Solventless Pechmann condensation of various phenols with crotonic acid, malic acid, fumaric acid or maleic acid, using sulfuric acid or anhydrous zinc chloride under microwave irradiation yielded coumarins and chromanones.
ParkO.S., and JangB. S.Arch, Pharm. Res.1995, 18, 277.
2.
BuckleD.R., CantelloB. C. C., SmithH., and SpicerB. A., J. Med. Chem., 1975, 18, 726.
3.
(a) StinsonS.Use of microwave heating to speed organic reactions continues to grow, Chem. Eng. News, 1996, 73, 45; (b) D. M. P. Mingos and D. R. Baghurst, Chem. Soc. Rev., 1991, 20, 1; (c) A. Loupy, Spectra Analyt., 1993, 22, 175, 33; (d) C. R. Strauss and R. W. Trainor, Aust. J. Chem. 1995, 48, 1665; (e) S. Caddick, Tetrahedron, 1995, 38, 10403; (f) S. A. Galema, Chem. Soc. Rev., 1997, 26, 233; (g) R. S. Verma, Green Chemistry, February, 1999, 43; (h) L. Perreux and A. Loupy, Tetrahedron, 2001, 57, 9199; (i) P. Lidstrom, J. Tierney, B. Wathey and J. Westman, Tetrahedron, 2001, 57, 9225.
