One-pot synthesis of 3-[(N-alkylanilino)(aryl)methyl]indoles via a transition metal assisted three-component condensation at room temperature

Article abstract of DOI:10.1002/jhet.1909

A simple and highly efficient protocol for the one-pot synthesis of a series of 3-[(N-alkylanilino)(aryl)methyl]indoles has been developed based on low-cost and environmentally benign zirconium oxychloride octahydrate and copper chloride dihydrate catalysts via three-component condensation between indoles, aromatic aldehydes, and N-alkylanilines at room temperature under neat condition. Mild reaction conditions, operational simplicity, high atom-economy, good yields in relatively shorter reaction times, use of low-cost and eco-friendly catalysts are some of the salient features of this protocol. A simple and highly efficient protocol for the one-pot synthesis of a series of 3-[(N-alkylanilino)(aryl)methyl]indoles has been developed based on low-cost and environmentally benign zirconium oxychloride octahydrate and copper chloride dihydrate catalysts via three-component condensation between indoles, aromatic aldehydes, and N-alkylanilines at room temperature under neat condition. Mild reaction conditions, operational simplicity, high atom-economy, good yields in relatively shorter reaction times, and use of low-cost and eco-friendly catalysts are the key advantages of the present protocol.

Full text of DOI:10.1002/jhet.1909

Month 2014 One-Pot Synthesis of 3-[(N-Alkylanilino)(aryl)methyl]indoles via a Transition
Metal Assisted Three-Component Condensation at Room Temperature
*
Goutam Brahmachari and Suvankar Das
Department of Chemistry, Visva-Bharati University, Santiniketan 731 235, West Bengal, India
*
E-mail: brahmg2001@yahoo.co.in
Received August 13, 2012
DOI 10.1002/jhet.1909
Published online 00 Month 2014 in Wiley Online Library (wileyonlinelibrary.com).
In memory to Santosh Kr. Brahmachari.
R4
R3
ZrOCl2.8H2O (10 mol%)
or
HN
R2
N
R2
CuCl2.2H2O (10 mol%)
R4
R3−CHO
+
+
R1
N
neat, rt, 0.4 − 2.5 h
H
N
R1
H
R1 = H, Me ; R2 = H, Br
R3 = aryl
1a-n
up to 96%
R4 = Me, Et
A simple and highly efficient protocol for the one-pot synthesis of a series of 3-[(N-alkylanilino)(aryl)
methyl]indoles has been developed based on low-cost and environmentally benign zirconium oxychloride
octahydrate and copper chloride dihydrate catalysts via three-component condensation between indoles,
aromatic aldehydes, and N-alkylanilines at room temperature under neat condition. Mild reaction conditions,
operational simplicity, high atom-economy, good yields in relatively shorter reaction times, use of low-cost
and eco-friendly catalysts are some of the salient features of this protocol.
J. Heterocyclic Chem., 00, 00 (2014).
INTRODUCTION
available in the literature for accessing 3-aminoalkyaled
indoles by using multi-component reaction (MCR) protocols
[9,10]. MCRs have already emerged as a powerful tool for
the construction of novel and complex molecular structures
because of their advantages over conventional multistep
synthesis [11]; the major advantages of MCRs include lower
costs, shorter reaction times, high atom-economy, energy
saving, and avoidance of time-consuming expensive purifi-
cation processes [12]. In recent times, a few methods have
been reported describing one-pot multicomponent synthesis
of 3-[(N-alkylanilino)(aryl)methyl]indoles based on acid
catalysts such as PMA–SiO2 [10a], 2,4,6-trichloro-1,3,5-
triazine [10b], bromodimethylsulfonium bromide [10c],
zwitterionic-type molten salt [10d], silver triflate [10e],
Yb(OTf)3/SiO2 [10f], and PANI-HBF4 [10g] from the reac-
tion of aromatic aldehydes, N-alkyl anilines, and substituted
indoles. However, these methods suffer from certain limita-
tions such as use of expensive catalysts and organic solvents,
heating condition, and long reaction time. Hence, develop-
ment of clean and efficient protocols for the synthesis
of these derivatives through a more convenient and eco-
friendly procedure is still warranted.
The indole scaffold represents a “privileged” structural
motif well distributed in pharmaceutical drugs and natural
products [1]. Indole derivatives have become increasingly
important and useful in the field of pharmaceuticals because
of their promising and multi-directional biological properties
including antibacterial, antioxidant, anticancer, and anti-tumor
activity [1]. Therefore, new methods to access unique indole
derivatives are of importance for drug lead synthesis. Among
various derivatives of indole, 3-substituted indoles have
gained much attention because of their wide distribution in
numerous natural products from terrestrial and marine
organisms exhibiting broad spectrum of biological activities
[1–3]. Very particularly, 3-aminoalkylated indole scaffolds
are found to be present in numerous biologically potent
natural products [4] and regarded as venerable pharmaco-
phores in the on-going drug discovery processes [1i,5];
natural products containing such indole moieties (Fig. 1)
are reported to possess various pharmacological potentials
[1b,2b,3b,4a,6]. In addition, indole scaffolds find useful
applications as versatile intermediates for the synthesis of a
wide range of indole compounds [7]. Hence, such immense
potential of indole nucleus as drug candidates has eventually
motivated the synthetic chemists to explore different methods
suitable for the synthesis of 3-substituted indoles.
In recent years, zirconium oxychloride octahydrate
(ZrOCl2.8H2O) [13, 15e] and copper chloride dihydrate
(CuCl2.2H2O) [14] both have been proved to be very useful
as Lewis acid catalysts in carrying out various organic trans-
formations. Both of these metal salts have received extensive
recognitions in organic synthesis because of their unique
Although several methods have been developed for the
synthesis of substituted indoles [7a–10], a few reports are
© 2014 HeteroCorporation

G. Brahmachari and S. Das
Vol 000
Me
O
S
N
OH
N
F
N
H
N
N
H
HO
Br
O
O
N
N
H
N
H
Et
1 Bacillamide having
algicidal activity
2
N-p-Coumaroylserotonin showing
antifungal activity
3 Aromatase inhibitor
N
NH
R
N
R
N
R
R
H
N
HO
N
R
OH
H
O
N
H
R
O
HO
10
11
R
R
= COCH CH COOH, R = H
= COMe ,
4 Meridianin A:
5 Meridianin B:
6 Meridianin C:
7 Meridianin D:
8 Meridianin E:
R
R
R
R
R
= OH, R = R = R = H
= OH, R =H, R = Br, R = H
= Br, R = R = R = H
= R = H, R = Br, R = H
=OH, R = H, R = Br, R = H
(both exhibit cytotoxicity
against murine P388
lymphocytic leukemia
cells)
O
N
H
9
Hyrtiosin B (cytotoxic against human
epidermoid carcinoma KB cells)
R
=
Me
(show cytotoxicity toward murine tumour cell lines)[4a,6c]
N
H
Figure 1. Example of some natural 3-substituted indoles of pharmaceutical promise [1b,2b,3b,4a,6c–e.]
properties of being readily affordable, commercially avail-
able, low-cost, ecologically friendly, and low toxicity and
stability towards moisture. In continuation of our effort to
develop green synthetic methodologies for organic transfor-
mations [15], we have recently developed a facile multicom-
ponent one-pot synthesis of 3-[(N-alkylanilino)(aryl)methyl]
indoles in good yields by using either commercially avail-
able ZrOCl2.8H2O or CuCl2.2H2O as an inexpensive and
environmentally benign catalyst from the reaction of
aromatic aldehydes, N-alkylanilines, and substituted indoles
under neat condition at room temperature. The present
method is not only cost-effective and environmentally more
friendly but also experimentally safe and simple, easy to
handle, and efficient.
desired product, 3-[(N-alkylanilino)(phenyl)methyl]-1H-indole
1a (Table 3, entry 1), respectively in 87 and 88% yields,
characterized by its physical as well as spectral properties
1
including IR, H NMR and 13C NMR [10]. We have also
observed that the same reaction afforded the desired product
1a in the absence of any catalyst under neat condition furnish-
ing considerable amount of yield of 66% within 24 h at room
temperature (Table 1, entry 8 and Table 2, entry 6); in addi-
tion, we have repeated such catalyst-free reaction with
2-methyl-1H-indol, piperonal, and N-methyl aniline that
furnished the desired product (1n; Table 3, entry 14) with
47% yield at room temperature under neat condition in 24 h.
However, we have discarded the catalyst-free condition
because of the slow reaction rate and relatively lower yields.
To explore the scope and generality of this three-component
one-pot reaction under optimized conditions, a variety of
aromatic aldehydes containing electron donating or electron
withdrawing substituents in the aromatic ring such as –Me, –
OMe, –OCH2O–, –Cl, and –NO2 were reacted with N-alkyl
amines and a number of substituted indoles. The reaction time
and percentage yield for each of the products 1a–n are shown
in Table 3. 1H-Indole, 5-bromo-1H-indole, and 2-methyl-1H-
indole were employed as the indole derivatives in carrying out
this three-component reaction. Both of N-methylanilines and
N-ethylanilines were successfully used as secondary amines
in the reaction. In general, aromatic aldehydes with both
activating and deactivating groups reacted smoothly to afford
the corresponding products in almost equally good yields
(Table 3). Piperonal was also found to furnish the desired
product (1n) in 81% yield in 0.6 h (36 min) (Table 3, entry
14). It was also observed that 2-methyl-1H-indole reacts at a
RESULTS AND DISCUSSION
Firstly, the standard reaction conditions were established
based on a series of trial reactions of indol (1 mmol) with
benzaldehyde (1 mmol), and N-methyl aniline (2 mmol) in
the presence or in the absence of different Lewis acids
(Scheme 1, Table 1) at room temperature with varying
amounts of catalyst-loading and solvents (Scheme 2, Table 2).
N-Methyl aniline was used in excess to prevent the formation
of bisindoyl alkane derivatives [10a]. The best results were
obtained from reaction of these components in the presence
of 10 mol% of either ZrOCl2.8H2O (Table 1, entry 3; Table 2,
entry 4) or CuCl2.2H2O (Table 1, entry 7; Table 2, entry 4)
(no significant improvement upon increasing catalyst loading
to 20 mmol% was observed; Table 2, entry 5) under solvent-
free conditions at room temperature affording the
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Month 2014
One-Pot Synthesis of 3-[(N-Alkylanilino)(aryl)methyl]indoles via a Transition Metal
Assisted Three-Component Condensation at Room Temperature
Scheme 1. One-pot synthesis of 3-[(N-alkylanilino)(phenyl)methyl]-1H-indole (1a) in the presence and/or absence of different catalysts.
Me
CHO
HN
Catalysts
neat, rt
N
+
+
Me
N
H
N
H
1a
faster rate than the other indole derivatives employed thereby
suggesting that it can attack the iminium ion intermediate with
greater ease, possibly because of presence electron donating
methyl group (Scheme 4). Surprisingly, cinnamaldehyde and
butyraldehyde were unable to produce desired products;
aliphatic amines such as piperidine and morpholine also
remained unreactive for 10 h of reaction. The results are sum-
marized in Scheme 3 and Table 3.
All the synthesized compounds are well characterized by
IR, 1H NMR, 13C NMR, and elemental analyses. The char-
acterization data for five new compounds (Table 3, entries
4, 10, 12–14) are reported in the experimental section, and
all other known compounds had physical and spectroscopic
data identical to the literature values [10].
A probable mechanistic pathway for this three-component
reaction is outlined in Scheme 4, which is in analogy to the
established mechanism as reported in the literature [10].
ZrOCl2.8H2O and CuCl2.2H2O both can serve as Lewis acid
catalyst individually for the reaction of N-alkylaniline and
aromatic aldehyde to give the corresponding iminium ion
intermediate, which is then attacked by an electron rich indole
to afford 3-[(N-alkylanilino)(aryl)methyl]indole 1 (Scheme 4).
ZrOCl2.8H2O and CuCl2.2H2O both are likely to enhance the
rate of this multi-step reaction.
Table 1
Screening of the catalyst in one-pot synthesis of 3-[(N-alkylanilino)(aryl)
methyl]indole (1a).a
Entry
Catalyst (10 mmol%)
Time (h)
% Yieldb
1
2
3
4
5
6
7
8
FeCl3.6H2O
NiCl2.6H2O
2.5
4.0
1.4
2.0
3.0
2.5
1.3
24
45
78
87
55
45
42
88
66
ZrOCl2.8H2O
Bi(NO3)3.5H2O
Fe(NO3)3.9H2O
Cu(NO3)3.3H2O
CuCl2.2H2O
No catalyst
Bold represents standardized reaction conditions.
aExperimental conditions: indole (1 mmol), benzaldehyde (1 mmol), N-methyl
aniline (2 mmol), and catalyst (0.10 mmol) under solvent-free condition at
room temperature.
bIsolated yields.
Scheme 2. One-pot synthesis of 3-[(N-alkylanilino)(phenyl)methyl]-1H-indole (1a) in varying amounts of catalyst and solvent.
Me
ZrOCl2.8H2O
CHO
HN
or
CuCl2.2H2O
N
+
+
Me
N
rt, solvent / solvent-free
H
N
H
1a
Table 2
Screening of solvent system and amount of catalyst-loading in one-pot synthesis of 3-[(N-alkylanilino)(aryl)methyl]indoles (1a).a
Entry
Solvent
ZrOCl2.8H2O (mol%)
Time (h)
%Yieldb
CuCl2.2H2O (mol%)
Time (h)
%Yieldb
1
2
3
4
5
6
EtOH
H2O
—
—
—
10
10
5
10
20
—
2.0
3.0
3.0
1.4
1.2
24
81
Trace
82
87
89
10
10
5
10
20
—
2.0
3.0
3.0
1.3
1.2
24
78
Trace
75
88
89
—
66
66
Bold represents standardized reaction conditions.
aExperimental conditions: Indole (1 mmol), benzaldehyde (1 mmol), N-methyl aniline (2 mmol), and ZrOCl2.8H2O or CuCl2.2H2O in varying amounts
under different solvent and/or solvent-free conditions at room temperature.
bIsolated yields.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

G. Brahmachari and S. Das
Vol 000
Table 3
ZrOCl2.8H2O and/or CuCl2.2H2O catalyzed synthesis of 3-[(N-alkylanilino)(aryl)methyl]indoles via one-pot multicomponent reaction.
ZrOCl2.8H2O CuCl2.2H2O
Time (h)
Entry
1
R1
H
R2
H
R3
R4
Product
%Yielda
87
Time (h)
%Yielda
88
Me
1a
1.4
1.3
2
3
H
H
H
H
Me
Me
1b
1c
1.5
91
91
1.0
87
88
1.0
2.5
0.9
2.0
4
H
H
Me
1d
79
78
5
6
7
H
H
H
H
H
H
Me
Me
Me
1e
1f
1.0
1.0
2.0
81
83
65
1.2
1.1
2.0
84
82
64
1g
8
H
H
H
H
Br
Br
Br
H
Me
Me
Et
1h
1i
1.2
1.7
2.0
1.5
72
73
85
82
1.3
1.6
2.0
1.5
76
77
87
77
9
10
11
1j
Et
1k
12
13
14
Me
Me
Me
H
H
H
Me
Me
Me
1l
1m
1n
0.5
0.4
0.6
96
82
81
0.6
0.5
92
83
74
0.75
aIsolated yields.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

Month 2014
One-Pot Synthesis of 3-[(N-Alkylanilino)(aryl)methyl]indoles via a Transition Metal
Assisted Three-Component Condensation at Room Temperature
Scheme 3. Three-component one-pot synthesis of 3-[(N-alkylanilino)(aryl)methyl]indoles.
R4
R3
ZrOCl2.8H2O (10 mol%)
or
HN
R2
N
R2
CuCl2.2H2O (10 mol%)
R4
R3−CHO
+
+
R1
N
H
neat, rt, 0.4 − 2.5 h
N
R1
H
R1 = H, Me ;
R3 = aryl
R
2 = H, Br
1a-n
up to 96%
R4 = Me, Et
Scheme 4. A plausible mechanism for the one-pot synthesis of 3-[(N-alky-
out over silica gel (Merck 60-120 mesh), and TLC was performed
by using silica gel 60 F254 (Merck) plates. All the chemicals were
purchased from Sigma-Aldrich Chemical Company (USA);
solvents (analytical grade) used were obtained from Merck (India).
General procedure for the synthesis of 3-[(N-alkylanilino)
lanilino)(aryl)methyl]indoles.
R4
HN
R4
+
N
Lewis acid catalyst
R3−CHO
+
ZrOCl2.8H2O
or
CuCl2.2H2O
R3
(aryl)methyl]indoles (1a–1n)
An oven-dried screw cap test
(iminium ion)
tube was charged with a magnetic stir bar, aromatic aldehyde
(1mmol), N-alkylaniline (2 mmol), and ZrOCl2.8H2O (10mol %)
or CuCl2.2H2O (10 mol %); the mixture was then started to stir at
room temperature. After 20 min, indole (1mmol) was added to the
reaction mixture, and stirring was continued up to completion of
the reaction as monitored by TLC. After completion of the
reaction, the resulting mixture was diluted with distilled water
(15 mL) and extracted with ethyl acetate. The combined organic
phase was filtered and evaporated under reduced pressure. The
crude product was purified via column chromatography by using
silica gel (60–120 mesh) and petrol ether–ethyl acetate mixture to
obtain pure indole derivative, characterized by conventional
spectroscopic methods, and elemental analyses. Characterization
data for all the five new compounds (1d, 1j, 1l, 1m, and 1n) are
given in the succeeding text.
R2
(nucleophilic attack)
..
R1
N
H
R3
R3
N
N
R2
R2
R4
H
R4
+
N
R1
N
R1
H
H
CONCLUSIONS
Characterization data for new compounds
3-[(4-Hydroxy-3-methoxyphenyl)(N-methylanilino)methyl]-
In conclusion, we have developed a simple and efficient
Deep pink solid; mp 145–148ꢀC; IR (KBr):
method for the high-yielding synthesis of 3-[(N-alkylanilino)
(aryl)methyl]indoles via a facile three-component condensation
between indoles, aromatic aldehydes, and N-alkylanilines in
the presence of either ZrOCl2.8H2O or CuCl2.2H2O as catalyst
at room temperature under neat condition. Mild reaction condi-
tions, good yields, relatively short reaction times, operational
simplicity, high atom-economy, and use of inexpensive and
environmentally more friendly catalysts are the key advantages
of the present MCRs protocol that make it an attractive alterna-
tive to the existing procedures for the synthesis of such impor-
tant fine chemicals.
1H-indole (1d).
nmax /cmÀ1 3499, 3410, 2922, 2847, 1602, 1429, 1026, 746. H
NMR (400MHz, CDCl3) d = 2.83 (s, 3H, –CH3), 3.76 (s, 3H, –
OCH3), 5.51 (s, 1H, –CH–), 5.82 (s, 1H, –OH), 6.57 (s, 1H,
ArH), 6.63–6.65 (m, 2H, ArH), 6.77 (d, J = 4 Hz, 1H, ArH), 6.81
(t, J = 4, 10 Hz, 1H, ArH), 6.89 (s, 1H, ArH), 6.98–7.01 (m, 1H,
ArH), 7.05 (t, J = 8, 10.8 Hz, 1H, ArH), 7.13–7.19 (m, 2H, ArH),
7.25 (d, J = 8Hz, 1H, ArH), 7.32–7.42 (m, 2H, ArH), 7.93 (br s,
1H, –NH–). 13C NMR (100 MHz, CDCl3) d = 39.82, 47.62,
55.83, 110.98, 111.39, 113.95, 119.15, 119.91, 121.26, 121.85,
121.95, 123.50, 123.85, 127.01, 129.73, 136.06, 136.42, 136.65,
143.77, 146.29; Anal. Calcd for C23H22N2O2: C 77.07, H 6.19, N,
7.82; found: C 77.11, H 6.23, N 7.84.
1
5-Bromo-3-[(4-chlorophenyl)(N-ethylanilino)methyl]-1H-indole
(1j). Dark violet solid; mp 79–82οC; IR (KBr): nmax /cmÀ1 3414,
3019, 1920, 1611, 1514, 1458, 793, 662, 446. 1H NMR (400 MHz,
CDCl3) d =1.17 (t, J=6.8, 7.2 Hz, 3H, –CH3), 3.06 (q, J= 7.2, 7.2,
6.8 Hz, 2H, –CH2–), 5.38 (s, 1H, –CH–), 6.47–6.53 (m, 3H, ArH),
6.88 (d, J= 8.4 Hz, 2H, ArH), 7.03 ( d, J= 8 Hz, 2H, ArH),
7.10–7.19 (m, 5H, ArH), 7.28 (d, J= 1.2 Hz, 1H, ArH), 7.94 (br s,
1H, –NH–). 13C NMR (100 MHz, CDCl3) d = 14.75, 38.94, 47.05,
112.52, 112.70, 112.85, 113.18, 119.81, 122.27, 124.74, 125.02;
125.10, 128.37, 128.57, 128.62, 129.57, 129.86, 130.15, 131.85,
132.24, 135.31, 142.76, 146.47. Anal. Calcd for C23H20N2BrCl: C
62.82, H 4.58, N 6.37; found: C 62.86, H 4.54, N 6.41.
EXPERIMENTAL
General Infrared spectra were recorded by using a Shimadzu
(FT-IR 8400S) FT-IR spectrophotometer with the used of KBr disc.
1H and 13C NMR spectra were obtained at 400 and 100 MHz,
respectively, with the use of Bruker DRX spectrometer and
CDCl3 as the solvent. Elemental analyses were performed with an
Elementar Vario EL III Carlo Erba 1108 micro-analyzer
instrument. Melting point was recorded on a Sunvic melting point
apparatus and is uncorrected. Column chromatography was carried
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

G. Brahmachari and S. Das
Vol 000
[3] (a) Leze, M. P.; Borgne, M. L.; Marchand, P.; Loquet, D.;
Kogler, M.; Baut, G. L.; Palusczak, A.; Hartmann, R. W. J Enzyme Inhib
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2-Methyl-3-[(N-methylanilino)(4-methylphenyl)methyl]-1H-
indole (1l). Deep brown solid; mp 166–169ꢀC; IR (KBr): nmax
/
cmÀ1 3397, 3036, 2920, 1607, 1591, 1435, 837, 756, 669, 451. 1H
NMR (400 MHz, CDCl3) d 1.19 (s, 3H, –CH3), 1.93 (s, 3H, –
CH3), 2.72 (s, 3H, –CH3), 5.52 ( s, 1H, –CH–), 6.49 (d, J=8.8Hz,
1H, ArH), 6.74–6.82 (m, 2H, ArH), 6.90–7.03 (m, 8H, ArH), 7.06
(d, J= 8 Hz, 1H, ArH), 7.10–7.15 (m, 1H, ArH), 7.55 (br s, 1H, –
NH–). 13C NMR (100 MHz, CDCl3) d = 29.68, 31.39, 38.81, 46.51,
109.91, 109.98,113.01, 113.56, 118.98, 119.37, 119.68, 120.50,
120.58, 128.76, 128.89, 128.98, 129.90, 131.71, 135.01, 135.22,
135.28, 140.57, 141.44, 146.49. Anal. Calcd for C24H24N2: C
84.67, H 7.11, N 8.23; found: C 84.69, H 7.13, N 8.27.
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2-Methyl-3-[(4-chlorophenyl)(N-methylanilino)methyl]-1H-indole
(1m).
Light brown solid; mp 199–202ꢀC; IR (KBr): nmax/cmÀ1
3385, 3053, 2918, 2861, 1609, 1524, 1476, 1446, 820, 784, 594,
1
444. H NMR (400 MHz, CDCl3) d = 1.98 (s, 3H, –CH3), 2.76 (s,
3H, –CH3), 5.88 (s, 1H, –CH–), 6.60 (d, J= 8.4 Hz, 1H, ArH), 6.77–
6.86 (m, 2H, ArH), 6.90 (t, J=6.4, 8Hz, 1H, ArH), 6.94–6.99 (m,
3H, ArH), 7.05 (d, J= 8.4 Hz, 1H, ArH), 7.09–7.20 (m, 5H, ArH),
7.66 (br s, 1H, –NH–). 13C NMR (100 MHz, CDCl3) d = 29.68,
38.71, 46.39, 110.03, 110.13, 112.85, 113.97, 114.96, 119.19,
119.45, 120.75, 120.85, 128.19, 128.74, 129.95, 130.43, 131.59,
131.84, 135.03, 135.19, 142.35, 142.94, 145.63. Anal. Calcd for
C23H21N2Cl: C 76.55, H 5.87, N 7.76; found: C 76.59, H 5.84, N 7.81.
2-Methyl-3-[(N-methylanilino)(3,4-methylenedioxyphenyl)
methyl]-1H-indole (1n). Reddish brown solid; mp 172–174ꢀC;
IR nmax (KBr): nmax/cmÀ1 3397, 3048, 2922, 2855, 1611, 1504,
1491, 1431, 1231, 1096, 1038, 746, 615, 449. 1H NMR
(400MHz, CDCl3): d = 1.21 (s, 3H, –CH3), 1.95 (s, 3H, –CH3),
5.80 (s, 1H, –CH–), 5.82 (s, 2H, –ΟCH2O–), 6.53–6.68 (m, 4H,
ArH), 6.73–6.88 (m, 3H, ArH), 6.93–6.99 (m, 3H, ArH), 7.14
(t, J = 8, 8.4Hz, 2H, ArH), 7.61 (br s, 1H, –NH–). 13C NMR
(100MHz, CDCl3): d = 29.67, 38.94, 46.62, 100.70, 107.75,
109.74, 109.95, 113.44, 114.47, 119.07, 119.26, 119.57, 120.58,
121.34, 121.89, 121.96, 128.85, 129.88, 131.72, 135.00,
137.83,145.64, 146.21, 147.51. Anal. Calcd for C24H22N2O2: C
77.81, H 5.99, N 7.56; found: C 77.89, H 5.96, N 7.59.
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Acknowledgments. The authors are thankful to CDRI, Lucknow,
and Chemistry Department, Kalyani University, India for spectral
measurements. S. D. is grateful to the UGC, New Delhi for
awarding him a Junior Research Fellowship. Financial support
from CSIR, New Delhi [Grant No. 02(0110)/12/EMR-II] is also
deeply acknowledged.
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Journal of Heterocyclic Chemistry
DOI 10.1002/jhet