Pyrimidine nucleosides of 2-amino-2-deoxy-D-galactose

Abstract 2-Deoxy-2-( p -methoxybenzylidene)amino- D -galactose was acetylated, and the resulting product was treated with hydrochloric acid, giving 1,3,4,6-tetra- O -acetyl-2-amino-2-deoxy-β- D -galactopyranose hydrochloride ( 3 ). Treatment of 3 with trifluoroacetic anhydride yielded 1,3,4,6-tetra- O -acetyl-2-deoxy-2-(trifluoroacetamido)-β- D -galactopyranose ( 4 ), which was converted into 3,4,6-tri- O -acetyl-2-deoxy-2-(trifluoroacetamido)-α- D -galactopyranosyl bromide ( 5 ) by a previously published procedure. Condensation of 5 with bis(trimethylsilyl)cytosine yielded 1-[3,4,6-tri- O -acetyl-2-deoxy-2-(trifluoroacetamido)-β- D -galactopyranosyl]cytosine, which was deacylated with methanolic ammonia to give 1-(2-amino-2-deoxy-β- D -galactopyranosyl)cytosine. Condensation of 5 with bis(trimethylsilyl)thymine yielded 1-[3,4,6-tri- O -acetyl-2-deoxy-2-(trifluoroacetamido)-β- D -galactopyranosyl]thymine ( 8 ), which was deacylated with methanolic ammonia to give 1-(2-amino-2-deoxy-β- D -galactopyranosyl)thymine ( 9 ). Condensation of 2-acetamido-3,4,6-tri- O -acetyl-2-deoxy-α- D -galactopyranosyl chloride with bis(trimethylsilyl)thymine gave 1-(2-acetamido-3,4,6-tri- O -acetyl-2-deoxy-β- D -galactopyranosyl)thymine ( 11 ), but in substantially lower yield than 8 . Compound 11 was also obtained by acetylation of 9 .