反应详情

To a solution of 6-chloropurine (213 mg, 1.37 mmol), diisopropyl (E)-3-(t-butyldiphenylsilyloxy)methyl-4-hydroxybut-1-enylphosphonate (694 mg, 1.37 mmol) and triphenyl phosphine (540 mg, 2.06 mmol) in N,N-dimethylformamide (22 ml) stirred at 0° C. under dry nitrogen was added diethyl azodicarboxylate (358 mg, 2.06 mmol). The solution was stirred at room temperature for 16 h. The solvent was removed and the residue purified by column chromatography on silica gel eluting with acetone-hexane (1:4, 1:2) then ethyl acetate-methanol (99:1, 9:1) to give (E)-9-[2-(t-butyldiphenylsilyloxy) methyl-4-(diisopropoxyphosphoryl)but-3-enyl]-6-chloropurine as a colourless gum (244 mg, 28%); λmax (EtOH) 265 (9,215nm; υmax (film) 2980, 2930, 1590, 1560, 1425, 1385, 1335 and 1245 cm-1 ; δH (CDCl3) 1.10 (9H, s, CH3), 1.20 (12H, m, CH (CH3)2), 3.07 (1H, m, CH), 3.69 (2H, d, J 6 Hz, CH2O ), 4.50 (4H, m, CH2N and CH(CH3)2), 5.57 (1H, pseudo-t, J 17 Hz, PCH=CH), 6.66 (1H, ddd, J 8 Hz, 17 Hz and 26 Hz, PCH=CH), 7.30-7.70 (10H, m, Ph), 8.00 (1H, s, H-2/H-8), 8.73 (1H, s, H-2/H-8) (Found: M+ 641.2459. C32H42N4ClO4PSi requires M+ 641.2479).

1. customThe solvent was removed
2. customthe residue purified by column chromatography on silica gel eluting with acetone-hexane (1:4, 1:2)