Zn/NH4Cl–mediated reactions of aldehyde 1 with nitro compounds 2 afford 2-(N-alkyl/arylamino)-3-formylchromones 4, which on heating with 70% H2SO4 produces 9a-d and 11e-h from 4a-d and 4e-h, respectively.
AkamaT., ShidaY., SugayaT., IshidaH., GomiK., and KasaiM., J. Med. Chem., 1996, 39, 3461 and references therein.
2.
(a) GamillR.B., JudgeT. M., and MorrisJ., WO 90\06921; (b) M. Mazzei, A. Balbi, G. Roma, M. Di Braccio, G. Leoncini, E. Buzzi, and M. Maresca, Eur. J. Med. Chem., 1988, 23, 237.
3.
(a) ErmilliA., RomaG., MazzeiM., BalbiA., Di BraccioM., SchianterelliP., and CadelS., Farm. Ed. Sci.1974, 29, 225; (b) A. Ermili, M. Mazzei, G. Roma and C. Cacciatore, Farm. Ed. Sci., 1977, 32, 375; (c) A. Ermilli, A. Balbi, M. Di Braccio and G. Roma, Farm. Ed. Sci., 1977, 32, 713.
4.
BantickJ.R., and SuschitzkyJ. L., J. Heterocycl. Chem., 1981, 18, 679.
5.
MorrisJ., WishkaD. G., and FangY., J. Org. Chem., 1992, 57, 6502.
6.
MorrisJ., WishkaD. G., and FangY., Synth. Commun., 1994, 24, 849.
7.
(a) IsharM.P. S., KumarK., and SinghR., Tetrahedron Lett., 1998, 39, 6547; (b) M. P. S. Ishar, G. Singh, K. Kumar and R. Singh, Tetrahedron, 2000, 56, 7818; (c) G. Singh, R. Singh, N. K. Girdhar and M. P. S. Ishar, Tetrahedron, 2002, 58, 2471.
8.
(a) Gautheron-ChapoulandV., PandyaS. U., CividinoP., MassonG., PyS., and ValleeY., Synlett., 2001, 1281; (b) Review: J. P. Adams, J. Chem. Soc., Perkin Trans. 1, 2002, 2586.
9.
GenissonV.B., BouniolA-V., and NepveuF., Synlett., 2001, 700.
10.
BandyopadhyayC., SurK. R., PatraR., and SenA., Tetrahedron, 2000, 56, 3583.
11.
Reviews: (a) DarbarwarM., and SundaramurthyV., Synthesis, 1982, 337; (b) C. K. Ghosh, J. Indian Chem. Soc. 1990, 67, 5; 1991, 68, 21 and references therein.
