2-Hydroxy-2-methyl-2H-1-benzopyran-3-carboxamide Derivatives produced by Knoevenagel Condensation†

Abstract

The reaction of 2-hydroxybenzaldehydes with 3-oxobutanamide affords 2,4-dihydroxy-2-methyl-2H-3,4-dihydro-1-benzopyran-3-car boxamides and 2-hydroxy-2-methyl-2H-1-benzopyran-3-carboxamides, depending on the particular aldehyde and the experimental conditions used.

References

1. E. E. Schwiezer and D. Meeher-Nycz, in Chromenes, Chromanones and Chromones, ed. G. P. Ellis, Wiley, New York, 1977, p. 29.
2. See, e.g. K. Mukai, J. Kageyama, T. Ishida and K. Fukuda, J. Org. Chem., 1989, 54, 552; T. Rosenan and W. D. Habicher, Synlett., 1996, 427.
3. T. R. Kasturi and T. Manithomas, Tetrahedron Lett., 1967, 2573; D. R. Boyd, N. D. Sharma, R. Boyle, T. A. Evans, J. F. Malone, K. M. McCombe, H. Dalton and J. Chima, J. Chem. Soc., Perkin Trans. 1, 1966, 1757.
4. See, e.g., F. Cassidy, J. M. Evans, M. S. Hadley, A. H. Haladi, P. E. Leach and G. Stemp, J. Med. Chem., 1992, 35, 1623.
5. cf. C. J. Roxburgh, Synthesis, 1996, 307.
6. G. Jones, Org. React. (N.Y.), 1967, 15, 204.
7. C. N. O'Callaghan, T. B. H. McMurry and C. J. Cardin, J. Chem. Res., 1990, (S) 132; (M) 0901.
8. C. N. O'Callaghan and T. B. H. McMurry, J. Chem. Res., 1989, (S) 329; (M) 2501.
9. W. D. Cotterill, D. A. Johnston and R. Livingstone, J. Chem. Res., 1995, (S) 226; (M) 1466.
10. N. P. Buu-Hoi, T. B. Loc and N. D. Xuong, Bull. Soc. Chim. Fr., 1957, 561.
11. P. Czerney, H. Hartmann and J. Liebscher, Ger. (East) Pat. 140,252, 1980(Chem. Abstr., 1980, 93, 114 327).
12. E. Knoevenagel and R. Schroeter, Ber. Dtsch. Chem. Ges., 1904, 37, 4484.