Synthesis and Characterization of Some Fluorinated Chromenes, Chromeno[3,4-c]pyridines, Chromeno[3,4-c][1,8]naphthyridine Derivatives.

[摘要] The reaction of cyanoacetamide derivatives 1a,b with salicylaldehyde, and 2-hydroxy-1- naphthaldehyde in ethanolic ammonium acetate afforded 2-iminochromene derivatives 3 and 4.Chromeno[3,4-c]pyridine derivatives 5 and 6 were obtained by refluxing of chromene 3 and benzochromenes4 with malononitrile. In a similar manner, condensation of compounds 3b,4b with ethyl cyanoacetate indioxane under reflux in the presence of piperidine furnished chromeno[3,4-c]pyridines 8 andbenzochromeno[3,4-c]pyridine 9. Refluxing of chromene derivative 3b with malononitrile dimer in dioxane inthe presence of catalytic amount of triethylamine produced chromeno[3,4-c][1,8]naphthyridine-2-carbonitrilederivative 13. The structures of the titled compounds cited in this article were elucidated by spectroscopic data1 13 (IR, HNMR, CNMR spectra).

[学科分类] 工程和技术（综合）

[关键词] Fluorinated Chromenes;Michael reaction;chromeno[3;4-c]pyridines;chromeno[3;4-c][1;8]naphthyridine.