Carbanion cleavage in 3-benzoylcyclopropane-1,1,2,2-tetracarbonitrile effected by alcoholates

Full text of DOI:10.1134/S1070428007100296

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2007, Vol. 43, No. 10, pp. 1565−1566. © Pleiades Publishing, Ltd., 2007.
Original Russian Text © I.N. Bardasov, O.V. Kayukova, Ya.S. Kayukov, O.V. Ershov, O.E. Nasakin, M.Yu. Belikov, 2007, published in Zhurnal
Organicheskoi Khimii, 2007, Vol. 43, No. 10, pp. 1568−1569.
SHORT
COMMUNICATIONS
Carbanion Cleavage
in 3-Benzoylcyclopropane-1,1,2,2-tetracarbonitrile Effected
by Alcoholates
I. N. Bardasov, O. V. Kayukova, Ya. S. Kayukov, O. V. Ershov, O. E. Nasakin, and M. Yu. Belikov
Ulyanov Chuvash State University, Cheboksary, 428015 Russia
e-mail: barkas12@mail.ru
Received April 25, 2007
DOI: 10.1134/S1070428007100296
Tetracyanocyclopropanes containing five or six
electron-withdrawing groups are known to be prone to
chemical reactions with nucleophilic reagnts, therewith
reactions with hard nucleophiles, alcohols or oximes,
occur prevailingly at cyano or acyl groups with retention
of the cyclopropane ring, and with soft nucleophiles, with
the opening of the cycle. However in contrast to this
general trend in some reactions with alcoholates and
oximates the cycle opening was observed leading to the
formation of furan [1–3] or pyrroline [4] derivatives.
A similar transformation we found studying reactions of
3-benzoylcyclopropane-1,1,2,2-tetracarbonitrile (I) [5]
with alcoholates.
2-phenylfuran-3(2H)-ylidene]malononitriles IIa–IIc
were obtained in 90–95% yield (see Scheme).
The structure of dehydrofurans IIa–IIc obtained was
confirmed by IR, 1H NMR, and mass spectra.
In the first stage of the mechanism we presume the
alcoholate acting as a base abstracts a sufficiently acidic
hydrogen from the cyclopropane ring providing a cyclo-
propyl carbanion A. Further the cycle opening follows
which may be regarded either as a three-centered four-
electron electrocyclic reaction or as electrophilic carb-
anion cleavage resulting in propenoid B stabilized by
resonance. The process completes by the formation of
furan derivative D via intermediate hemiketal C. The
final reaction products, dehydrofurans IIa–IIc, arise at
neutralizing the reaction mixture with sulfuric acid .
In reaction of compound I with sodium alcoholate in
the corresponding alcohol [2-alkoxy-5-amino-4-cyano-
Scheme.
O
CN
O
NC
O
H
NC
NC
CN
CN
CN
RO_
_ROH
CN
CN
_
CN
CN
NC
NC
А
B
I
CN
CN
CN
OH
NC
RO
NC
CN
CN
CN
H2SO4
ROH
NH
NH2
O
O
RO
RO
IIа_IIc
NC
C
D
R = CH3 (a), CH2CH2OH (b), CH2CH3 (c).
1565

BARDASOV et al.
1566
ppm: 10.35 s (2H, NH2), 7.5 m (5H, C6H5), 3.75 q (2H,
[5-Amino-4-cyano-2-methoxy-2-phenylfuran-
OCH2CH3), 1.3 t (3H, OCH2CH3). Mass spectrum, m/z
(Irel, %): 292 (30). Found, %: C 65.78; H 4.10; N 19.10.
C16H12N4O2. Calculated, %: C 65.75; H 4.14; N 19.17.
3(2H)-ylidene]malononitrile (IIa). To a solution of
1.08 g (0.02 mol) of sodium methylate in 10 ml of
methanol was added at stirring a dispersion of 2.46 g
(0.01 mol) of compound I in 10 ml of methanol. The
stirring was continued till the completion of the reaction
(TLC monitoring). Then the reaction mixture was
neutralized with 5% sulfuric acid solution and extracted
with ethyl acetate. The organic layer was dried with
calcined sodium sulfate, the solvent was distilled off,
the residue was ground with 10 ml of water. The
precipitate was filtered off and washed with water. Yield
2.36 g (90%), mp 138–139°C (decomp.) (ethyl acetate–
hexane). IR spectrum, ν, cm–1: 1683 (C=C), 2225 (C≡N),
The purity of compounds synthesized was checked
by TLC on Silufol UV-254 plates, development under
UV irradiation, in iodine vapor, and by thermal treatment.
IR spectra were recorded on an IR Fourier spectrometer
FSM-1202 from thin films (or mulls in mineral oil).
1H NMR spectra were registered on a spectrometer
Bruker DRX-500, operating frequency 500.13 MHz,
solvent DMSO-d6, internal reference TMS. Mass spectra
were measured on a Finnigan MAT INCOS-50 instrument
(electron impact, 70 eV).
1
3140, 3280 (NH2). H NMR spectrum, δ, ppm: 10.35 s
(2H, NH2), 7.5 m (5H, C6H5), 3.5 m (3H, OCH3). Mass
spectrum, m/z (Irel, %): 278 (30). Found, %: C 64.55;
H 3.66; N 20.10. C15H10N4O2. Calculated, %: C 64.74;
H 3.62; N 20.13.
REFERENCES
1. Yashkanova, O.V., Nasakin, O.E., Urman, Ya.G.,
Khrustalev, V.N., Antipin, M.Yu., Lukin, P.M., and
Vershinin, E.V., Zh. Org. Khim., 1997, vol. 33, p. 542.
2. Yashkanova, O.V., Lukin, P.M., Nasakin, O.E., Khrusta-
lev, V.N., Nesterov, V.N.,Antipin, M.Yu., and Urman, Ya.G.,
Zh. Org. Khim., 1997, vol. 33, p. 533.
3. Kayukova, O.V., Kayukov, Ya.S., Lukin, P.M., Nasa-
kin, O.E., Khrustalev, V.N., Nesterov, V.N., and Anti-
pin, M.Yu., Khim. Geterotsikl. Soedin., 1998, p. 170.
4. Siaka, S., Lukin, P.M., Nasakin, O.E., Khrustalev, V.N.,
Nesterov, V.N.,Antipin, M.Yu., and Pul’kherovskaya, O.V.,
Zh. Org. Khim., 1997, vol. 33, p. 905.
Compounds IIb and IIc were similarly prepared.
[5-Amino-4-cyano-2-(2-hydroxyethyloxy)-2-
phenylfuran-3(2H)-ylidene]malononitrile (IIb). Yield
(95%), mp 132–133°C (decomp.). IR spectrum, ν, cm–1:
1685 (C=C), 2223 (C≡N), 3150, 3270 (NH2). 1H NMR
spectrum, δ, ppm: 10.35 s (2H, NH2), 7.45–7.55 m (5H,
C6H5), 4.9 t (1H, OCH2CH2OH), 3.6–3.7 m (4H,
OCH2CH2OH). Mass spectrum, m/z (Irel, %): 308 (10).
Found, %: C 62.37 H 3.94; N 18.20. C16H12N4O3.
Calculated, %: C 62.33; H 3.92; N 18.17.
[5-Amino-4-cyano-2-ethoxy-2-phenylfuran-3(2H)-
ylidene]malononitrile (IIc). Yield (90%), mp 155–
156°C (decomp.). IR spectrum, ν, cm–1: 1681 (C=C),
2226 (C≡N), 3160, 3280 (NH2). 1H NMR spectrum, δ,
5. Sheverdov, V.P., Ershov, O.V., Nasakin, O.E., Selyuni-
na, E.V., Tikhonova, I.G., Chernushkin, A.N., and Khrus-
talev, V.N., Zh. Obshch. Khim., 2000, vol. 70, p. 1334.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 43 No. 10 2007