SYNTHESIS OF METHYL 3,6-DIOXO-endo-TRICYCLO[6.2.1.02,7]UNDECA-.. .
349
1
350 ml of 5% hydrochloric acid, and extracted with
ether (3 250 ml). The combined extracts were
as an oily substance. IR spectrum (CCl4), , cm :
3050 w, 2950 s, 1745 s, 1685 v.s, 1230 s, 1200 m,
washed with water, dried over magnesium sulfate, and 920 w, 840 w, 700 s. H NMR spectrum (CDCl3), ,
1
evaporated on a rotary evaporator. The residue was
recrystallized from water. Yield 11 g (65 mmol, 94%),
mp 86 87 C; published data [11]: mp 88 C. IR spec-
ppm: 6.23 br.s (2H, 4-H, 5-H), 5.58 6.16 m (2H, 9-H,
10-H), 3.66 s (3H, OCH3), 3.33 m (2H, 1-H, 8-H),
2.80 m (1H, 7-H), 0.9 1.6 m (2H, 11-H). Mass spec-
trum, m/z (Irel, %): 232 M+ (0.39), 168 (17.5), 150
1
trum (KBr), , cm : 3320 v.s, 3010 m, 2930 m,
1685 v.s, 1615 s, 1500 m, 1220 s, 1185 s, 810 w, (4.85), 137 (13.19), 136 (50.54), 108 (30.87), 91
1
870 s, 680 s. H NMR spectrum (CDCl3), , ppm:
10.17 s (1H), 7.20 s (1H), 6.85 m (2H), 5.0 s (1H),
3.9 s (3H).
(2.7), 66 (9.3), 59 (7.90).
The authors are grateful to the Research Council
of the Guilan University for financial support.
Methyl 3,6-dioxo-1,4-cyclohexadienecarboxylate
(XXII). Anhydrous Na2CO3, 5 g (36.2 mmol), and
freshly prepared Ag2O, 7.5 g (32.4 mmol), were added
to a solution of ester XXI, 2.5 g (14.9 mmol), in
25 ml of toluene. The mixture was heated in the dark
to 60 C, stirred for 1 h at that temperature, and fil-
tered while hot (in the dark), and the precipitate was
washed with 50 ml of hot toluene. The filtrate was
dried over K2CO3 and evaporated under reduced
pressure, and the residue was recrystallized from
dry carbon disulfide. Yield 57%, yellow crystals,
mp 50 52 C; published data [12]: mp 53.5 54 C. IR
REFERENCES
1. Balaci, M., Sutbeyaz, Y., and Secen, H., Tetra-
hedron, 1990, vol. 46, p. 3715.
2. Zwanenburg, B., Mgani, Q., Klunder, A.J.H., and
Nknuya, M.H.H., Tetrahedron Lett., 1995, vol. 36,
p. 4660.
3. Ley, S.V. and Yeung, L.L., Synlett., 1992, p. 997.
4. Nakajima, M., Tomida, I., and Takei, S., Chem. Ber.,
1959, vol. 90, p. 246.
5. Nakajima, M., Tomida, I., and Takei, S., Chem. Ber.,
1
spectrum (CS2), , cm : 2950 m, 2800 m, 1645 s,
1660 v.s, 1360 s, 1045 m, 850 s.
1959, vol. 92, p. 163.
6. Knapp, S., Ornaf, R.M., and Rodriques, K.E., J. Am.
Chem. Soc., 1983, vol. 105, p. 5494.
Methyl 3,6-dioxo-endo-tricyclo[6.2.1.02,7]undeca-
4,9-diene-2-carboxylate (VIII). A solution of 0.44 g
(6.66 mmol) of freshly distilled cyclopentadiene in
5 ml of toluene was added to a cold (0 C) solution of
1.02 g (6.66 mmol) of quinone XXII in 25 ml of
toluene. The mixture was allowed to warm up to room
temperature and was stirred for 12 h. The solvent was
removed under reduced pressure, and the residue was
subjected to column chromatography using hexane
ethyl acetate (3:2) as eluent. A fraction containing
the target product and traces of ester XXI was col-
lected. The latter was removed by dissolving the
product in Et2O and shaking the solution with 5%
aqueous sodium hydroxide. The ether solution was
washed with water, dried over MgSO4, and evaporated
to obtain 0.3 g (1.3 mmol, 21%) of compound VIII
7. Marchand, A.P. and Allen, R.W., J. Org. Chem.,
1974, vol. 39, p. 1596.
8. Klunder, A.J.H., de Valk, W.C.G.M., Verlaak, J.M.J.,
Schellekens, J.W.M., Noordik, J.H., Parthasarathi, V.,
and Zwanenburg, B., Tetrahedron, 1985, vol. 41,
p. 963.
9. Zhu, J., Klunder, A.J.H., and Zwanenburg, B., Tetra-
hedron, 1995, vol. 51, no. 17, p. 5099.
10. Zwanenburg, B., Dols, P.M.A., Verstappen, M.M.H.,
and Klunder, A.J.H., Tetrahedron, 1993, vol. 49,
p. 11353.
11. Dictionary of Organic Compounds, London: Chap-
man and Hall, 1982, 5th ed.
12. Cason, J., Org. React., 1948, vol. 4, p. 354.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 38 No. 3 2002