Reactions of chromone-3-carboxylic acid and chromone-3-carboxamides with cyanoacetic acid hydrazide

Heteroannulated Coumarins and Chromones from Chemical Transformations of 6,8‐Dimethylchromone‐3‐carbonitrile

“…Also, coumarins (2 H ‐chromen‐2‐ones) displayed various biological applications such as antifungal, antibacterial, antioxidant, anticoagulant, antiinflammatory, antiviral, anticancer, antitumor, anti‐diabetic, antitubercular, antiplasmodial, and antimalarial activities, as well as fluorescent sensors . 3‐Substituted chromones bearing electron withdrawing groups at position 3 revealed a diversity of transformations upon treatment with nucleophilic reagents . In continuation to our aforementioned work related to γ‐pyrone ring opening followed by ring closure , the present work aims to study the ring opening ring closure reactions of 6,8‐dimethylchromone‐3‐carbonitrile with some nuclophilic reagents under different reaction conditions.…”

Synthesis of Chromone-Related Pyrazole Compounds

“…Other 4-(2-hydroxyaroyl)pyrazoles were synthesized through the reaction of 3-formylchromone with arylhydrazines in an alcoholic potassium hydroxide solution, under microwave irradiation at 120 °C [ 105 ]. A similar one-pot protocol was achieved with the reaction of the parent 3-formylchromone with cyanoacetic acid hydrazide in the presence of sodium ethoxide in refluxing ethanol to afford 4-(2-hydroxybenzoyl)pyrazole [ 106 ]. Rindhe and coworkers used a two-step strategy involving the reaction of 3-formylchromones with 2,4-difluorohydrazine using a catalytic amount of acetic acid in ethanol at 40 °C to give the corresponding hydrazones, which after treatment with potassium hydroxide at 50 °C provided the respective 4-(2,5-dihydroxybenzoyl)pyrazoles [ 107 ].…”

An experimental and computational study of new spiro-barbituric acid pyrazoline scaffolds: restricted rotationvs.annular tautomerism

“…Hence, as part of our efforts to construct spirocyclic compounds with nitrile imine through a 32CA reaction, we present an efficient, chemoselective, and regioselective synthesis of spirocyclic compounds. The addition of an excessive amount of hydrazine hydrate was investigated without the need for heating or additional acid or base 16 to evaluate the stability of the synthesized spiro-barbiturate scaffolds and the preparation of substituted phenolic pyrazoles. Notably, the introduction of a Cl substituent onto the phenolic pyrazole core led to the formation of a mixture of two atropoisomers observed in the 1 H NMR spectra (Scheme 1).…”