Ultrasound assisted, ruthenium-exchanged FAU-Y zeolite catalyzed alkylation of indoles with epoxides under solvent free conditions

Article abstract of DOI:10.1016/j.ultsonch.2011.11.003

Ruthenium-exchanged FAU-Y zeolite (RuY) was used as a recyclable catalyst for regioselective ring-opening of epoxides with indoles under irradiation of sonic waves. It was found that a solvent free process, under the above mentioned conditions provides go

Full text of DOI:10.1016/j.ultsonch.2011.11.003

Ultrasonics Sonochemistry 19 (2012) 570–575
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Ultrasonics Sonochemistry
journal homepage: www.elsevier.com/locate/ultsonch
Ultrasound assisted, ruthenium-exchanged FAU-Y zeolite catalyzed alkylation
of indoles with epoxides under solvent free conditions
⇑
Alireza Khorshidi
Department of Chemistry, Faculty of Sciences, University of Guilan, P.O. Box 41335-1914, Iran
a r t i c l e i n f o
a b s t r a c t
Article history:
Ruthenium-exchanged FAU-Y zeolite (RuY) was used as a recyclable catalyst for regioselective ring-open-
ing of epoxides with indoles under irradiation of sonic waves. It was found that a solvent free process,
under the above mentioned conditions provides good yields of the desired 3-alkylated indole derivatives.
Ó 2011 Elsevier B.V. All rights reserved.
Received 10 November 2010
Received in revised form 3 August 2011
Accepted 7 November 2011
Available online 16 November 2011
Keywords:
Ultrasonic irradiation
Ruthenium-exchanged zeolite
Regioselective
Epoxides
Indoles
1. Introduction
Ultrasound irradiation, on the other hand, has emerged as an
efficient technique for reagent activation in organic synthesis.
The investigation of the chemistry of indoles has been, and con-
tinues to be, one of the most active areas of heterocyclic chemistry
[1,2]. Various indole derivatives occur in many pharmacologically
and biologically active compounds [3]. In particular, 3-alkylindole
derivatives have significant medical importance [4–6], and can be
prepared by ring-opening of epoxides using indoles. In the litera-
ture, this type of reaction has been reported using different
methods such as acid catalysis [7], high pressure conditions [8],
lanthanide triflates [9], nanocrystalline titanium(IV) oxide [10]
and HBF4–SiO2 [11]. The drawbacks of these methods are long
reaction times, high temperatures, a large excess of reagents, high
pressure and unsatisfactory yields, especially, with regard to
aliphatic epoxides. As a significant improvement in this context,
we have recently reported a homogeneous ruthenium-based pro-
tocol for alkylation of indoles with epoxides [12], which still in-
volves challenges like inorganic waste, necessity of addition of a
protic acid in some cases and rather long reaction times. In recent
years, the use of solid acid catalysts such as zeolite and ion-
exchanged molecular sieves in the manufacture of fine chemicals
has attracted increasing attention owing to the special features
such as selectivity, thermal stability, eco-friendly nature and above
all, reusability, which are most sought after in green chemistry
[13].
Using cavitation as an energy source to promote molecular interac-
tions, results in shorter reaction times. Rarefaction–compression
cycle in the cavitation process, which involves separation of mole-
cules of the liquid and then collapse of the bubbles, provides vio-
lent impulsions that generate short-lived regions with high
temperature and pressure. Such localized hot spots can be thought
as micro reactors in which the energy of sound is transformed into
a useful chemical form [14–16]. In continuation of our recent work
on indole derivatives and catalytic reactivity of ruthenium [17–21],
we now describe our study of ruthenium-exchanged FAU-Y zeolite
catalyzed regioselective ring-opening of epoxides with indoles
under ultrasound irradiation.
2. Results and discussion
Scheme 1 summarizes the optimized details of the ultrasound
promoted Friedel–Crafts alkylation reaction of indoles using vari-
ous epoxides, under heterogeneous ruthenium-exchanged FAU-Y
(RuY) catalysis.
In order to optimize the reaction conditions, phenyl glycidyl
ether and indole were selected as model substrates, and the pro-
gress of the reaction was monitored by TLC. Solvent screening
experiments under ultrasonic irradiation showed that the yields
were solvent dependent (Table 1). Using the epoxide substrate as
solvent, however, better yields were obtained.
⇑
The effect of catalyst-type on the yield of alkylated product was
also studied. These results are summarized in Table 2. In order to
Tel.: +98 911 339 7159; fax: +98 131 322 0066.
E-mail address: rucatalyst@yahoo.com
1350-4177/$ - see front matter Ó 2011 Elsevier B.V. All rights reserved.
doi:10.1016/j.ultsonch.2011.11.003

A. Khorshidi / Ultrasonics Sonochemistry 19 (2012) 570–575
571
explore the role of different acid sites (Lewis and Bronsted) in the
reaction, a comparison was made between Hb, HY and RuY. In situ
DRIFT (pyridine adsorption) measurements were used to deter-
mine the acidity of the catalysts. Correlation between DRIFT signals
and coordination site of pyridine (Lewis or Bronsted acid sites
which are responsible for the catalytic activity of zeolites) is well
reported [22–24]. As it is shown, the yield of product increases in
the order Hb < HY, which is the same order of the increasing acid
site density of the catalysts. Ru3+ exchanged Y zeolite, however,
showed better activity than the parent HY zeolite owing to its
higher Lewis acidity. Other physico-chemical properties of the zeo-
lites are also, embedded in Table 2. As it is shown, decrease in the
particle size of zeolites results in an increase of the reaction yield.
This may be attributed to increase of the external acid sites with
decrease in crystal size of the zeolites [25,26]. BET surface areas
also, have a similar effect on the reaction yield. A correlation be-
tween the pore size of the zeolites and the reaction yield, however,
Scheme 1. Ultrasound assisted, RuY catalyzed alkylation of indoles with epoxides.
Table 1
Effect of solvents on the yield of 1-(1H-indol-3-yl)-3-phenoxypropan-2-ol.
Entrya
Solvent
Time (h)
Yieldb (%)
1
2
3
4
5
CH2Cl2
CH3Cl
CH3CN
C2H5OH
Solvent free
1
1
1
1
1
50
55
48
35
65
a
The reaction was carried out according to general experimental procedure.
Isolated yields.
b
Table 2
Effect of catalyst on the yield of 1-(1H-indol-3-yl)-3-phenoxypropan-2-ol.
Entrya
Catalystb
Si/Al ratio
Particle size (
lm)
BET surface area (m2/g)
Pore volume (cm3/g)
Irradiation time (h)
Yieldc (%)
1
2
3
4
No catalyst
Hb
HY
RuY
–
15
3
–
1
0.5
0.5
–
–
2.5
2.5
2.5
1
0
40
52
65
575
647
628
0.225
0.285
0.282
3
a
b
c
The reaction was carried out according to general experimental procedure.
Catalyst loading: 0.1 g per mmol of indole.
Isolated yields.
Table 3
The effect of irradiation intensity on the reaction yield.
Max. power densitya
Yieldb
92 W cmÀ2
20
184 W cmÀ2
32
276 W cmÀ2
43
368 W cmÀ2
55
460 W cmÀ2
65
a
The reaction was carried out according to general experimental procedure.
Isolated yields.
b
Table 4
Ultrasound assisted, alkylation of various indoles with epoxides.
Entrya
1
Epoxide
Indole
Indole
Product
Time (h)
1
Yieldb (%)
65
Phenyl glycidyl ether
2
3
2-Methyl indole
5-Bromo indole
1
75
65
1.5
4
5-Cyano indole
1.5
60
(continued on next page)

572
A. Khorshidi / Ultrasonics Sonochemistry 19 (2012) 570–575
Table 4 (continued)
Entrya
5
Epoxide
Indole
Indole-2-acetic acid
Product
Time (h)
1.5
Yieldb (%)
50
6
7-Aza indole
0.5
98
7
8
Allyl glycidyl ether
Indole
1
1
62
60
2-Methyl indole
9
Butyl glycidyl ether
Indole
1
1
55
60
10
2-Methyl indole
a
All products were characterized by 1H NMR, 13C NMR and IR data.
Isolated yields.
b
could not be established (entries 3 and 4), which may be attributed
to the bulky nature of the product and its formation on the external
surface of the catalyst.
underwent ring-opening by indoles. These results are also embed-
ded in Table 1. Electron-rich substituents on the glycidyl ether,
however, decreased the yield and rate of the reaction. One interest-
ing exception was the reaction of 7-azaindole with phenyl glycidyl
ether, which furnished an excellent yield of the N-alkylation
product. The product was insoluble in the reaction media and the
white solid precipitate was filtered and washed with methanol,
then dissolved in chloroform to remove catalyst by filtration and
finally recrystallization from chloroform provided pure product
(entry 6).
Table 3, summarizes the effect of irradiation intensity on the
reaction yield. As it is shown, increase in the rated power of the
ultrasonic horn from 20% to 100% (92 to 460 W cmÀ2, respectively),
resulted in increase of reaction yield. This could be due to maximi-
zation of cavitation and effective distribution of the reactants
throughout the reaction mixture. In order to investigate the effect
of the irradiation frequency, an ultrasonic cleaner with a frequency
of 50–60 kHz and a normal power of 250 W was also, used.
Running in the same conditions, the ultrasonic cleaner produced
much lower noise, but the yield of the isolated product was only
42%.
In order to evaluate reusability of the solid catalyst, the reaction
of indole and phenyl glycidyl ether was carried out in presence of
the recycled catalyst (see experimental) in successive runs. These
results are shown in Table 5.
With the optimized conditions in hand (Scheme 1), various in-
doles and an array of epoxides were used and indicated the gener-
ality and scope of the reaction. Typical results are shown in Table 4.
Treatment of indole (5 mmol) with phenyl glycidyl ether (5 mL) in
the presence of Ru3+ exchanged FAU-Y zeolite (RuY, 0.5 g, activated
at 300 °C for 3 h) at rt for 1 h under ultrasonic irradiation gave
1-(3-indolyl)-3-phenoxy-2-propanol in 65% yield (entry 1). The
observed regioselectivity toward the less hindered carbon of the
epoxide ring, which is evident from NMR spectral data, suggests
a Lewis acid mechanism, as we have proposed previously [12].
The reaction can be used for substituted indoles with either
electron-donating or electron-withdrawing groups (Table 1,
entries 2–5), and the same regioselectivity was observed in each
case. Electron rich indoles, however, gave better yields and reacted
with lower reaction times. Allyl- and butyl-glycidyl ethers, also,
As it is shown, only 5% loss of efficiency in terms of the product
yield was observed after five runs, which promises minimization of
the waste.
Table 5
Reaction of indole and phenyl glycidyl ether in presence of the recycled catalyst in
successive runs.
Run
Catalyst:indole ratio
0.1 g:1 mmol
Time (h)
Yielda (%)
1
2
3
4
5
1
1
1
1
1
65
65
63
60
60
a
Isolated yields.

A. Khorshidi / Ultrasonics Sonochemistry 19 (2012) 570–575
573
4.3.1. 1-(1H-Indol-3-yl)-3-phenoxypropan-2-ol (Table 4, entry 1)
Solid, m.p. 82–84 °C, IR (KBr):
(cmÀ1); 690, 752, 814, 1037,
3. Conclusions
t
1083, 1172, 1244, 1296, 1338, 1427, 1456, 1494, 1595, 2877,
2926, 3056, 3326, 3416, 3545. 1H NMR (500 MHz, CDCl3, 25 °C):
d = 2.23 (1H, br), 3.15 (1H, dd, J = 14.5, 7.0 Hz), 3.20 (1H, dd,
J = 14.5, 6.2 Hz), 4.01 (1H, dd, J = 9.3, 6.4 Hz), 4.07 (1H, dd, J = 9.3,
3.9 Hz), 4.41 (1H, m), 6.96 (2H, d, J = 8.3 Hz), 7.02 (1H, t,
J = 7.3 Hz), 7.15 (1H, s), 7.18 (1H, t, J = 7.8 Hz), 7.27 (1H, t,
J = 7.6 Hz), 7.31–7.36 (2H, m), 7.42 (1H, d, J = 8.2 Hz), 7.70 (1H, d,
J = 7.9 Hz), 8.11 (1H, br) ppm. 13C NMR (125 MHz, CDCl3, 25 °C):
d = 29.86, 70.57, 71.59, 111.66, 111.84, 115.06, 119.30, 120.06,
121.50, 122.69, 123.35, 128.03, 129.94, 136.77, 159.09 ppm. Anal.
Calcd for C17H17NO2: C, 76.38; H, 6.41; N, 5.24; found: C, 76.40;
H, 6.45; N, 5.23.
In conclusion, we have developed a convenient method for the
addition of indoles to epoxides. Highlights of the present work are:
(i) Simultaneous application of sonic waves and RuY resulted in
more efficiency in terms of reaction time and yield.
(ii) Regioselectivity toward the less hindered site of attack on
the epoxide ring, resulted in secondary alcohol products,
selectively.
(iii) Reusability of the solid acid catalyst and solvent free condi-
tions are also, noticeable.
4. Experimental
4.3.2. 1-(2-Methyl-1H-indol-3-yl)-3-phenoxypropan-2-ol (Table 4,
entry 2)
4.1. General
Pink viscous liquid, IR (KBr):
t
(cmÀ1); 690, 754, 815, 1039,
1082, 1172, 1240, 1298, 1435, 1460, 1495, 1595, 2873, 2922,
3057, 3292, 3417, 3529. 1H NMR (500 MHz, CDCl3, 25 °C):
d = 2.40 (3H, s), 2.53 (1H, br), 3.11 (1H, dd, J = 14.4, 6.6 Hz), 3.15
(1H, dd, J = 14.4, 7.0 Hz), 3.97 (1H, dd, J = 9.3, 6.1 Hz), 4.02 (1H,
dd, J = 9.3, 3.9 Hz), 4.37 (1H, m), 6.96 (2H, d, J = 8.2 Hz), 7.04
(1H, t, J = 7.3 Hz), 7.15–7.22 (2H, m), 7.31–7.37 (3H, m), 7.61
(1H, d, J = 7.7 Hz), 7.94 (1H, br) ppm. 13C NMR (125 MHz, CDCl3,
25 °C): d = 12.19, 28.89, 70.97, 71.28, 107.29, 110.82, 115.07,
118.46, 119.95, 121.50, 121.67, 129.32, 129.97, 133.13, 135.76,
159.09 ppm. Anal. Calcd for C18H19NO2: C, 76.84; H, 6.81; N,
4.98; found: C, 76.88; H, 6.87; N, 4.99.
IR spectra were recorded on a Shimadzu FTIR-8400S spectrom-
eter. DRIFT spectra were recorded on the same spectrophotometer
equipped with a high temperature vacuum chamber. 1H NMR
spectra were obtained on a Bruker DRX-500 Avance spectrometer
and 13C NMR spectra were obtained on a Bruker DRX-125 Avance
spectrometer. Chemical shifts of 1H and 13C NMR spectra were ex-
pressed in ppm downfield from tetramethylsilane. Melting points
were measured on a Büchi Melting Point B-540 instrument and
are uncorrected. The BET specific surface areas were determined
by nitrogen adsorption at liquid nitrogen temperature on a Sibata
SA-1100 surface area analyzer. X-ray diffraction measurements
were recorded by a D8 Bruker Advanced diffractometer with Cu-
4.3.3. 1-(5-Bromo-1H-indol-3-yl)-3-phenoxypropan-2-ol (Table 4,
entry 3)
K
a
radiation.
Elemental analyzes were made by a Carlo-Erba EA1110 CNNO-S
Solid, m.p. 77–79 °C, IR (KBr):
t
(cmÀ1); 692, 754, 797, 883,
analyzer and agreed with the calculated values. The ultrasonic de-
vise used was a UP 400 S instrument, emitting 24 kHz ultrasound
at tunable intensity levels (up to a maximum of 460 W cmÀ2).
Due to an increase in the reaction temperature during sonication,
a current of water was used to maintain the temperature at rt. A
TECNO-GAZ Tecna
50–60 kHz and a normal power of 250 W was also, used for a
comparison.
1041, 1081, 1244, 1296, 1458, 1495, 1595, 2873, 2924, 3062,
3336, 3419. 1H NMR (500 MHz, CDCl3, 25 °C): d = 2.40 (1H, br),
3.08 (1H, dd, J = 14.5, 7.0 Hz), 3.13 (1H, dd, J = 14.5, 6.0 Hz), 3.98
(1H, dd, J = 9.3, 6.5 Hz), 4.05 (1H, dd, J = 9.3, 3.8 Hz), 4.37 (1H, m),
6.96 (2H, d, J = 8.6 Hz), 7.02 (1H, t, J = 6.9 Hz), 7.16 (1H, d,
J = 2.3 Hz), 7.27–7.36 (4H, m), 7.81 (1H, d, J = 1.7 Hz), 8.17 (1H,
br) ppm. 13C NMR (125 MHz, CDCl3, 25 °C): d = 29.63, 70.74,
71.45, 111.74, 113.10, 113.36, 115.01, 121.60, 122.02, 124.55,
125.52, 129.81, 129.99, 135.31, 158.94 ppm. Anal. Calcd for
3 ultrasonic cleaner with a frequency of
C17H16BrNO2: C, 58.97; H, 4.66; N, 4.05; found: C, 58.93; H, 4.68;
4.2. Materials
N, 4.04.
Na-forms of b and FAU-Y zeolites were converted into the H-
form by repeated ion-exchange with 1 M NH4NO3 solution and
subsequent calcination of the resulting filtered material in air at
550 °C. The Ru3+ ion-exchanged zeolite (RuY), was obtained by stir-
ring HY with 0.05 M ruthenium chloride hydrate (15 mL/g of zeo-
lite) overnight and subsequent filtration and calcination at
550 °C. All other materials were purchased from Merck and used
without further purification.
4.3.4. 3-(2-Hydroxy-3-phenoxypropyl)-1H-indole-5-carbonitrile
(Table 4, entry 4)
Yellow oil, IR (KBr):
t
(cmÀ1); 692, 754, 812, 1045, 1078, 1244,
1296, 1460, 1495, 1595, 2222, 2879, 2929, 3064, 3285, 3379. 1H
NMR (500 MHz, CDCl3, 25 °C): d = 2.26 (1H, br), 3.80 (1H, dd,
J = 11.4, 5.5 Hz), 3.89 (1H, dd, J = 11.4, 3.7 Hz), 4.08–4.10 (2H, m),
4.17 (1H, m), 6.96 (2H, d, J = 8.5 Hz), 7.03 (1H, t, J = 7.4 Hz), 7.27–
7.36 (5H, m), 7.46 (1H, s), 8.06 (1H, br) ppm. 13C NMR (125 MHz,
CDCl3, 25 °C): d = 29.58, 69.49, 70.80, 111.82, 112.52, 113.21,
114.92, 121.77, 122.28, 125.27, 125.41, 125.55, 128.12, 129.32,
135.14, 158.77 ppm. Anal. Calcd for C18H16N2O2: C, 73.95; H,
5.52; N, 9.58; found: C, 73.94; H, 5.55; N, 9.61.
4.3. General procedure for the ultrasound assisted, RuY catalyzed
alkylation of indoles with epoxides
Indole (5 mmol) and RuY (0.5 g) were added to an epoxide con-
taining vial (5 mL, excess) and the reaction mixture was irradiated
at room temperature for the appropriate time (Table 1). After com-
pletion of the reaction (as indicated by TLC), the mixture was fil-
tered and the catalyst washed thoroughly with dichloromethane,
then filtered and dried. The combined washings and filtrate were
concentrated in vacuum. The crude product was purified by
preparative TLC (n-hexane/ethyl acetate:10/3). The recovered cat-
alyst was reactivated at 550 °C.
4.3.5. 3-(2-Hydroxy-3-phenoxypropyl)-1H-indole-2-carboxylic acid
(Table 4, entry 5)
viscous liquid, IR (KBr):
t
(cmÀ1); 690, 750, 829, 1197, 1242,
1307, 1458, 1495, 1537, 1595, 1718, 2875, 2925, 3058, 3257,
3334, 3404. 1H NMR (500 MHz, CDCl3, 25 °C): d = 2.92 (1H, br),
4.15 (1H, dd, J = 9.5, 5.9 Hz), 4.20 (1H, dd, J = 9.4, 4.7 Hz), 4.45
(1H, m), 4.60 (1H, dd, J = 9.3, 5.9 Hz), 4.64 (1H, dd, J = 9.3, 4.6 Hz),
6.98 (2H, d, J = 8.2 Hz), 7.04 (1H, t, J = 7.4 Hz), 7.21 (1H, t,

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A. Khorshidi / Ultrasonics Sonochemistry 19 (2012) 570–575
J = 7.8 Hz), 7.32–7.40 (3H, m), 7.46 (1H, d, J = 8.3 Hz), 7.74 (1H, d,
J = 8.1 Hz), 9.11 (1H, br) ppm. 13C NMR (125 MHz, CDCl3, 25 °C):
d = 66.19, 69.00, 69.18, 109.92, 112.39, 114.97, 121.41, 121.89,
123.14, 126.16, 127.00, 127.81, 130.06, 137.44, 158.68,
162.43 ppm. Anal. Calcd for C18H17NO4: C, 69.44; H, 5.50; N,
4.50; found: C, 69.51; H, 5.53; N, 4.53.
4.3.10. 1-Butoxy-3-(2-methyl-1H-indol-3-yl)propan-2-ol (Table 4,
entry 10)
Yellow oil, IR (KBr):
t
(cmÀ1); 742, 842, 1012, 1114, 1238, 1299,
1436, 1462, 1618, 2867, 2930, 2957, 3055, 3325, 3402, 3544. 1H
NMR (500 MHz, CDCl3, 25 °C): d = 0.97 (3H, t, J = 7.4 Hz), 1.42
(2H, m), 1.61 (2H, m), 2.42 (1H, br), 2.44 (3H, s), 2.96 (2H, m),
3.38 (1H, dd, J = 9.5, 6.9 Hz), 3.45–3.54 (3H, m), 4.11 (1H, m),
7.13 (1H, t, J = 7.9 Hz), 7.17 (1H, t, J = 7.9 Hz), 7.31 (1H, d,
J = 8.2 Hz), 7.56 (1H, d, J = 7.6 Hz), 7.90 (1H, br) ppm. 13C NMR
(125 MHz, CDCl3, 25 °C): d = 12.22, 14.41, 19.79, 28.80, 32.24,
71.25, 71.66, 74.40, 107.82, 110.62, 118.53, 119.76, 121.53,
129.37, 132.79, 135.65 ppm. Anal. Calcd for C16H23NO2: C, 73.53;
H, 8.87; N, 5.36; found: C, 73.55; H, 8.86; N, 5.32.
4.3.6. 1-Phenoxy-3-(1H-pyrrolo[2,3-b]pyridin-1-yl)propan-2-ol
(Table 4, entry 6)
White solid, m.p. 224–226 °C, IR (KBr):
t
(cmÀ1); 694, 731, 757,
912, 1012, 1118, 1174, 1242, 1313, 1361, 1454, 1483, 1492, 1599,
2696, 2765, 2871, 3036, 3064, 3101. 1H NMR (500 MHz, (CD3)2SO,
25 °C): d = 4.02 (2H, d, J = 4.8 Hz), 4.51–4.59 (2H, m), 5.05 (1H, dd,
J = 12.3, 2.5 Hz), 5.98 (1H, br), 6.59 (1H, d, J = 2.4 Hz), 6.93–6.97
(4H, m), 7.30 (2H, t, J = 7.6 Hz), 7.68 (1H, d, J = 2.4 Hz), 8.05 (1H,
d, J = 6.1 Hz), 8.21 (1H, d, J = 7.4 Hz) ppm. 13C NMR (125 MHz,
(CD3)2SO, 25 °C): d = 57.37, 67.82, 71.05, 101.54, 109.44, 115.44,
121.64, 129.99, 130.37, 131.84, 133.05, 144.63, 148.84,
159.31 ppm. Anal. Calcd for C16H16N2O2: C, 71.62; H, 6.01; N,
10.44; found: C, 71.65; H, 6.05; N, 10.41.
Acknowledgements
The authors are grateful to the Research Council of University of
Guilan for partial support of this study. A. Khorshidi is thankful to
Dr. M.A. Faramarzi for his generous support.
References
[1] T.L. Gilchrist, Heterocyclic Chemistry, Academic Press, London, 1997.
[2] G.R. Humphrey, J.T. Kuethe, Practical methodologies for the synthesis of
indoles, Chem. Rev. 106 (2006) 2875–2911.
4.3.7. 1-(Allyloxy)-3-(1H-indol-3-yl)propan-2-ol (Table 4, entry 7)
Viscous liquid, IR (KBr):
t
(cmÀ1); 742, 810, 928, 1010, 1094,
[3] H.-C. Zhang, H. Ye, A.F. Moretto, K.K. Brumfield, B.E. Maryanoff, Facile solid-
1339, 1420, 1456, 1616, 1657, 2869, 2928, 2960, 3055, 3414. 1H
NMR (500 MHz, CDCl3, 25 °C): d = 2.30 (1H, br), 3.61 (2H, d,
J = 5.9 Hz), 3.72 (1H, dd, J = 9.5, 6.4 Hz), 3.81 (1H, dd, J = 9.5,
5.4 Hz), 4.08 (2H, d, J = 5.7 Hz), 4.12 (1H, m), 5.28 (1H, dd, J = 8.6,
1.6 Hz), 5.35 (1H, dd, J = 16.1, 1.8 Hz), 5.91–5.98 (1H, m), 7.05
(1H, d, J = 2.3 Hz), 7.08 (1H, t, J = 7.1 Hz), 7.20 (1H, t, J = 7.6 Hz),
7.38 (1H, d, J = 7.8 Hz), 7.65 (1H, d, J = 7.9 Hz), 7.95 (1H, br) ppm.
13C NMR (125 MHz, CDCl3, 25 °C): d = 29.11, 71.45, 72.81, 74.12,
107.72, 111.46, 119.40, 120.15, 120.76, 121.86, 122.14, 127.65,
137.00, 137.74 ppm. Anal. Calcd for C14H17NO2: C, 72.70; H, 7.41;
N, 6.06; found: C, 72.72; H, 7.44; N, 6.10.
phase construction of indole derivatives based on
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entry 8)
Yellow oil, IR (KBr):
t
(cmÀ1); 742, 829, 926, 1091, 1240, 1299,
1435, 1462, 1491, 1620, 1687, 2858, 2914, 3055, 3336, 3400, 3531.
1H NMR (500 MHz, CDCl3, 25 °C): d = 2.42 (3H, s), 2.44 (1H, br),
2.98 (2H, d, J = 6.9 Hz), 3.43 (1H, dd, J = 9.5, 6.7 Hz), 3.52 (1H, dd,
J = 9.5, 3.5 Hz), 4.05 (2H, d, J = 5.6 Hz), 4.15 (1H, m), 5.24 (1H, dd,
J = 10.4, 1.2 Hz), 5.33 (1H, dd, J = 17.3, 1.6 Hz), 5.93–6.01 (1H, m),
7.13 (1H, t, J = 6.8 Hz), 7.17 (1H, t, J = 6.9 Hz), 7.30 (1H, d,
J = 7.8 Hz), 7.57 (1H, d, J = 7.6 Hz), 7.95 (1H, br) ppm. 13C NMR
(125 MHz, CDCl3, 25 °C): d = 12.22, 28.85, 71.30, 72.71, 73.99,
107.66, 110.68, 117.64, 118.51, 119.77, 121.54, 129.33, 132.90,
135.02, 135.68 ppm. Anal. Calcd for C15H19NO2: C, 73.44; H, 7.81;
N, 5.71; found: C, 73.41; H, 7.80; N, 5.73.
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Yellow oil, IR (KBr):
t
(cmÀ1); 742, 812, 1012, 1097, 1230, 1338,
1429, 1458, 1620, 2868, 2929, 2956, 3055, 3334, 3414. 1H NMR
(500 MHz, CDCl3, 25 °C): d = 0.97 (3H, t, J = 7.3 Hz), 1.45 (2H, m),
1.63 (2H, m), 2.46 (1H, br), 3.02 (2H, d, J = 6.5 Hz), 3.43 (1H, dd,
J = 9.5, 7.1 Hz), 3.47–3.57 (3H, m), 4.18 (1H, m), 7.12 (1H, d,
J = 2.2 Hz), 7.17 (1H, t, J = 7.1 Hz), 7.25 (1H, t, J = 7.1 Hz), 7.41
(1H, d, J = 7.8 Hz), 7.68 (1H, d, J = 7.9 Hz), 8.13 (1H, br) ppm. 13C
NMR (125 MHz, CDCl3, 25 °C): d = 14.40, 19.78, 29.80, 32.20,
70.91, 71.69, 74.68, 111.59, 112.30, 119.37, 119.87, 122.52,
123.18, 128.09, 136.69 ppm. Anal. Calcd for C15H21NO2: C, 72.84;
H, 8.56; N, 5.66; found: C, 72.86; H, 8.56; N, 5.61.
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