Potassium Carbonate → 9-(4-benzoylbenzyl)-6-chloro-9H-purine

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Reaction Steps

The synthesis of 9'-(4-benzoylbenzyl)-9H-adenine (20) was achieved by the following procedure (Scheme 9). A mixture of 6-chloropurine (3.09 g, 20 mmol), 4-benzoyl-benzyl chloride (6.05 g, 22 mmol) and K2CO3 (3.04 g, 22 mmol) in DMF (50 ml) was stirred overnight at rt, diluted with water (400 ml), and extracted with EtOAc (3×100 ml) (Scheme 9)52. The combined organic layers were washed with water and brine, dried over MgSO4, concentrated in vacuo, and subjected to flash-chromatography on silica gel eluting with CH2Cl2 -acetone (80:20). The fractions containing the higher Rf, the major component, were combined and concentrated in vacuo to give 2.86 g (41%) of 9-(4-benzoylbenzyl)-6-chloro-9H-purine. To a solution of this iminochloride (1.05 g, 3 mmol) in EtOH (20 ml) was added a 2M solution of NH3 in MeOH. This medium was warmed overnight at 90° C. under pressure (constant volume). It was then cooled and concentrated in vacuo. The residue was washed successively with a 1M solution of NaHCO3, water, iPrOH, and hot CH2Cl2, and then was recrystallized from butanol to give 0.53 g (54%) of 9-(4-benzoylbenzyl)-9H-adenine (20). 1H NMR (DMSO) δ 5.49 (s, 2H, CH2), 7.27-7.71 (m, 9H, H--Ar), 8.15 (s, 1H, H-2), 8.30 (s, 1H, H-8). ##STR10## Synthesis of 9-[(4-bis-phenyl)buten-4-yl]-9H-adenine (21)

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