Highly Efficient Synthesis of New 3,5-Substituted (Isoxazolines) and 2,3,5-Trisubstituted (Pyrazolines) Mediated by Chloramin-T and Their Evaluation of Antioxidant and Antibacterial Activities

Two short series of five membered heterocyclic 3,5-disubstituted–isoxazolines derivatives ( Va – f ) and 2,3,5-trisubstituted-pyrazolines derivatives ( VIIa – f ) were synthesized via 1,3-dipolar cycloaddition reaction of 2-(allyloxy)-4,6-dimethoxypyrimidine ( III ) with aromatic aldoximes ( IV ) which undergo oxidative–dehydrogenation with Chloramine-T to give 3,5-disubstituted–isoxazolines derivatives ( Va – f ) and oxidative cyclization of diphenyl hydrazones ( VI ) using Chloramine-T to give 2,3,5-trisubstituted-pyrazoline derivatives ( VIIa – f ) in good yield. The newly synthesized compounds were screened for anti-oxidant and anti-microbial activities. 2,3,5-trisubstituted-pyrazolines derivatives ( VIIb – e ) revealed higher antioxidant activity at 10 µg/mL while 3,5-disubstituted-isoxazolines derivatives ( Va – c ) and 2,3,5-trisubstituted-pyrazolines derivatives ( VIIa – c ) showed better anti-microbial activity at 100 µg/mL compared with standard vitamin C and ciprofloxacin, respectively. Structures of newly synthesized compounds were established on the basis of their elemental analysis and spectral IR, 1 H-NMR and 13 C-NMR.