Synthesis of novel nitro functionalized 1,4-dihydropyridines under neat condition: Spectral characterization, crystallographic study and ADMET predictions

Abstract

A cost-effective and sustainable protocol has been developed to synthesize novel nitro-functionalized N-methyl-1,4-dihydropyridines. This one-pot, three-component reaction was performed by using active methylene compounds with aromatic aldehydes and N-benzyl-N-methyl-2-nitroethene-1,1-diamine(nitroketene-N,N-acetal) in the presence of DMAP 10 mol% under neat conditions. Standard spectroscopic techniques like IR, 1H and 13C NMR, HRMS and elemental analysis are employed to characterize all synthesized compounds. The molecular structure of 2-amino-6-(benzylamino)-4-(4-chlorophenyl)-1-methyl-5-nitro-1,4-dihydropyridine-3-carbonitrile (4h) and 2-amino-6-(benzylamino)-1-methyl-5-nitro-4-(p-tolyl)-1,4-dihydropyridine-3-carbonitrile (4k) were confirmed by the single crystal XRD analysis. The spectral data is well correlated with the anticipated structure. The ADMET calculations of the prepared novel compounds were done, and vital pharmacokinetic properties were predicted. This solvent-free approach offers several distinguishing characteristic features including a short reaction time, low-cost solid catalyst, high yields, easy work-up, and no requirement for chromatography.