Study On The Ring-closing Mechanism Of 1,5-disubstituted Pyrazole-4-carboxylic Acid Ethyl Ester And The Biological Activity Of Its Derivative

Pyrazole carboxylate derivatives are widely applied in molecular design and synthesis with various pharmacological activities,such as anti-inflammatory,antibacterial,anticancer,etc.In our previous work,a series of 1,5-disubstituted pyrazole-4-carboxylates with special regional-selective were obtained by annularity with ethyl（Z）-2-（ethoxymethylene）-4,4,4-trifluoro-3-oxobutanoate and substituted phenyl hydrazine.Based on the previous work,synthesis conditions of 1,5-disubstitued pyrazole-4-carboxylates,such as solvents,temperature,and reactants,were explored.Then the cyclization mechanism was further confirmed by DFT.Various pyrazole derivatives were designed and synthesized,and the anticancer activities and antifungal activities have been evaluated by MMT and mycelial growth rate method,respectively.Regioselective 1,5-disubstituted pyrazole-4-carboxylate were obtained by cyclo-condensation reaction between substituted ethyl（Z）-2-（ethoxy methylene）-3-oxobutanoate and mono-substituted hydrazine（isopropyl hydrazine,isopropyl hydrazine,and aryl hydrazine）.It was an efficiency and eco-friendly reaction without selectivity for solvents and temperature.Cyclization mechanism study revealed that the primary amine with more nucleophilic attacked the C2 atom to form intermediate M-Ph（1,5）,then another N atom attacked C1 atom to obtain 1,5-disubstituted pyrazole-4-carboxylate.Thirty-one pyrazole derivatives were designed and synthesized based on pyrazole carboxylate intermediates.Some of them exhibited certain anticancer activities and antifungal activities.For instance,compound T26、T27、T30 and T31 presented good anti-prostate cancer cell activities,and the IC₅₀values were 8.6,4.8,6.7 and 4.7μM,respectively.These compounds also exhibited good anti-leukemia cell activities,and the IC₅₀ values were 15.7,6.8,15.5 and 13.2μM,respectively.Compound T16 presented better inhibitory activity against Thanatephorus cucumeris with the EC₅₀ value of 22.0μg/m L.Preliminary mechanism study demonstrated that the compound could destroy the cell membrane and influence normal penetration.This work reported a novel cyclization mechanism of 1,5-disubstituted pyrazole-4-carboxylates and its application.We hoped that the 1,5-disubstituted pyrazole-4-carboxylates could take some reference for medicinal molecular design in medicinal chemistry and pesticide chemistry in the future to find novel pyrazole derivatives with broad spectrum pharmacological activity.