Synthesis and Antimicrobial Activities of Chromene Derivatives

Abstract

The design and synthesis of chalcone and chromene derivatives and their antibacterial activities were studied in this research. Conveniently, all products were synthesized from commercially available acetophenone, 4-hydroxybenzaldehyde and dimedone. Different synthetic strategies were used to obtain an easily accessible chromene scaffold with appropriate handles. At first, this research work was involved in an efficient procedure for the attachment of 4-hydroxybenzaldehyde and acetophenone in the presence of 10% NaOH to produce 3-(4-Hydroxy-phenyl)-1-phenyl-propenone. 4-{3-[(2,4-Dinitro-phenyl)-hydrazono]-3-phenyl-propenyl}-phenol phenylamine has been synthesized by the reaction of 2,4 dinitro phenyl hydrazine with chalcone. Reaction of dimedone with chalcone under refluxing condensation using dry benzene and zinc chloride as a catalyst to give the corresponding chromene derivative 4-(4-Hydroxy-phenyl)-7,7-dimethyl-2-phenyl-4,6,7,8-tetrahydro-chromen-5-one. This reaction also carried out by Microwave Irradiation and use ethanol as a solvent, without any catalyst. It was found that the preparation time for the compounds was reduced from 72 hours to 5-10 minutes during microwave irradiation. The structures of the all synthesized compounds were characterized by their IR, 1H NMR spectral data. The antibacterial and antifungal activity of the compounds was also investigated. The antimicrobial activity of the compounds at concentration 300 μg/disc was performed against three gram-positive bacteria (Bacillus cereus, Staphylococcus aureus and Listeria monocytogenes) and three gram-negative bacteria (Escherichia coli, Salmonella typhimurium, and citobacteria frundi) by Kirby-Bauer disc diffusion method using Ciprofloxacin as standard. Antifungal screening was carried out against one fungi (Tricodarma harzianum) using Michonazole as standard. Compound, I, 3-(4-Hydroxy-phenyl)-1-phenyl-propenone exhibits no activity against the tested bacterial strains Bacillus cereus, Listeria monocytogenes, Escherichia coli, Salmonella typhimurium, Citrobacter freundii, but showed moderate activity against the tested bacteria Staphylococcus aureus having inhibition zone 8 mm and also show antifungal activity aganist Trichoderma harzianum inhibition zone 10mm. Compound, II, 4-{3-[(2,4-Dinitro-phenyl)-hydrazono]-3-phenyl-propenyl}-phenol exhibits no activity against gram negative, gram positive strains but showed antifungal activity against Trichoderma harzianum inhibition zone 6 mm. Compound, III, 4-(4-Hydroxy-phenyl)-7,7-dimethyl-2-phenyl-4,6,7,8-tetrahydro-chromen-5-one showed activity against Gram positive, Gram negative except Listeria monocytogenes, Escherichia coli, Salmonella typhimurium. This compound, III also showed antifungal activity against Trichoderma harzianum inhibition zone 8 mm.