Cross Coupling Studies of Alkyl-Aryl-Sulfide/Sulfone Derivatives and the Preparation of Polyurethane Coating

Abstract

This dissertation is divided into three chapters and each chapter has its own references and compounds numbering. General introduction describes the importance and different syntheses approaches towards the precursor which we have used in our studies. This research work describes the synthesis of the Iridium (Ir) catalyzed borylation of sulfur containing substrate and also includes the synthesis of polyurethane (PU)/epoxy coatings. In this research work, different alky-aryl-sulfone/tirfluoromethylthioanisole/ methylthioanisole boronic esters were synthesized and tested for different functional group transformation. PU/epoxy coating were synthesized and their properties assessment were done. The results obtained through this study are encouraging which are discussed separately in forthcoming chapters 1, 2 and 3. In the 1st chapter, alky-aryl sulfone borylation and functionalization of boronic ester are described. In this research work we have synthesized thirty six boronic esters analogues of alky-aryl-sulfone. Ten analogues of (biaryl/aryl-heteroaryl) were synthesized with help of Suzuki cross-coupling from different substrate with different aryl/heteroaryl halide. Five analogues were synthesized from the selective nucleophilic substitution reaction of boronic ester that are not possible through classical methods. All these compounds were characterized through NMR, GC-MS, FT-IR and HR-EI-MS. In 2nd chapter, alkyl-aryl thioanisole borylation are described. In this research work we have synthesized substituted methylthioanisole/trifluoromethylthioanisole forty two boronic ester analogues with help of Ir catalyzed borylation. The selectivity of XXVII

substrate showed that bulk at 2/3/4 position lead to selective borylation by minimizing the chances of isomer formation. SMe/SCF3 act as ortho directing group in each case but their directing effect in case of NH2/F were not effective at all. All these compounds were characterized through NMR, GC-MS, FT-IR and HR-EI-MS. In 3rd chapter, the synthesis of polyurethane (PU) and epoxy coatings and their properties assessment are described. We have developed top layer approach which is applicable for both kinds of thermosets. Our approach is also applicable in case of nanofillers too which lead to haziness by in situ mixing method. The coating obtained (Dura clear) were then assessed for omniphobic, mechanical and durability testing. All these tests shows that our design PU/Epoxy coatings have an excellent omniphobic, mechanical and durability properties. The coatings as well as their precursors were characterized through NMR, SEM, XPS, FT-IR, DSC analysis.