Article
Tumtin et al.
Procedure for the synthesis of (7a-7f) and (8a-8c) under
ArH), 7.87 (s, 1H, NH); 13C NMR (CDCl3, 100 MHz): d 6.75,
18.40, 35.06, 41.76, 110.12, 114.32, 117.66, 118.25, 120.44,
120.99, 126.15, 135.26, 210.46; MS: m/z = 202 [M+1]+, 224
[M+Na]+; Anal. Calcd. For C13H15NO: C, 77.58; H, 7.51; N,
6.96%; Found: C, 77.52; H, 7.57; N, 6.99%. 3-(1H-indol-3-yl)-
1,3-bisphenylpropan-1-one (7c): mp 130-133 oC;IR (KBr) cm-1:
3309, 3017, 1672; 1H NMR (CDCl3, 400 MHz): d 3.65 (dd, 1H,
CH), 3.75 (dd, 1H, CH), 5.00 (t, 1H, CH), 6.93 (s, 1H, ArH),
7.05-7.87 (m, 14H, ArH), 7.89 (s, 1H, NH); 13C NMR (CDCl3,
100 MHz): d 38.21, 45.20, 111.10, 119.34, 119.42, 119.56,
121.40, 122.56, 126.29, 126.63, 127.83, 128.10, 128.43, 128.57,
133.00, 136.61, 137.12, 144.21, 198.55; MS: m/z =348 [M+Na]+;
Anal. Calcd. For C23H19NO: C, 84.89; H, 5.89; N, 4.30%; Found:
C, 84.85; H, 5.92; N, 4.34%. 4-(bis(1H-indol-3-yl)methyl)benz-
aldehyde (3x): mp 197-199 oC; IR (KBr) cm-1: 3381, 3045, 1715;
1H NMR (CDCl3, 400 MHz): d 5.89 (s, 1H, CH), 6.59 (s, 2H, 2 ´
ArH), 6.92-7.71 (m, 12H, ArH), 7.93 (s, 2H, 2 ´ NH), 9.89 (s, 1H,
CHO); 13C NMR (CDCl3, 100 MHz): d 41.16, 112.11, 119.32,
119.90, 121.48, 122.97, 123.46, 125.61, 127.44, 129.21, 134.23,
135.71, 143.71, 189.85; MS: m/z =351 [M+1]+; Anal. Calcd. For
C24H18N2O: C, 82.26; H, 5.18; N, 7.99%; Found: C, 82.22; H,
5.21; N, 7.96%. 3-((4-(bis(1H-indol-3-yl)methyl)phenyl)(1H-
microwave conditions: A mixture of indole/substituted indole
(6.83 mmol), a,b-unsaturated carbonyl compounds (5a-5c) (6.83
mmol) and TEBA (1.69 mmol) in water (3 mL) was irradiated in a
microwave digester at 100 oC, 5–10 bar, 80–120 W for 100–240
seconds (Table 3). After the reaction was completed (monitored
by TLC) the resultant mixture was purified by column chroma-
tography using ethyl acetate/hexane as eluent to afford the pure
compounds.
Procedure for the synthesis of 3y under Reflux condi-
tions: To a stirring solution of indole (4.48 mmol) and tere-
phthaladehyde (2 mmol) in water (10 mL), TEBA(1.0 mmol) was
o
added. The reaction mixture was refluxed at 100 C for 1-2 hrs
(Table-2). After the completion of the reaction (monitored by
TLC), the resultant mixture was extracted with ethyl acetate (3 ´
10 mL) and the solvent removed under reduced pressure. The
crude product was purified by column chromatography using
ethyl acetate/hexane as eluent to afford pure products in good to
excellent yields.
Procedure for the synthesis of 3y under microwave con-
ditions: A mixture of indole (4.48 mmol), terephthaladehyde (2
mmol) and TEBA (1.0 mmol) in water (3 mL) was irradiated in a
microwave digester at 100 oC, 5–10 bar, 80–120 W for 180–250
seconds (Table 2). After the reaction was completed (monitored
by TLC) the resultant mixture was purified by column chroma-
tography using ethyl acetate/hexane as eluent to afford the pure
compounds.
o
indol-3-yl)methyl)-1H-indole (3y): mp 197-200 C; IR (KBr)
cm-1: 3386, 3089, 2930; 1H NMR (CDCl3, 400 MHz): d 5.70 (s,
2H, CH), 6.27 (s, 4H, 4 ´ ArH), 6.92-7.34 (m, 20H, ArH), 7.44 ( s,
4H, 2 ´ NH); 13C NMR (CDCl3, 100 MHz): d 39.86, 11.09,
118.99, 119.68, 119.97, 121.75, 123.64, 127.06, 128.54, 136.60,
141.55; MS: m/z = 567 [M+1]+; Anal. Calcd. For C40H30N4: C,
84.78; H, 5.34; N, 9.89%; Found: C, 84.73; H, 5.39; N, 9.83%.
Procedure for preparation of Schiff base (17a-17h): A
mixture of aniline (5 mmol) and aromatic aldehyde (5 mmol)
o
were mixed together at 0 C and brought to room temperature.
TLC was checked. If it showed completion of reaction, the crude
mixture was recrystallised from hot ethanol. If not, then it was ir-
radiated at 5 bars, 100 watt, 100 oC for 60-180 sec and recrystal-
lised in the same manner.
ACKNOWLEDGEMENTS
Financial assistance from UGC in the form of fellow-
ship and Spectral analysis by SAIF, NEHU, Shillong are
greatly acknowledged.
Analytical data for some selected compounds: 4-(bis-
(1H-indol-3-yl)methyl)-2-methoxyphenol (3g): mp 110-112
1
REFERENCES
oC; IR (KBr) cm-1: 3312, 3018, 2917; H NMR (CDCl3, 400
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MHz): d 3.68 (s, 3H, OCH3), 5.43 (s, 1H, CH), 5.73 (s, 1H, OH),
6.57 (s, 2H, 2 ´ ArH), 6.70-7.33 (m, 11H, ArH), 7.84 (s, 2H, 2 ´
NH); 13C NMR (CDCl3, 100 MHz): d 38.81, 54.83, 109.99,
110.36, 112.94, 118.15, 118.90, 120.24, 120.86, 122.51, 126.00,
135.04, 135.64, 142.77, 145.29; MS: m/z = 369 [M+1]+; Anal.
Calcd. For C24H20N2O2: C, 78.24; H, 5.47; N, 7.60%; Found: C,
78.33; H, 5.59; N, 7.45%. 1-(1H-indol-3-yl)pentan-3-one (7b):
mp 83-86 oC; IR (KBr) cm-1: 3324, 3018, 1706; 1H NMR (CDCl3,
400 MHz): d 0.97 (t, 3H, CH3), 2.34 (q, 2H, CH2), 2.75 (t, 2H,
CH2), 2.99 (t, 2H, CH2), 6.92 (s, 1H, ArH), 7.03-7.53 (m, 4H,
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J. Chin. Chem. Soc. 2015, 62, 321-327