Expeditious strategies towards the construction of C-C and C-heteroatom bonds
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The contents of this thesis has been divided into five chapters based on the results of experimental works performed during the complete course of the research period. The introductory chapter of the thesis presents an overview of cascade reactions for heterocycle synthesis, different aspect of CH functionalization and the oxirane chemistry for the construction of CC and Cheteroatom bonds. All other chapters’ highlight on CC, CN, CO, and CS bond forming reactions via cascade strategy involving reactions of 2-halobenzamides with (aryl)methanamines and o-alkynylanilines with aroyl isothiocyanates, CH functionalization strategies like directing-group assisted CH activation followed by annulation and cross-dehydrogenative coupling and lastly oxirane ring opening with aroyl/acyl isothiocyanates. Chapter II demonstrates a CuO nano particle catalyzed domino synthesis of 2,3-disubstituted quinazolinones from 2-halobenzamides and (aryl)methanamines.Chapter III describes a base promoted cascade synthesis of quinoline-4(1H)-thiones via an in situ generated o-alkynylthiourea obtained by reacting o-alkynylanilines with aroyl/acyl isothiocyanates.Chapter IV illustrates a Ru(II)-catalyzed regiospecific CH/SH annulation of quinoline-4(1H)-thiones with alkynes leading to the synthesis of thiopyrano[2,3,4-de]quinolines.Chapter V elucidates a Cu(II)-catalyzed oxidative methylene-bridged dimerization of two analogous imidazo[1,2-a]pyridine using N,N-dimethylacetamide (DMA) as solvent cum methylene source.Chapter VI describes a regioselective and concomitant transfer of thiocyanate (SCN) and aroyl/acyl (COR) group from aroyl/acyl isothiocyanate onto oxiranes giving thiocyanato benzoates.Each of these chapters comprises of introduction, previous work, present work, experimental section, references, spectral data and few representative spectra.
Supervisor: Bhisma K. Patel