反应详情

A mixture of 4.46 g. of 2-acetamido-6-methylthiopurine, 4.87 g. of 2,3,5-tri-O-benzyl-α-D-arabinofuranosylchloride, 2 g. of triethylamine and 200 ml. of acetonitrile was stirred with 4-A molecular sieves at room termperature for one week. The mixture was filtered, and the filtrate, which contained the product, was evaporated to a syrup in vacuo. The syrup was dissolved in methanol treated with Dowex-1 (bicarbonate) and the product was purified by chromatography on a Silica gel column, eluted with benzene-ethyl acetate. Evaporation of the solvent gave the syrup 2-acetamido-6-methylthio-9-(2,3,5-tri-O-benzyl-β-D-arabinofuranosyl) purine. To a solution of 1.13 g. of the compound isolated from the previous step in 20 ml. of ethanol, 0.25 ml. of 10N NaOH plus 0.5 ml. of water were added. The stirred solution was kept at 70° for 30 min. and then evaporated to dryness in vacuo. The product was extracted into ether. After evaporation of the ether, 0.92 g. of 2-amino-6-methylthio-9-( 2,3,5-tri-O-benzyl-β-D-arabinofuranosyl) purine was obtained. The identity was established by its NMR spectrum.

1. additionA mixture of 4.46 g
2. filtrationThe mixture was filtered
3. customwas evaporated to a syrup in vacuo
4. dissolutionThe syrup was dissolved in methanol
5. additiontreated with Dowex-1 (bicarbonate)
6. customthe product was purified by chromatography on a Silica gel column
7. washeluted with benzene-ethyl acetate
8. customEvaporation of the solvent