To a suspension of NaH (0.20 g) in dry DMF (3 ml), 6-chloro-8-propyl-purine (0.06 g, 0.3 mmol) was added, and the mixture was stirred at 40° C. for 20 minutes. t-Butyl-4-bromomethylbiphenyl-2'-carboxylate (0.11 g, 0.31 mmol) was then added at room temperature and stirring continued for 3 hours at 40° C. The content of the flask was poured into ice-water (100 ml and extracted with ethylacetate. The organic phase was separated and dried over MgSO4. Removal of the solvent under reduced pressure gave the crude product which was then purified by flash-chromatography on silica-gel using ethylacetate-hexane (1:1). The pure titled compound was obtained as a glass-like solid (0.073 g, 53%). NMR (CDCl3): δ 1.04 (t, J=9 Hz, 3H), 1.213 (s, 9H), 1.91 (m, 2H), 2.89 (t, 2H), 5.52 (s, 2H), 7.15-7.52 (m, 7H), 7.79 (dd, J1 =8 Hz and J2 =2 Hz, 1H), 8.72 (s, 1H); FAB-MS: m/e 463 and 465 (M+H).
