Synthesis of 2-substituted derivatives of the naturally occurring glycosidase inhibitor, salacinol and its nitrogen analogues

This thesis describes the synthesis of 2-amino- and amido- derivatives of the nitrogen analogue of the naturally occurring glycosidase inhibitor, salacinol, the attempted synthesis of 2-amino- and acetamido derivatives of salacinol itself, the synthesis of 2-fluorinated and 1,2-ene derivatives of salacinol, and the synthesis of a suitable precursor for elaboration of 4'-thionucleosides and 4'-thiooligonucleotides. Glycosidases are involved in many biological processes such as cell-cell or cell-virus recognition, immune responses, cell growth, and viral and parasitic infections. The controlled inhibition of glycosidases has potential for the treatment of many diseases such as diabetes, viral infections, and cancer. The synthesis of potential inhibitors of the enzyme human maltase glucoamylase (MGA) that catalyzes the breakdown of glucose-containing oligosaccharides, and hexosaminidase enzymes that cleave the ß-glycosidic linkage of 2-acetamido-2-deoxy-ß-D-glucopyranosides are described. The compounds were intended to mimic the oxacarbenium ion transition state in the enzyme-catalyzed reactions. Seven 2-amino- or 2-amido- derivatives of the nitrogen analogues of salacinol were synthesized. Interestingly, alkylation reactions of the nitrogen atom were observed during hydrogenation of the 2-azido derivatives. Circumvention of this side reaction yielded the 2-substituted analogues which showed marginal activity (