Stereoselective Synthesis of 5′-S-(5-Acetamido-3,5-dideoxy-D-glycero-α-and-β-D-Galacto-2-nonulopyranosylonic Acid)-5′-thio Cytidixe

Abstract

Methyl 5-Acetamido-4,7,8,9-Tetra-O-Acetyl-2-Chloro-2,3,5-Trideoxy-D-Glycero-β-D-Galacto-2-Nonulopyranosonate (1) Underwent Displacement With Fluorine Ion, To Yield, After 2-S-Acetylation, Methyl 5-Acetamido-4,7,8, 9-Tetra-O-Acetyl-2-S-Acetyl-3,5-Dideoxy-D-Glycero-β-D-Galacto-2-Nonulopyranosonate (4), Which Was Converted, By Selective S-Deacetylation, Into The Corresponding Sodium Salt (6). Condensation Of The α- And β-Sodium Salts (5 And 6) With 2′,3′-Di-O-Acetyl-N ⁴-Benzoyl-5′-Bromo-5′-Deoxycytidine (9), Derived From N ⁴-Benzoylcytidine (7) In Two Steps, Gave Their Respective Coupled Products. These Were Converted By O-Deacetylation, N ⁴-Debenzoylation, And Hydrolysis Of The Methyl Ester Group, Into The Title Compounds.