Reaction of ethyl acetoacetate and 2′-hydroxychalcones: Efficient route to 9-aryl-6<i>H</i>-benzo[c]chromen-6-ones

Abstract

ABSTRACT. The reaction of ethyl acetoacetate and 2′-hydroxychalcones under atmospheric air to furnish a series of functionalized 6H-benzo[c]chromen-6-ones in moderate yields is reported. The reaction proceeds through trans-esterification, intra-molecular Michael addition, Robinson annulation and oxidative aromatization.

Oxidant-free, three-component synthesis of 7-amino-6H-benzo[c]chromen-6-ones under green conditions

“…Interestingly, when concentration was increased (1.5 mL of solvent at 0.5 mmol scale), the yield was increased to 78% (entry 12). Further attempts to improve the product yield by using other protic solvents including MeOH, i-PrOH and t-BuOH were not successful (entries [13][14][15]. Finally, in order to achieve a green protocol for this three-component cascade process, the reaction was carried out in a set of common green solvents such as PEG-200, glycerol and water in the presence of Sc(OTf) 3 (entries [16][17][18].…”

“…12 Almost simultaneously, ve examples of 7-hydroxy-6H-benzo[c]chromen-6-ones were synthesized using a diethylamine-catalyzed approach in 51-59% yield. 13 Despite these few methods, the synthesis of 6H-benzo [c]chromen-6-ones from readily available starting materials via multicomponent reactions remains almost unexplored. Consequently, we envisioned to develop a straightforward, oxidant-free, three-component, one-pot approach for the synthesis of 7-amino-6H-benzo[c]chromen-6-ones involving the simultaneous generation of both the B and C rings.…”

DMAP-Catalyzed Reaction of Diethyl 1,3-Acetonedicarboxylate with 2-Hydroxybenzylideneindenediones: Facile Synthesis of Fluorenone-Fused Coumarins

“…28 The base-mediated reactions of diethyl 1,3-acetonedicarboxylate with 2-hydroxychalcones have been employed in the synthesis of benzene fused coumarins (Scheme 1). [29][30][31] O OMe However, the reaction of substituted -keto esters with 2-(2-hydroxybenzylidene) of both cyclic and acyclic 1,3-dicarbonyl compounds have never been studied. This type of reactions could provide a template for the synthesis of a wide variety of new fused coumarins.…”

Synthetic protocols on 6$H$-benzo[$c$]chromen-6-ones: a review

“…Masesane and Mazimba outlined a protocol for the synthesis of 9-aryl-6H -benzo[ c ]chromen-6-ones (62,(66)(67)(68)(69)(70) from the reaction of 2 ′ -hydroxychalcones (60) and ethyl acetoacetate (61). 26 The reaction key steps were transesterification, intra-molecular Michael addition, Aldol condensation, and oxidative aromatization as outlined in Scheme 7. This synthetic protocol was applied to the synthesis of thiophen 1,3-bis-silyl enol ethers (137) was used to transform 3-formylchromone (136) into benzophenone (139).…”