BioGecko Vol 12 Issue 03 2023 ISSN NO: 2230-5807 4390 A Journal for New Zealand Herpetology RECENT ADVANCES IN THE SYNTHESIS AND APPLICATIONS OF INDOLE FUSED DERIVATIVES: A BRIEF REVIEW Shreya Talreja 1 & Prof. Dr. Shashank Tiwari 2 Research Scholar 1 & Research Supervisor 2 Faculty of Pharmacy, Bhagwant University, Ajmer,Rajsthan, India Abstract In this review researcher focuses recent advances of indole in multicomponent processes for the synthesis of fused heterocyclic compounds, covering last four years since 2018 to 2022. Indole is one of the most versatile and ubiquitous nitrogen-based heterocyclic scaffolds, it is often used as a building block in the synthesis of many chemical compounds.Because of their usefulness in medicine and biological processes, heterocyclic molecules like indole are very relevant.Particularly, the past decade have seen an increase in the synthesis of indole derivatives as researchers have attempted to achieve promising new heterocycles with chemical and biomedical relevance through the design of polycyclic structures by the incorporation of multiple fused heterocyclic scaffolds. Some of the environmentally friendly methods that are overtaking conventional methods for the synthesis of indole and their fused derivatives include the use of ionic liquids, water (solvent), use of solid acid catalyst, microwave irradiation technique, and some other. Furthermore, substituted indoles fused compounds have enormous potential in many other fields. Key words: Heterocyclic compound, Indole, synthesis, biological potential Introduction Today, the majority of molecules are heterocyclic, therefore studying them is becoming more popular. Among the heterocycles, indole-based compounds have a wide range of uses in the fields of medicine, agrochemistry, dyes, etc. Indole derivatives have numerous applications as sanitizers, corrosion inhibitors, copolymers, anti-cancer, anti-HIV, anti-cancer, anti-inflammatory, anti-tubercular, anti-microbial, anti- viral, anti-cancer, and anti-tumor medications (1-4).With a variety of pharmacological actions owing to various modes of action, indole is an exceptional heterocyclic molecule, a privileged scaffold, and a flexible pharmacophore.Many compounds with crucial biological roles have bicyclic heterocyclic structures; indole is particularly flexible due to its structure. Indole nucleus also act as inhibitor like Hepsin inhibitor,Histone deacetylase inhibitor, Phosphodiesterase 4 (PDE4) inhibitor, Urease inhibitor and VEGFR-2 tyrosine kinase inhibitor, Aromatase inhibitor, etc (5).An indole, also known as benzopyrrole, is an organic molecule with the formula C8H7N that has been noted as a key building block in the area of medicinal chemistry because of the fusion of its six-membered benzene ring with the five-membered nitrogen-containing pyrrole ring (4,6). In terms of chemistry, Indole is just slightly basic. As a result of nitrogen lone-pair delocalization into the - electronic system, which may move freely around the indole ring, this occurs.Therefore, owing to the preservation of aromaticity, the protonation of C-3 is more thermodynamically preferable than that of N-1, and the lone pair of electrons on nitrogen is not readily available for protonation. That's why the C-3 position is a centre for a wide range of chemical processes, including electrophilic substitution, organometallic indole anion complexes, carbon lithiation, oxidation, cyclo-addition, and more besides.At room temperature, indole is a solid. It is the odorous compound found naturally in human stool. At lesser concentrations, however, it gives a floral aroma and is used in perfumes, colognes, and even coal tar In addition to this, indole participates in a wide variety of essential metabolic processes. Spore formation, plasmid stability, drug resistance, biofilm development, and virulence are only few of the bacterial physiological processes that are controlled by this protein (6).