Synthesis and evaluation of some novel 2-[4-(1-acyl-5-aryl-4,5-dihydro-1H-pyrazol-3-yl)phenoxy]acetic acid hydrazide and amide derivatives as potential pesticides

3-Aryl-1-(4-hydroxyphenyl)prop-2-en-1-ones (9–15), prepared by base catalyzed condensation of 4-hydroxyacetophenone (l) with araldehydes (2–8), are refluxed with hydrazine hydrate in alkanoic acids to give 1-acyl-5-aryl-4,5-dihydro-3-(4-hydroxyphenyl)-1H-pyrazoles (16–32).  Alkylation of 16–32 with ethyl chloroacetate gives the corresponding substituted phenoxyacetates (33–49).  The esters 33–49 are subjected to nucleophilic displacement reactions with hydrazine hydrate, isopropylamine, morpholine and piperidine to yield the title compounds, 2-[4-(1-acyl-5-aryl-4,5-dihydro-1H-pyrazol-3-yl)phenoxy]acetic acid hydrazide (50–66) and amide derivatives (67–104).  The compounds are identified with the help of their IR and 1H NMR spectra and elemental analysis.  All the compounds are tested for their activity against five phytopathogenic fungi, (Sclerotinia sclerotiorum, Rhizoctonia bataticola, Rhizoctonia solani, Alternaria brassicae. and Fusarium solani), two saprophytic fungi (Aspergillus niger, Penicillium digitatum) and one phytopathogenic bacterium (Xanthomonas campestris pv. Citrii).  Many compounds inhibit the growth of S. sclerotiorum at a concentration of 200 mg litre-1.  The compounds 53, 54 and 78 show non-specific activity against several fungi tested.