Synthesis, ionization constant, toxicity, antimicrobial and antioxidant screening of 1-Phenyl-3-(phenylamino) propan-1-one and Phenyl (2-[phenyl amino) methyl] phenyl) peroxyanhydride Mannich bases

Abstract

Synthesis of 1-Phenyl-3-(phenylamino) propan-1-one (BO1) and Phenyl (2-[phenyl amino) methyl] phenyl) peroxyanhydride (BO2) both of which are Mannich bases were achieved in this study. Analysis and characterisation of the Mannich Bases were also achieved by UV, IR, and NMR Spectroscopy. The ionization constant (pKa) of the products is also reported.  The pKa at 8.1 obtained by non-aqueous titration may enable the lone pair of electron on nitrogen in the compounds to be protonated at physiological pH. The result of the Brine shrimp lethality test showed that both BO1 and BO2 with LC₅₀ values 17345.1µg/ml and 33520µg/ml respectively, were non – toxic. The result of the antimicrobial screening of BO1 and BO2 using Escherichia coli, Staphylococcus aereus, Bacillus subtilis, Pseudomonas aeruginosa, Klebsiellae pneumoniae, Salmonellae typhi, Candida albicans, Rhizopus stolonifer, Aspergillus niger and Penicillum nonatum showed that the two compounds possess significant antimicrobial activity when compared with the standards, Gentamicin and Tioconazole. In vitro antioxidant screening of both compounds by DPPH free radical scavenging method, scavenging effect on Hydrogen peroxide and peroxide oxidation by Ferric thiocyanate method showed that the compounds possessed significant antioxidant activity when compared with antioxidant standards Ascorbic acid, BHA and ?-Tocopherol . They possessed the highest %inhibition in peroxide oxidation by Ferric thiocyanate method.

Keywords: Mannich bases, 1-Phenyl-3-(phenylamino) propan-1-one, Phenyl (2-[phenyl amino) methyl] phenyl) peroxyanhydride, ionization constant, antimicrobial, antioxidant