Silver nitrate catalysed tandem reactions of o-ethynylanilines with aryl aldehydes: Selective one-pot synthesis of bis(indolyl)methanes

Article abstract of DOI:10.3184/174751912X13394919935692

Bis(indolyl)methanes are an important class of indole derivatives that have been widely used in medical treatments. A novel silver nitrate-catalysed one-pot synthesis of bis(indolyl)methanes has been developed. In the presence of silver nitrate, cycloisomerisation and bis-addition of o-ethynylanilines with aromatic aldehydes were carried out efficiently to afford the corresponding bis(indolyl)methanes in good to excellent yields.

Full text of DOI:10.3184/174751912X13394919935692

468 RESEARCH PAPER
AUGUST, 468–471
JOURNAL OF CHEMICAL RESEARCH 2012
Silver nitrate catalysed tandem reactions of o-ethynylanilines with aryl
aldehydes: selective one-pot synthesis of bis(indolyl)methanes
Bo-Lun Hu,a Hua-Nan Hub and Ri-Yuan Tanga*
aCollege of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325035, P. R. China
bSchool of Pharmaceutical and Chemistry Engineering, Taizhou University, Taizhou 317000, P. R. China
Bis(indolyl)methanes are an important class of indole derivatives that have been widely used in medical treatments.
A novel silver nitrate-catalysed one-pot synthesis of bis(indolyl)methanes has been developed. In the presence of
silver nitrate, cycloisomerisation and bis-addition of o-ethynylanilines with aromatic aldehydes were carried out
efficiently to afford the corresponding bis(indolyl)methanes in good to excellent yields.
Keywords: silver nitrate, tandem reaction, indole, aldehyde, bis(indolyl)methane
Bis(indolyl)methanes are a significant class of indole deriva-
tives with a wide range of biological properties that have
been used in therapeutic areas, such as tranquilisers,1 anti-
carcinogens,2 chronic fatigue and irritable bowel syndrome.3
Furthermore, bis(indolyl)methanes can be used as metal ion
probes4 and colorimetric anion sensors.5
Two common strategies are available for the synthesis
of bis(indolyl)methanes: (1) bis-addition of indoles with car-
bonyl compounds;6–17 and (2) one-pot cycloisomerisation/bis-
addition of o-ethynylanilines with aldehydes (Scheme 1).18,19
In the bis-addition process, Lewis acids,6–11 Brönsted
acids12,13, protic solvents14–16 and selectfluor17 have proved to
be efficient catalysts for this transformation. However, the pur-
suit of a one-pot synthesis of bis(indolyl)methanes by tandem
reaction of o-ethynylanilines with aldehydes is more challeng-
ing. AuCl and FeCl3/PdCl2 are typically required to facilitate
this process.18, 19
The few reported tandem reaction methodologies for the
synthesis of bis(indolyl)methanes are restricted to moderate
yields and an expensive catalytic system. Thus, the develop-
ment of tandem reactions for the synthesis of bis(indolyl)-
methanes using stable and inexpensive catalysts is urgently
required. Here we report a silver nitrate catalysed selective
synthesis of bis(indolyl)methanes by tandem reactions of
o-ethynylanilines with aryl aldehydes.
solvent for this transformation (entries 7–9). It turned out that
for substrate (2a) the loading significantly affected the yield,
with a 71% yield obtained using 2 equiv. of benzaldehyde (2a)
and a 47% yield using 1 equiv. of (2a) (entries 10 and 11).
Unfortunately, the reaction at ambient temperature did not
occur (entry 12). Overall, our initial investigations established
that the use of DMSO as a solvent with a 5 mol% loading of
AgNO3 at 80°C for 12 h represented the optimal conditions for
the transformation.
With the optimised conditions, the scope of both o-ethynyl-
anilines and aldehydes was investigated for the transformation
affording possible products (4–20) (Table 2). Initially, a vari-
ety of aldehydes were reacted with 2-(phenylethynyl)aniline
(1a) (entries 1–9). The results showed that both electron-
donating and electron-withdrawing groups, such as methyl,
methoxy, chloro, bromo and nitro, were well tolerated on the
aromatic ring of the aldehydes (entries 1–8). Aryl aldehyde
(2c) bearing a methoxyl group, for example, underwent the
addition with indoles generated in situ from substrate (1a) to
afford the corresponding product (5) in 94% yield (entry 2).
Excellent yields could be obtained from the reactions of
both halo-substituted arylaldehydes (2e) and (2f) (entries 4 and
5). The nitro group, on the aromatic ring of aldehyde, did not
have an obviously adverse effect on the reaction, providing the
corresponding product (9) in 86% yield (entry 6). Note that a
moderate yield can be obtained from the reaction of furan-2-
carbaldehyde (2h) (entry 7). Cinnamaldehyde (2i) was also
compatible with the conditions, providing the corresponding
product (11) in 56% (entry 8). 3-Phenylpropanal (2j), how-
ever, was not a suitable substrate for this transformation
(entry 9).
Results and discussion
The reaction of 2-(phenylethynyl)aniline (1a) with benzalde-
hyde (2a) was conducted to screen the optimal reaction condi-
tions, and the results are summarised in Table 1. Initially, silver
salts, such as AgSbF6, AgBF4, AgNO3 and AgOTf, were tested
(entries 1–4). These silver salts were found to be efficient in
DMSO at 80 °C, providing the target product (3) in excellent
yields (entries 1–4). AgNO3 was then chosen to conduct the
next optimisation. AgNO3 loading could be reduced to 5 mol%
without reduction in the yield (entry 5). However, 2 mol% of
AgNO3 lowers the yield to 86% (entry 6). Several solvents
were then screened, DMSO was found to be the most efficient
Within the scope of the o-ethynylanilines (1) examined
(entries 10–17), the substituents, including methyl, methoxyl
and chloro groups, were also well tolerated, on the aromatic
ring of o-ethynylanilines (entries 10–15). Substrate (1f) with a
chloro and a methoxyl groups, for example, smoothly under-
went the cycloisomerisation and addition with an aldehyde
(2a), affording the corresponding product (16) in 92% yield
(entry 13). An 84% yield of product (17) could be obtained
Scheme 1 Methods for the synthesis of bis(indolyl)methanes.
* Correspondent. E-mail: try@wzu.edu.cn

JOURNAL OF CHEMICAL RESEARCH 2012 469
Table 1 Screening optimal conditionsa
Table 2 Continued
Entry
Aniline 1
Aldehyde 2
(2h)
Product
Yield
/%b
7
(1a)
(10) 73
Entry
[Ag]/mol%
Solvent
Yield/%e
1
2
AgSbF6 (10)
AgBF4 (10)
AgNO3 (10)
AgOTf (10)
AgNO3 (5)
AgNO3 (2)
AgNO3 (5)
AgNO3 (5)
AgNO3 (5)
AgNO3 (5)
AgNO3 (5)
AgNO3 (5)
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
Toluene
DCE
95
97
3
97
8c
(1a)
(1a)
(2i)
(11) 56
4
83
5
95
6
86
7
47
8
42
9
DMF
53
9
(2j)
(12) trace
10b
11c
12d
DMSO
DMSO
DMSO
71
47
Trace
a Reaction conditions: 1a (0.2 mmol) and 2a (0.3 mmol) in
solvent (1 mL) at 80 °C under air atmosphere for 12 h. b 2a
(0.2 mmol), c 2a (0.1 mmol), d at ambient temperature. e Isolated
yield.
10
(1b)
(2a)
(13) 93
Table 2 AgNO3-catalysed tandem reactions of o-ethynylanilines
(1) with aldehydes (2)a
11
12
(1c)
(1d)
(2a)
(2a)
(14) 90
(15) 95
Entry
1
Aniline 1
Aldehyde 2
Product
Yield
/%b
(1a)
(2b)
(4) 95
13
(1f)
(1g)
(1h)
(1i)
(2a)
(2a)
(2a)
(2a)
(2a)
(16) 92
(17) 84
(18) 93
2
3
4
5
6
(1a)
(1a)
(1a)
(1a)
(1a)
(2c)
(2d)
(2e)
(2f)
(5) 94
(6) 93
(7) 93
(8) 92
(9) 86
14
15
16c
17c
(19)
0
0
(1j)
(20)
a Reaction conditions: 1 (0.2 mmol), 2 (0.3 mmol), AgNO3
(5 mol%) in DMSO (1 mL) at 80 °C under air atmosphere for
12 h. b Isolated yield. c Reaction for 24 h.
(2g)

470 JOURNAL OF CHEMICAL RESEARCH 2012
δ 11.35 (brs, 2H), 7.37–7.12 (m, 17H), 6.98 (t, J = 7.4 Hz, 2H),
6.87 (d, J = 7.9 Hz, 2H), 6.65(t, J = 7.4, 2H), 5.95 (s, 1H); 13C NMR
(75 MHz, C2D6SO) δ 146.9, 137.7, 136.7, 134.2, 130.7, 130.1, 129.7
(4C), 129.6, 129.5 (4C), 128.7, 127.5, 122.4, 122.2, 120.0, 115.6,
112.8, 40.3; IR (KBr, cm−1): 3735, 3649, 2919, 2360; LRMS (EI,
70 eV) m/z (%): 474 (M+, 100), 397 (84), 281 (97), 204 (44).
from the reaction of 2-(thiophen-2-ylethynyl)aniline (1g)
(entry 14). Unfortunately, both substrate (1i) with a nitro group
and substrate (1j) with an aliphatic alkyl group at the terminal
alkyne were found to be unsuitable for this reaction (entries 16
and 17).
Based on the present results and reported mechanisms, a
possible mechanism as outlined in Scheme 2 was proposed.18,
19 AgNO3 is firstly combined with a carbon–carbon triple bond
to afford an intermediate A, followed by an intramolecular
nucleophilic addition, leading to an intermediate B. Indole C
generated from intermediate B then reacts with aldehyde D
to give an intermediate E. Azafulvene intermediate F is then
formed from the reaction of intermediate E with AgNO3.
Finally, intermediate F undergoes the addition with an indole
C to afford the bis(indolyl)methanes derivatives.
3,3′-(p-Tolylmethylene)bis(2-phenyl-1H-indole) (4): Yellow solid,
1
m.p. 246.5–247.3 °C (uncorrected); H NMR (300 MHz, C2D6SO)
δ 11.36 (brs, 1H), 11.26 (brs, 1H); 7.37–7.07 (m, 16H), 7.01–6.96
(m, 3H), 6.65 (s, 3H), 5.86 (s, 1H), 1.71 (s, 3H); 13C NMR (75 MHz,
C2D6SO) δ 145.0, 137.3, 134.2, 131.9, 130.5, 130.01, 129.65 (4C),
129.2, 128.6, 127.9, 127.0, 122.4, 121.8, 120.1, 112.8, 39.6, 20.1; IR
(KBr, cm−1): 3397, 2923, 2360, 1705, 1456; LRMS (EI, 70 eV) m/z
(%): 488 (M+, 100), 397 (33), 295 (66), 218 (35); HRMS (EI) for
C36H28N2 (M+): Calcd 488.2247; found 488.2245.
3,3′-((4-Methoxyphenyl)methylene)bis(2-phenyl-1H-indole) (5):
Yellow solid, m.p. 259.6–261.5 °C (lit.17 m.p. 201–203 °C); 1H NMR
(300 MHz, C2D6SO) δ 11.31 (brs, 2H), 7.36–7.28 (m, 6H), 7.20–7.18
(m, 6H), 7.03–6.90 (m, 6H), 6.81 (d, J = 8.7 Hz, 2H), 6.66 (t, J =
7.3 Hz, 2H), 5.89(s, 1H), 3.70(s, 3H); 13C NMR (75 MHz, C2D6SO)
δ 158.8, 138.8, 137.7, 136.6, 134.2, 131.0, 129.7 (4C), 129.6, 129.5
(4C), 128.6, 122.3 (4C), 119.9, 116.0, 115.0, 112.7, 56.3, 40.4; IR
(KBr, cm−1): 3397, 3057, 1508; LRMS (EI, 70 eV) m/z (%): 504 (M+,
100), 488 (48), 397 (43), 311 (95), 295 (39); HRMS (EI) for C36H28N2O
(M+): Calcd 504.2196; found 504.2193.
3,3′-(Benzo[d][1,3]dioxol-5-ylmethylene)bis(2-phenyl-1H-indole)
(6): Yellow solid, m.p. 256.8–258.6 °C (uncorrected); 1H NMR
(300 MHz, C2D6SO) δ 11.34 (brs, 2H), 7.38–7.30 (m, 6H), 7.21–7.19
(m, 6H), 7.00–6.97 (m, 4H), 6.81 (d, J = 8.0 Hz, 1H), 6.71 (t, J =
7.5 Hz, 2H), 6.63 (d, J = 8.0 Hz, 1H), 6.58 (s, 1H), 5.96 (s, 2H), 5.88
(s, 1H); 13C NMR (75 MHz, C2D6SO) δ 148.8, 146.8, 141.0, 137.7,
136.7, 134.2, 129.7, 129.53, 129.48 (4C), 128.7, 123.0, 122.4, 122.2,
120.1, 115.8, 112.8, 110.5, 109.3, 102.3, 61.2, 40.3; IR (KBr, cm−1):
3397, 1653, 1023, 996; LRMS (EI, 70 eV) m/z (%): 518 (M+, 100),
441 (23), 397 (32), 325 (98), 259 (24); HRMS (EI) for C36H26N2O2
(M+): Calcd 518.1989; found 518.1988.
Conclusions
In summary, we have developed a novel AgNO3-catalysed
protocol for one-pot synthesis of bis(indolyl)methanes. In the
presence of AgNO3, cycloisomerisation and bis-addition of
o-ethynylanilines with aromatic aldehydes were conducted to
afford the corresponding bis(indolyl)methanes in good to
excellent yields. The present tandem strategy has several
advantages over the previously reported methods, in that cheap
and readily available AgNO3 can be used as catalyst and the
experimental operation is conducted under mild and aerobic
conditions.
Experimental
NMR spectroscopy was performed on a Bruker AV-300 spectrometer.
Mass spectrometry was performed on a GCMS-QP2010 Plus
(SHIMADZU). HRMS spectrometry was performed on a GCT-MS
spectrometer (Micromass). IR spectrometry was performed on a
Nicolet IS10 spectrometer.
3,3′-((4-Chlorophenyl)methylene)bis(2-phenyl-1H-indole)(7):White
1
solid, m.p. 238.8–240.0 °C (lit.17 212–214 °C); H NMR (300 MHz,
C2D6SO) δ 11.39 (brs, 2H), 7.37–7.19 (m, 14H), 7.11 (d, J = 8.4 Hz,
2H), 7.00 (t, J = 7.3 Hz, 2H), 6.90 (d, J = 8.1 Hz, 2H), 6.72–6.67 (m,
2H), 5.92 (s, 1H); 13C NMR (75 MHz, C2D6SO) δ 146.0, 137.7, 137.0,
134.0, 131.9 (4C), 129.8 (4C), 129.7, 129.5 (4C), 129.3, 128.8, 122.5,
122.0, 120.1, 115.0, 112.9, 40.1; IR (KBr, cm−1): 3393, 3057, 2925,
2360, 1705; LRMS (EI, 70 eV) m/z (%): 508 (M+, 100), 431 (27), 397
(61), 315 (86), 204 (43).
3,3′-((2-Bromophenyl)methylene)bis(2-phenyl-1H-indole) (8): Yellow
solid, m.p. 262.5–264.5 °C (uncorrected); 1H NMR (300 MHz,
C2D6SO) δ 11.35 (brs, 2H), 7.55–7.47 (m, 2H), 7.37–6.96 (m, 17H),
6.66–6.65 (m, 3H), 6.08 (s, 1H); 13C NMR (75 MHz, C2D6SO) δ
145.6, 137.5, 134.5, 134.2, 132.9, 129.9, 129.8 (4C), 129.6, 129.3
(4C), 128.8, 125.9, 122.3, 121.2, 120.2, 112.8, 42.5; IR (KBr, cm−1):
General procedure
A mixture of o-ethynylaniline 1 (0.2 mmol), aldehyde 2 (0.3 mmol),
AgNO3 (5 mol%) and DMSO (1 mL) was stirred at 80 °C under an air
atmosphere for the indicated time. After the reaction was finished, the
mixture was poured into ethyl acetate, and then washed with saturated
brine, followed by extraction with ethyl acetate (3 × 10 mL). The
combined organic layers were dried with anhydrous Na2SO4 and
evaporated in vacuo. The residue was purified by flash column
chromatography on silica gel (hexane/ethyl acetate) to afford the pure
product.
3,3′-(Phenylmethylene)bis(2-phenyl-1H-indole) (3): Yellow solid,
m.p. 267.1–267.9 °C (lit.18 266–268 °C); 1H NMR (300 MHz, C2D6SO)
Scheme 2 A possible mechanism.

JOURNAL OF CHEMICAL RESEARCH 2012 471
3421, 1653, 1024, 1004; LRMS (EI, 70 eV) m/z (%): 554 (M++2, 98),
552 (M+, 100), 397 (64), 361 (68), 359 (69), 280 (70), 204 (69);
HRMS (EI) for C35H25BrN2 (M+): Calcd 552.1196; found 552.1193.
3,3′-((4-Nitrophenyl)methylene)bis(2-phenyl-1H-indole) (9): Yellow
solid, m.p. 246.8–248.5 °C (uncorrected); 1H NMR (300 MHz, CDCl3)
δ 8.17 (brs, 2H), 8.05 (d, J = 8.8 Hz, 2H), 7.43 (d, J = 8.0 Hz, 2H),
7.34 (d, J = 8.0 Hz, 2H), 7.17–7.10 (m, 12H), 6.99 (d, J = 8.0 Hz, 2H),
6.85 (t, J = 8.0 Hz, 2H), 6.16 (s, 1H); 13C NMR (75 MHz, CDCl3)
δ 154.0, 147.3, 136.9, 136.9, 133.5, 131.0, 129.5 (4C), 129.2 (4C),
128.8, 124.5, 123.0, 122.2, 120.9, 114.8, 111.9, 41.2; IR (KBr, cm−1):
3393, 2925, 1704, 1324; LRMS (EI, 70 eV) m/z (%): 519 (M+, 100),
397 (58), 326 (21), 204 (40); HRMS (EI) for C35H25N3O2 (M+): Calcd
519.1941; found 519.1945.
(75 MHz, CDCl3) δ 157.7, 144.6, 134.9, 132.1, 130.2, 130.1, 129.0,
127.0, 125.4, 122.5, 121.9, 121.2, 121.1, 116.7, 112.3, 111.5, 56.2,
41.0; IR (KBr, cm−1): 3420, 2929, 2360, 1705, 1465; LRMS (EI,
70 eV) m/z (%): 602 (M+, 93), 525 (61), 345 (100), 330 (32), 268
(41); HRMS (EI) for C37H28Cl2N2O2 (M+): Calcd 602.1522; found
602.1521.
3,3′-(Phenylmethylene)bis(5-chloro-2-(thiophen-2-yl)-1H-indole)
(17): Yellow solid, m.p. 195.1–196.3 °C (uncorrected); 1H NMR
(300 MHz, CDCl3) δ 8.21 (brs, 2H), 7.29–7.19 (m, 9H), 7.04 (d,
J = 8.6 Hz, 2H), 6.87–6.82 (m, 4H), 6.70 (d, J = 2.0 Hz, 2H), 6.18 (s,
1H); 13C NMR (75 MHz, CDCl3) δ 143.2, 134.2, 133.4, 130.9, 129.8,
129.0, 128.6, 127.7, 126.7, 126.3, 126.0, 125.4, 122.6, 120.5, 115.0,
111.7, 40.3; IR (KBr, cm−1): 3309, 2923, 2360, 1701; LRMS (EI,
70 eV) m/z (%): 556 (M++2, 77), 554 (M+, 100), 477 (52), 321 (80),
286 (37); HRMS (EI) for C31H20Cl2N2S2 (M+): Calcd 554.0439; found
554.0435.
3,3′-(Phenylmethylene)bis(5-methyl-2-phenyl-1H-indole) (18): Yellow
solid, m.p. 118.9–122.0 °C (uncorrected); 1H NMR (300 MHz, CDCl3)
δ 7.95 (brs, 2H), 7.31 –7.13 (m, 17H), 6.95–6.89 (m, 4H), 6.10 (s,
1H), 2.18(s, 6H); 13C NMR (75 MHz, CDCl3) δ 145.9, 136.6, 135.3,
134.2, 130.2, 130.1, 130.0, 129.3 (4C), 129.2 (4C), 129.1, 128.3,
126.8, 124.2, 122.8, 116.3, 111.2, 40.8, 22.5; IR (KBr, cm−1): 3397,
2920, 1699, 1449; LRMS (EI, 70 eV) m/z (%): 502 (M+, 100), 425
(80), 295 (80), 218 (31); HRMS (EI) for C37H30N2 (M+): Calcd
502.2404; found 502.2401.
3,3′-(Furan-2-ylmethylene)bis(2-phenyl-1H-indole) (10): Yellow
1
solid, m.p. 193.7–195.6 °C (lit.8 256–257 °C); H NMR (300 MHz,
C2D6SO) δ 11.34 (brs, 2H), 7.53 (s, 1H), 7.36–7.33 (m, 3H), 7.32–
7.27 (m, 4H), 7.24–7.21 (m, 5H), 7.03–6.97 (m, 4H), 6.73 (t, J =
7.2 Hz, 2H), 6.42–6.40 (m, 1H), 5.93–5.92 (m, 1H), 5.82 (s, 1H); 13
C
NMR (75 MHz, C2D6SO) δ 159.3, 143.3, 137.5, 136.6, 134.0, 129.8
(4C), 129.4 (4C), 129.3, 128.8, 122.5, 121.5, 120.2, 113.8, 112.7,
111.8, 109.2, 35.9; IR (KBr, cm−1): 3397, 1653, 1023, 993; LRMS (EI,
70 eV) m/z (%): 464 (M+, 100), 271 (64), 193 (40), 142 (39).
(E)-3,3′-(3-Phenylprop-2-ene-1,1-diyl)bis(2-phenyl-1H-indole)
(11): Yellow solid, m.p. 215.1–216.5 °C (uncorrected); 1H NMR
(300 MHz, C2D6SO) δ 11.45 (brs, 1H), 11.32 (brs, 1H), 7.60–7.58 (m,
1H), 7.51–6.89 (m, 23H), 6.54 (d, J = 7.2 Hz, 1H), 5.31 (d, J = 6.2 Hz,
1H); 13C NMR (125 MHz, C2D6SO) δ 1442.6, 136.5, 136.4, 136.0,
135.3, 132.8, 132.0, 129.8, 129.5, 129.0, 128.7, 128.5, 128.4, 128.2,
127.9, 127.7, 127.6, 127.3, 126.2, 125.9, 124.2, 122.0, 121.3, 119.9,
119.8, 118.7, 111.5, 111.4, 109.8, 45.2; IR (KBr, cm−1): 3393, 1653,
1023, 996; LRMS (EI, 70 eV) m/z (%): 500 (M+, 40), 306 (80), 294
(100), 206 (27), 193 (82); HRMS (EI) for C37H28N2 (M+): Calcd
500.2247; found 500.2245.
3,3′-(Phenylmethylene)bis(2-p-tolyl-1H-indole) (13): Yellow solid,
m.p. 258.4–259.1 °C (lit.8 250–252 °C); 1H NMR (300 MHz, CDCl3)
δ 8.00 (brs, 2H), 7.31–7.26 (m, 4H), 7.25–7.22 (m, 3H), 7.10–6.94
(m, 12H), 6.81 (t, J = 8.0 Hz, 2H), 6.11 (s, 1H), 2.29 (s, 6H); 13C NMR
(75 MHz, CDCl3) δ 144.9, 137.1, 135.8, 135.6, 130.1, 129.2, 129.0
(4C), 128.8, 128.1, 128.0 (4C), 125.9, 121.7, 121.4, 119.4, 115.3,
110.5, 39.9, 21.2; IR (KBr, cm−1): 3398, 2923, 1705, 1456; LRMS (EI,
70 eV) m/z (%): 502 (M+, 100), 425 (58), 295 (71), 280 (49).
3,3′-(Phenylmethylene)bis(2-(4-methoxyphenyl)-1H-indole) (14):
Yellow solid, m.p. 258.6–261.9 °C (uncorrected); 1H NMR (300 MHz,
C2D6SO) δ 11.24 (brs, 2H), 7.34 (d, J = 8.0, 2H), 7.24–7.21 (m, 7H),
7.13–7.11 (m, 2H), 6.96 (t, J = 7.8 Hz, 2H), 6.89 (d, J = 8.0 Hz, 2H),
6.78 (d, J = 8.7 Hz, 4H), 6.64 (t, J = 7.8 Hz, 2H), 5.87 (s, 1H), 3.69
(s, 6H); 13C NMR (75 MHz, C2D6SO) δ 159.9 (2C), 147.1, 137.5,
136.8, 130.8 (4C), 130.1, 129.7, 129.6, 127.4, 126.6, 122.0, 119.8,
115.2 (4C), 114.9, 112.6, 56.5, 40.4; IR (KBr, cm−1): 3398, 2928,
1502, 1456, 1249; LRMS (EI, 70 eV) m/z (%): 534 (M+, 83), 457 (52),
311 (100), 223 (70); HRMS (EI) for C37H30N2O2 (M+): Calcd 534.2302;
found 534.2300.
This work is supported by the Opening Foundation of
Zhejiang Provincial Top Key Discipline (No. 100061200110)
and the Zhejiang Provincial Natural Science Foundation of
China (No. LY12B02004).
Received 16 April 2012; accepted 14 May 2012
Paper 1201265 doi: 10.3184/174751912X13394919935692
Published online: 8 August 2012
References
1
J. Povszasz, G.P. Katakin, S. Foleat and B. Malkovics, Acta Phys. Acad.
Sci. Hung., 1996, 29, 299.
2
C. Hong, G.L. Firestone and L.F. Bjeldanes, Biochem. Pharmacol., 2002,
63, 1085.
3
4
M.A. Zeligs, J. Med. Food, 1998, 1, 67.
R. Martínez, A. Espinosa, A. Tárraga and P. Molina, Tetrahedron, 2008, 64,
2184.
5
X.M. He, S.Z. Hu, K. Liu, Y. Guo, J. Xu and S.J. Shao, Org. Lett., 2006, 8,
333.
6
7
B.P. Bandgar and K.A. Shaikh, Tetrahedron Lett., 2003, 44, 1959.
S.K. Ko, C.C. Lin, Z.J. Tu,Y.F. Wang, C.C. Wang and C.F.Yao, Tetrahedron
Lett., 2006, 47, 487.
8
9
L.-P. Mo, Z.-C. Ma and Z.-H. Zhang, Synth. Commun., 2005, 35, 1997.
L. Wang, J. Han, H. Tian, J. Sheng, Z. Fan and X. Tang, Synlett, 2005,
337.
10 S. Podder, J. Choudhury, U.K. Roy and S. Roy, J. Org. Chem., 2007, 72,
3100.
11 V. Nair, K.G. Abhilash and N. Vidya, Org. Lett., 2005, 7, 5857.
12 W.-J. Li, X.-F. Lin, J. Wang, G.-L. Li and Y.-G Wang. Synth. Commun.,
2005, 35, 2765.
13 R. Nagarajan and P.T. Perumal, Chem. Lett., 2004, 3, 288.
14 H. Hagiwara, M. Sekifuji, T. Hoshi, K. Qiao and C. Yokoyama, Synlett.,
2007, 1320.
3,3′-(Phenylmethylene)bis(5-chloro-2-phenyl-1H-indole) (15): Yellow
1
solid, m.p. 178.1–179.3 °C (lit.6 190–193 °C); H NMR (300 MHz,
C2D6SO) δ 11.60 (brs, 2H), 7.37 (d, J = 8.6 Hz, 2H), 7.31–7.15 (m,
15H), 7.01 (d, J = 8.6 Hz, 2H), 6.72 (d, J = 1.8 Hz, 2H), 5.93 (s, 1H);
13C NMR (75 MHz, C2D6SO) δ 146.0, 138.7, 136.1, 133.6, 130.7,
130.5, 130.0, 130.0, 129.8 (4C), 129.5 (4C), 129.2, 127.9, 124.6,
122.4, 121.0, 115.0, 114.3, 40.3; IR (KBr, cm−1): 3403, 1653, 1023,
1000; LRMS (EI, 70 eV) m/z (%): 542 (M+, 93), 465 (72), 315 (100),
280 (75); HRMS (EI) for C35H24Cl2N2 (M+): Calcd 542.1311; found
542.1313.
3,3′-(Phenylmethylene)bis(5-chloro-2-(2-methoxyphenyl)-1H-indole)
(16): Yellow solid, m.p. 128.3–131.3 °C (uncorrected); 1H NMR
(300 MHz, CDCl3) δ 8.30 (brs, 2H), 7.30–7.12 (m, 9H), 6.99–6.93
(m, 4H), 6.85 (d, J = 2.0 Hz, 2H), 6.71 (d, J = 7.9 Hz, 2H), 6.63 (t,
J = 7.5 Hz, 2H), 5.98 (s, 1H), 3.62 (s, 6H), 2.18 (s, 6H); 13C NMR
15 V.Y. Sosnovskikh, R.A. Irgashev and A.A. Levchenko, Tetrahedron, 2008,
64, 6607.
16 V.Y. Sosnovskikh and R.A. Irgashev, Tetrahedron Lett., 2007, 48, 7436.
17 B.S. kumar, R.K. Hunnur, K.M. Reddy, R.H. Udupi and V. Hima Bindu,
Heterocycl. Commun., 2009, 15, 115.
18 V. Terrasson, J. Michaux, A. Gaucher, J. Wehbe, S. Marque, D. Prim and
J.-M. Campagne, Eur. J. Org. Chem., 2007, 5332.
19 C. Praveen, Y.W. Sagayaraj and P.T. Perumal, Tetrahedron Lett., 2009, 50,
644.

Copyright of Journal of Chemical Research is the property of Science Reviews 2000 Ltd. and its content may
not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written
permission. However, users may print, download, or email articles for individual use.