-H), 7.09
(t, 2H, J = 7.8 Hz, Ar-H), 7.16–7.23 (m, 6H, Ar-H), 7.25
(d, 2H, J = 1.2 Hz, Ar-H), 7.30–7.40 (m, 6H, Ar-H), 744
(dd, 2H, J = 7.8, 1.2 Hz, Ar-H), 7.64 (t, 2H, J = 8.4 Hz,
Ar-H), 8.01 (d, 2H, J = 8.4 Hz, Ar-H); 13C NMR (75 MHz,
CDCl3) dC: 122.1, 125.3, 126.8, 126.9, 127.8, 128.0 (3C), 128.3,
129.2, 129.4, 129.6, 129.7, 129.9, 131.1, 132.1, 136.1, 142.1,
145.9, 150.9, 158.6. Anal. calcd for C42H26Br2N2S: C, 67.21;
H, 3.49; N, 3.73% Found C, 67.18; H, 3.44; N, 3.78%.
Di[2-(4-chlorophenyl)-4-phenyl-3-quinolyl]
sulfide
(3c).
Isolated as a colorless solid; IR (KBr): 3055 (C-H), 1558
1
Di(6-chloro-2,4-diphenyl-3-quinolyl) sulfide (3h). Isolated as
(CQN) cmÀ1; H NMR (300 MHz, CDCl3) dH: 6.65 (d, 2H,
a colorless solid; IR (KBr): 3056 (C-H), 1561 (CQN) cmÀ1
;
1H NMR (300 MHz, CDCl3) dH: 6.67 (d, 2H, J = 7.5 Hz, Ar-H),
6.95 (d, 2H, J = 7.5 Hz, Ar-H), 7.14 (d, 2H, J = 2.1 Hz,
Ar-H), 7.17–7.39 (m, 16H, Ar-H), 7.53 (dd, 2H, J = 9.0,
2.1 Hz, Ar-H), 7.91 (d, 2H, J = 9.0 Hz, Ar-H); 13C NMR
(75 MHz, CDCl3) dC: 124.0, 127.3, 127.8, 128.1, 128.2 (2C),
128.3, 129.1, 129.4, 129.6, 129.8, 130.1, 130.7, 132.4, 135.7,
139.8, 144.3, 149.4, 160.1. Anal. calcd for C42H26Cl2N2S: C,
76.24; H, 3.96; N, 4.23%. Found C, 76.20; H, 3.93; N, 4.27%.
J = 7.2 Hz, Ar-H), 6.92 (d, 2H, J = 7.5 Hz, Ar-H), 7.14–7.28
(m, 12H, Ar-H), 7.33–7.39 (m, 6H, Ar-H), 7.67 (t, 2H, J = 8.4 Hz,
Ar-H), 8.15 (d, 2H, J = 8.4 Hz, Ar-H); 13C NMR (75 MHz,
CDCl3) dC: 125.4, 126.8, 127.2, 128.0, 128.1 (2C), 128.2, 128.3,
128.4, 129.5, 129.7, 130.1, 130.7, 134.8, 135.9, 137.1, 145.0,
151.6, 158.3. Anal. calcd for C42H26Cl2N2S: C, 76.24; H, 3.96;
N, 4.23%. Found C, 76.19; H, 3.93; N, 4.27%.
Di[2-(4-bromophenyl)-4-phenyl-3-quinolyl]
sulfide
(3d).
Isolated as a colorless solid; IR (KBr): 3057 (C-H), 1557
1
Di[6-chloro-2-(4-methylphenyl)-4-phenyl-3-quinolyl] sulfide
(CQN) cmÀ1; H NMR (300 MHz, CDCl3) dH: 6.66 (d, 2H,
(3i). Isolated as a colorless solid; IR (KBr): 3052 (C-H),
1555 (CQN) cmÀ1 1H NMR (300 MHz, CDCl3) dH: 2.40
;
(s, 6H, CH3), 6.64 (d, 2H, J = 7.5 Hz, Ar-H), 6.95 (d, 2H,
J = 7.5 Hz, Ar-H), 7.07 (d, 4H, J = 7.8 Hz, Ar-H), 7.12
(d, 2H, J = 2.1 Hz, Ar-H), 7.16–7.24 (m, 8H, Ar-H), 7.37
(t, 2H, J = 7.2 Hz, Ar-H), 7.53 (dd, 2H, J = 9.0, 2.1 Hz,
Ar-H), 7.90 (d, 2H, J = 9.0 Hz, Ar-H); 13C NMR (75 MHz,
J = 7.2 Hz, Ar-H), 6.90 (d, 2H, J = 7.5 Hz, Ar-H), 7.11–7.23
(m, 10H, Ar-H), 7.29–7.37 (m, 8H, Ar-H), 7.63 (td, 2H,
J = 8.4, 1.2 Hz, Ar-H), 7.99 (d, 2H, J = 8.4 Hz, Ar-H);
13C NMR (75 MHz, CDCl3) dC: 122.7, 125.3, 126.8 (2C),
127.9, 128.0 (2C), 128.2, 129.2, 129.5, 129.7, 129.9, 130.8,
130.9, 136.2, 139.0, 146.0, 150.7, 158.8. Anal. calcd for
c
2610 New J. Chem., 2011, 35, 2607–2613
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CDCl3) dC: 21.3, 124.0, 127.3, 128.0, 128.2, 128.3, 128.5, 129.1,
129.5, 129.6, 129.7, 130.0, 130.7, 132.1, 135.9, 137.0, 138.2,
144.4, 149.2, 160.2. Anal. calcd for C44H30Cl2N2S: C, 76.62;
H, 4.38; N, 4.06%. Found C, 76.59; H, 4.34; N, 4.10%.
122.2, 124.1, 127.5, 127.7, 128.3, 128.4, 128.5, 129.2, 129.3,
129.6, 129.8, 130.6, 131.0, 131.4, 132.1, 133.0, 135.4, 141.6,
144.3, 150.0, 158.7. Anal. calcd for C42H24Br2Cl2N2S: C,
61.56; H, 2.95; N, 3.42%. Found C, 61.52; H, 2.90; N, 3.47%.
Di[6-chloro-2-(4-chlorophenyl)-4-phenyl-3-quinolyl] sulfide
Di[2-(2-naphthyl)-4-phenyl-3-quinolyl] disulfide (5a). Isolated
as a colorless solid; IR (KBr): 3058 (C-H), 1561 (CQN) cmÀ1
;
(3j). Isolated as a colorless solid; IR (KBr): 3059 (C-H),
1557 (CQN) cmÀ1 1H NMR (300 MHz, CDCl3) dH: 6.64
;
1H NMR (300 MHz, CDCl3) dH: 7.04 (b, 2H Ar-H), 7.20
(b, 8H, Ar-H), 7.41–7.47 (m, 16H, Ar-H), 7.78–7.83 (m, 4H,
Ar-H), 8.20 (d, 2H, J = 8.4 Hz, Ar-H); 13C NMR (75 MHz,
CDCl3) dC: 125.8, 126.3, 126.7, 126.8, 127.0, 127.2, 127.4,
127.7 (3C), 128.5, 129.2, 129.6, 130.5, 132.7, 132.8, 136.5,
137.8, 147.2, 154.2, 162.7; m/e 725.0 [M + 1] (calcd 725.2
[M + 1]); Anal. calcd for C50H32N2S2: C, 82.84; H, 4.45; N,
3.86%. Found C, 82.80; H, 4.42; N, 3.89%.
(d, 2H, J = 7.2 Hz, Ar-H), 6.89 (d, 2H, J = 7.5 Hz, Ar-H),
7.13 (d, 2H, J = 2.4 Hz, Ar-H), 7.17–7.28 (m, 12H, Ar-H),
7.38 (t, 2H, J = 7.5 Hz, Ar-H), 7.57 (dd, 2H, J = 9.0, 2.4 Hz,
Ar-H), 7.92 (d, 2H, J = 9.0 Hz, Ar-H); 13C NMR (75 MHz,
CDCl3) dC: 124.1, 127.4, 128.1, 128.3, 128.4 (2C), 129.1, 129.4,
129.7, 130.5, 130.6, 130.8, 132.8, 134.6, 135.6, 138.0, 144.4,
149.8, 158.9. Anal. calcd for C42H24Cl4N2S: C, 69.05; H, 3.31;
N, 3.83%. Found C, 69.00; H, 3.28; N, 3.87% .
Di[2-(4-methylphenyl)-4-phenyl-3-quinolyl] disulfide (5b).
Di[2-(4-bromophenyl)-6-chloro-4-phenyl-3-quinolyl] sulfide
Isolated as a colorless solid; IR (KBr): 3057 (C-H), 1559
1
(3k). Isolated as a colorless solid; IR (KBr): 3058 (C-H),
1558 (CQN) cmÀ1 1H NMR (300 MHz, CDCl3) dH: 6.65
;
(CQN) cmÀ1; H NMR (300 MHz, CDCl3) dH: 2.30 (s, 6H,
CH3), 6.87 (b, 10H, Ar-H), 7.20 (d, 2H, J = 8.1 Hz, Ar-H),
7.30 (b, 8H, Ar-H), 7.41 (t, 2H, J = 8.1 Hz, Ar-H), 7.77 (t, 2H,
J = 8.1 Hz, Ar-H), 8.19 (d, 2H, J = 8.1 Hz, Ar-H); 13C NMR
(75 MHz, CDCl3) dC: 21.2, 126.5, 126.9, 127.6, 128.0, 129.6
(2C), 130.4, 136.8, 137.4, 137.8, 147.4, 154.3, 162.9. Anal.
calcd for C44H32N2S2: C, 80.95; H, 4.94; N, 4.29%. Found C,
80.90; H, 4.90; N, 4.33%.
(d, 2H, J = 7.8 Hz, Ar-H), 6.89 (d, 2H, J = 7.5 Hz, Ar-H),
7.14 (d, 2H, J = 2.4 Hz, Ar-H), 7.16–7.28 (m, 6H, Ar-H),
7.33–7.44 (m, 8H, Ar-H), 7.57 (dd, 2H, J = 9.0, 2.4 Hz,
Ar-H), 7.92 (d, 2H, J = 9.0 Hz, Ar-H); 13C NMR (75 MHz,
CDCl3) dC: 118.4, 123.0, 124.1, 127.4, 128.2, 128.3, 129.0,
129.1, 129.5, 129.7, 130.5, 130.8, 131.0, 132.8, 135.5, 138.5,
144.4, 149.8, 158.9. Anal. calcd for C42H24Br2Cl2N2S: C,
61.56; H, 2.95; N, 3.42%. Found C, 61.52; H, 2.90; N, 3.46%
Di[2-(4-chlorophenyl)-4-phenyl-3-quinolyl] disulfide (5c).
Isolated as a colorless solid; IR (KBr): 3059 (C-H), 1561
1
Di[6-chloro-2-(2-naphthyl)-4-phenyl-3-quinolyl] sulfide (3l).
(CQN) cmÀ1; H NMR (300 MHz, CDCl3) dH: 6.97 (b, 6H,
Isolated as a colorless solid; IR (KBr): 3054 (C-H), 1554
1
Ar-H), 7.11 (b, 8H, Ar-H), 7.23 (d, 2H, J = 8.1 Hz, Ar-H),
7.36 (b, 4H, Ar-H), 7.45 (t, 2H, J = 8.1 Hz, Ar-H), 7.79
(td, 2H, J = 8.1, 0.9 Hz, Ar-H), 8.19 (d, 2H, J = 8.1 Hz,
Ar-H); 13C NMR (75 MHz, CDCl3) dC: 127.1, 127.2, 127.6,
127.8, 127.9, 129.6(2C), 130.8, 131.2, 134.1, 136.5, 138.7,
147.3, 154.1, 161.4; m/e 693.0 [M + 1] (calcd 693.1 [M + 1]);
Anal. calcd for C42H26Cl2N2S2: C, 72.72; H, 3.78; N, 4.04%.
Found C, 72.69; H, 3.74; N, 4.09%.
(CQN) cmÀ1; H NMR (300 MHz, CDCl3) dH: 6.74 (d, 2H,
J = 7.5 Hz, Ar-H), 6.80 (d, 2H, J = 7.8 Hz, Ar-H), 7.12–7.22
(m, 6H, Ar-H), 7.30 (t, 2H, J = 7.5 Hz, Ar-H), 7.39 (t, 2H,
J = 7.2 Hz, Ar-H), 7.47–7.65 (m, 12H, Ar-H), 7.82 (d, 2H,
J = 9.0 Hz, Ar-H), 7.87 (d, 2H, J = 7.8 Hz, Ar-H); 13C NMR
(75 MHz, CDCl3) dC: 123.9, 126.0, 126.4, 126.6, 127.0, 127.3,
127.5 (2C), 128.1, 128.2, 128.5, 128.6, 129.7, 129.8, 130.0,
130.1, 130.8, 132.4, 132.6, 133.0, 135.6, 137.2, 144.3, 149.7,
160.2. Anal. calcd for C50H30Cl2N2S: C, 78.84; H, 3.97; N,
3.68%. Found C, 78.80; H, 3.94; N, 3.72%.
Di[6-chloro-2-(2-naphthyl)-4-phenyl-3-quinolyl] disulfide (5d).
Isolated as a colorless solid; IR (KBr): 3055 (C-H), 1561
1
(CQN) cmÀ1; H NMR (300 MHz, CDCl3) dH: 7.10 (b, 10H
Di[6-chloro-2-(3-chlorophenyl)-4-phenyl-3-quinolyl] sulfide
Ar-H), 7.48 (b, 14H, Ar-H), 7.74 (dd, 2H, J = 9.0, 2.1 Hz,
Ar-H), 7.78 (b, 2H, Ar-H), 8.13 (d, 2H, J = 9.0 Hz, Ar-H);
13C NMR (75 MHz, CDCl3) dC: 125.6, 126.0, 126.5, 126.8,
127.2, 127.5, 127.9, 128.2, 128.4, 128.6, 129.3, 129.6, 131.3,
131.5, 132.6, 132.8, 132.9, 135.8, 137.4, 145.8, 154.0, 162.8.
Anal. calcd for C50H30Cl2N2S2: C, 75.65; H, 3.81; N, 3.53%.
Found C, 75.62; H, 3.78; N, 3.58%.
(3m). Isolated as a colorless solid; IR (KBr): 3059 (C-H),
1561 (CQN) cmÀ1 1H NMR (300 MHz, CDCl3) dH: 6.69
;
(d, 2H, J = 7.5 Hz, Ar-H), 6.91 (d, 2H, J = 7.5 Hz, Ar-H),
7.10–7.19 (m, 6H, Ar-H), 7.24–7.33 (m, 8H, Ar-H), 7.41
(td, 2H, J = 7.5, 1.8 Ar-H), 7.57 (dd, 2H, J = 9.0, 2.1 Hz,
Ar-H), 7.94 (d, 2H, J = 9.0 Hz, Ar-H); 13C NMR (75 MHz,
CDCl3) dC: 124.1, 127.3, 127.4, 128.4, 128.5 (3C), 129.1, 129.2
(2C), 129.6, 129.8, 130.5, 130.9, 133.0, 133.9, 135.4, 141.4,
144.3, 150.0, 158.8. Anal. calcd for C42H24Cl4N2S: C, 69.05;
H, 3.31; N, 3.83%. Found C, 69.00; H, 3.28; N, 3.88%.
Di[6-chloro-2-(4-chlorophenyl)-4-phenyl-3-quinolyl] disulfide
(5e). Isolated as a colorless solid; IR (KBr): 3057 (C-H),
1559 (CQN) cmÀ1; yield: 1H NMR (300 MHz, CDCl3)
dH: 6.99 (br s, 8H, Ar-H), 7.14 (b, 6H Ar-H), 7.18 (d, 2H,
J = 2.4 Hz, Ar-H), 7.42 (b, 4H, Ar-H), 7.74 (dd, 2H, J = 8.7,
2.4 Hz, Ar-H), 8.12 (d, 2H, J = 8.7 Hz, Ar-H); 13C NMR
(75 MHz, CDCl3) dC: 125.7, 127.6, 128.0 (2C), 128.3, 129.3,
131.0, 131.1, 131.8, 133.2, 134.4, 135.7, 138.1, 145.6, 154.2,
161.4. Anal. calcd for C42H24Cl4N2S2: C, 66.15; H, 3.17; N,
3.67%. Found C, 66.11; H, 3.14; N, 3.70%.
Di[2-(3-bromophenyl)-6-chloro-4-phenyl-3-quinolyl] sulfide
(3n). Isolated as a colorless solid; IR (KBr): 3057 (C-H),
1562 (CQN) cmÀ1 1H NMR (300 MHz, CDCl3) dH: 6.67
;
(d, 2H, J = 7.8 Hz, Ar-H), 6.92 (d, 2H, J = 7.5 Hz, Ar-H),
7.09–7.23 (m, 4H, Ar-H), 7.26–7.29 (m, 4H, Ar-H), 7.38–7.48
(m, 8H, Ar-H), 7.58 (dd, 2H, J = 9.0, 2.4 Hz, Ar-H), 7.95
(d, 2H, J = 9.0 Hz, Ar-H); 13C NMR (75 MHz, CDCl3) dC:
c
This journal is The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2011
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Acknowledgements
The authors thank DST for funds under IRHPA program
towards high resolution NMR spectrometer. Financial
support from UGC, New Delhi, to NP is gratefully
acknowledged.
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22 The filtrate of the reaction between diphenacyl sulfide and amino-
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starting materials 2a and 1 (1 : 2 molar ratio) are added and refluxed
for two hours. The product 3a is separated by recrystallisation and
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23 Crystallographic data (excluding structure factors) for compounds
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New J. Chem., 2011, 35, 2607–2613 2613