1
482
Vol. 56, No. 10
Table 3. Effect of Solvent on the Reaction Times, Yields and Molar Ratio
of Products 5a and 6
Acknowledgements We gratefully acknowledge financial support of the
Research Council of Shahid Beheshti University.
a)
Yield (%)
References
Entry
Solvent
1) Jones G., “Organic Reactions,” Vol. 15, 1967, pp. 204—599.
2) Tietze L. F., Beifuss U., “Comprehensive Organic Synthesis,” Vol. 2,
ed. by Trost B. M., Fleming I., Heatheak C. H., Pergamon Press, Ox-
ford, 1991, pp. 341—394.
3) Freeman F., Chem. Rev., 80, 329—350 (1981).
4) Tietze L. F., Chem. Rev., 96, 115—136 (1996).
5) Ayoubi S. A. E., Texier-Boullet F., Hamelin J., Synthesis, 1994, 258—
260 (1994).
5
a
6
1
2
3
4
5
H O
90 min
12 h
12 h
12 h
12 h
95
50
40
0
0
2
EtOH
10
20
0
CH CN
3
CH Cl
2
2
C H CH
0
0
6
5
3
6)
7)
8)
9)
Binev I. G., Binev Y. G., Stamboliyska B. A., Juchnovski I. N., J. Mol.
Struct., 435, 235—239 (1997).
Brufola G., Fringuelli F., Piermatti O., Pizzo F., Heterocycles, 45,
a) Tetracyanoethylene (1.0 mmol), 4-methoxybenzaldehyde (1.0 mmol), and Mel-
drum’s acid (10 mol%) at 80 °C in various organic solvents.
1
715—1721 (1997).
Prajapati D., Lekhok K. C., Sandhu J. S., Ghosh A. C., J. Chem. Soc.,
Perkin Trans. 1, 1996, 959—960 (1996).
Bose D. S., Narsaiah A. V., J. Chem. Res., 2001, 36—38 (2001).
1
1
0) Reddy T. I., Verma R. S., Tetrahedron Lett., 38, 1721—1724 (1997).
1) Kubota Y., Nishizaki Y., Ikeya H., Saeki M., Hida T., Kawazu S.,
Yoshida M., Fuji H., Sugi Y., Microporous Mesoporous Mater., 70,
1
35—149 (2004).
1
1
1
1
2) Bennazha J., Zahouilly M., Boukhari A., Hol E. A., J. Mol. Catal. A:
Chem., 202, 247—252 (2003).
3) Harjani J. R., Nara S. J., Salunkhe M. M., Tetrahedron Lett., 43,
1
127—1130 (2002).
4) Khan F. A., Dash J., Satapathy R., Upadhyaya S. K., Tetrahedron Lett.,
5, 3055—3058 (2004).
5) Breslow R., Rideout D. C., J. Am. Chem. Soc., 102, 7816—7817
1980).
4
(
1
1
1
1
6) Breslow R., Acc. Chem. Res., 24, 159—164 (1991).
7) Sheldon R., Chem. Ind., 1997, 12—15 (1997).
8) Fatiadi A. J., Synthesis, 1987, 749—789 (1987).
9) Fatiadi A. J., Synthesis, 1987, 959–978 (1987).
Chart 3. Proposed Mechanism
20) Dhar D. N., Chem. Rev., 67, 611—622 (1967).
2
2
1) Shaabani A., Rahmati A., Rezayan A. H., Darvishi M., Badri Z., Sar-
vary A., QSAR Comb. Sci., 26, 973—979 (2007).
2) Shaabani A., Soleimani E., Rezayan A. H., Tetrahedron Lett., 48,
2185—2188 (2007).
matic aldehydes with tetracyanoethylene in the presence of
Meldrum’s acid has not yet been established experimentally,
a possible explanation is proposed in Chart 3. It is reasonable 23) Shaabani A., Soleimani E., Rezayan A. H., Sarvari. A., Org. Lett., 10,
2
581—2584 (2008).
4) Shaabani A., Soleimani E., Rezayan A. H., Tetrahedron Lett., 48,
137—6141 (2007).
to assume that intermediate 7 is formed from the initial at-
tack of the Meldrum’s acid on the tetracyanoethylene. Inter-
mediate 7 rearranges to generate malononitrile 8 and inter-
mediate 9, which condensation of malononitrile 9 with aryl-
2
2
6
5) Shaabani A., Maleki A., Moghimi-Rad J., J. Org. Chem., 72, 6309—
6311 (2007).
benzaldehyde to produce the product 5. Intermediate 9 in the 26) Shaabani A., Rezayan A. H., Rahmati A., Sarvary A., Synlett, 2007,
1
458—1460 (2007).
presence of water is converted to intermediate 10, then, elim-
inating of 2-oxomalononitrile 11 from it to regenerate the
Meldrum’s acid under the reaction conditions.
2
2
2
3
3
7) Shaabani A., Rezayan A. H., Sarvary A., Khavasi H. R., Tetrahedron
Lett., 49, 1469—1472 (2008).
8) Shaabani A., Rezayan A. H., Sarvary A., Rahmati A., Synth.
Commun., 38, 274—281 (2008).
9) Shaabani A., Rezayan A. H., Sarvary A., Rahmati A., Khavasi H. R.,
Catal. Commun., 9, 1082—1086 (2008).
0) Rao S. P., Venkataratnam R. V., Tetrahedron Lett., 32, 5821—5822
Conclusions
In conclusion, we have demonstrated a very simple and
highly efficient approach for the condensation of aromatic,
heteroaromatic, and conjugated aldehydes with tetracyano-
ethylene in water to give Knoevenagel products in good
yields within 90 min at 80 °C. The work-up procedure is very
simple. To the best of our knowledge this is the first report on
the synthesis of arylidenemalononitrile using Meldrum’s acid
as a catalyst. Further on reactivity studies and synthetic ap-
(1991).
1) Moison H., Texier-Boullet F., Foucaud A., Tetrahedron, 43, 537—542
(1987).
2) Ford J. A., Wilson, C. V., J. Org. Chem., 26, 1433—1437 (1961).
3) Song A., Wang X., Lam K. S., Tetrahedron Lett., 44, 1755—1758
3
3
(2003).
3
4) Leelavathi P., Ramesh Kumar S., J. Mol. Catal. A: Chem., 240, 99—
102 (2005).
plication of this methodology are in progress in our labora- 35) Hayashi M., Nakamura N., Yamashita K., Tetrahedron, 60, 6777—
6
783 (2004).
tory.