Synthesis, Antibacterial and Antioxidant Activities of Some Heterocyclic Compounds from Chalcone

Abstract

The present project deals with the synthesis of new heterocyclic derivatives, and the starting material, resorcinol was treated with acetic acid in presence of anhydrous zinc chloride to get acetylresorcinol (2). The 2-amino-1,3,4-thiadiazole (5) were synthesized by reaction of 3,5-Dinitrobenzoic acid (4) with thiosemicarbazide (3) in the presence of concentrated sulfuric acid, which reacted with nitrous ion to form diazonium salt, followd) by coupling reaction with Azo-resacetophenone compound (2) to form azo dye (6). 5-arylfuran-2-carbaldehyde (7) was prepared by the Meerwein arylation of furan-2-carbaldehyde with aniline (A), which react with azo dye (6) by Claisen Schmidt condensation to give an azo Chalcone dye (8), which could be also obtained by the reaction of resacetophenone compound (2) with 5-arylfuran-2-carbaldehyde (7) to give compound (R) and which reacted with 2-amino-1,3,4-thiadiazole (5) by azotation reaction afforded the azo Chalcone dye (8) as pure products in high yields. The reaction of this chalcone (8) was used for further cyclocondensation reactions with (hydrazine hydrate, 2,4-dinitrophenyl hydrazine, phenylhydrazine, thiosemicarbazide, hydroxylamine hydrochloride, urea, thiourea and malononitrile) compounds to give the heterocyclic derivatives of pyrazoline 8a–8c, 8h, Isoxazol (8d), Oxazine (8ee), Thiazen (8ff), pyrimidine (8e & 8f) and pyridine (8g), respectively. Pyrazoline compounds (8h) have been reacted with chloroacetic acid to produce 4-thiazolidinones compounds (8hh).All prepared compounds were characterized by melting points and the purity of the prepared compounds were determind by TLC technique, and some of the prepared compounds have been characterized by FT-IR techniques. The results obtained confirmed the formation of the desired products. The final products were screened for their antibacterial and antioxidant activities. The synthesized compounds has been investigated for their antibacterial activity against the Gram-positive bacteria (Staphylococcus aureus, Staphylococcus epidermidis and Streptococcus pyogenes) and Gram-negative bacteria (Escherichia coli, Klebsilla pneumpniae and Salmonella typhi) using the agar well diffusion method. Gentamycin and Ciprofloxacin were used as standards for antibacterial activity. Compound (8b) and (5) inhibited the highest activity against Staphylococcus epidermidis and Salmonella typhi, with an inhibition zone of 46 and 45 mm, respectively. Compound (5) shows good activity against Staphylococcus epidermidis, with an inhibition zone of 30 mm, Compound (8hh) shows good activity against broad spectrum. The antioxidant activity of the synthesized compounds was evaluated by the Ferric Reducing Antioxidant Power (FRAP), Phosphomolybdenum (PM), Cupric ion reducing antioxidant capacity (CUPRAC) capacity and Hydrogen Peroxide Scavenging Activity methods.