Synthesis, spectral characterizations and in silico study of some 2-amino-4,6-diarylpyrimidines derived from chalcones

Abstract Four 2-amino-4,6-diarylpyrimidines were synthesized from their respective 1,3-diphenylprop-2-en-1-one (chalcone) precursors. The chalcones were condensed with guanidine carbonate by refluxing in dimethylformamide for 4 hours at 140°C to obtained the title compounds: 4,6-Diphenyl-pyrimidin-2-ylamine (PAA1), 4-(4-Nitro-phenyl)-6-phenyl-pyrimidin-2-ylamine (PAA2), 4-Phenyl-6-(3,4,5-trimethoxy-phenyl)pyrimidin-2-ylamine (PAA3) and 4-Phenyl-6-(3,4,5-trimethoxy-phenyl)pyrimidin-2-ylamine (PAA4). TLC was used to ascertain the purity of the synthesized compounds and their melting points were determined using the open capillary method. They were characterized using IR, 1H-NMR, 13C-NMR and GC-MS. Biological activities of the title compounds were predicted using Gaussian 16 software suite36 (for full geometry optimization in chloroform and gas phase) and SwissADME web tool for the lipophilicity and hydrophylicity. The compounds were obtained in good yield and the characteristic N-H stretch of the -NH2 group (free and H-bonded) was observed at 3503, 3380 cm-1(PAA1); 3492, 3317 cm-1(PAA2); 3194,3309 cm-1 for (PAA3) and 3466, 3313 cm-1(PAA4). The logP values revealed that the lipophilicity of the compounds is in the order: PAA1< PAA2< PAA3< PAA4. The computations on the optimized geometry established the possible application of the compounds in the synthesis of modern pharmaceuticals.