الفهرس 
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Abstract
The presented thesis comprises three chapters. The first chapter is the introduction, which includes a survey of the literature reports on the studies on trehalose type disaccharides. Bimolecular nucleophilic displacement are also reviewed with some emphasis on the most common strategies employed in inversion reactions. Moreover, regioselective acylation and alkylation of sugar derivatives are cited.
The second chapter is devoted to a discussion of the original work of the candidate.
The first part of Chapter II deals with the synthesis of a-D-galactopyanosyl α-D- galactopyranoside (7) by the inversion of configuration at C-4 and C-4’ of the known 2,3,6-tri-O-benzoyl- a-D-glucopyranosyl 2,3,6-tri-O-benzoyl- a-D-glucopyranoside (3), through the use of its 4,4’-ditriflate derivative (4) followd by a displacement reaction using sodium nitrite, or potassium acetate in the presence of appropriate crown ether to give either 2,3,6-tri-O-benzoyl- a-D-galactopyranosyl 2,3,6-tri-O- benzoyl- a-D-galactopyranoside (5) or 4-0-acetyl-2,3,6-tri-O-benzoyl- α-D-
galactopyranosyl
4-O-acetyl-2,3,6-tri-O-benzoyl-
a-D-galactopyranoside (6)
respectively. Zempien-O-deacylation of compound 5 or 6 using sodium methoxide at room temperature afforded a-D-galactopyranosyl a-D-galactopyranoside (7).
The second section of Chapter II deals with the preparation of 4-azido-4-deoxy- a-D-galactopyranosyl 4-azido-4-deoxy-a-D-galactopyranoside (9) using the 4,4’-O-di triflate derivative (4), followed by inversion of configuration at C-4’, b.