New synthetic methods for organonitrogen compounds

2017-05-16This dissertation describes the development of new methodologies for the synthesis of organonitrogen compounds, which include β-fluoroethylamines, mono-fluorinated α-amino acids and β-amino esters, primary anilines, nitrosoarenes, and azoxy and azobenzenes. It also expounds on the utilization of polyamines and imines in preparation of solid adsorbents for efficient capture and release of carbon dioxide. ❧ Chapter 1 provides a brief overview of Nitrogen atom, its incorporation into living organisms, the important role of organonitrogen compounds as well as some multi-component reactions for their synthesis. The aim and scope of this dissertation is also included in Chapter 1. ❧ Chapter 2 describes the development of a direct multi-component protocol for the synthesis of highly diverse derivatives of β-fluoro(phenylsulfonyl)ethylamine by a Mannich-type reaction from their molecular sub-units, α-fluoro-α-nitro(phenylsulfonyl)methane (FNSM), or α-fluorobis(phenylsulfonyl)methane (FBSM), formalin, and various primary and secondary amines. The products are obtained in high yields and selectivity even without the use of base in many cases. ❧ In Chapter 3, the multi-component protocol is extended to furnish fluorinated α- amino acids and β-amino esters. The methodology employs simple molecular units, an organofluorine unit, an amine and a carbonyl unit to generate the fluorinated organonitrogen compounds. ❧ Boron trifluoride monohydrate is an excellent Brønsted acid catalyst system for a wide range of reactions. It is a non-oxidizing acid catalyst prepared easily by bubbling BF₃ into water. Chapter 4 deals with the application of boron trifluoride monohydrate/sodium azide combination as an efficient reagent system for electrophilic amination of aromatics. The present method avoids the use of expensive superacids such as trifluoromethane sulfonic acid and provides a facile access to aromatic amines directly from aromatics. ❧ Nitroso compounds are versatile reagents in synthetic organic chemistry. A feasible protocol for the ipso-nitrosation of aryl boronic acids using chlorotrimethylsilane/sodium nitrite combination as a unique nitrosation reagent system is described in Chapter 5. ❧ Chlorotrimethylsilane is a readily available reagent widely used in organic chemistry. As a reducing agent it is used mainly in combination with other reducing agents. Chapter 6 describes the use of chlorotrimethylsilane as the sole reagent in the reduction of nitrosobenzene to azoxybenzene. Attempts to extend the substrate scope of the reaction are also described in this chapter. The protocol is based on the high reactivity of nitrosoarenes and the extraordinary affinity of silicon towards oxygen. ❧ Synthetic design of innovative materials with high adsorption capacity is essential for capturing, storing and recycling carbon dioxide (CO₂) efficiently. CO₂ recycling is a crucial step towards the “Methanol Economy” which is based on methanol as a viable renewable energy storage medium and also as a chemical feedstock. Chapter 7 delineates the development of new fibrous nanosilica-supported polyamine materials for CO₂ adsorption. It also describes the use caffeine to effect higher pore volumes and average pore diameters of the mesoporous silica nanospheres, which displayed high CO₂ adsorption values when impregnated with polyamines