Palladium-catalysed synthesis of 9H-pyrrolo[1,2-a]indol-9-ones and the isomeric indeno[2,1-b]pyrrol-8-ones

Article abstract of DOI:10.1002/ejoc.201300737

9H-Pyrrolo[1,2-a]indol-9-ones and isomeric indeno[2,1-b]pyrrol-8-ones could be obtained in moderate to good isolated yields, by subjecting the same substrates, 2-bromophenyl N-tosyl-2-pyrrolyl ketones, to different palladium catalysts. 9H-Pyrrolo[1,2-a]indol-9-ones and isomeric indeno[2,1-b]pyrrol-8-ones could be selectively obtained by treatment of 2-bromophenyl N-tosylpyrrol-2-yl ketones with different palladium catalysts.

Full text of DOI:10.1002/ejoc.201300737

FULL PAPER
DOI: 10.1002/ejoc.201300737
Palladium-Catalysed Synthesis of 9H-Pyrrolo[1,2-a]indol-9-ones and the
Isomeric Indeno[2,1-b]pyrrol-8-ones
Shuyang Wang,[a] Qinghua Yang,[a] Jingjing Dong,[a] Changwei Li,[a] Li Sun,[a]
Chuanjun Song,*[a] and Junbiao Chang*[a]
Keywords: Amination / C–H activation / Palladium / Nitrogen heterocycles / Cyclization
9H-Pyrrolo[1,2-a]indol-9-ones and isomeric indeno[2,1-
b]pyrrol-8-ones could be obtained in moderate to good iso-
lated yields, by subjecting the same substrates, 2-bromo-
phenyl N-tosyl-2-pyrrolyl ketones, to different palladium cat-
alysts.
Introduction
reaction of 2-(pyrrol-1-yl)benzaldehydes with arylamines,[6]
or the annulation of pyrrole-2-carboxylates with benzyne.[7]
The palladium-catalysed amination reaction has found
widespread application in the construction of heterocycles,
as well as in natural-product synthesis.[8] However, to the
best of our knowledge, this reaction has never been used
for fluorazone synthesis. In this paper, we report a one-pot
process consisting of a detosylation and a palladium-cata-
lysed intramolecular amination reaction of 2-bromophenyl
N-tosyl-2-pyrrolyl ketones 1 for the synthesis of fluorazones
2 (Scheme 1). The required precursors 1 can be easily ob-
tained by regioselective acylation of N-tosylpyrroles[9] with
2-bromobenzoic acid derivatives in the presence of TFAA.
With the same substrates 1, palladium-catalysed intra-
9H-Pyrrolo[1,2-a]indol-9-one (fluorazone) and its ana-
logues have shown a wide range of biological activities.[1]
Moreover, fluorazone itself is the key precursor to the cyto-
static mitomycin family.[2] Among the many strategies de-
veloped to date for the synthesis of fluorazones, the most
appealing seems to be the intramolecular acylation of 2-
(pyrrol-1-yl)benzoic acid derivatives.[3] However, this route
requires multiple steps, including the transformation of 2-
aminobenzoic acids into 2-aminobenzoate derivatives,
Clauson–Kaas pyrrole synthesis, ester hydrolysis to reveal
the free carboxylic acid functionalities (in most cases fol-
lowed by activation to an acyl chloride), and cyclization.
Other less well-proven methods include the palladium-cata-
lysed cyclocarbonylation of N-(2-iodophenyl)pyrrole,[4] the molecular C–H activation followed by detosylation would
direct double metallation of N-phenylpyrrole followed by result in the formation of isomeric indeno[2,1-b]pyrrol-8-
treatment of the resulting dilithium salt with ethyl N,N- ones 3. Fluorenone analogues of this type have barely been
dimethylcarbamate,[5] the hydrolysis of 9-arylimino-9H- reported in the literature, although many examples are
pyrrolo[1,2-a]indoles, which in turn were obtained by the known in which one or both of the phenyl rings are re-
Scheme 1. Synthesis of 9H-pyrrolo[1,2-a]indol-9-ones 2 and isomeric indeno[2,1-b]pyrrol-8-ones 3.
placed by other heterocycles, such as thiophene, benzothio-
[a] College of Chemistry and Molecular Engineering, Zhengzhou phene, furan, benzofuran, indole, etc.[1a,2,3e,4,10]
University,
100 Science Avenue, Zhengzhou 450001, P. R. of China
E-mail: chjsong@zzu.edu.cn
Results and Discussion
changjunbiao@zzu.edu.cn
http://hxx.zzu.edu.cn
The palladium-catalysed intramolecular C–H activation
reaction was examined first. Pd(OAc)2 was found to be the
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejoc.201300737.
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S. Wang, Q. Yang, J. Dong, C. Li, L. Sun, C. Song, J. Chang
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best catalyst. In the presence of Pd(OAc)2, Ph3P, and
K2CO3 in DMF as solvent, a variety of 2-bromophenyl N-
tosyl-2-pyrrolyl ketones including those with sterically hin-
dered (1b), electron-donating (1c), or electron-withdrawing
(1d) substituents on the phenyl ring, as well as those with a
5-aryl-substituted pyrrolyl moiety (1e–g) underwent a one-
pot palladium-catalysed C–H activation/detosylation reac-
tion to give indeno[2,1-b]pyrrol-8-ones 3a–g in moderate to
good isolated yields (Scheme 2).[9e] When substrates with a
fluorinated phenyl ring (1h, 1i) were subjected to the same
reaction conditions, instead of indeno[2,1-b]pyrrol-8-ones,
the corresponding 9H-pyrrolo[1,2-a]indol-9-ones (i.e., 2h
and 2i) were isolated in 55 and 25% yields, respectively
(Scheme 3). It appears that the presence of a fluorine atom
on the phenyl ring hampered the oxidative addition process,
and 2h and 2i were produced by sequential deprotection of
the tosyl group and in situ palladium-catalysed intramolec-
ular amination reaction.[11] This was further confirmed by
the fact that only 9H-pyrrolo[1,2-a]indol-9-one 2a (see
Scheme 4) was obtained when 2-bromophenyl pyrrol-2-yl
ketone was subjected to the same reaction conditions.[9e]
Scheme 4. One-pot detosylation/Pd(PPh3)4-catalysed intramo-
lecular amination for the synthesis of 9H-pyrrolo[1,2-a]indol-9-
ones 2a–i.
different regioselectivity observed with the different catalyst
might be due to the ability of the acetate anion from
Pd(OAc)2 to facilitate the oxidative addition process.
Conclusions
We have developed
a valuable approach to 9H-
pyrrolo[1,2-a]indol-9-ones and isomeric indeno[2,1-b]-
pyrrol-8-ones by subjecting the same substrates to different
palladium catalysts. The former compounds were produced
in a one-pot detosylation/palladium-catalysed intramolecu-
lar amination reaction, the latter by a palladium-catalysed
C–H activation/detosylation sequence.
Scheme 2. One-pot Pd(OAc)2-catalysed C–H activation/detosyl-
ation for the synthesis of indeno[2,1-b]pyrrol-8-ones 3a–g.
Experimental Section
General Remarks: Solvents were dried according to standard pro-
cedures where necessary. Melting points were determined with an
XT4A hot-stage apparatus. IR spectra were obtained with an
IFS25 FTIR spectrometer. 1H and 13C NMR spectra were obtained
with Bruker AV300 or AV400 instruments. Mass spectra were re-
corded with a Micromass Q-TOF mass spectrometer.
General Procedure for the Synthesis of Compounds 2a–i: A mixture
of 1a–i (1.0 mmol), Pd(PPh3)4 (0.01 mmol), and Cs2CO3
(2.0 mmol) in dry DMF (20 mL) under N2 was heated to 120 °C
for 12 h, and then the mixture was allowed to cool. The mixture
was partitioned between EtOAc (100 mL) and H2O (200 mL). The
separated aqueous phase was extracted with EtOAc (3ϫ 100 mL).
The combined organic extracts were washed with brine (200 mL),
then dried (Na2SO4) and filtered, and the solvents were evaporated.
The residue was purified by column chromatography.
Scheme 3. One-pot detosylation/Pd(OAc)2-catalysed intramo-
lecular amination for the synthesis of 9H-pyrrolo[1,2-a]indol-9-
ones 2h and 2i.
The above results indicated that a one-pot detosylation/
palladium-catalysed intramolecular amination of other 2-
bromophenyl N-tosyl-2-pyrrolyl ketones to produce 9H-
pyrrolo[1,2-a]indol-9-ones is possible if a suitable catalyst,
which can efficiently catalyse the amination reaction but
not the C–H activation, is used. When Pd(PPh3)2Cl2 or
Pd2(dba)3 were tested as catalysts under a variety of condi-
tions, they failed to deliver either indeno[2,1-b]pyrrol-8-
ones or indeno[2,1-b]pyrrol-8-ones in acceptable yields. To
our delight, when Pd(PPh3)4 was used as catalyst, the one-
pot reaction proceeded smoothly with all the 2-bro-
mophenyl N-tosyl-2-pyrrolyl ketones tested (i.e., 1a–i) to
give 9H-pyrrolo[1,2-a]indol-9-ones 2a–i in moderate to
good isolated yields, uncontaminated by the corresponding
9H-Pyrrolo[1,2-a]indol-9-one (2a): Yellow solid (78%); m.p. 112–
113 °C (ref.[5] m.p. 121–122 °C). IR: ν = 1681, 1617, 1546, 1478,
˜
1469, 1449, 1403, 1359, 1338, 1262, 1181, 1076 cm–1. 1H NMR
(400 MHz, [D6]DMSO): δ = 6.38 (t, J = 3.2 Hz, 1 H), 6.84 (d, J =
4.0 Hz, 1 H), 7.21 (td, J = 7.2, 1.2 Hz, 1 H), 7.52–7.61 (m, 3 H),
7.68 (d, J = 2.8 Hz, 1 H) ppm. 13C NMR (100 MHz, [D6]DMSO):
δ = 111.2, 113.8, 115.7, 121.6, 123.6, 125.4, 129.0, 130.5, 134.6,
143.1, 178.4 ppm. MS (ESI): m/z (%) = 192 (50) [M + Na]+, 170
(100) [M + H]+. HRMS: calcd. for C11H8NO [M + H]+ 170.0606;
found 170.0589.
5-Methyl-9H-pyrrolo[1,2-a]indol-9-one (2b): Yellow solid (75%);
indeno[2,1-b]pyrrol-8-ones (Scheme 4). We assume that the m.p. 129–132 °C (ref.[3a] m.p. 137–139 °C). 1H NMR (400 MHz,
7632
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Palladium-Catalysed Synthesis of N-Heterocycles
CDCl3): δ = 2.43 (s, 3 H), 6.27 (dd, J = 3.6, 2.7 Hz, 1 H), 6.80 (d, H), 7.04–7.14 (m, 3 H), 7.27 (dd, J = 7.2, 2.4 Hz, 1 H) ppm. 13C
J = 3.6 Hz, 1 H), 7.03 (t, J = 7.6 Hz, 1 H), 7.13 (d, J = 2.7 Hz, 1
H), 7.16 (d, J = 7.6 Hz, 1 H), 7.38 (d, J = 7.6 Hz, 1 H) ppm. 13C
NMR (100 MHz, CDCl3): δ = 17.5, 113.3, 115.6, 121.8, 122.04,
122.2, 125.2, 130.1, 132.1, 136.7, 142.0, 179.8 ppm. MS (ESI): m/z
NMR (75 MHz, CDCl3): δ = 110.7 (d, J = 7.5 Hz), 111.7 (d, J =
22.5 Hz), 114.4, 115.6, 119.4, 119.7, 131.4 (d, J = 7.5 Hz), 131.9,
139.3, 160.3 (d, J = 244.5 Hz), 177.6 ppm. MS (ESI): m/z (%) =
210 (100) [M + Na]+, 188 (17) [M + H]+. HRMS: calcd. for
(%) = 206 (100) [M + Na]+, 184 (38) [M + H]+. HRMS: calcd. for C11H6FNNaO [M + Na]+ 210.0331; found 210.0339.
C12H10NO [M + H]+ 184.0726; found 184.0749.
6-Fluoro-9H-pyrrolo[1,2-a]indol-9-one (2i): Yellow solid (25%); m.p.
7-Methoxy-9H-pyrrolo[1,2-a]indol-9-one (2c): Yellow solid (74%);
121–123 °C. ν = 1682, 1617, 1528, 1484, 1434, 1400, 1361, 1297,
˜
m.p. 120–121 °C (ref.[3a] m.p. 124–125 °C). 1H NMR (300 MHz,
1244, 1201, 1134, 1066 cm–1. 1H NMR (300 MHz, CDCl3): δ =
CDCl3): δ = 3.79 (s, 3 H), 6.23 (dd, J = 3.6, 2.7 Hz, 1 H), 6.74 (d, 6.33 (dd, J = 3.6, 2.7 Hz, 1 H), 6.78–6.87 (m, 3 H), 7.06 (m, 1 H),
J = 3.6 Hz, 1 H), 6.89 (dd, J = 8.4, 2.7 Hz, 1 H), 7.00 (m, 2 H),
7.56 (dd, J = 8.4, 5.4 Hz, 1 H) ppm. 13C NMR (75 MHz, CDCl3):
7.11 (d, J = 2.7 Hz, 1 H) ppm. 13C NMR (75 MHz, CDCl3): δ = δ = 99.1 (d, J = 28.5 Hz), 111.4 (d, J = 22.5 Hz), 113.8, 115.9,
55.8, 109.6, 110.9, 114.1, 115.3, 119.2, 119.5, 131.5, 132.1, 137.3, 119.0, 125.8 (d, J = 7.5 Hz), 132.1, 145.1 (d, J = 12.6 Hz), 166.3
157.8, 179.4 ppm. MS (ESI): m/z (%) = 222 (100) [M + Na]+, 200 (d, J = 244.5 Hz), 177.8 ppm. MS (ESI): m/z (%) = 210 (100) [M
(28) [M + H]+. HRMS: calcd. for C12H9NNaO2 [M + Na]+
222.0531; found 222.0540.
+ Na]+, 188 (47) [M + H]+ HRMS: calcd. for C11H6FNNaO [M +
Na]+ 210.0331; found 210.0331.
7-Nitro-9H-pyrrolo[1,2-a]indol-9-one (2d): Yellow solid (66%); m.p.
198–200 °C (ref.[3a] m.p. 200–201 °C). 1H NMR (300 MHz, [D6]-
DMSO): δ = 6.49 (dd, J = 3.6, 2.7 Hz, 1 H), 6.99 (d, J = 3.6 Hz,
General Procedure for the Synthesis of Compounds 3a–g: A mixture
of 1a–g (1.0 mmol), Pd(OAc)2 (0.05 mmol), PPh3 (0.1 mmol), and
K2CO3 (3.0 mmol) in dry DMF (20 mL) under N2 was heated to
1 H), 7.48 (d, J = 8.4 Hz, 1 H), 7.81 (d, J = 2.7 Hz, 1 H), 8.12 (d, 120 °C for 11 h, and then the mixture was allowed to cool. The
J = 2.1 Hz, 1 H), 8.48 (dd, J = 8.4, 2.1 Hz) ppm. 13C NMR
(75 MHz, [D6]DMSO): δ = 112.2, 116.2, 17.9, 118.9, 123.3, 130.2,
mixture was partitioned between EtOAc (100 mL) and H2O
(200 mL). The separated aqueous phase was extracted with EtOAc
131.0, 132.1, 145.0, 147.1, 176.1 ppm. MS (ESI): m/z (%) = 237 (3ϫ 100 mL). The combined organic extracts were washed with
(71) [M + Na]+, 215 (100) [M + H]+. HRMS: calcd. for C11H7N2O3 brine (200 mL), then dried (Na2SO4) and filtered, and the solvents
[M + H]+ 215.0457; found 215.0455.
were evaporated. The residue was purified by column chromatog-
raphy.
3-Phenyl-9H-pyrrolo[1,2-a]indol-9-one (2e): Yellow solid (50%);
m.p. 91–92 °C. ν = 1690, 1612, 1540, 1515, 1474, 1448, 1391, 1354,
Indeno[2,1-b]pyrrol-8(1H)-one (3a): Red solid (80%); m.p. 205–
206 °C. ν = 3222, 1690, 1632, 1607, 1509, 1450, 1357, 1319, 1272,
˜
˜
1338, 1310, 1267, 1237, 1216 cm–1. 1H NMR (300 MHz, CDCl3):
δ = 6.27 (d, J = 3.9 Hz, 1 H), 6.86 (d, J = 3.9 Hz, 1 H), 6.95 (d, J 1098 cm–1. 1H NMR (300 MHz, [D6]DMSO): δ = 6.19 (m, 1 H),
= 7.8 Hz, 1 H), 7.09 (t, J = 7.8 Hz, 1 H), 7.26 (td, J = 7.8, 1.2 Hz,
6.99–7.27 (m, 5 H), 12.00 (s, 1 H) ppm. 13C NMR (75 MHz, [D6]-
1 H), 7.49–7.62 (m, 6 H) ppm. 13C NMR (75 MHz, CDCl3): δ = DMSO): δ = 103.8, 119.0, 122.6, 126.9, 131.2, 131.7, 133.2, 138.0,
111.8, 114.0, 116.3, 123.9, 124.9, 128.3, 128.7, 128.8, 130.4, 132.7,
133.6, 137.5, 143.8, 178.8 ppm. MS (ESI): m/z (%) = 268 (26) [M
+ Na]+, 246 (100) [M + H]+. HRMS: calcd. for C11H12NO [M +
H]+ 246.0919; found 246.0932.
139.1, 142.9, 180.0 ppm. MS (ESI): m/z (%) = 192 (100) [M +
Na]+, 170 (53) [M + H]+. HRMS: calcd. for C11H7NNaO [M +
Na]+ 192.0425; found 192.0416.
4-Methylindeno[2,1-b]pyrrol-8(1H)-one (3b): Red solid (77%); m.p.
3-(4-Fluorophenyl)-9H-pyrrolo[1,2-a]indol-9-one (2f): Yellow solid
198–200 °C. ν = 3180, 1690, 1677, 1607, 1599, 1474, 1462, 1394,
˜
1
(55%); m.p. 162–164 °C. ν = 1689, 1613, 1546, 1522, 1478, 1442,
1357, 1322 cm–1. H NMR (300 MHz, [D6]DMSO): δ = 2.23 (s, 3
˜
1418, 1384, 1353, 1311, 1267, 1238, 1218, 1158, 1101, 1072 cm–1.
H), 6.19 (m, 1 H), 6.88–7.10 (m 4 H), 12.00 (s, 1 H) ppm. 13C
NMR (75 MHz, [D6]DMSO): δ = 17.8, 105.0, 120.2, 126.9, 129.1,
1H NMR (300 MHz, CDCl3): δ = 6.26 (d, J = 3.6 Hz, 1 H), 6.86–
6.88 (m, 2 H), 7.10 (td, J = 8.1, 0.6 Hz, 1 H), 7.20–7.29 (m, 3 H), 130.9, 131.4, 134.9, 137.2, 137.8, 142.5, 180.2 ppm. MS (ESI): m/z
7.56–7.63 (m 3 H) ppm. 13C NMR (75 MHz, CDCl3): δ = 111.5,
113.9, 115.3, 115.9 (d, J = 45.0 Hz), 124.1, 125.0, 126.5 (d, J =
3.0 Hz), 130.3, 130.5 (d, J = 7.5 Hz), 132.6, 133.6, 136.1, 143.6,
162.8 (d, J = 225.0 Hz), 178.7 ppm. MS (ESI): m/z (%) = 286 (100)
[M + Na]+, 264 (55) [M + H]+. HRMS: calcd. for C17H11FNO [M
+ H]+ 264.0825; found 264.0795.
(%) = 206 (100) [M + Na]+, 184 (100) [M + H]+. HRMS: calcd.
for C12H10NO [M + H]+ 184.0762; found 184.0747.
6-Methoxyindeno[2,1-b]pyrrol-8(1H)-one (3c): Red solid (55%);
m.p. 198–200 °C. ν = 3162, 1679, 1618, 1513, 1463, 1431, 1365,
˜
1313, 1277, 1259, 1215, 1193 cm–1. 1H NMR (300 MHz, [D6]-
DMSO): δ = 3.72 (s, 3 H), 6.09 (m, 1 H), 6.67 (dd, J = 7.8, 2.4 Hz,
1 H), 6.76 (d, J = 2.4 Hz, 1 H), 6.93 (d, J = 7.8 Hz, 1 H), 7.63 (t,
J = 2.4 Hz), 11.91 (s, 1 H) ppm. 13C NMR (75 MHz, [D6]DMSO):
δ = 55.4, 103.4, 111.3, 114.9, 119.7, 130.9, 131.4, 131.5, 140.3,
143.8, 158.9, 179.2 ppm. MS (ESI): m/z (%) = 222 (100) [M +
Na]+, 200 (18) [M + H]+. HRMS: calcd. for C12H9NNaO2 [M +
3-(4-Methoxyphenyl)-9H-pyrrolo[1,2-a]indol-9-one (2g): Yellow so-
lid (54%); m.p. 152–154 °C. ν = 1681, 1606, 1580, 1546, 1504, 1458,
˜
1417, 1373, 1327, 1312, 1294, 1246, 1185, 1157, 1114, 1071 cm–1.
1H NMR (300 MHz, CDCl3): δ = 3.92 (s, 3 H), 6.23 (d, J = 3.9 Hz,
1 H), 6.86 (d, J = 3.9 Hz, 1 H), 6.97 (d, J = 7.8 Hz, 1 H), 7.04 (d,
J = 8.4 Hz, 2 H), 7.10 (t, J = 7.8 Hz, 1 H), 7.27 (t, J = 7.8 Hz, 1 Na]+ 222.0531; found 222.0540.
H), 7.52 (d, J = 8.4 Hz, 2 H), 7.61 (d, J = 7.8 Hz, 1 H) ppm. 13C
6-Nitroindeno[2,1-b]pyrrol-8(1H)-one (3d): Red solid (54%); m.p.
NMR (75 MHz, CDCl3): δ = 55.0, 111.7, 113.7, 114.2, 115.9, 122.7,
123.9, 124.8, 130.1, 130.6, 132.4, 133.5, 137.6, 143.8, 160.0,
178.7 ppm. MS (ESI): m/z (%) = 298 (100) [M + Na]+, 276 (60) [M
+ H]+. HRMS: calcd. for C18H14NO2 [M + H]+ 276.1025; found
276.1009.
252–254 °C. ν = 3119, 1682, 1617, 1528, 1484, 1400, 1361, 1337,
˜
1
1297, 1273, 1244, 1201 cm–1. H NMR (300 MHz, [D6]DMSO): δ
= 6.28 (d, J = 2.7 Hz, 1 H), 7.04 (d, J = 2.7 Hz, 1 H), 7.24 (dd, J
= 8.1, 0.9 Hz, 1 H), 7.80 (m, 1 H), 8.25 (m, 1 H), 12.22 (s, 1 H)
ppm. 13C NMR (75 MHz, [D6]DMSO): δ = 105.9, 116.9, 117.2,
126.2, 128.2, 130.0, 140.3, 141.7, 146.6, 148.3, 182.8 ppm. MS
(ESI): m/z (%) = 237 (100) [M + Na]+, 215 (80) [M + H]+. HRMS:
calcd. for C11H6N2NaO3 [M + Na]+ 237.0276; found 237.0282.
7-Fluoro-9H-pyrrolo[1,2-a]indol-9-one (2h): Yellow solid (32%);
m.p. 118–119 °C (ref.[3a] m.p. 124 °C). 1H NMR (300 MHz,
CDCl3): δ = 6.30 (dd, J = 3.6, 2.7 Hz, 1 H), 6.80 (d, J = 3.6 Hz, 1
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[2] V.-S. Li, D. Choi, Z. Wang, L. S. Jimenez, M.-S. Tang, H.
Kohn, J. Am. Chem. Soc. 1996, 118, 2326–2331.
2-Phenylindeno[2,1-b]pyrrol-8(1H)-one (3e): Red solid (47%); m.p.
219–221 °C. ν = 3196, 1682, 1605, 1541, 1503, 1455, 1357, 1419,
˜
[3] a) F. Aiello, A. Garofalo, F. Grande, Tetrahedron Lett. 2010,
51, 6635–6636; F. Aiello, A. Garofalo, F. Grande, Tetrahedron
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Tetrahedron 2010, 66, 274–277; b) A. D. Josey, E. L. Jenner, J.
Org. Chem. 1962, 27, 2466–2470; c) V. J. Mazzola, K. F.
Bernady, R. W. Franck, J. Org. Chem. 1967, 32, 486–489; d)
A. S. Bailey, P. W. Scott, M. H. Vandrevala, J. Chem. Soc. Per-
kin Trans. 1 1980, 97–101; e) V. Lisowki, S. Léonce, L. Kraus-
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D.-H. Caignard, P. Renard, S. Rault, J. Med. Chem. 2004, 47,
1448–1464.
1382, 1318, 1289, 1274, 1246 cm–1. 1H NMR (300 MHz, [D6]-
DMSO): δ = 6.74 (s, 1 H), 7.05–7.12 (m, 2 H), 7.21–7.46 (m, 3 H),
7.43 (t, J = 7.2 Hz, 2 H), 7.80 (d, J = 7.2 Hz, 2 H), 12.47 (s, 1 H)
ppm. 13C NMR (75 MHz, [D6]DMSO): δ = 101.7, 119.1, 122.5,
124.9, 127.2, 128.1, 128.9, 131.0, 132.5, 133.1, 138.2, 138.6, 143.7,
143.8, 179.7 ppm. MS (ESI): m/z (%) = 268 (60) [M + Na]+, 246
(100) [M + H]+. HRMS: calcd. for C11H12NO [M + H]+ 246.0919;
found 246.0921.
2-(4-Fluorophenyl)indeno[2,1-b]pyrrol-8(1H)-one (3f): Red solid
(63%); m.p. 263–265 °C. ν = 3192, 1678, 1604, 1548, 1504, 1456,
˜
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5620.
1419, 1324, 1291, 12775, 1246, 1162, 1129, 1072 cm–1. 1H NMR
(300 MHz, [D6]DMSO): δ = 6.71 (s, 1 H), 7.02–7.09 (m, 2 H), 7.17–
7.30 (m, 4 H), 7.79–7.84 (m, 2 H), 12.42 (s, 1 H) ppm. 13C NMR
(75 MHz, [D6]DMSO): δ = 101.9, 116.0, 116.3, 119.3, 122.7, 127.2
(d, J = 7.5 Hz), 127.4, 127.8 (d, J = 3.0 Hz), 132.6, 133.3, 138.5 (d,
J = 32.0 Hz), 142.8, 143.9, 161.9 (d, J = 244.5 Hz), 179.9 ppm. MS
(ESI): m/z (%) = 264 (100) [M + H]+. HRMS: calcd. for
C17H11FNO [M + H]+ 264.0825; found 264.0798.
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5479.
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rikawa, H. Konishi, Tetrahedron 2007, 63, 4356–4359.
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Chem. 2008, 120, 6438–6461; Angew. Chem. Int. Ed. 2008, 47,
6338–6361.
2-(4-Methoxyphenyl)indeno[2,1-b]pyrrol-8(1H)-one (3g): Red solid
[9] a) C. Song, D. W. Knight, M. A. Whatton, Tetrahedron Lett.
2004, 45, 9573–9576; b) C. Song, P. Zhao, Y. Liu, H. Liu, W.
Li, S. Shi, J. Chang, Tetrahedron 2010, 66, 5378–5383; c) C.
Song, Y. Liu, P. Zhao, X. Sun, W. Li, H. Liu, J. Chang, Synthe-
sis 2011, 45–50; d) M. Hong, H. Liu, L. Sun, F. Jia, Y. Liu, Q.
Jiang, C. Song, J. Chang, Synlett 2011, 2995–2996; e) J. Chang,
L. Sun, J. Dong, Z. Shen, Y. Zhang, J. Wu, R. Wang, J. Wang,
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5320; b) A. P. Kozikowski, D. Ma, Tetrahedron Lett. 1991, 32,
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T. Uemura, K. Yamashita, Heterocycles 2003, 60, 405–411; e)
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rion, C. L. Cara, O. Cruz-Lopez, M. Tolomeo, S. Grimaudo,
A. D. Cristina, M. R. Pipitone, J. Balzarini, N. Zonta, A. Bran-
cale, E. Hamel, Bioorg. Med. Chem. 2009, 17, 6862–6871; g)
P. J. Perry, M. A. Read, R. T. Davies, S. M. Gowan, A. P.
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1999, 42, 2679–2684; h) M. L. Greenlee, J. B. Laub, G. P.
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lof, G. G. Hammond, Bioorg. Med. Chem. Lett. 1999, 9, 3225–
3230; i) S. J. Gould, C. R. Melville, M. C. Cone, J. Chen, J. R.
Carney, J. Org. Chem. 1997, 62, 320–324.
(47%); m.p. 257–258 °C. ν = 3191, 1681, 1606, 1580, 1546, 1504,
˜
1458, 1417, 1373, 1327, 1312, 1294, 1246, 1185 cm–1. 1H NMR
(300 MHz, [D6]DMSO): δ = 3.79 (s, 3 H), 6.63 (s, 1 H), 6.99 (d, J
= 8.7 Hz, 2 H), 7.05–7.09 (m, 2 H), 7.17 (d, J = 7.5 Hz, 1 H), 7.25
(t, J = 7.5 Hz, 1 H), 7.73 (d, J = 8.7 Hz, 2 H), 12.28 (s, 1 H) ppm.
13C NMR (75 MHz, [D6]DMSO): δ = 55.3, 100.9, 114.5, 119.0,
122.3, 123.6, 126.5, 127.2, 131.8, 133.0, 138.4, 138.5, 144.1, 144.2,
159.3, 179.2 ppm. MS (ESI): m/z (%) = 298 (53) [M + Na]+, 276
(100) [M + H]+. HRMS: calcd. for C18H14NO2 [M + H]+ 276.1025;
found 276.0995.
Supporting Information (see footnote on the first page of this arti-
1
cle): Copies of the H and 13C NMR spectra of compounds 2a–i
and 3a–g.
Acknowledgments
We are grateful to the National Natural Science Foundation of
China (Grant Nos. 20902085 and 21172202) for financial support.
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Received: May 18, 2013
Published Online: October 2, 2013
7634
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Eur. J. Org. Chem. 2013, 7631–7634