ew 4-(substituted)-Pyrazolone. Part 2: Antifungal Activity of Synthesis and In vitro Antimalarial Activity of Some New 4-Aminoquinoline Mannich Base Derivatives

A new series of 4-aminoquinoline Mannich base derivatives were prepared by selectively modifying the aliphatic diethyl amino function of isoquinewith different aliphatic/aromatic heterocyclic primary amino moieties at Mannich side chain. The synthesized compounds were characterized by their physical,analytical and spectral data, and screened for in vitro antimalarial activity against a chloroquine-sensitive 3D7 strain of Plasmodium falciparum. All the compounds showed in vitro antimalarial activity at the tested dose; which, however, was considerably less than that of the standard reference drug, chloroquine. Among the synthesized compounds, compounds with cyclohexyl (2f), methyl (2c) substitutions showed comparatively better activity than other compounds with n-octyl (2a), propyl (2b), 3-aminopropyl (2d) and furan-2-ylmethyl (2e) substitutions at aminomethyl side chain. The results clearly demonstrate that compound with saturated cycloalkylmoiety (cyclohexyl) exhibitedto some extentmore activity as compared to the compound with heterocyclicmoiety (furan-2-ylmethyl); and compounds with short chain alkyl substitutions (methyl, propyl etc.) were found to be more potent than that of compounds with long chain alkyl substitution (n-octyl).