To a solution of 8-chloro-3-pentyl-7-(2-propen-1-yl)-3,7-dihydro-1H-purine-2,6-dione (0.10 g, 0.34 mmol), 3-{3-[(4-chlorophenyl)methyl]-1,2,4-oxadiazol-5-yl}-1-propanol (0.086 g, 0.34 mmol) and triphenylphosphine (0.186 g, 0.69 mmol) in THF (5 ml) was added dibenzylazodicarboxylate (0.204 g, 0.68 mmol) and the solution stirred for 18 h. The solution was then concentrated and the residues chromatographed over silica (20 g, SPE) eluting with DCM initially then DCM/Et2O mixtures to yield the title compound contaminated with dibenzylazodicarboxylate by-products (0.18 g). Material used crude in deprotection step.
