GREEN PROTOCOLS FOR C-C, C-N, C-S BOND FORMATION AND SYNTHESIS OF HETEROCYCLIC COMPOUNDS

Abstract

The thesis entitled "Green protocols for C-C, C-N, C-S bond formation and synthesis of heterocyclic compounds" has been divided into five chapters. The title of the thesis reflects our objective observably, which includes the generation of green and promising protocols for the synthesis of a variety of Michael adducts, thiazolidinone derivatives and benzoheterocycles and their characterization. Furthermore we have also synthesized various novel biologically important coumarin and 1,4- benzoxazine derivatives. Chapter 1: Introduction This chapter details a brief review on the importance and application of green synthesis in organic chemistry via solid state approach and by choosing alternative green solvents as a reaction medium. With the growing awareness in industry and academic corridor for sustainable development, the international chemical community is under increasing pressure to alter current working practices and to find greener alternatives. Solid state synthesis has become one of the most significant aims in synthetic organic chemistry, agricultural chemistry, medicinal chemistry, natural products chemistry and pharmaceutical chemistry. The use of green synthetic approach for the synthesis of a variety of molecules is one of the most elegant and desirable methods in terms of atom economy and a progressively more important issue in organic chemistry. Several examples illustrating the solid state approaches are discussed in this chapter along with the synthetic transformations for achieving biologically and pharmaceutically active heterocyclic compounds. Chapter 2: Solid-State Synthesis of Nitroamines and Nitrosulphides This chapter deals with the catalyst-free and solvent-free Michael addition of carbon nucleophiles to electron-deficient nitroalkenes. The adducts nitroamines and nitrosulfides are versatile buildings blocks for the preparation of natural products and pharmacologically important targets and are important structural motifs in medicinal chemistry. Moreover, the generation of two chiral centres in a single step makes this transformation more interesting and challening. Herein we report our results on near absolute green protocol for the synthesis of nitroamines and nitrothiols by Michael addition of aromatic amines and aromatic thiols to vi 1 Abstract nitroolefins under solvent-free and catalyst-free conditions. Initially we synthesized several substituted nitroalkenes by a modified protocol in 73-97% yield (Scheme ..................