## Doctoral Dissertations

Fall 1995

Dissertation

Chemistry

#### Degree Name

Doctor of Philosophy

Part I. 5-Nitro-N-(p-toluenesulfonyl)-1,2,3-benzoxathiazole-2,2-dioxide was synthesized and reacted with various nucleophiles. Nitrogen nucleophiles attacked the exocyclic sulfur atom resulting in cleavage of the tosyl group. This is due in part to the acidity of the parent benzoxathiazole ring. A series of substituted N-H-1,2,3-benzoxathiazole-2,2-dioxides were synthesized and their pK$\sb{\rm a}$ values were determined. An ab initio study was also undertaken on a simple sulfamate model in order to determine the origin of the increased acidity of the cyclic sulfamates, compared to their acyclic analogues. It was determined that the increased acidity was directly affected by the conformation of the neighboring heteroatoms. This is primarily due to heteratom-sulfur delocalization. Investigations of the role of d-orbitals on the stabilization of the system were inconclusive. An ab initio study of the increased acidity of the cyclic compounds compared to their acyclic analogues of sulfamide, methyl sulfonamide and vinyl sulfonamide was undertaken. The sulfamide and methyl sulfonamide models gave results consistent with experimental results, the former showing an increased acidity, the latter showing no change in acidity. Vinyl sulfonamide gave results contrary to those observed experimentally. The calculation suggested no increase in acidity, although one is observed experimentally.