Synthesis and characterization of a novel series of 1,4-dihydropyridine analogues for larvicidal activity against Anopheles arabiensis

The new-fangled bis(4-substituted benzyl) 4-(4-substitued phenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate derivatives were synthesized by the union of substituted aryl aldehyde, tert-butyl acetoacetate, ammonium carbonate with 4-substituted benzyl alcohol via Hantzsch ester synthesis in aqueous medium under catalyst-free conditions. The newly synthesized compounds were characterized by spectroscopic techniques such as IR, NMR (H-1 and C-13), ESI mass, elemental analysis, and single-crystal X-ray diffraction. The characterized title compounds were evaluated for the larvicidal activity against Anopheles arabiensis by standard WHO larvicidal assay method using Temephos as standard at 4g/ml. The title compounds bis(4-methoxybenzyl) 2,6-dimethyl-4-(4-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate and bis(4-chlorobenzyl) 2,6-dimethyl-4-(4-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate exhibited promising larvicidal activity at 65.6% and 72.2%, respectively, when compared with the standard compound at 98.9%.