SYNTHESIS, CHARCTERIZATION AND ANTIMICROBIAL STUDIES OF CARBAZOLES

Abstract

The work presented in this thesis involves the synthesis, characterization and antimicrobial studies of carbazoles. Carbazoles, both isolated and synthesized, are privileged heterocyclic compound that are dowered with exclusive properties as photoelectric material, florescent agent, dyes and have tremendous role in medicinal chemistry as antitumor, antimicrobial, antihistaminic, antineoplastic, antioxidative, anti-inflammatory, anti HIV agent etc. Carbazole nucleus has been stimulating the researchers to find new pathways for its synthesis and its novel derivatives because of their extensive biological properties especially their amazing pharmacological profile and their role as an emerging antibiotic. The current thesis work was designed based on the documented facts highlighting the incredible applications of carbazole derivatives in the field of chemistry. The work undertaken in this project was divided in two sections. The first portion of section I focuses on synthesis of some known potential carbazole derivatives (140-144 and 146-148) by adopting novel and feasible synthetic protocols affording comparably effective yield. While the second portion presents synthesis of some new carbazole derivatives with efficient synthetic protocols and novelty. Novel carbazoles (149-151) were synthesized and among these compounds 151 was found very reactive towards different functional which strongly assist its further role in design and development progress of carbazoles. 151 was further derivatized to successfully synthesize other novel carbazole derivatives such as 151-157, 163-164, 166-170. All the synthesized compounds were characterized from their spectral analysis i.e., UV, IR, 1 HNMR and mass spectrometry. Having succeeded in attempt to synthesize carbazoles, these compounds were evaluated and discussed for their antibacterial and anti-fungal activities in section II. For the purpose of primary screening by agar well diffusion method reference strains (ATCC) of three microbes Multi resistant staphylococcus aureus (gram positive bacteria), Salmonella typhi (gram negative bacteria) and Candida albicans (fungi) were used and then the minimum inhibitory concentration of each of the synthesized compounds to kill these pathogens was found by agar dilution assay using different clinical isolates of all three microbes. Synthesized carbazoles showed significant activities against the tested microbes ranging from 50mg/mL to 2μg/mL. Thesevii synthesized compounds were having potential to serve as important leads to fight against drug resistant microbes among biologically active carbazoles. O O N O N NH N HN N H NH O N H O 151 O 170 O O N N MeO N NH N H OMe 166 Some synthesized novel carbazoles