Facile sonochemical synthesis of novel pyrazolyne derivates at ambient conditions

► We reported a simple synthesis to obtain pyrazolinic derivatives. ► The advantages of carrying out the reaction induced by U.S radiation. ► Comparable methods reported in the literature regarding reaction time and yield. ► Efficient protocol for the U.S assisted synthesis of heterocyclic compounds. Claisen–Schmidt condensation reaction of 4-acetamidoacetophenone with aromatic aldehydes under ultrasonic irradiation affords acetylaminochalcones (yields: 71–90%) which also under ultrasonic irradiation and in the presence of sodium acetate and acetic acid aqueous undergo facile and clean cyclocondensation with hydrazine to afford 3-(4-acetamidophenyl)-5-(aryl)-1-H-pyrazolines. The pyrazolines were obtained in good to excellent yields (81–89%), and were characterized by conventional spectral data. The work-up is simple and the results obtained indicate that, unlike classical heating, ultrasonic irradiation results in higher yields, shorter reaction times (1.5–2.3h) and milder conditions.