Nucleophilic reactions with the novel condensation product derived from 3-formylchromone and 4-hydroxycoumarin

Abstract

Condensation of 3-formylchromone and 4-hydroxycoumarin gave a novel 3-[(chromon-3-yl)methylidene]-2H-chromene-2,4(3H)-dione (3). The reactivity of the electrophilic centers within the synthesized substrate 3 was examined toward a variety of nucleophiles. Reaction of compound 3 with a diversity of primary amines yielded enaminones. Treatment of compound 3 with malononitrile and ethyl cyanoacetate produced pyran derivatives. Condensation of compound 3 with hydrazine hydrate afforded chromeno[4,3-c]pyrazole 13. Boiling compound 3 with cyanoacetohydrazide in DMF gave pyrazole derivative 12, while in boiling acetic acid gave pyrazolo[3,4-b]pyridine 15. Ttreating compound 3 with phenylhydrazine and hydroxylamine hydrochloride furnished pyrazole 16 and isoxazole 17, respectively. Reaction of compound 3 with guanidine and cyanoguanidine gave pyrimidine derivatives 18 and 19. Reacting compound 3 with ethylenediamine in 1:1 and 1:2 molar ratio furnished diazepine 20 and chromeno[4,3-e][1,4]diazepine 21. Finally, condensing compound 3 with o-phenylenediamine, o-aminophenol and o-aminothiophenol gave benzodiazepine 22, benzoxazepine 23, and benzothiazepine 24, respectively.