tm
Mar-Apr 2006
479
Selectfluor : A Simple and Efficient Catalyst
[2] R. D. H. Murray, J. Medez, S. A. Brown, The Natural
Coumarins: Occurrence, Chemistry and Biochemistry, Wiley: New
York (1982).
[3] M. Maeda, Laser Dyes, Academic Press: New York
(1984).
temperature, we carried out several experiments at
various temperatures under solvent-free conditions.
The best result was obtained with 0.5:1:1 molar ratio
TM
of selectfluor , resorcinol and ethylacetoacetate
respectively at 120 °C.
In conclusion, we have demonstrated a simple, cost-
effective and efficient alternative method for the prepara-
[4] L. A. Singer, N. P. Kong, J. Am. Chem. Soc., 88, 5213
(1966).
[5] S. M. Sethna, N. M. Shah, Chem. Rev., 36, 1 (1945).
[6] S. M. Sethna, R. Phadke, Org. React., 7, 1 (1953).
[7a] G. Jones, Org. React., 15, 204 (1967); [b] F. Bigi, L.
Chesini, R. Maggi, G. Sartori, J. Org. Chem., 1033 (1999).
[8] R. L. Shirner, Org. React., 1, 1 (1942).
[9a] N. S. Narasimhan, R. S. Mali, M. V. Barve, Synthesis, 906
(1979); [b] I. Yavari, R. Hekmat-Shoar, A. Zonousi, Tetrahedron
Lett., 39, 2391 (1998).
tion of substituted coumarins via Pechmann condensation
TM
using selectfluor
as catalyst. Prominent among the
advantages of this method are operational simplicity, good
yields in short reaction times, solvent-free conditions, and
easy workup procedure employed.
[10a] H. J. Appel, Chem. Soc., 1031 (1935); [b] L. L. Woods, J.
Sapp, J. Org. Chem., 27, 3703 (1962); [c] Z. S. Ahmed, R. D. Desai,
Proc. Indian. Acad. Sci., 5a, 277 (1937); Chem. Abstr., 31, 5785
(1937); [d] R. Robinson, F. J. Weygand, J. Chem. Soc., 386 (1941).
[11] E. V. O. John, S. S. Israelstam, J. Org. Chem., 26, 240
(1961).
[12a] A. J. Hoefnagel, E. A. Gennewagh, R. S. Downing, H. V.
Bekkum, J. Chem. Soc. Chem. Commun., 225 (1995); [b] R.
Pankajkumar Singh, U. Devendrapratap Singh, D. Shriniwas Samant,
Synlett, 11, 1909 (2004).
[13a] V. Singh, J. Singh, K. P. Kaur, G. L. Kad, J. Chem. Res.,
Synop. 58 (1997); [b] J. Singh, J. Kaur, S. Nayyar, G. L. Kad, J.
Chem. Res. Synop. 280 (1998); [c] A. de la Hoz, A. Moreno, E.
Vazquez, Synlett, 608 (1999); [d] S. Frere, V. Thiery, T. Besson,
Tetrahedron Lett., 42, 2791 (2001).
EXPERIMENTAL
General Procedure.
To the weighed quantity of phenol (10 mmol) and β-ketoester
TM
(10 mmol), the selectfluor
(5 mmol) was added and the reac-
tion mixture was stirred at 120 °C. After completion of the reac-
tion at the desired time as indicated in Table, the reaction mixture
was poured into cold water and the resultant product was col-
lected by filtration. The products were further purified by col-
umn chromatography. All the compounds are well known and in
agreement with spectral and physical data.
Acknowledgement.
[14] C. Amit Khandekar, M. Bhushan Khadilkar, Synlett, 1,
152 (2002).
[15] A. Russell, J. R. Frye, Org. Synth., 21, 22 (1941).
[16a] H. Simmonis, P. Remmert, Chem. Ber., 47, 2229 (1914);
[b] A. Robertson, W. F. Sandrock, C. B. Henry, J. Chem. Soc., 2426
(1931).
The authors are thankful to UGC, New Delhi for financial
assistance and to the director, IICT, Hyderabad for H NMR and
mass spectral analysis.
1
REFERENCES AND NOTES
[17a] J. Liu, C. H. Wong, Tetrahedron Lett., 43, 3915 (2002); [b]
J. Liu, C. H. Wong, Tetrahedron Lett., 43, 4037 (2002); [c] J. S.
Yadav, B. V. S. Reddy, Ch. Srinivas Reddy, Tetrahedron Lett., 45,
1291 (2004).
[1] R.O. Kennedy, R. D. Thornes, Coumarins: Biology,
Applications and Mode of Action, Wiley and Sons: Chichester
(1997).