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ꢀ
saturated with CO
2
at 50 C. Aer saturation, TPD was carried ¼ 3.6 Hz, 1H), 7.35(d, J ¼ 8 Hz, 1H), 7.43 (m, 1H), 7.95(s, 1H);
ꢀ
ꢀ
ꢀ
ꢂ1
13
out from 25 C to 1000 C at temperature ramp of 10 C min
using helium as inert gas at ow rate of 20 cm min . The 120.8, 110.0, 102.3, 102.1, 33.0; GC-MS: (m/z) 156 (M ).
C-NMR (100 MHz, CDCl ) d 138.1, 131.1, 128.1, 126.4, 124.4,
3
3
ꢂ1
+
experiment performed using the Initiator Biotage microwave
instrument. Chemical shis are reported in parts per million (d) yield; H-NMR (400 MHz, CDCl
relative to tetramethylsilane as internal standard. J (coupling Hz, 1H), 7.02 (d, J ¼ 3.6 Hz, 1H), 7.15 (d, J ¼ 7.6 Hz, 1H), 7.23 (s,
5-Bromo-1-methyl-1H-indole (3d). Yellowish liquid; 89%
1
3
) d 3.73 (s, 3H), 6.41 (d, J ¼ 2.4
1
3
constant) were reported in Hz, Splitting patterns of proton are 1H), 7.28 (q, J ¼ 2 Hz, 7.2 Hz, 1H), 7.74 (d, J ¼ 2.4 Hz, 1H); C-
described as s (singlet), d (doublet), t (triplet), q (quartet), m NMR (100 MHz, CDCl ) d 135.3, 130.1, 130.0, 124.2, 123.2, 112.6,
multiplet). 110.6, 100.5, 32.9; GC-MS: (m/z) 209 (M ).
,5-Dimethyl-1H-indole (3f). Colourless liquid, 75% yield;
3
+
(
1
1
H-NMR (500 MHz, CDCl ) d 7.43 (s, 1H), 7.25 (d, J ¼ 8.5 Hz, 1H),
General experimental procedure
3
7
.07 (dd, J ¼ 8.5, 1.5 Hz, 1H), 7.02 (d, J ¼ 3.0 Hz, 1H), 6.41 (d, J ¼
ꢀ
The MgO was rst calcinated at 550 C. A reaction vial was
charged with an indole or phenol derivatives (1 mmol), DMC (4
equiv.), MgO (4 equiv.) and DMF (1.5 mL). The mixture was
heated by microwave treatment at 170 C for 30 minutes. The
reaction mass was cooled to room temperature, ltered to
separate MgO and the ltrate was diluted with ethyl acetate and
water. The organic later was dried over Na SO then evaporated
2 4
in vacuo. The product was characterised by using the GC, GC-
MS, NMR techniques.
+
3
.0 Hz, 1H), 3.88 (s, 3H), 2.78 (s, 3H); GC-MS: (m/z) 145 (M ).
1
1
-Methoxy-4-nitrobenzene (3m). White solid; 93% yield: H
NMR (CDCl
GC-MS (m/z): 153.04 [M ].
,4-Diuoro-1-methoxybenzene (3o). Colourless liquid; 94%
3
, 400 MHz) d 8.20 (m, 2H), 6.96 (m, 2H), 3.91 (s, 3H);
ꢀ
+
2
1
yield; H-NMR (500 MHz, CDCl ) d 6.95–6.75 (m, 3H) 3.86 (s,
3
+
3H); GC-MS (m/z): 144 [M ].
1
,2,4-Trimethoxybenzene (3p). Yellowish liquid; 96% yield;
H-NMR (500 MHz, CDCl
1
3
) d 6.79 (d, J ¼ 8.5 Hz, 1H), 6.52 (d, J ¼
2
3
.0 Hz, 1H), 6.38 (dd, J ¼ 9.0, 3.0 Hz, 1H), 3.85 (s, 3H), 3.83 (s,
Scale up experimental procedure
+
H), 3.76 (s, 3H); GC-MS (m/z): 168 [M ].
An indole (5 g), DMC (4 equiv.), MgO (4 equiv.) and DMF (65 mL)
was charged in a 100 mL-stainless steel autoclave. The reaction
was performed for 170 C for 1 hour. The mixture was cooled to
Acknowledgements
ꢀ
room temperature and vented to discharge the pressure The author STG is thankful to Council of Scientic and Indus-
generated during the course of the reaction. The reaction mass trial Research (CSIR) for providing the senior research
was cooled to room temperature, ltered to separate MgO and fellowship.
the ltrate was diluted with ethyl acetate and water. The organic
2 4
later was dried over Na SO then evaporated in vacuo. The
product was conrmed by using the GC, GC-MS, NMR
Notes and references
techniques.
1 (a) A. K. Ghosh, X. M. Xu, J. H. Kim and C. X. Xu, Org. Lett.,
2
008, 10, 1001–1004; (b) N. Fukuda, K. Sasaki,
T. V. R. S. Sastry, M. Kanai and M. Shibasaki, J. Org. Chem.,
006, 71, 1220–1225.
Recycle study of MgO
2
Aer completion of the reaction the MgO was ltered out,
2
3
(a) X. Liu, T. Wang, Q. Xu, C. Ma and J. M. Cook, Tetrahedron
Lett., 2000, 41, 6299; (b) S. Christophe, C. Kuehm-Caube're,
P. Renard, B. Pfeiffer and P. Caube're, Tetrahedron Lett.,
washed with the methanol to remove the organic content if
ꢀ
present. The MgO was dried and calcinated at 550 C. The MgO
was stored under an inert atmosphere and used for the recycle
experiments.
1998, 39, 9431.
(a) S. T. Hilton, T. C. T. Ho, G. Pljevaljcic, M. Schulte and
K. J. Jones, J. Chem. Soc., Chem. Commun., 2001, 209; (b)
S. T. Hilton, T. C. T. Ho, G. Pljevaljcic and K. Jones, Org.
Lett., 2000, 2, 2639; (c) O. Ottoni, R. Cruz and R. Alves,
Tetrahedron, 1998, 54, 13915; (d) C. B. de Koning,
J. P. Michael and A. L. Rousseau, J. Chem. Soc., Perkin
Trans. 1, 2000, 1705; (e) C. Tratrat, S. Giorgi-Renault and
H.-P. Husson, J. Org. Chem., 2000, 65, 6773.
Characterisation data of the products
1
1
-Methyl-1H-indole (3a). Yellow liquid; 96% yield; H NMR
(
1
1
400 MHz, CDCl ) d 7.63 (d, J ¼ 7.9 Hz, 1H), 7.31 (d, J ¼ 8.2 Hz,
3
H), 7.24–7.18 (m, 1H), 7.13–7.08 (m, 1H), 7.02 (d, J ¼ 3.1 Hz,
13
H), 6.48 (d, J ¼ 3.1 Hz, 1H), 3.75 (s, 3H); C NMR (100 MHz,
) d 136.6, 128.7, 128.4, 121.4, 120.8, 119.2, 109.1, 100.8,
CDCl
2.7; GC-MS (m/z) ¼ 131 [M ].
-Chloro-1-methyl-1H-indole (3b). Yellowish liquid; 99%
3
+
3
4 (a) P. Tundo and M. Selva, Acc. Chem. Res., 2002, 35, 706; (b)
S. V. Chankeshwara, Synlett, 2008, 624; (c) M. Selva and
A. Perosa, Green Chem., 2008, 10, 457; (d) F. Arico and
P. Tundo, Russ. Chem. Rev., 2010, 79, 479; (e) Y. Ono, Catal.
Today, 1997, 35, 15; (f) P. Tundo, Pure Appl. Chem., 2001,
73, 1117; (g) S. Memoli, M. Selva and P. Tundo,
Chemosphere, 2001, 43, 115; (h) D. Delledonne, F. Rivetti
and U. Romano, Appl. Catal., A, 2001, 221, 241; (i)
P. Tundo, L. Rossi and A. Loris, J. Org. Chem., 2005, 70,
5
1
yield; H-NMR (400 MHz, CDCl
3
) d 3.77 (s, 3H), 6.42 (d, J ¼ 2.4
Hz, 1H), 7.06 (d, J ¼ 2.8 Hz), 7.16 (q, J ¼ 2.4 Hz, 8.8 Hz, 1H), 7.23
1
3
(
t, J ¼ 6.8 Hz, 1H), 7.58 (d, J ¼ 1.6 Hz, 1H); C-NMR (100 MHz,
CDCl ) d 134.9, 130.0, 129.4, 125.1, 121.8, 120.2, 110.2, 100.6,
3
3
+
3.0; GC-MS: (m/z) 165 (M ).
5-Cyano-1-methyl-1H-indole (3c). Yellowish solid; 95% yield;
1
H-NMR (400 MHz, CDCl ) d 3.82 (s, 3H), 6.56 (m, 1H), 7.17 (d, J
3
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