Synthesis and bioefficacy evaluation of 2-[4-(3-arylprop-2-enoyl)phenoxy]N-substituted acetamides and 2-[4-(5-aryl-4,5-dihydro-1H-pyrazol-3-yl)phenoxy]acetic acid hydrazides as potential pesticides

Base catalyzed condensation of 4-hydroxyacetophenone 1 with araldehydes 2-8 yields 3-aryl-1-(4-hydroxyphenyl)prop-2-en-1-ones 9-15. The compounds 9-15 are alkylated with ethyl chloroacetate to furnish ethyl [4-(3-arylprop-2-enoyl)phenoxy]acetates 16-22. The esters 16-22 are subjected to nucleophilic displacement reactions with isopropylamine and morpholine to give the title compounds, 2-[4(-3-arylprop-2-enoyl)phenoxyl-N-isopropylacetamides 23-29 and 4-[{4-(3-arylprop-2-enoyl)phenoxylacetyl]morpholine 30-36, respectively. The esters 16-22 are cyclized with excess of hydrazine hydrate in ethanol to give the title compounds, 2-[4-(5aryl-4,5-dihydro-1H-pyrazol-3-yl)phenoxy]acetic acid hydrazides 37-43. All the compounds are tested for their toxicity against five phytopathogenic fungi, Rhizoctonia solani, Rhizoctonia bataticola, Sclerotinia sclerotiorum, Alternaria brassicae, and Fusarium solani, two saprophytic fungi Penicillium digitatum, and Aspergillus niger and one phytopathogenic bacterium Xanthomonas campestris pv. citrii. Some of the compounds inhibit the growth of S. sclerotiorum, A. niger and X. campestris pv. citrii at a concentration of 200 ppm.