Synthesis and in vitro carbonic anhydrase and acetylcholinesterase inhibitory activities of novel hydrazide–hydrazone compounds containing 1,2,4-triazole ring

In this work, 1,2,4-triazole derived hydrazide–hydrazones were synthesized with a five-step synthesis pathway. The novel derivatives were characterized by various analytical methods. Acetylcholinesterase (AChE), and human carbonic anhydrase (hCA) inhibitory qualifications of these thirteen original compounds (4, 5a–l) were also determined. The overall biological activity results were very interesting. The reported compounds were found to be very effective inhibitors of hCA I, hCA II, and AChE enzymes with IC₅₀ values in the range of 17.33−77.00 nM for hCA I (Acetazolamide IC₅₀: 62.80 nM), 13.07−46.20 nM for hCA II (Acetazolamide IC₅₀: 57.75 nM) and 4.91−36.47 nM for AChE (Tacrine IC₅₀: 28.88 nM). Within the new compounds, 5i displayed the best hCA I, hCA II and AChE inhibitory activities with IC₅₀ values of 17.33 nM, 13.07 nM, and 4.91 nM, respectively.