Synthesis of Substituted 1, 4-Dihydropyridines in the presence of Theophylline Phosphoric Acid and Evaluation of their in-vitro Antimicrobial Activity

 In this research project, novel derivatives of 1, 4-dihydropyridines were synthesized via the three-component reaction of 4-aminocoumarin, barbituric acid and aromatic aldehydes in the presence of theophylline phosphoric acid (TPA). For the antibacterial and antifungal test of the products, Minimum inhibitory concentration (MIC) was performed according to Macrodilution standard in Tryptic Soy Broth (TSB) and Minimum Bactericidal concentration (MBC) in Müller-Hinton agar on Gram-positive bacteria (e.g. Enterococcus Faecalis andStaphylococcus aureus), Gram negative bacteria (e.g. Escherichia coli, Acinetobacter baumannii) and MFC method for Candida albicans as a fungus.

1, 4-dihydropyridine derivatives were synthesized via the three-component reaction of 4-aminocoumarin, barbituric acid and aromatic aldehydes in the presence of theophylline phosphoric acid (TPA). Reaction monitoring was performed via Thin Layer Chromatography (TLC) (n-hexane: Ethanol 5: 2) and the products were characterized via FTIR, TGA, 1HNMR, and 13CNMR, CHN and mass spectroscopies. Antimicrobial tests were performed in twelve dilutions. Bacterial suspension with the density of 1×106 CFU/mL were added to all the tubes and the antibacterial activity of the products were checked after 18-20 hours of incubation.

The antimicrobial screening data show that the compounds 4c and 4d have the ability to inhibit the growth of bacteria as well as the bacteria in an equal concentration.

All compounds in MIC, MBC test Showed excellent antibacterial and antifungal activity compared to control drugs.