Essential to the entire field of Organic Chemistry is the nature of the carbon to carbon bond. Our current concepts and guiding principles concerning it are almost solely constructed from aliphatic compounds, certain simple ring species, and aromatic systems. Except for special cases, aliphatic and aromatic types are felt to be mildly strained or free from internal tension while the alicylic small and medium ring compounds are the so-called strained molecules. These strained compounds involve bending back or compression of two of the four carbon bonds from an equilibrium position. Distortions of more complex origin occur in the paracyclophanes and hexahelicine, etc. The theory considering strain of two of the four carbon bonds might well be extended to include three bonds. Simple caged compound core types testing three-bond strain. are the tetrahedron, trigonal prism , and cube. The successful synthesis of a unique compound, 4-methyl tricyclo[1.1.0.02-4] butane-1,2,3-tricarboxylic acid containing the three-bond strained tetrahedral core was reported by Beesley, Thorpe, and Ingold thirty eight years ago. With the exception of unsuccessful efforts by Woodward and Larson, this area of chemistry has remained virtually inactive since that time. Our reinvestigation of this remarkable synthesis has revealed method omissions vital to acquiring the compounds leading to l. These methods, a preliminary objective of this research and apparently commonplace in the laboratory of Thorpe, particularly involved the preparation of 1,1,1-ethane triacetic acid, II, and triethyl tribromo-1,1,1-ethane triacetate, III. The tri acid II was very difficult to purify by crystallizing with the techniques of frequent present-day use. Thorpe made no mention of temperature in his accounts, but obtained the acid in good condition. Our work has shown the acid can be easily purified by crystallizing from 50 % hydrochloric acid solution at 65°-70° C. This higher purity product can then be brominated with phosphorus pentabromide under special conditions. These are only partially stated by Thorpe. Our work has shown that III can be brominated by making phosphorus pentabromide in situ with slow bromine addition to a mixture of II and phosphorus tribromide. Compounds necessary to the acquisition of II and III are ethyl isodehydracetate IV, ethyl β-methyl glutaconate V, and ethyl a-cyano β,β-dimethylpropane tricarboxylate VI . Discussion of the plausible reasons for method omissions, the synthesis deletions and results of greater interest, reaction schemes leading each compound to it's successor, and the experimental details of compounds II through VI are presented in the Thesis. Appended is a proposed manuscript for publishing in the Journal of the American Chemical Society.
College and Department
Chemistry and Biochemistry
BYU ScholarsArchive Citation
Gurney, John A., "The bromination of 1,1,1-Ethanetriacetic acid" (1958). Theses and Dissertations. 8217.
Bromination, Organic acids