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.