Microwave assisted synthesis of some novel pyrazoline derivatives as potential antifungal agents

Microwave irradiation method has been used for synthesis of pyrazolines. Claisen Schmidt reaction of different aromatic aldehydes with acetanilide gives acrylamides 1a-h which on further reaction with hydrazine hydrate (in the presence of glacial acetic acid) affords pyrazolines 2a-h. Physical data of all the synthesized compounds have been recorded. Pyrazolines are characterized by their IR and H-1 NMR spectra. The characteristic >C=O stretching vibration of acrylamides is absent in IR spectra of pyrazolines which assured the ring formation. All the synthesized pyrazolines have been screened for their antifungal activity against fungi namely Drechslera maydis and Rhizoctonia solani isolated from maize. Chloro substituted pyrazolines are found to be more effective than other compounds. Among the ortho- and para-chloro substituted pyrazolines, the latter exhibits better control than the former against both the fungi. None of the synthesized pyrazolines are as effective as Bavistin against both the fungi.