Synthesis of some new azole, azepine, pyridine, and pyrimidine derivatives using 6‐hydroxy‐4H‐4‐oxo[1]‐benzopyran‐3‐ carboxaldehyde as a versatile starting material

Abstract

Condensation of 3-formyl chromone

Studies on the Chemical Reactivity of 6,8‐dibromo‐7‐hydroxychromone‐3‐carboxaldehyde Towards Some Nitrogen Nucleophilic Reagents

“…The chemical reactivity of carboxaldehyde 1 towards a variety of 1,4‐ N , N ‐binucleophiles was also studied. From the literature data, about six different types of products were obtained in the reaction of o ‐phenylenediamine with 3‐formylchromones, depending on the reaction time, the reaction conditions, and the solvent used . Herein, we found that only one product was isolated from the condensation of carboxaldehyde 1 with o ‐phenylenediamine, in different polar solvents such as methanol, ethanol, and acetic acid.…”

3-Formylchromones as diverse building blocks in heterocycles synthesis

“…Condensation of carboxaldehyde 1f with ethyl 2-cyano-2-(3-phenyl-5-oxo-1,3-thiazolan-2-ylidene) acetate (121) gave the corresponding arylidene derivative 122 (Scheme 59) [61].…”

Ring transformation of chromone-3-carboxylic acid under nucleophilic conditions

“…[1][2][3][4] The introduction of an electron-withdrawing group at 3-position of chromone system changes crucially the reactivity of the pyrone ring with respect to nucleophiles, and provides a broad synthetic potential of 3-substituted chromones. [5][6][7] The diversity of properties of these compounds is due to the highly reactive push-pull alkene system with a good leaving group at the β-carbon atom, whose role is played by the phenolate anion. Also, 3-substituted chromones have the ability to undergo additional transformation related to γ-pyrone ring opening at C-2 position and ring closure (RORC) at C-4 position or at the substituent at C-3 position.…”