Trifluoroacetic acid → (2S)-(2R,3S,4R,5R)-2-((((((2R,3S,5R)-5-(4-amino-2-oxopyrimidin-1(2H)-yl)-2-((phosphonooxy)methyl)tetrahydrofuran-3-yl)oxy)(hydroxy)phosphoryl)oxy)methyl)-5-(6-amino-9H-purin-9-yl)-4-hydroxytetrahydrofuran-3-yl 2-amino-5-azido-4-(tert-butyldisulfanyl)pentanoate

Participants

Reaction Steps

The aforementioned crude product of (2S)-(2R,3S,4R,5R)-2-((((((2R,3S,5R)-5-(4-amino-2-oxopyrimidin-1(2H)-yl)-2-((phosphonooxy)methyl)tetrahydrofuran-3-yl)oxy) (hydroxy)phosphoryl)oxy)methyl)-5-(6-amino-9H-purin-9-yl)-4-hydroxytetrahydrofuran-3-yl 5-azide-2-((tert-butoxycarbonyl)amino)-4-(tert-butyldisulfanyl)pentanoate (Compound 42) (53 mg) was suspended by adding dichloromethane (2 ml) thereto, after which trifluoroacetic acid (0.5 mL) was added at room temperature, and the mixture was stirred at the same temperature for 30 minutes. Following concentration under reduced pressure, the resulting residue was purified by reverse-phase silica gel column chromatography (0.05% aqueous trifluoroacetic acid solution/0.05% trifluoroacetic acid-acetonitrile solution) to afford (2S)-(2R,3S,4R,5R)-2-((((((2R,3S,5R)-5-(4-amino-2-oxopyrimidin-1(2H)-yl)-2-((phosphonooxy)methyl)tetrahydrofuran-3-yl)oxy)(hydroxy)phosphoryl)oxy)methyl)-5-(6-amino-9H-purin-9-yl)-4-hydroxytetrahydrofuran-3-yl 2-amino-5-azido-4-(tert-butyldisulfanyl)pentanoate (Orn(N3) (4-SStBu)-pdCpA) (Compound 43) (24 mg, 31% in two steps).

Provenance & Evidence