Synthesis, Characterization and Pharmacological Screening of Novel Substituted Isoxazole Derivatives

As per our previous paper published (AJRC vol. 04, issue 7, 2011), here some more substituted novel isoxazole derivatives were synthesized to enhance its biological activities, so we found that the ortho and meta position has shown highest activity than para, particularly Nitro substituted groups have shown good activity than others. The present research work was aimed to synthesize some novel substituted isoxazole derivatives and screened them for anti-microbial and analgesic activities. The prevalence of isoxazole cores in natural and biologically active molecules has stimulated the need for elegant and efficient ways to make these heterocycles as lead. In this research work the 3- substituted N-(4-hydroxyphenyl) propanamides (B1-B10) were prepared by the reaction of N-(4-hydroxy phenyl) acetamide (A) with various substituted aryl aldehydes by refluxing in ethanol. The resultant compounds on refluxing with hydroxylamine hydrochloride gave the title compounds 4-(5'-substituted-aryl-4', 5'-dihydro-isoxazole-3'-ylamino) phenols (C1-C10). The structure of newly synthesized compounds has been characterized and established by spectral data viz, FT-IR, ¹HNMR and Mass. All the derivatives synthesized were subjected for their anti-bacterial and antifungal activities by cup-plate method at the concentration level of 100 μg/ml and compared with the standard Amoxicillin and clotrimazole used. Some of the compounds were subjected for their possible analgesic activity by tailflick method at the dose of 50 mg/kg and compared with that of standard paracetamol.