反应详情

Sodium methoxide (120 mg, 2.2 mmol) was added to a solution of 5-Amino-3-(2-deoxy-3,5-di-O-(p-toluoyl)-β-D-erythropentofuranosyl)thiazolo[4,5-d]pyrimidin-2,7-dione (35; 0.465g, 0.87 mmol) in anhydrous methanol (100 mL) and the resulting solution stirred at room temperature for 8 hours. The solution was neutralized with Dowex 50W-X8 (H+ form) resin, filtered, and evaporated to dryness and the residue treated with anhydrous ether (35 mL). After trituration, the suspension was decanted to give a dry powder which was crystallized (charcoal treatment, Norit A) from ethanol. After filtering off the initial precipitate, 110 mg (42%) of the β isomer could be recovered by fractional crystallization using ethanol. mp>170° C. (scinters), UV 1H NMR (Me2SO-d6) σ4.68 (t, 1, J=5.7 Hz, C3 'OH, exchanged with D2O), 5.20 (d, 1, J=3.9 Hz, C5 'OH, exchanged with D2O), 6.24 (t, 1, J=7.2 Hz C1 'H), 6.94 (bs, 2, NH2, exchanged with D2O), 11.23 (bs, 1, N6H, exchanged with D2O); Anal. Calcd. for C10H12N4O5S: C, 40.00; H, 4.03; N, 18.66; S, 10.68; Found: C, 40.27; H, 3.92; N, 18.75; S, 10.42.

1. filtrationfiltered
2. customevaporated to dryness
3. additionthe residue treated with anhydrous ether (35 mL)
4. customAfter trituration, the suspension was decanted
5. customto give a dry powder which
6. customwas crystallized (charcoal treatment, Norit A) from ethanol
7. filtrationAfter filtering off the initial precipitate, 110 mg (42%) of the β isomer
8. customcould be recovered by fractional crystallization