Nucleoside von Fluorzuckern,XV. Synthese von Thymin-Nucleosiden der 6-Fluor-D-glucopyranose und 6-Fluor-D-galaktopyranose

Nucleosides of Fluorine Carbohydrates. XV. Synthesis of Thymine Nucleosides of 6-Fluoro-D -glucopyranose and 6-Fluoro-D -galactopyranose 1-β-D -glucopyranosyl thymine 1 and 1-β-D -galactopyranosyl thymine 13 react with equimolar amounts of tosyl or mesyl chloride to give predominantly the 6′-O-sulphonyl derivatives 6 and 7 or 14 and 15 . Simultaneously small amounts of the 2′,6′-di-O-sulphonyl derivatives 4 and 5 are obtained. The tosyl derivative 6 reacts easily with alkali fluoride to give the 6′-deoxy-6′-fluoro nucleoside 10 . In contrast to the glucose series the corresponding conversion of the 6′-sulphonyloxy-galactose derivatives is difficult to achieve. The condensation of 2,3,4-tri-O-acetyl-6-O-tosyl-D -glucopyranosyl bromide 2 or 6-deoxy-6-fluoro-1,2,3,4-tetra-O-acetyl-D -galactopyranose 18 with 2,4-bis-O-trimethylsilyl thymine 3 affords, after deacetylation, 6 and 1-(6′-deoxy-6′-fluoro-β-D -galactopyranosyl)thymine 20 , respectively.