Novel bis(1-acyl-2-pyrazolines) of potential anti-inflammatory and molluscicidal properties

A variety of bis[3-aryl-4,5-dihydro-1H-pyrazol-1-carboxaldehydes] 4a-h were obtained via reaction of bis[1-aryl-2-propen-1-ones] 3a-h with hydrazine hydrate in refluxing formic acid. In addition, the corresponding bis[1-acetyl-3-aryl-4,5-dihydro-1H-pyrazoles] 4i-m were formed through conducting the reaction of 3 with hydrazine hydrate in refluxing acetic acid. The starting bis(2-propen-1-ones) 3a-h were prepared stereoselectively as E,E'-geometric isomer via condensation of bisbenzaldehydes 1a,b with (un)substituted acetophenones 2 in ethanolic KOH solution. Anti-inflammatory as well as ulcerogenic activities of the prepared pyrazolines were evaluated in vivo and compared with that of a standard drug (indomethacin). Many of the tested compounds show remarkable anti-inflammatory properties with an ulcerogenic liability (especially 4f, g, j, and k) lower than that of the standard used drug. Compound 4f was established to be the best effectively prepared anti-inflammatory active pyrazoline derivative and safer than indomethacin with respect to its ulcerogenic liability. Molluscicidal activity of the prepared compounds against Biomphalaria alexandrina snails (the intermediate host of Schistosoma mansoni) was screened. Where, some of the prepared compounds show considerable activities.