Studies on the synthesis and reactivity of 2-cyanoacrylate esters and 2-cyanoacrylic acid

Abstract

This thesis is about studies carried out on the synthesis and reactivity of 2- cyanoacrylic acid and 2-cyanoacrylate esters, and is divided into four chapters. Chapter 1 provides an introduction and includes a complete survey of approaches to these compounds (2-cyanoacrylic acid and 2-cyanoacrylate esters) and studies on the reactivity of alkyl (methyl and ethyl) 2-cyanoacrylates reported in the literature. Chapter 2 discusses the attempted synthesis of some of these 2-cyanoacrylate compounds using condensation reactions. For this purpose, the syntheses of tert-butyl and of benzyl 2-cyanoacrylates were attempted using the reactions of tert-butyl and of benzyl 2-cyanoacetate with paraformaldehyde. The synthesis of 2-cyanoacrylic acid from different precursors was also attempted using either protonolysis or oxidation reactions. Chapter 3 describes attempts to use the readily available ethyl 2-cyanoacrylate for the synthesis of 2-cyanoacrylic acid and 2-cyanoacrylate esters. A three-step process was carried out which involves the protection of the double bond of ethyl 2-cyanoacrylate, hydrolysis or transesterification and regeneration of the double bond. The protection of the double bond of ethyl 2-cyanoacrylate is required in order to prevent polymerisation when either hydrolysis or transesterification of the ethyl ester is tried. Chapter 4 describes three completely novel approaches to 2-cyanoacrylic acid. The first approach involves the attempted opening with cyanide ion of the episulfide ring of thiirancarboxylic acid to afford a precursor to 2-cyanoacrylic acid. The second approach deals with the attempted palladium-catalyzed cyanation reaction of tert-butyl 2-bromoacrylate. The third approach describes preliminary investigations into the use of solid phase supports for the synthesis of these compounds