Efficient N-aroylation of substituted indoles with N-aroylbenzotriazoles

Article abstract of DOI:10.1055/s-2007-990889

Stable and easily accessible N-aroylbenzotriazoles react with indoles in the presence of a base to afford the corresponding N-aroylindoles in yields averaging 70%. This method is effective even when both coupling reagents possess electron-donating substit

Full text of DOI:10.1055/s-2007-990889

PAPER
3673
Efficient N-Aroylation of Substituted Indoles with N-Aroylbenzotriazoles
E
fficient
N
-Acyla
t
l
ion of
S
a
ubstituted
n
Indole
s
w
ith
N
-Acy
R
lbenzotriazoles. Katritzky,*a Levan Khelashvili,a Prabhu P. Mohapatra,a Peter J. Steelb
a
Center for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville, FL 32611-7200, USA
Chemistry Department, University of Canterbury, Christchurch, New Zealand
Fax +1(352)3929199; E-mail: katritzky@chem.ufl.edu
b
Received 12 April 2007; revised 17 August 2007
for the 5-unsubstituted indoles, were 32–46% and for 5-
methoxyindole only 0–15%.
Abstract: Stable and easily accessible N-aroylbenzotriazoles react
with indoles in the presence of a base to afford the corresponding N-
aroylindoles in yields averaging 70%. This method is effective even
when both coupling reagents possess electron-donating substitu-
ents.
N-Acylbenzotriazoles are easily prepared activated deriv-
atives of carboxylic acids.7 Applications of N-acylbenzo-
triazoles include (i) N-acylation of amines, amides,8 and
sulfonamides;9 (ii) O-acylation of aldehydes,10 steroids,11
hydroxyterpenes, and alcohols;12 (iii) many C-acylations,
viz: pyrroles and indoles,13 ketones and heteroaromatics,14
alkyl sulfones,15 alkyl cyanides,16 alkyl azines,17 a-ni-
troalkanes,18 furans, and thiophenes;19 and (iv) syntheses
of peptides,20 oxazolines,21 esters,22 benzodioxin-4-
ones,23 ketones,24 benzodiazepin-2-ones,25 thiol esters,26
alcohols,27 hydrazides,28 and heteroaromatics.29
Earlier we13a,14b and others12 have reported regiospecific
C-acylation of pyrroles and indoles using N-acylbenzotri-
azoles. Herein, we report the efficient synthesis of elec-
tron-rich N-aroylindoles from N-aroylbenzotriazoles in
the presence of a base via N-aroylation of indoles.
Key words: N-aroylbenzotriazoles, indoles, N-aroylindoles, elec-
tron-donating substituents
N-Aroylindoles are well-known nonsteroidal anti-inflam-
matory drugs (NSAIDS) (e.g., indomethacin, a 5-meth-
oxyindole derivative).1 N-Aroyl-5-nitro-1H-indoles are
utilized as intermediates for the synthesis of 2-aryl-5-ni-
tro-1H-indoles effective as bacterial NorA efflux pump
inhibitors.2 5-Substituted N-aroylindoles also exhibit se-
lective cyclooxygenase-2 inhibitor activity,3 and 5-ami-
no-1-(3,5-dimethylbenzoyl)-1H-indole possesses anti-
angiogenic activity.4 Furthermore, suitably substituted N-
aroylindoles are used as precursors for the synthesis of
benzannulated indolizidines.5
Commercially available indole (1a) and 5-methoxyindole
(1b) were used as substrates for N-aroylation reactions. N-
Aroylbenzotriazoles 2a–c (Figure 1) were readily pre-
pared from 1H-benzotriazole (BtH) and the correspond-
ing carboxylic acid in yields of 85–95% according to a
literature procedure.20 Reaction of 2,6-dimethoxybenzoic
acid with BtH and thionyl chloride in dichloromethane at
room temperature for one hour gave benzotriazol-1-yl-
(2,6-dimethoxyphenyl)methanone (2d) (95%) (Figure 1),
characterized by 1H NMR, 13C NMR, and CHN analyses.
A variety of methods have been reported for the direct N-
aroylation of indoles. When neither the aroylating agent
nor the indole contains an electron-donating substituent,
several procedures are satisfactory.6 However, useful N-
aroylations of indoles to a product in which either the aryl
group or indole nucleus contains a strong electron-donor
substituent are rare. N-Aroylindoles have been prepared
by (i) indolide anion formation with sodium hydride fol-
lowed by reaction with an acid chloride (36–82%),6a (ii)
direct aroylation of indoles with carboxylic acids using
boric acid (50–82%),6c and (iii) phase-transfer-catalyzed
aroylation of indoles (77–94%).6d Most recently, Bremner
et al.6b N-aroylated 5-substituted indoles with an electron-
withdrawing substituent (NO2, CN or F) in the 5-position
with carboxylic acids via DCC/DMAP coupling to give
73–95% yields of the N-aroylindoles. However, the yields
Reaction of the sodium salt of indole (1a) with benzotria-
zol-1-yl-phenylmethanone (2a) in THF at 25 °C for 12
hours gave the corresponding 1-benzoyl-1H-indole (3a)
in 81% yield (Table 1). Previously 3a was prepared in
32% yield from 1a and benzoyl chloride.6a We tested the
generality of this method by reacting indoles 1a and 1b
with electron-rich N-acylbenzotriazoles 2a–d (Figure 1).
Reaction of 1a with 2b and 2c gave 1-(4-methoxyben-
MeO
MeO
N
Bt
Bt
Bt
Bt
N
OMe
Bt =
N
O
O
O
O
MeO
2a
2b
2c
2d
Figure 1 N-Acylbenzotriazoles (R1COBt) 2a–d
SYNTHESIS 2007, No. 23, pp 3673–3677
x
x.
x
x
.
2
0
0
7
Advanced online publication: 13.11.2007
DOI: 10.1055/s-2007-990889; Art ID: M02507SS
© Georg Thieme Verlag Stuttgart · New York

3674
A. R. Katritzky et al.
PAPER
zoyl)-1H-indole (3b) and 1-(2-methoxybenzoyl)-1H-in- pare 3f from the corresponding acid chloride was unsuc-
dole (3c) in 91% (Lit.6b 46%) and 90% yield (Lit.6b 34%), cessful.6c In order to confirm unambiguously the
respectively (Table 1).
structures of these products the X-ray crystal structure of
a representative example, 3f, was determined.30 Figure 2
shows a perspective view of the structure which is in ac-
cord with that proposed and confirms the N-aroylation.
Reaction of 1b with 2a, 2b, and 2c gave 1-benzoyl-5-
methoxy-1H-indole (3d) (87%, Lit.6b 15%), 5-methoxy-1-
(4-methoxybenzoyl)-1H-indole (3e) (77%, Lit.6b 9%), and
the novel 5-methoxy-1-(2-methoxybenzoyl)-1H-indole Reactions of 1a and 1b with more electron-rich (thus less
(3f) (42%, Lit.6b 0%) (Table 1). A previous attempt to pre- reactive) N-aroylbenzotriazole 2d gave novel 1-(2,6-
Table 1 Preparation of N-Aroylindoles 3a–h
Entry
Indole
RCOBt
Product
Yield (%)a–c
Lit.6b yield (%)
1
1a
2a
3ad
3bd
81
32
N
O
2
3
1a
1a
2b
2c
91
90
46
34
N
O
OMe
N
3c
O
MeO
MeO
MeO
MeO
4
5
1b
1b
2a
2b
3d
3e
87
77
15
9
N
O
N
O
OMe
N
6
7
8
1b
1a
1b
2c
2d
2d
3f
42
60
36
0
O
MeO
OMe
N
3g
3h
this work
this work
O
MeO
MeO
OMe
N
O
MeO
a Isolated yield after column purification and determined from a single experiment.
b TLC profile (EtOAc–hexanes, 1:4).
c Silica gel column chromatography (5–20% EtOAc in hexanes).
d H-3¢ proton appears as a singlet because the coupling constants between H-3¢ and H-2¢ are 2–4 Hz (low resolution).
Synthesis 2007, No. 23, 3673–3677 © Thieme Stuttgart · New York

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Efficient N-Aroylation of Substituted Indoles with N-Aroylbenzotriazoles
3675
1H NMR (300 MHz, CDCl3): d = 8.41 (d, J = 7.8 Hz, 1 H), 7.72 (d,
J = 6.9 Hz, 2 H), 7.61–7.49 (m, 4 H), 7.40–7.29 (m, 3 H), 6.61 (s, 1
H).
13C NMR (75 MHz, CDCl3): d = 168.7, 135.9, 134.5, 131.8, 130.7,
129.1, 128.5, 127.6, 124.9, 123.9, 120.8, 116.3, 108.5.
Anal. Calcd for C15H11NO: C, 81.43; H, 5.01; N, 6.33. Found: C,
81.50; H, 4.95; N, 6.37.
1-(4-Methoxybenzoyl)-1H-indole (3b)
Yield: 0.24 g (91%); white crystals; mp 138–139 °C (Lit.6b mp 138–
139 °C).
1H NMR (300 MHz, CDCl3): d = 8.34 (d, J = 7.8 Hz, 1 H), 7.74 (d,
J = 8.5 Hz, 2 H), 7.60 (d, J = 7.2 Hz, 1 H), 7.36–7.25 (m, 3 H), 7.00
(d, J = 8.4 Hz, 2 H), 6.61 (s, 1 H), 3.89 (s, 3 H).
Figure 2 X-ray crystal structure of 3f30
dimethoxybenzoyl)-1H-indole (3g) and 1-(2,6-dimethoxy-
benzoyl)-5-methoxy-1H-indole (3h) in 60% and 36%
yield, respectively (Table 1). These results demonstrate
that the present method of synthesis is compatible with up
to a total of three electron-donating substituents in both
the indole and phenyl rings. Readily available electron-
rich N-aroylbenzotriazoles under basic conditions effi-
ciently N-aroylate indoles, including those with an elec-
tron-donor substituent at the 5-position.
13C NMR (75 MHz, CDCl3): d = 168.2, 162.6, 136.0, 131.7, 130.6,
127.7, 126.5, 124.6, 123.6, 120.8, 116.1, 113.8, 108.0, 55.5.
Anal. Calcd for C16H13NO2: C, 76.48; H, 5.21; N, 5.57. Found: C,
76.34; H, 5.08; N, 5.83.
1-(2-Methoxybenzoyl)-1H-indole (3c)
Yield: 0.225 g (90%); colorless glassy solid (Lit.6b pinkish-red
glassy solid).
1H NMR (300 MHz, CDCl3): d = 8.37 (br d, J = 7.7 Hz, 1 H), 7.51–
7.18 (m, 5 H), 7.03–6.94 (m, 3 H), 6.47 (d, J = 3.7 Hz, 1 H), 3.71 (s,
3 H).
13C NMR (75 MHz, CDCl3): d = 167.2, 156.3, 135.5, 132.1, 130.9,
129.0, 127.4, 124.8, 124.8, 123.9, 120.8, 120.7, 116.5, 111.4, 108.6,
55.7.
1
Melting points are uncorrected. H NMR and 13C NMR spectra
were recorded on a FT-Bruker AT-300 instrument using TMS as an
internal standard and CDCl3 as solvent. Compounds were character-
ized by elemental analysis using a Carlo-Erba EA1112 instrument.
Benzotriazol-1-yl-(2,6-dimethoxyphenyl)methanone (2d)
2,6-Dimethoxybenzoic acid (1.82 g, 10 mmol) was placed in a 100
mL Schlenk flask and anhyd CH2Cl2 (20 mL) was added. Then,
benzotriazole (3.63 g, 30.5 mmol) and CH2Cl2 (20 mL) were added
followed by SOCl2 (0.77 mL, 10.5 mmol). The solid precipitate was
difficult to stir and hence it was shaken in a New Brunswick Scien-
tific apparatus at a speed of 40 rpm for 1 h at r.t. The white precip-
itate was filtered and the filtrate was evaporated under reduced
pressure to give the crude product, which was then washed with an-
hyd Et2O (2 × 10 mL) to obtain the pure 2d (2.62 g, 95%); white
crystals; mp 154–155 °C.
1H NMR (300 MHz, CDCl3): d = 8.45 (d, J = 8.2 Hz, 1 H), 8.13 (d,
J = 8.2 Hz, 1 H), 7.70 (t, J = 7.3 Hz, 1 H), 7.53 (t, J = 7.3 Hz, 1 H),
7.45 (t, J = 8.4 Hz, 1 H), 6.67 (d, J = 8.4 Hz, 2 H), 3.76 (s, 6 H).
13C NMR (75 MHz, CDCl3): d = 165.6, 158.2, 146.4, 132.9, 131.4,
130.3, 126.3, 120.2, 114.8, 112.7, 104.1, 56.2.
Anal. Calcd for C16H13NO2: C, 76.48; H, 5.21; N, 5.57. Found: C,
76.21; H, 4.83; N, 5.67.
1-Benzoyl-5-methoxy-1H-indole (3d)
Yield: 0.218 g (87%); white crystals; mp 106–107 °C (Lit.6b mp
106–107 °C).
1H NMR (300 MHz, CDCl3): d = 8.25 (d, J = 9.1 Hz, 1 H), 7.65 (dd,
J = 6.9, 1.5 Hz, 2 H), 7.55–7.41 (m, 3 H), 7.18 (dd, J = 3.0, 0.5 Hz,
1 H), 6.99 (d, J = 2.5 Hz, 1 H), 6.92 (dd, J = 8.9, 2.5 Hz, 1 H), 6.47
(d, J = 3.7 Hz, 1 H), 3.80 (s, 3 H).
13C NMR (75 MHz, CDCl3): d = 168.4, 156.6, 134.5, 131.7, 130.6,
129.1, 128.5, 128.2, 117.2, 113.3, 108.5, 103.5, 55.6.
Anal. Calcd for C16H13NO2: C, 76.48; H, 5.21; N, 5.57. Found: C,
76.36; H, 5.15; N, 5.50.
5-Methoxy-1-(4-methoxybenzoyl)-1H-indole (3e)
Yield: 0.218 g (77%); white crystals; mp 106–108 °C (Lit.6b mp
105–106 °C).
Anal. Calcd for C15H13N3O3: C, 63.60; H, 4.63; N, 14.83. Found: C,
63.37; H, 4.44; N, 14.73.
1H NMR (300 MHz, CDCl3): d = 8.33 (d, J = 9.1 Hz, 1 H), 7.78 (tt,
J = 9.7, 2.7, 2.0 Hz, 2 H), 7.38 (d, J = 3.7 Hz, 1 H), 7.12 (d, J = 2.5
Hz, 1 H), 7.07–7.02 (m, 3 H), 6.56 (d, J = 3.7 Hz, 1 H), 3.94 (s, 3
H), 3.92 (s, 3 H).
13C NMR (75 MHz, CDCl3): d = 167.8, 162.5, 156.4, 131.6, 131.5,
130.7, 128.3, 126.4, 116.9, 113.7, 113.2, 107.9, 103.3, 55.6, 55.4.
N-Aroylindoles 3; General Procedure
The sodium salt of the appropriate indole was prepared by adding
NaH (1.1 equiv) portionwise to a stirred solution of the indole in an-
hyd THF (10 mL) at r.t. After the salt had formed, the appropriate
N-acylbenzotriazole (1.1 equiv) in anhyd THF (10 mL) was added
dropwise and the mixture was allowed to stir at r.t. until the reaction
was complete (monitored by TLC, hexanes–EtOAc, 5:1). The re-
sulting mixture was concentrated in vacuo and chromatographed on
silica gel (10–20% EtOAc in hexanes) to give the N-(hete-
ro)aroylindole 3. Sometimes additional purification was achieved
by washing the product with hexanes or recrystallization from hex-
anes.
Anal. Calcd for C17H15NO3: C, 72.58; H, 5.37; N, 4.98. Found: C,
72.84; H, 5.32; N, 4.85.
5-Methoxy-1-(2-methoxybenzoyl)-1H-indole (3f)30
Yield: 0.119 g (42%); white crystals; mp 93–95 °C.
1H NMR (300 MHz, CDCl3): d = 8.35 (br d, J = 7.3 Hz, 1 H, H-2),
7.50 (td, J = 9.0, 1.6 Hz, 1 H, H-6¢), 7.43 (dd, J = 7.5, 1.6 Hz, 1 H,
H-4¢), 7.08 (d, J = 7.4 Hz, 1 H, H-7), 7.05–7.00 (m, 3 H, H-4,3¢,5¢),
6.97 (dd, J = 8.9, 2.4 Hz, 1 H, H-3), 6.47 (d, J = 3.7 Hz, 1 H, H-6),
3.87 (s, 3 H, OCH3), 3.79 (s, 3 H, OCH3).
1-Benzoyl-1H-indole (3a)
Yield: 0.22 g (81%); white crystals; mp 63–64 °C (Lit.6b mp 63–
64 °C).
Synthesis 2007, No. 23, 3673–3677 © Thieme Stuttgart · New York

3676
A. R. Katritzky et al.
PAPER
(7) (a) Katritzky, A. R.; Suzuki, K.; Wang, Z. Synlett 2005,
13C NMR (75 MHz, CDCl3): d = 166.8 (C=O), 156.6 (C-2¢), 156.3
(C-5), 132.0 (C-4¢), 131.9 (C-6¢), 130.2 (C-3a), 129.0 (C-7a), 128.1
(C-2), 124.7 (C-1¢), 120.7 (C-5¢), 117.2 (C-3¢), 113.0 (C-7), 111.4
(C-6), 108.5 (C-3), 103.6 (C-4), 55.7 (OCH3).
1656. (b) Katritzky, A. R.; Zhang, Y.; Singh, S. K. Synthesis
2003, 2795. (c) Katritzky, A. R.; Meher, N. K.; Cai, C.;
Singh, S. K. Rev. Soc. Quim. Mex. 2004, 48, 275; Chem.
Abstr. 2005, 143, 26540.
Anal. Calcd for C16H13NO2: C, 72.58; H, 5.37; N, 4.98. Found: C,
72.93; H, 5.35; N, 4.88.
(8) (a) Katritzky, A. R.; He, H.-Y.; Suzuki, K. J. Org. Chem.
2000, 65, 8210. (b) Katritzky, A. R.; Yang, H.; Zhang, S.;
Wang, M. ARKIVOC 2002, (xi), 39.
1-(2,6-Dimethoxybenzoyl)-1H-indole (3g)
Yield: 0.17 g (60%); pinkish-white crystals; mp 141–142 °C.
1H NMR (300 MHz, CDCl3): d = 8.78 (br d, J = 5.9 Hz, 1 H, H-7),
7.64 (d, J = 8.1 Hz, 1 H, H-2), 7.46 (t, J = 8.4 Hz, 2 H, H-4,6), 7.37
(t, J = 7.1 Hz, 1 H, H-4¢), 7.03 (br s, 1 H, H-5), 6.69 (d, J = 8.4 Hz,
2 H, H-3,5Ar), 6.59 (br s, 1 H, H-3), 3.80 (s, 6 H, OCH3).
(9) Katritzky, A. R.; Hoffmann, S.; Suzuki, K. ARKIVOC 2004,
(xii), 14.
(10) Katritzky, A. R.; Pastor, A.; Voronkov, M. V. J. Heterocycl.
Chem. 1999, 36, 777.
(11) Katritzky, A. R.; Suzuki, K.; Singh, S. K.; He, H.-Y. J. Org.
Chem. 2003, 68, 5720.
13C NMR (75 MHz, CDCl3): d = 165.5 (C=O), 157.5 (C-2¢,6¢),
135.5 (C-4¢), 131.9 (C-7a), 131.2 (C-3a), 127.3 (C-2), 124.9 (C-5),
124.0 (C-6), 120.8 (C-4), 117.0 (C-7), 114.0 (C-1¢), 108.6 (C-3¢,5¢),
104.1 (C-3), 56.0 (OCH3).
(12) Zou, X.; Wang, X.; Cheng, C.; Kong, L.; Mao, H.
Tetrahedron Lett. 2006, 47, 3767.
(13) (a) Katritzky, A. R.; Pastor, A. J. Org. Chem. 2000, 65,
3679. (b) Katritzky, A. R.; Jiang, R.; Suzuki, K. J. Org.
Chem. 2005, 70, 4993.
(14) (a) Katritzky, A. R.; Meher, N. K.; Singh, S. K. J. Org.
Chem. 2005, 70, 7792. (b) Katritzky, A. R.; Abdel-Fattah,
A. A. A.; Wang, M. J. Org. Chem. 2003, 68, 1443.
(c) Katritzky, A. R.; Abdel-Fattah, A. A. A.; Wang, M. J.
Org. Chem. 2003, 68; 4932.
Anal. Calcd for C17H15NO3: C, 72.58; H, 5.37; N, 4.98. Found: C,
72.50; H, 5.32; N, 4.90.
1-(2,6-Dimethoxybenzoyl)-5-methoxy-1H-indole (3h)
Yield: 0.113 g (36%); white crystals (from hexanes); mp 134–
135 °C.
1H NMR (300 MHz, CDCl3): d = 8.59 (d, J = 8.5 Hz, 1 H, H-2),
7.39 (t, J = 8.4 Hz, 1 H, H-4¢), 7.04 (s, 1 H, H-7), 7.00 (s, 1 H, H-4),
6.94 (d, J = 2.1 Hz, 1 H, H-3), 6.63 (d, J = 8.5 Hz, 2 H, H-6,3¢), 6.46
(d, J = 2.1 Hz, 1 H, H-5¢), 3.86 (s, 3 H, OCH3), 3.74 (s, 6 H, OCH3).
13C NMR (75 MHz, CDCl3): d = 165.1 (C=O), 157.5 (C-2¢,6¢),
156.8 (C-5), 132.2 (C-4¢), 131.9 (C-3a), 130.3 (C-7a), 128.0 (C-2),
117.7 (C-7), 113.9 (C-6), 113.1 (C-1¢), 108.6 (C-3¢,5¢), 104.0 (C-3),
103.7 (C-4), 56.0 (OCH3), 55.8 (OCH3).
(15) Katritzky, A. R.; Abdel-Fattah, A. A. A.; Akhmedova, R. G.
ARKIVOC 2005, (vi), 329.
(16) Katritzky, A. R.; Abdel-Fattah, A. A. A.; Gromova, A. V.;
Witek, R.; Steel, P. J. J. Org. Chem. 2005, 70, 9211.
(17) Katritzky, A. R.; Suzuki, K.; Singh, S. K. Croat. Chem. Acta
2004, 77, 175; Chem. Abstr. 2004, 142, 134399.
(18) Katritzky, A. R.; Suzuki, K.; Singh, S. K. Synthesis 2004,
2645.
(19) Katritzky, A. R.; Angrish, P.; Hür, D.; Suzuki, K. Synthesis
2005, 397.
Anal. Calcd for C18H17NO4: C, 69.44; H, 5.50; N, 4.50. Found: C,
69.49. H, 5.47. N, 4.38.
(20) (a) Katritzky, A. R.; Angrish, P.; Suzuki, K. Synthesis 2006,
411. (b) Katritzky, A. R.; Todadze, E.; Cusido, J.; Angrish,
P.; Shestopalov, A. A. Chem. Biol. Drug Des. 2006, 68, 37.
(c) Katritzky, A. R.; Todadze, E.; Shestopalov, A. A.;
Cusido, J.; Angrish, P. Chem. Biol. Drug Des. 2006, 68, 42.
(d) Katritzky, A. R.; Meher, G.; Angrish, P. Chem. Biol.
Drug Des. 2006, 68, 326. (e) Katritzky, A. R.; Tao, H.;
Jiang, R.; Suzuki, K.; Kirichenko, K. J. Org. Chem. 2007,
72, 407. (f) Katritzky, A. R.; Cai, C.; Suzuki, K.; Singh, S.
K. J. Org. Chem. 2004, 69, 811. (g) Katritzky, A. R.; Singh,
S. K.; Cai, C.; Bobrov, S. J. Org. Chem. 2006, 71, 3364.
(21) Katritzky, A. R.; Yang, H.; Zhang, S.; Wang, M. ARKIVOC
2002, (xi), 39.
(22) (a) Katritzky, A. R.; Rogovoy, B. V.; Kirichenko, N.;
Vvedensky, V. Bioorg. Med. Chem. Lett. 2002, 12, 1809.
(b) Katritzky, A. R.; Angrish, P. Steroids 2006, 71, 660.
(c) Katritzky, A. R.; Singh, S. K.; Akhmedova, R.; Cai, C.;
Bobrov, S. ARKIVOC 2007, vi, 6.
(23) Katritzky, A. R.; Le, K. N. B.; Khelashvili, L.; Mohapatra,
P. P. J. Org. Chem. 2006, 71, 9861.
Acknowledgment
We thank Dr. C. D. Hall for checking the manuscript.
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Synthesis 2007, No. 23, 3673–3677 © Thieme Stuttgart · New York

PAPER
Efficient N-Aroylation of Substituted Indoles with N-Aroylbenzotriazoles
3677
(30) Crystal data for 3f: C17H15NO3, MW 281.30, monoclinic,
space group Cc, a = 15.1850 (14), b = 4.3143 (4), c = 21.398
(2) Å, b = 103.703 (3)°, V = 1362.0(2) Å3, F(000) = 592,
Z = 4, T = –170 °C, m (MoKa) = 0.095 mm–1, Dcalcd = 1.372
g.cm–3, 2qmax 50° APEX II CCD area detector, MoKa
radiation, SHELXS and SHELXL, GOF = 1.08,
wR(F2) = 0.074 (all 2244 data), R = 0.029 (2039 data with I
> 2sI). CCDC # 639667. Copies of the crystal data can be
obtained free of charge from CCDC, 12, Union Road,
Cambridge CB2 1EZ, UK; fax: + 44 1223 336 033; e-mail:
deposit@ccdc.cam.ac.uk.
Synthesis 2007, No. 23, 3673–3677 © Thieme Stuttgart · New York