5-Bromo-2,3-diphenyl-1-vinyl-1H-pyrrole and 2,3,5-triphenyl-1-vinyl-1H- pyrrole

Full text of DOI:10.1134/S1070428008090273

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2008, Vol. 44, No. 9, pp. 1397–1398. © Pleiades Publishing, Ltd., 2008.
Original Russian Text © B.A. Trofimov, O.V. Petrova, L.N. Sobenina, A.I. Mikhaleva, 2008, published in Zhurnal Organicheskoi Khimii, 2008, Vol. 44,
No. 9, pp. 1414–1415.
SHORT
COMMUNICATIONS
5-Bromo-2,3-diphenyl-1-vinyl-1H-pyrrole and 2,3,5-Triphenyl-
1-vinyl-1H-pyrrole
B. A. Trofimov, O. V. Petrova, L. N. Sobenina, and A. I. Mikhaleva
Favorskii Irkutsk Institute of Chemistry, Siberian Division, Russian Academy of Sciences,
ul. Favorskogo 1, Irkutsk, 664033 Russia
e-mail: boris_trofimov@irioch.irk.ru
Received March 17, 2008
DOI: 10.1134/S1070428008090273
1-Vinylpyrroles are promising as monomers for the
preparation of materials for photoelectronics, as well
as highly reactive building blocks for the synthesis of
various pyrrole derivatives [1]. 1-Vinylpyrroles having
several aryl substituents and polymers derived there-
from attract specific attention due to their enhanced
ability to transmit electronic excitation. In addition, di-
and triarylpyrroles exhibit specific biological activity,
and they are widely used in the design of hypo-
glycemic and antisclerotic drugs (an example is
atorvastatin) [2].
vinyl group in the initial compound remained intact
(Scheme 1).
Bromopyrrole II can be used as base compound for
the preparation of various 5-substituted 2,3-diphenyl-
1-vinyl-1H-pyrroles, including 5-aryl-2,3-diphenyl-1-
vinyl-1H-pyrroles, via cross coupling and nucleophilic
substitution reactions. As an example, we describe here
palladium-catalyzed cross-coupling of bromopyrrole II
with phenylmagnesium bromide according to the pro-
cedure reported in [7] (Scheme 2). As catalyst we used
[1,1′-bis(diphenylphosphino)ferrocene]palladium(II)
chloride (PdCl2·dppf). The yield of 2,3,5-triphenyl-1-
vinyl-1H-pyrrole (III) was 75%.
1-Vinylpyrroles are commonly prepared by vinyla-
tion of NH-pyrroles with acetylene [3] or by one-pot
Trofimov reaction from ketone oximes and acetylene
[1, 4]. However, introduction of an aryl substituent into
the 5-position of the pyrrole ring (provided that the
2-position is already occupied) involves difficulties:
for example, the yield of 2,5-diphenylpyrrole from
acetophenone oxime and phenylacetylene is as poor as
17% [5]. We have found that accessible 2,3-diphenyl-
1-vinyl-1H-pyrrole (I) [4] can be used as initial com-
pound for the synthesis of 5-substituted 2,3-diphenyl-
1-vinyl-1H-pyrroles. Pyrrole I was selectively bromi-
nated at C5 by the action of N-bromosuccinimide under
the conditions described in [6] to give 5-bromo-2,3-
diphenyl-1-vinyl-1H-pyrrole (II) in 65% yield, i.e., the
Scheme 2.
Ph
+
PhMgBr
Ph
Br
CH2
N
II
Ph
PdCl2–dppf, THF, 60–63°C
Ph
Ph
CH2
N
III
Scheme 1.
Ph
Ph
5-Bromo-2,3-diphenyl-1-vinyl-1H-pyrrole (II).
A solution of 1.227 g (5.0 mmol) of 2,3-diphenyl-1-
vinyl-1H-pyrrole (I) in 20 ml of THF was cooled to
10–12°C, 1.068 g (6.0 mmol) of N-bromosuccinimide
was added, and the mixture was stirred until it became
homogeneous (10–15 min) and kept for 18 h in the
NBS, THF, 8–12°C
Ph
Ph
Br
CH2
N
N
CH2
I
II
1397

TROFIMOV et al.
1398
cold (8–10°C). Sodium sulfate, 1.00 g, was then added,
the solvent was removed under reduced pressure, the
residue was treated with 5 ml of carbon tetrachloride,
and the precipitate was filtered off and washed with
3 ml of carbon tetrachloride. The solvent was removed
from the filtrate, and the residue was purified by
chromatography on aluminum oxide using petroleum
ether (bp 40–70°C) as eluent. Yield 1.05 g (65%),
ppm: 136.6, 135.1, 134.1, 133.7, 132.5, 132.1, 130.1,
129.2, 129.1, 128.9, 128.5, 127.9, 126.4, 124.9, 112.1,
109.7. Found, %: C 89.86; H 5.92; N 4.20. C24H19N.
Calculated, %: C 89.68; H 5.96; N 4.36.
The H and 13C NMR spectra were recorded from
solutions in CDCl3 on a Bruker DPX 400 instrument at
400.13 and 100.6 MHz, respectively, using HMDS as
internal reference.
1
1
mp 70–71°C (from hexane). H NMR spectrum, δ,
ppm: 7.40 m (3H, Harom), 7.24 m (2H, Harom), 7.15 m
(2H, Harom), 7.10 m (3H, Harom), 6.62 d.d (1H, HX, J =
9.0, 15.6 Hz), 6.51 s (1H, 4-H), 4.98 d (1H, HA, J =
9.0 Hz), 4.96 d (1H, HB, J = 15.6 Hz). 13C NMR spec-
trum, δC, ppm: 135.9, 133.1, 132.2, 132.0, 131.6,
129.3, 129.0, 128.9, 128.8, 126.8, 113.8, 111.4. Found,
%: C 66.46; H 4.25; Br 24.98; N 4.38. C18H14BrN.
Calculated, %: C 66.68; H 4.35; Br 24.65; N 4.32.
REFERENCES
1. Trofimov, B.A. and Mikhaleva, A.I., N-Vinilpirroly
(N-Vinylpyrroles), Novosibirsk: Nauka, 1984; Trofi-
mov, B.A., Adv. Heterocycl. Chem., 1990, vol. 51, p. 177;
Trofimov, B.A., Pyrroles. Part 2. The Synthesis, Reac-
tivity, and Physical Properties of Substituted Pyrroles,
Jones, R.A., Ed., New York: Wiley, 1992, p. 131.
2. Bellina, F. and Rossi, R., Tetrahedron, 2006, vol. 62,
2,3,5-Triphenyl-1-vinyl-1H-pyrrole (III).
5-Bromo-2,3-diphenyl-1-vinyl-1H-pyrrole (II), 1.85 g
(5.7 mmol), was dissolved in 5 ml of THF, 0.042 g
(5.7×10–5 mmol) of PdCl2·dppf and 13.2 ml of a 1 M
solution of phenylmagnesium bromide in THF were
added under argon, and the mixture was heated for 3 h
at 60–63°C. The mixture was cooled, diluted with
water (1:3), and extracted with diethyl ether. The ex-
tract was dried over Na2SO4 and evaporated, and the
residue was subjected to column chromatography on
Al2O3 using hexane as eluent. Yield 1.37 g (75%),
p. 7213.
3. Trofimov, B.A., Mikhaleva, A.I., Korostova, S.E., Vasil’-
ev, A.N., and Balabanova, L.N., Khim. Geterotsikl.
Soedin., 1977, p. 213; Trofimov, B.A., Korostova, S.E.,
Shevchenko, S.G., Polubentsev, E.A, and Mikhaleva, A.I.,
Zh. Org. Khim., 1990, vol. 26, p. 1110.
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Mikhaleva, A.I., Zh. Org. Khim., 1978, vol. 14, p. 2182.
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Kalabin, G.A., Khim. Geterotsikl. Soedin., 1977, p. 994;
Korostova, S.E., Mikhaleva, A.I., Trofimov, B.A., Shev-
chenko, S.G., and Sigalov, M.V., Khim. Geterotsikl.
Soedin., 1992, p. 485.
1
mp 141–142°C. H NMR spectrum, δ, ppm: 7.49 m
(2H, Harom), 7.38–7.30 m (7H, Harom), 7.17 m (5H,
6. Gilow, H.M. and Burton, D.E., J. Org. Chem., 1981,
Harom), 7.09 m (1H, Harom), 6.67 d.d (1H, HX, J = 8.8,
vol. 46, p. 2221.
15.8 Hz), 6.50 s (1H, 4-H), 4.70 d (1H, HA, J = 8.8 Hz),
4.46 d (1H, HB, J = 15.8 Hz). C NMR spectrum, δC,
7. Bumagin, N.A., Sokolova, A.F., Beletskaya, I.P., and
13
Vol’ts, G., Zh. Org. Khim., 1993, vol. 29, p. 162.
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