Reactivity of p-Phenyl Substituted β-Enamino Compounds using K-10/ultrasound. I. Synthesis of Pyrazoles and Pyrazolinones

Article abstract of DOI:10.1002/jhet.5570350136

The reactivity of the β-enamino ketones, 3-amino-l-(p-phenyl-substituted)-2-buten-l-ones la-d and β-enamino esters. Ethyl-3-amino-3-(p-phenyl-substituted)-2-propenoates 5a-d were evaluated by systematic studies of the reactions with hydrazine and methylhydrazine by reactions with solid support K-10/ultrasound and homogeneous media (reflux in ethanol or dichloromethane) yielding pyrazole rings 2a-d, Af-methylpyrazoles 3a-d, 4a-d and N-methylpyrazolinones 6a-c and 7a-c. The regiochemistry of the cyclization showed dependence of the reaction conditions employed as well as the substituent in the aromatic ring.