The synthesis and derivation of tetra-substituted methylene bridge calix[4]arenes

Chapter 1 discusses the history of calix[n]arenes dating back to the initial investigation of the phenol-formaldehyde procedure up to the seminal work by Gutsche that developed the synthesis of these macrocycles allowing ease of access. Modification of these macrocycles is discussed on the upper- and lower-rim followed by a detailed look into different methods utilised to build functionalisation at the methylene bridge. Finally, methods of introducing multiple functionalities to the methylene bridge is considered. Chapter 2 presents the synthesis of a previously reported calix[4]arene which has been mono-substituted at the methylene bridge containing a saturated 1,4 diketone. This compound is then used as an intermediate to the synthesis of pyrrole appended C[4]s through the Paal-Knorr synthesis with a range of different anilines. A library of these C[4]s is presented with observations and discussions. Chapter 3 contains a further look into the Paal-Knorr synthesis using the saturated 1,4 diketone intermediate with a set of long chain alkyl-amines. The exploration into other heterocycles is then discussed including a synthesis of a thiophene using the 1,4 saturated intermediate and a 1,4 unsaturated diketone with subsequent pyridazine ring closure. The deprotection of the pyridazine, Thiophene and a long chain alkyl pyrrole is discussed along with issues encountered, how they are overcome and decomposition of these compounds. Chapter 4 discusses introducing pyridyl functionality at the methylene bridge using the Paal-Knorr synthesis. The different methods considered and trialled followed by synthesis of two extended anilines and the reaction of 2-,3- and 4-(pyridyl)aniline with the 1,4 saturated diketone forming the respective pyrroles, the products synthesised and how these could be used to form asymmetrical calix[4]arenes. Chapter 5 is a summary and overview of the work presented in this thesis with a small section on the possible future work in this area

Scripture and reform

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