RECENT ADVANCES IN THE SYNTHESIS OF PHARMACOLOGICALLY BENIGN COUMARIN AND INDOLE HETERO-STRUCTURED DERIVATIVES: A REVIEW

Indole and coumarin are the most versatile and cogent heterocyclic scaffolds which are not only decisively used in the synthesis of various organic compounds but also play a consequence role in natural product synthesis, modulation of biofilm formation, virulence and stress responses. In last few decades, an individual has witnessed considerable activity towards the synthesis of indole derivatives due to the possibilities for the design of polycyclic structures by the incorporation of multiple fused heterocyclic scaffolds in an attempt to achieve promising new heterocycles with chemical and biomedical relevance. Whereas, coumarin is a 2-oxo-2H-1-benzopyran and, also, have a wide range of application in the pharmaceutical field. In this review, we provide an overview of the synthesis of coumarin and indoles and their pharmacological evolution. The coumarin was synthesized using phenols, salicylaldehyde, benzaldehyde, phenylacetate, styrenes, and cinnamic acid with different catalyst and photocatalyst to give the best yield. Similarly, Indoles were synthesized iodobenzoic acid, alkynes, amines, alcohols, Nitrobenzaldehyde with the different catalyst under conventional and irradiation method. The effect of various catalytic medium, solvents and operational condition are discussed for obtaining the best yield. A comparative account of various reaction pathways like one-pot synthesis (Multicomponent reaction) and the multistep reaction of coumarin and indoles are discussed.