Determining the Synthesis of Pyrazoles via Multi-Component Reaction and Cyclization Cascade of Hydrazono Ugi Adducts

In organic synthesis, multicomponent reactions (MCR) and cascade reactions are frequently used. Different substituted pyrazoles are accessed using these two synthetic methods. In the first section, we’re interested in learning how to make aminocyanopyrazoles using a multicomponent process. The current study outlines a useful protocol for multicomponent reactions (MCRs) involving malononitrile, an orthoester, and hydrazine derivatives, all of which take place in the presence of an acid catalyst. The manufacture, isolation, and characterisation of a series of aminocyanopyrazoles 4 were indeed carried out. Such pyrazoles reacted with sodium nitrite, secondary amine reagent, and formic acidpyrazolotriazines 6 and pyrazolopyrimidinones 7 after being exposed to sodium nitrite. Sulfamoyl chloride was used to convert some of the aminopyrazoles into the corresponding sulfamides. The human (h) hCA I, II, IX, and XII isoforms of carbonic anhydrase (CA, EC were tested as inhibitors of four carbonic anhydrase (CA, EC isoforms. As a result, many of them revealed that these enzymes were inhibited at low micromolar or submicromolar concentrations. Low nanomolar CA inhibitors were found in the matching sulfamides. Acidic hydrolysis of Ugi adducts generated from -hydrazonocarboxylic acids and amino acetaldehyde dimethyl acetal leads to fragmentation of aminoacetaldehyde residues and the synthesis of pyrazoles in the second section. The essential phase of the cascade is proposed to be an aldol-type reaction of the hydrazone. MCR multicomponent reactions and Ugi cascade synthesis are efficient and interesting methods for obtaining good to moderate yields of pyrazoles.

Author(S) Details

Fatma Allouche
Laboratory of Medicinal and Environmental Chemistry, Superior Institute of Biotechnology of Sfax, University of Sfax, 3018, Sfax, Tunisia.

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