C᎐CH), 6.19 (1H, d, J 12.0, C᎐CH), 6.61 (2H, m, C᎐CH), 7.05–
With DDQ. A solution of ethyl 1-ethoxycarbonyl-2,5-bis(3-
᎐
᎐
᎐
7.32 (18H, m, Ar-H); m/z 365 (Mϩ 5c, 1%), 363 (Mϩ, 7), 361
(Mϩ, 13), 332 (5), 316 (13), 300 (8), 293 (Mϩ 5a, 15%), 288
(100), 264 (8), 220 (51). Fraction three gave a mixture of the
methyl esters 5b and 5d as a yellow oil (0.016 g); δH(270 MHz,
CDCl3) 3.67 (3H, s, CH3), 3.69 (3H, s, CH3), 4.1 (4H, br s,
NH ), 6.07 (1H, d, J 11.9, C᎐CH), 6.17 (1H, d, J 12.0, C᎐CH),
nitrophenyl)imidazolidine-4-carboxylate (syn-exo) 7i (0.22 g,
0.46 mmol) and DDQ (0.10 g, 0.46 mmol) was refluxed in tolu-
ene (cm3) for 12 h. The solvent was evaporated and the residue
was purified using column chromatography on silica, eluting
with ethyl acetate–light petroleum (40–60 ЊC), to give 15 as a
pale yellow oil (0.154 g, 71%) (Found: MHϩ, 471.152. Calc. for
᎐
᎐
2
6.60 (1H, d, J 11.9, C᎐CH), 6.63 (1H, d, J 11.9, C᎐CH), (18H,
C22H23N4O8: M, 471.152); νmax(liquid film)/cmϪ1 1739 (C᎐O),
᎐
᎐
᎐
m, Ar-H); m/z 351 (Mϩ 5d, 11%), 349 (Mϩ, 69), 347 (Mϩ 5b, 97),
332 (19), 316 (9), 300 (5), 288 (100), 279 (Mϩ, 30%), 264 (8), 179
(19).
1608 (C᎐C), 1531 and 1446 (NO ); δ (CDCl ) 1.18 (3H, t, J 7.0,
᎐
2
H
3
CH3), 1.37 (3H, t, J 7.0, CH3), 3.70 (1H, d, J 17.8, CHaN), 3.96
(1H, d, J 17.8, CHbN), 4.09 (2H, q, J 7.3, OCH2), 4.30 (2H, m,
OCH2), 4.64 (1H, d, J 9.2, H-4), 5.24 (1H, d, J 9.2, H-5), 7.62–
7.74 (2H, m, Ar-5ЈH), 7.85 (1H, d, J 7.9, Ar-6ЈH), 8.07 (1H, d,
J 7.9, Ar-6ЈH), 8.24 (1H, dd, J 7.9, 1.3, Ar-4ЈH), 8.31–8.38 (2H,
m, Ar-2ЈH and 4ЈH), 8.53 (1H, s, Ar-2ЈH); δC(68 MHz, CDCl3)
13.8 (CH3), 14.0 (CH3), 49.4 (CH2), 61.2 (CH2), 61.3 (CH2),
64.5 (CH), 67.2 (CH), 123.6 (CH), 124.0 (CH), 125.1 (quat.),
125.5 (CH), 127.8 (CH), 127.9 (quat.), 128.2 (CH), 128.5 (CH),
128.8 (CH), 129.0 (CH), 129.2 (quat.), 132.4 (quat.), 134.0
(quat.), 170.5 (quat. C᎐O), 173.0 (quat., C᎐O); m/z 471 (MHϩ,
Ethyl 1-ethoxycarbonyl-2,5-bis(3-nitrophenyl)imidazolidine-4-
carboxylate 7i
N-(Ethoxycarbonylmethyl)-3-nitrophenylmethanimine 2i (0.24
g, 1.02 mmol) was dissolved in anhydrous acetonitrile (20 cm3)
and MgClO4 (0.33 g, 1.5 mmol) was added, with stirring. The
reaction mixture was stirred for 24 h, and the reaction quenched
with sat. NH4Cl solution (20 cm3). The organic layer was separ-
ated and the aqueous phase extracted with diethyl ether (3 × 20
cm3). The combined organic extracts were dried (MgSO4) and
the solvent evaporated under reduced pressure to give a white
semi-solid (0.21 g, 88%), which was purified by column chroma-
tography on silica, eluting with ethyl acetate–light petroleum
(40–60 ЊC) (0:100 to 30:70), to give two fractions. Fraction one
gave the syn-exo isomer 7i as a colourless oil (78 mg, 33%)
᎐
᎐
97), 441 (13), 420 (14), 397 (100), 367 (12), 323 (9), 237 (11), 41
(62).
Acknowledgements
We thank the EPSRC for a studentship (T. S.), the University
of Sunderland for funding (A. A., I. G. and M. N.), and the
EPSRC National Mass Spectrometry Service Centre, Swansea,
for high resolution mass spectra.
(Found: Mϩ, 472.157. Calc. for C22H24N4O8: M, 472.159); νmax
(liquid film)/cmϪ1 3320 (NH), 2923 (CH), 2854 (CH), 1735
(C᎐O), 1531 (C᎐C); δ (270 MHz, CDCl ) 1.21 (3H, t, J 6.6,
-
᎐
᎐
H
3
CH3), 1.29 (3H, t, J 6.6, CH3), 3.23 (1H, d, J 17.0, CHa), 3.32
(1H, d, J 17.0, CHb), 3.87 (1H, d, J 6.6, H-4), 4.12 (2H, q, J 6.6,
CH2), 4.21–4.37 (2H, 2 × dq, CH2), 4.62 (1H, d, J 6.6, H-5),
5.35 (1H, s, H-2), 7.61 (1H, t, J 7.9, Ar-5ЈH), 7.62 (1H, t, J 7.9,
Ar-5ЈH), 7.91 (1H, d, J 7.9, Ar-6ЈH), 7.97 (1H, d, J 7.9,
Ar-6ЈH), 8.22 (2H, m, 2 × Ar-4ЈH), 8.36 (1H, d, J 2, Ar-2ЈH),
8.47 (1H, d, J 2, Ar-2ЈH); δC(68 MHz, CDCl3) 14.0 (CH3), 14.1
(CH3), 48.2 (CH2), 60.8 (CH2), 61.7 (CH2), 66.8 (CH), 68.4
(CH), 78.7 (CH), 122.8 (CH), 123.0 (CH), 123.2 (CH), 123.8
(CH), 133.5 (CH), 134.2 (CH), 142.6 (quat.), 143.0 (quat.),
References
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4 T. Takita, T. Tamura and H. Taniyama, J. Biochem., 1977, 81, 1759.
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6 P. W. Groundwater, T. Sharif, A. Arany, D. E. Hibbs, M. B.
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1789.
148.5 (2 × quat.), 169.7 (quat., C᎐O), 171.8 (quat., C᎐O); m/z
᎐
᎐
472 (Mϩ, 5%), 443 (32), 399 (61), 385 (82), 237 (100), 163 (95),
117 (76). Fraction two gave the syn-endo isomer 7iЈ as a white
solid (25 mg, 10%), mp 123–125 ЊC (Found: Mϩ, 472.158. Calc.
for C22H24N4O8: M, 472.159); νmax(liquid film)/cmϪ1 1724
(C᎐O), 1527 (C᎐C); δ (270 MHz, CDCl ) 0.87 (3H, t, J 7.3,
᎐
᎐
H
3
CH3), 1.20 (3H, t, J 7.2, CH3), 3.25 (1H, d, J 17, CHa), 3.39 (1H,
d, J 17, CHb), 3.55 (1H, dq, CHaЈ), 3.80 (1H, dq, CHaЈ), 4.08
(2H, q, J 7.3, CH2), 4.50 (1H, d, J 9.0, H-4), 4.87 (1H, d, J 9.0,
H-5), 5.27 (1H, s, H-2), 7.57 (1H, t, J 7.9, Ar-5ЈH), 7.69 (1H, t,
J 7.9, Ar-5ЈH), 7.85 (1H, d, J 7.9, Ar-6ЈH), 8.08 (1H, d, J 7.9,
Ar-6ЈH), 8.18 (1H, d, J 7.9, Ar-4ЈH), 8.30 (2H, m, Ar-4ЈH and
Ar-2ЈH), 8.52 (1H, s, Ar-2ЈH); δC(68 MHz, CDCl3) 14.0 (CH3),
14.5 (CH3), 48.6 (CH2), 61.2 (CH2), 61.8 (CH2), 65.1 (CH), 67.4
(CH), 79.6 (CH), 123.6 (2 × CH), 123.7 (CH), 124.7 (CH),
129.8 (CH), 130.6 (CH), 134.4 (CH), 134.5 (CH), 141.0 (quat.),
8 R. Grigg and V. Sridharan, in Advances in Cycloaddition, ed. D. P.
Curran, JAI Press, 1993, vol. 3, p. 161.
9 W. Nagata, T. Wakabayashi and Y. Hayase, Org. Synth., 1988, Coll.
141.8 (quat.), 148.6 (quat.), 149.1 (quat.), 170.2 (quat., C᎐O),
᎐
170.6 (quat., C᎐O); m/z 472 (Mϩ, 21%), 443 (100).
᎐
Vol. VI, 448.
10 R. Grigg, Chem. Soc. Rev., 1987, 16, 89.
11 R. Grigg, H. Q. N. Gunaratne and J. Kemp, J. Chem. Soc., Perkin
Trans. 1, 1984, 41.
12 R. Grigg and H. Q. N. Gunaratne, J. Chem. Soc., Chem. Commun.,
1982, 384.
13 K. Amornraksa, D. Barr, G. Donegan, R. Grigg, P. Ratananukul
and V. Sridharan, Tetrahedron, 1989, 45, 4649.
14 H. Cerecetto, R. Di Maio, M. Gonzalez and G. Seoane,
Heterocycles, 1997, 45, 2023.
15 M. Nyerges, M. Rudas, G. Toth, B. Herenyi, I. Bitter and L. Toke,
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1987, 52, 2523.
Reactions of imidazolidine 7i
With DBU. Ethyl 1-ethoxycarbonyl-2,5-bis(3-nitrophenyl)-
imidazolidine-4-carboxylate 7i,iЈ (0.47 g, 1 mmol) and DBU
(0.15 g, 0.14 cm3, 1 mmol) were dissolved in acetonitrile (10
cm3), with stirring, at room temperature. The mixture was
stirred overnight and the solvent evaporated under reduced
pressure, to give a yellow oil (0.19 g, 80%), which was purified
by wet flash chromatography on silica, eluting with ethyl
acetate–light petroleum (40–60 ЊC) (0:100 to 30:70), to give 5i
as a yellow semi-solid (0.11 g, 51%); spectral analysis showed
that the product was identical to that obtained previously.
J. Chem. Soc., Perkin Trans. 1, 1998
2845