2,3,4-Triphenyl-3-azabicyclo[3.2.0]hepta-1,4-diene
FULL PAPER
2-(1Ј,2Ј,5Ј-triphenyl-3Ј-pyrrolyl)ethyl acetate (6c) was obtained in
73% yield as a colourless powder. M.p. 165.8Ϫ166.5 °C. H NMR
ture, Japan. The authors are also grateful to the Ministry of Edu-
cation, Culture, Sports, Science, and Technology, Japan for pur-
chasing the high-field NMR instruments (JEOL JNM-A500 and
JNM-EX270) through the special fund to KM (Graduate School
of Human and Environmental Studies, Kyoto University) in 1992.
1
(270 MHz, CDCl3): δ ϭ 2.03 (s, 3 H), 2.86 (t, J ϭ 7.3 Hz, 2 H),
4.27 (t, J ϭ 7.3 Hz, 2 H), 6.43 (1 H, s), 6.92Ϫ7.21 (m, 15 H) ppm.
13
C NMR (67.8 MHz, CDCl3): δ ϭ 21.04, 25.84, 65.27, 110.30,
118.29, 126.11, 126.77, 127.75, 127.87, 128.41, 128.75, 130.80,
132.29, 133.03, 133.39, 134.16, 138.89, 171.09 ppm. C25H21NO2
(367.4): calcd. C 81.72, H 5.76, N 3.81; found C 81.55, H 5.69,
N 3.90.
[1]
Part of this work has previously been published as a communi-
cation; see: K. Matsumoto, S. Goto, N. Hayashi, T. Uchida,
A. Kakehi, J. Chem. Soc., Perkin 1 Commun. 1997, 2691.
[2]
R. P. Thummel, Acc. Chem. Res. 1980, 13, 70; B. Halton,
With Methanol: A solution of 5a (20 mg, 0.062 mmol) in methanol
(2 mL) was heated at reflux for 2 weeks. After evaporation of sol-
vent, the residue was recrystallised from dichloromethane/hexane
to afford 3-(2-methoxyethyl)-1,2,5-triphenylpyrrole (6d) as a white
powder in 36% yield (10 mg, 0.028 mmol). M.p. 165.5Ϫ166.5 °C.
1H NMR (270 MHz, CDCl3): δ ϭ 2.82 (t, J ϭ 7.3 Hz, 2 H), 3.25
(s, 3 H), 3.63 (t, J ϭ 7.3 Hz, 2 H), 6.44 (s, 1 H), 6.91Ϫ7.20 (m, 15
H). 13C NMR (67.8 MHz, CDCl3): δ ϭ 26.72, 58.51, 73.57, 110.35,
119.19, 125.97, 126.58, 126.67, 127.66, 127.82, 128.39, 128.75,
130.78, 132.44, 133.15, 134.02, 138.99. C25H23NO (353.5): calcd. C
84.95, H 6.56, N 3.96; found C 84.84, H 6.42, N 4.03.
Chem. Rev. 1973, 73, 113.
[3] [3a]
P. J. Garratt, K. P. C. Vollhardt, J. Am. Chem. Soc. 1972,
94, 7087. [3b] P. J. Garratt, D. N. Nicolaides, J. Org. Chem. 1974,
[3c]
39, 2222.
40, 970.
P. J. Garratt, S. B. Neoh, J. Org. Chem. 1975,
[4]
[4a] B. E. Ayres, S. W. Longworth, J. F. W. McOmie, Tetrahedron
[4b]
1975, 31, 1755.
K. P. C. Vollhardt, R. G. Bergman, J. Am.
Chem. Soc. 1972, 94, 8950; J. Am. Chem. Soc. 1973, 95, 7538.
[4c]
R. G. Bergman, K. P. C. Vollhardt, J. Chem. Soc., Chem.
[4d]
Commun. 1973, 214.
H. Hauptmann, Tetrahedron Lett.
[4e]
1974, 3589.
M. P. Cava, M. V. Lakshmikantham, M.
Behforouz, J. Org. Chem. 1974, 39, 206. [4f] P. Vogel, M. Hardy,
Helv. Chim. Acta 1974, 57, 196.
When the same reaction was performed at room temp. with a cata-
lytic amount of 1 HNO3, 6d was obtained in quantitative yield
(see Table 3).
[5]
[6]
[7]
[5a] P. J. Garratt, S. B. Neoh, J. Am. Chem. Soc. 1975, 97, 3255.
[5b]
P. J. Garratt, S. B. Neoh, J. Org. Chem. 1979, 44, 2667.
K. Matsumoto, H. Iida, T. Uchida, Y. Yabe, A. Kakehi, J. W.
Lown, Can. J. Chem. 1994, 72, 2108.
K. Matsumoto, Y. Kono, T. Uchida, J. Org. Chem. 1977, 42,
1103.
Treatment of 5a with Bromine: A solution of bromine (0.1 mL) in
chloroform (1 mL) was added dropwise to a stirred solution of 5a
(30 mg, 0.093 mmol) in chloroform (2.5 mL). Evaporation of the
solvent in vacuo gave 2-(1Ј,2Ј,5Ј-triphenyl- 3Ј-pyrrolyl)ethyl acetate
2-(4Ј-bromo-1Ј,2Ј,5Ј-triphenyl-3Ј- pyrrolyl)ethyl bromide as a white
[8]
[9]
R. P. Thummel, J. Chem. Soc., Chem. Commun. 1974, 899.
V. V. Dhekne, A. S. Rao, Synth. Commun. 1978, 8, 135.
[10] [10a]
1
S. Borcic, J. D. Roberts, J. Am. Chem. Soc. 1965, 87, 1056.
powder. M.p. 196.0Ϫ197.0 °C (dec). H NMR (270 MHz, CDCl3):
[10b] E. A. Hill, J. D. Roberts, J. Am. Chen. Soc. 1967, 89, 2047.
δ ϭ 3.11 (t, J ϭ 7.8 Hz, 2 H), 3.54 (t, J ϭ 7.8 Hz, 2 H), 6.84Ϫ7.25
(m, 15 H) ppm. 13C NMR (67.8 MHz, CDCl3): δ ϭ 30.01, 31.57,
99.66, 118.99, 127.04, 127.30, 127.53, 127.75, 128.07, 128.41,
128.61, 130.64, 130.89, 131.41, 132.74, 138.20 ppm. C24H19Br2N
(481.2): calcd. C 59.63, H 4.08, N 2.75; found C 59.90, H 3.98,
N 2.91.
[11] [11a]
G. Fraenkel, Y. Asahi, M. J. Mitchel, M. P. Cava, Tetra-
[11b]
hedron 1964, 20, 1179.
H. Hart, J. A. Hartlarger, R. W.
Fish, R. R. Rafos, J. Org. Chem. 1966, 31, 2244.
[12]
The heats of formation of the carbocations 7 and 8 were ob-
tained by use of the CAChe systems (Version 3.7, CAChe
Scientific, Oxford Molecular Group) AM1: M. J. S. Dewar, E.
G. Zoebisch, E. F. Hearly, J. J. P. Stewart, J. Am. Chem. Soc.
1985, 107, 3902; Heat of formation of cation 7: 331.63 kcal/
mol; heat of formation of cation 8: 311.62 kcal/mol; PM3: J. J.
Stewart, J. Comp. Chem. 1989, 10, 209; Heat of formation of
cation 7: 138.21 kcal/mol; heat of formation of cation 8: 120.12
kcal/mol.
R. P. Gandhi, V. K. Chadha, Indian J. Chem. 1971, 9, 305.
H. Prinzbach, R. Fuchs, R. Kitzing, Angew. Chem. Int.
Ed. Engl. 1968, 7, 67.
R. A. Jones, G. P. Bean, The Chemistry of Pyrroles, Academic
Press, London, 1977, chapter 6.
Treatment of 5a with DMAD: A solution of 5a (0.034 g, 0.11 mmol)
and DMAD (0.12 cm3, 1 mmol,) in 1,2-dichlorobenzene (3 mL)
was heated at reflux under argon for 3 h. After evaporation of sol-
vent, the residue was chromatographed on silica gel with hexane/
ethyl acetate as eluent to give the product, which was recrystallised
from ethanol to produce the azepine 13 as orange needles. M.p.
[13] [13a]
[13b]
258.3Ϫ263.0 °C (dec.). 1Η NMR (270 MHz, CDCl3):
δ ϭ
2.97Ϫ3.41 (m, 4 H), 3.55 (s, 3 H), 3.71 (s, 3 H), 6.75Ϫ7.87 (m, 15
H) ppm. 13C NMR (67.8 MHz, CDCl3): δ ϭ 29.22, 29.47, 52.31,
52.42, 112.71, 119.01, 119.68, 127.64, 128.05, 128.27, 128.39,
128.63, 128.68, 129.18, 132.29, 134.20, 134.63, 135.98, 142.05,
145.23, 146.51, 151.11, 165.25, 167.30 ppm. C30H25NO4 (463.5):
calcd. C 77.74, H 5.44, N 3.02; found C 77.80, H 3.08, N 2.99.
[14]
[15]
[16]
[17]
R. M. Acheson, Adv. Heterocycl. Chem. 1965, 1, 125; R. M.
Acheson, N. F. Elmore, Adv. Heterocycl. Chem. 1978, 23, 263.
R. M. Acheson, J. Bridson, T. S. Cameron, J. Chem. Soc., Per-
kin Trans. 1 1972, 968.
The heats of formation of 13, 14, and 15 were obtained by use
of the CAChe systems (Version 4.1.1, Oxford Molecular
Group) AM1: M. J. S. Dewar, E. G. Zoebisch, E. F. Hearly, J.
J. P. Stewart, J. Am. Chem. Soc. 1985, 107, 3902; 5a: 387.12538,
13: 29.70126, 14: 106.03925, 15: 65.75824, 16: 105.80957 kcal/
mol; PM3: J. J. Stewart, J. Comp. Chem. 1989, 10, 209; 5a:
350.41893, 13: 7.75890, 14, 55.42717, 15, 35.09190, 16:
78.16375 kcal/mol. As pointed out by one of the referees, there
are great differences in the heats of formation of a single inter-
mediate by different methods. These values are not absolute in
nature but only of relative comparison.
Crystal Structure Determination for Compound 13: The results were
already reported in a preliminarily communication.[1] CCDC-
207/142 contains the supplementary crystallographic data
for this paper. These data can be obtained free of charge at
www.ccdc.cam.ac.uk/conts/retrieving.html [or from the Cam-
bridge Crystallographic Data Centre, 12 Union Road, Cam-
bridge CB2 1EZ, UK; Fax: ϩ44-1223-336-033; E-mail:
deposit@ccdc.cam.ac.uk].
[18]
[19]
W. D. Ollis, S. P. Stanforth, C. A. Ramsden, Tetrahedron 1985,
41, 2295.
O. Tsuge, S. Kanemasa, Adv. Heterocyclic. Chem. 1989, 45, 231.
Received June 21, 2004
Acknowledgments
This work was supported in part by a Grant-in-Aid for Scientific
Research from the Ministry of Education, Science, Sports and Cul-
Eur. J. Org. Chem. 2004, 4667Ϫ4671
2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
4671