5-amino-3-(2,3,5-tri-O-benzoyl-beta-D-ribofuranosyl)thiazolo-[4,5-d]pyrimidine-2,7(6H)-dione → Isatoribine Anhydrous

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Reaction Steps

A solution of 6 (0.75 g, 1 mmol) in methanol (75 mL) was adjusted to pH 9 with NaOCH3 and stirred at room temperature for 16 h. The reaction mixture was evaporated to dryness and the residue was triturated with ether (2×75 mL). The ether insoluble solid was dissolved in water (15 mL) and acidified with acetic acid whereupon the crude product precipitated. Crystallization of this material from water gave a colorless powder: yield 0.31 g, 78%: mp 238° C. (decomp.): UV λmax (pH 1) 215 nm (ε2280), 245 (6900), 301 (8400): UV λmax (pH 7) 215 nm (ε22100), 245 (6900), 301 (8000): UV λmax (pH 11) 245 nm (ε5700), 291 (6000). NMR (DMSO-d6) δ5.79 (1H, d, J=5.32 Hz, C1, H), 6.90 (2H, s, NH2), 11.12 (1H, s, NH), and other sugar protons. Anal. Calcd. for C10H12N4O6S.H2O: C, 35.92: H, 4.22: N, 16.76: S, 9.59. Found: C, 35.82: H, 4.02: N, 16.92: S, 9.66.

Provenance & Evidence