Pd-C (5%) (500 mg) was added to a solution of 2,6-diazido-9-(2,3,5-tri-O-benzyl-β-D-arabinofuranosyl)purine (IV, 4.8 g, 8.0 mmol) in EtOH (500 ml), and the resulting mixture was hydrogenated at atmospheric pressure for 6 hr. The H2 atmosphere was changed after 30 min. and after 1 hr. The catalyst was removed by filtration and was washed with CHCl3 to dissolve precipitated product. The combined filtrate and washings were evaporated to dryness in vacuo, and the resulting residue was dissolved in boiling EtOH (80 ml). The crystals that formed on cooling the EtOH solution were collected by filtration, washed with EtOH, and dried in vacuo; yield 3.3 g (75%), mp 161°-162°, TLC (19:1 CHCl3 --MeOH). The analytically pure produce was obtained from a previous preparation: yield 69%; mp 162°; [α]D25 +44.4±0.7° (c, 1.06, CHCl3); λmax ]Mμ (ε× 10-3)], pH 1--254 (10.9), 292 (9.0); EtOH--256 (10.8), 283 (9.0); pH 7, 13--256 (9.0), 279 (9.1); vmax (cm-1)3460, 3350, 3310, 3140 (NH, CH), 2940, 2915 2890, 2865 (CH), 1660 (NH), 1590 (C=C, C=N), 1085, 1045, 1015 (COC), 730, 690 (phenyl).
