A facile and novel synthesis of thirteen 2-amino-3-cyanopyridine derivatives 5(a–m) by a one-pot multicomponent reactions (MCRs) is described for the first time, starting from aromatic aldehydes, malononitrile, methyl ketones, or cyclohexanone and ammonium acetate in the presence of the nanostructured diphosphate Na₂CaP₂O₇ (DIPH) at 80 °C under solvent-free conditions. These compounds were brought into existence in a short period with good to outstanding yields (84–94%). The diphosphate Na₂CaP₂O₇ was synthesized and characterized by different techniques (FT-IR, XRD, SEM, and TEM) and used as an efficient, environmentally friendly, easy-to-handle, harmless, secure, and reusable catalyst. Our study was strengthened by combining five new pyrido[2,3-d]pyrimidine derivatives 6(b, c, g, h, j) by intermolecular cyclization of 2-amino-3-cyanopyridines 5(b, c, g, h, j) with formamide. The synthesized products were characterized by FT-IR, ¹H NMR, and ¹³C NMR and by comparing measured melting points with known values reported in the literature. Gas chromatography/mass spectrometry was used to characterize the newly synthesized products and evaluate their purity. The operating conditions were optimized using a model reaction in which the catalyst amount, temperature, time, and solvent effect were evaluated. Antibacterial activity was tested against approved Gram-positive and Gram-negative strains for previously mentioned compounds.

A facile and novel synthesis of thirteen 2-amino-3-cyanopyridine derivatives 5(a-m), by a one-pot multicomponent reaction (MCRs), is described for the first time, starting from aromatic aldehydes, malononitrile, methyl ketones, or cyclohexanone and ammonium acetate in the presence of the nanostructured diphosphate Na2CaP2O7 (DIPH) at 80 °C, under solvent-free conditions. These compounds were synthesized in short reaction times with good to excellent yields (84-94%). The diphosphate Na2CaP2O7 is used as an efficient catalyst, environmentally, easy handling, non-toxic, stable, and reusable. Our study was strengthened by the synthesis of five new pyrido[2,3-d]pyrimidine derivatives 6(b, c, g, h, j) by intramolecular cyclization of 2-amino-3-cyanopyridines 5(b, c, g, h, j), with formamide. The synthesized products were characterized by FT-IR, SEM, XRD, TEM, 1H NMR, 13C NMR, TLC, and BET. The operating conditions were optimized using a model reaction in which the catalyst amount, temperature, time, and solvent effect were evaluated. The antibacterial activity was tested against Gram-positive and Gram-negative strains for the synthesized compounds.