Synthesis and Biological Screening of Certain Newer Medicinally Active Heterocyclic Compounds

Abstract

The present work was focused on the synthesis of newer heterocyclic compounds which can be used as antitubercular and antimicrobial agents. Isoniazid was selected as the starting material and microwave synthetic technique was applied appropriately to increase the yield and decrease the reaction time. After the careful analysis of the present work the following conclusion were made. Forty eight new heterocyclic compounds were synthesized by both conventional and microwave synthetic methods. All these compounds were derived from the starting compound isoniazid, one of the first-line antitubercular drug. Twenty four compounds exhibit antitubercular activity at 100µg/ml, seven compounds show the activity at 10µg/ml and two compounds show the activity at lµg/ml. Two compounds exhibit maximum antibacterial activity at 500µg/disc, while three of them show maximum activity at 250µg/dish. Twenty compounds were found to exhibit moderate antibacterial activity and eight of them show minimum activity. Four compounds exhibit maximum antifungal activity at 500µg/disc, while two of them show maximum activity at 250µg/disc. Twenty five compounds were found to exhibit moderate antifungal activity and three of them show minimum activity. Among the newly synthesized compounds, the Mannich base MB14 and the triazolo thiadiazepine SH4 exhibited the highest degree of antibacterial activity against Staphylococcus aureus. While considering the antibacterial activity against B.subtilis, the thiazolidin-4-one TZ5, Mannich base MB8, and the triazolo thiadiazepine SH4 exhibited superior antibacterial activity than the rest of the newly synthesized compounds. The triazolo thiadiazepine SH4 emerged to be the one showing most potent antibacterial activity against FE. coli than any other newly synthesized compounds. The thiazolidin-4-one series represented the most potent antibacterial agents against E.coli among the compounds synthesized, TZ5 and TZ2 are showing better activity. newline