Synthesis, Characterization & Biological Studies of Terphenyls, Quinoline & Pyridine Derivatives through Transition Metal Catalyzed Reactions

Abstract

This dissertation is divided into seven chapters. The first chapter is general overview which introduces transition metals catalyzed cross coupling reactions especially Palladium catalyzed cross-coupling reactions. These have recently emerged as one of the most powerful and fundamental transformations in organic syntheses. Among the several palladium catalyzed cross-coupling reactions, Suzuki-Miyura cross-coupling reaction has become an extremely important method for the construction of carbon-carbon bonds. The second chapter describes the synthesis of fluorinated terphenyls synthesized via Suzuki cross coupling reaction of 1, 4-dibromo-2, 5-difluorobenzene with different boronic acids. Fluorinated terphenyls were obtained in high yields. Structures of these compounds were confirmed by 1H-NMR, 13C-NMR, GC-MS, FT-IR and single crystal X-Ray analysis. Mono-arylation was also observed in a compound 4, 4’-dibromo-2, 5-difluorobiphenylby using 1 equivalent of arylboronic acid. The third chapter describes the syntheses of 3-arylated quinolines synthesized via Suzuki cross coupling reaction of 3-bromoquinoline with different boronic acids. Several trials were made to enhance yield of final products by using different catalytic systems. Extensively diversified arylated quinolines were synthesized in relatively high yields. Structures of these compounds were confirmed by 1H-NMR, 13C-NMR, GC-MS, FT-IR and single crystal X-Ray analysis. Synthesized arylated quinolines are not readily available by any other methodologies. The Fourth chapter describes the syntheses of 2, 5-diarylated pyridine synthesized via Suzuki cross coupling reaction of 2,5-dibromopyridine with different boronic acids. Diversified results were obtained as 4 different products 5, 6, 8 and 9 were obtained even after using 2.2 equivalents of different aryl boronic acids. Regioselectivity is also studied and well characterized with help of XRD analysis. Abstract x The fifth chapter describes the experimental procedures and characterization data of synthesized compounds. The sixth chapter describes the biological activities of the synthesized compounds. These compounds were subjected to various biological activities like anti-bacterial, anti-fungal, antinociceptive and urease inhibition activities. The overall biological activity screening demonstrated that majority of these compounds are significantly bioactive. The last chapter describes the solubilization of quinoline derivatives in micellar solutions of surfactants. In micellar solutions of surfactants the solubility of the quinoline derivatives increased linearly with the increase in surfactant concentration irrespective of the type of surfactant. The molar solubilization ratio (MSR), micelle-water partition coefficient (KM), and the Gibbs energy of solubilization (Δ𝐺𝑠𝑜) of these compounds in the micelles were determined and correlated with each other. This comparative study can be used to select an appropriate medium for the quinoline derivatives solubilization.