Carbamoyl 1,4-Dihydropyridine Derivatives: Synthesis and Impressive Antidiabetic Activity

1,4-Dihydropyridine is known as one of the most important heterocyclic frameworks found in numerous pharmaceuticals and drugs. A series of novel methyl 5-[(substituted phenyl)carbamoyl]-1-(2,2-dimethoxyethyl)-3-methoxy-4-oxo-1,4-dihydropyridine-2-carboxylates were synthesized by an in situ two-step procedure, starting from 1-(2,2-dimethoxyethyl)-5-methoxy-6-(methoxycarbonyl)-4-oxo-1,4-dihydropyridine-3-carboxylic acid. The compositions and structures of the synthesized diverse compounds were confirmed by elemental analysis and IR and ¹H and ¹³C NMR spectroscopy and mass spectrometry. Screening for in vitro α-amylase inhibitor activity revealed a high inhibitory activity of methyl 1-(2,2-dimethoxyethyl)-3-methoxy-5-[(4-methoxyphenyl)carbamoyl]-4-oxo-1,4-dihydro pyridine-2-carboxylate, comparable with that of the standard drug Acarbose (IC₅₀ = 28.83 and 26.81 μg/mL, respectively).