Studies in nonbenzenoid aromatic compounds-Thesis submitted to the IIc for the degree of Doctor of Philosophy in the faculty of science

Abstract

The thesis entitled “Studies in Nonbenzenoid Aromatic Compounds” is divided into two parts (Part I and Part II).

Part I Entitled “Studies on the Synthesis of 9,10-Phenanthrocyclopropenone”, it consists of three chapters:

Chapter 1: A brief review on the “Concept of Aromaticity”, including a historical outline and some current attempts at the definition of the elusive term “Aromatic Character”. Chapter 2: A review on the chemistry of cyclopropenones. Chapter 3: Describes the attempts by the author towards the synthesis of 9,10-phenanthrocyclopropenone (I). Favorskii reaction, viz., dehydrobromination of ?,?-dibromoketone (II) has been studied using different bases and reagents like triethylamine, diazabicycloundecene (DBU) (III), bis-1,8-(dimethylamino)naphthalene (proton sponge) (IV), and silver nitrate.

Some model studies on the dehydrobromination of dibromodibenzylketone are also reported. The structures of the products obtained from the reactions mentioned above have been elucidated with the help of IR, NMR spectroscopy, and mass spectrometry.

Part II Entitled “Studies on the Reactions of Acyl Pyruvic Esters”, it is divided into two chapters (Chapter 4 and Chapter 5):

Chapter 4: Consists of the self-condensation of acetylpyruvic esters (ethyl and methyl) and that of propionylpyruvic ester (methyl), and deals with the structural elucidation of the self-condensation products and their chemical degradation and transformation products. General formula: RCO-CH2?CO-COOR’\text{RCO-CH}_2-\text{CO-COOR'}RCO-CH2??CO-COOR’

Chapter 5: Consists of two sections: Section A: Deals with the attempts in effecting the condensation of methyl acetylpyruvate with different ketones, as a possible method to obtain alkylidene ketones. Section B: Describes the preliminary studies on the ?-alkylation of quasi-aromatic compounds, e.g., magnesium chelates of acetylacetone and ethyl acetylpyruvate.