Water → HCID 21853340, compound

Participants

Reaction Steps

To a solution of 5-acetamido-2-(2,3,5-tri-O-acetyl-β-D-ribofuranosyl)-1,2,4-thiadiazol-3-one (4, 0.5 g, 0.0011 mole) in anhydrous methanol (25 ml) was added 1N sodium methoxide in methanol, till the pH of the solution was 8.5 and the resulting solution was stirred at ambient temperature for 2.5 hr. Within 40 min the secondary O-acetyl groups were removed and by the end of 2 hr all the O-acetyl groups were removed as judged by tlc. After the O-deacetylation was complete, the sodium ions were removed by stirring the reaction mixture with Amberlite IRC-50 (H+) resin (7.0 g, dry weight) for 15 min before the neutral solution, free from resin, was evaporated to dryness. The residual gum was chromatographed on a silica gel column (3 × 27 cms) using ethyl acetate:water:n-propanol (4:2:1), v/v, upper phase). The appropriate fractions were pooled, solvent evaporated and the residue crystallized from aqueous ethanol to yield 0.23 g (67.0%), m.p. 204°-205° (dec.); [α]D25 -50.1° (c 1.0, water); 1H nmr (Me2SO-d6) δ2.28 (s, 3H, --NAc), 5.65 (d, J=5.0 Hz, C1'H); uv λmax (pH 1) 235 nm (ε 10,600), 275 (3500); λmax (pH 7) 254 nm (ε 9900), 277 sh (5400); λmax (pH 11) 254 nm (ε 12,700), 277 sh (5,900).

Provenance & Evidence