A Novel Method for the Synthesis of Disubstituted Ureas and Thioureas Under Microwave Irradiaton

Abstract

Several symmetrically disubstituted ureas and thioureas are synthesized by heating of urea or thiourea with aromatic amines or phenylhydrazine under environmentally benign conditions without any solvent in a conventional microwave oven.

References

1. A. F. M. Iqbal, Helv. Chim. Acta, 1976, 59, 655; K. Matsuda, Med. Res. Rev., 1994, 14, 271.
2. S. Liu, C. Tang, B. Ho, M. Ankersen, C. E. Stidsen and A. M. Crider, J. Med. Chem., 1998, 41, 4094.
3. F. Bigi, R. Maggi, G. Sartori and E. Zambonin, Chem. Commun., 1998, 513.
4. B. Thavonekham, Synthesis, 1997, 1189.
5. J. D. Armstrong, III, C. N. Wolfe, J. L. Keller, J. Lynch, M. Bhupathy and R. P. Volante, Tetrahedron Lett., 1997, 38, 1531.
6. M. Mikolajczyk and P. Kielbasinski, Tetrahedron, 1981, 37, 233.
7. Encyclopedia of Reagents for Organic Synthesis, ed L. A. Paquette, 1995, Chichester, vol. 7, p. 4683.
8. D. Xu, L. Ciszewski, T. Li, O. Repic and T. J. Blacklock, Tetrahedron Lett., 1998, 39, 1107 and references cited therein.
9. M. Ballabeni, R. Ballini, F. Bigi, R. Maggi, M. Parrini, G. Predierti and G. Sartori, J. Org. Chem., 1999, 64, 1029.
10. F. Bigi, B. Frullanti, R. Maggi, G. Sartori and E. Zambonin, J. Org. Chem., 1999, 64, 1004.
11. S. Caddick, Tetrahedron, 1995, 38, 10403; R. A. Abramovich, Org. Prep. Proced. Int., 1991, 23, 638; D. M. P. Mingos and D. R. Baghu Orust, Chem Soc. Rev., 1991, 20, 1.
12. A. Sharifi, M. M. Mojtahedi and M. R. Saidi, Tetrahedron Lett., 1999, 40, 1179; M. R. Saidi and K. Bigdeli, J. Chem. Res. (S), 1998, 800.
13. Dictionary of Organic Compounds, Chapman and Hall, New York, 5th edn., 4th supplement, 1986, B-01660, B-40114, D-07817 and D-08201.