synthesis and characterization of diverse heterocyclic scaffolds and their applications

Abstract

The five chapters that make up the current work are introduced by a discussion of heterocyclic chemistry and medicinal importance of heterocyclic compounds. This chapter also covered the introduction of green chemistry, green chemistry tools used in the synthesis of target molecules, trends in green chemistry, water as a green solvent, synthesis assisted by water, Multicomponent reactions, History and classification of MCRs, Different approach in MCRs, Introduction of Sonochemistry, History and fundamental of sonochemistry, sonochemistry reactions, sites of sonochemistry reactions and ultrasonic cleaning bath. newline newlineThe present chapter two consists of conventional and microwave assisted multi-step synthesis of 1,3,4-oxadiazole derivatives and their spectral characterization. 1,3,4-oxadiazole based chalcone derivatives are synthesized via four successive steps. Step 1: Synthesis of 5-(pyridin-4-yl)-1,3,4-oxadiazole-2-thiol, Step 2: Synthesis of N-(4-acetylphenyl)-2-chloroacetamide, Step 3: Synthesis of N-(4-acetylphenyl)-2-((5-(pyridine-4-yl)-1,3,4-oxadiazol-2-yl) thio) acetamide and Step 4: Synthesis of (E)-N-(4-(4-phenylbut-3-enoyl)phenyl)-2-((5-(pyridine-4-yl)-1,3,4-oxadiazol-2-yl)thio)acetamide which is final derivative of this reaction. newlineIn chapter three focus the synthesis of new 1,8-naphthyridine derivatives using a green and environmentally friendly method. A one-pot multicomponent reaction was performed using water as a solvent and ultrasonic irradiation. The method is simple, clean, safe and environmentally friendly. The synthesized compounds were confirmed using various spectroscopic techniques like FT-IR, Mass, 1H NMR and 13C NMR. The results showed that optimization studies were successful and a comparison was made between the green and conventional methos. newline newlineFurthermore, chapters four and five focus the one-pot, multi-component synthesis of heterocyclic compounds containing nitrogen and oxygen, which was accomplished using ultrasonic irradiation and morpholine as a catalyst in an aqueous environment. The