N2-Butyl-8-(methyloxy)-3H-purine-2,6-diamine trifluoroacetate (192 mg, 0.547 mmol) and potassium carbonate (189 mg, 1.368 mmol) were suspended in DMF (3 ml) and heated to 60° C. for 1 hour. The reaction mixture was cooled to room temperature and 1-bromo-5-chloropentane (0.072 ml, 0.547 mmol) was added and the reaction stirred for a further 18 hours. Hexahydro-1H-azepine (54.2 mg, 0.547 mmol) and triethylamine (0.076 ml, 0.547 mmol) were added and the reaction mixture heated to 70° C. for 24 hours. LCMS showed a major peak with MH+ 404 consistent with the formation of N2-butyl-9-[5-(hexahydro-1H-azepin-1-yl)pentyl]-8-(methyloxy)-9H-purine-2,6-diamine. The solvent was removed in vacuo and the residue partitioned between DCM (2 ml) and water (2 ml). The aqueous was extracted again with DCM (2 ml) and the combined organic extracts were concentrated and the residue was dissolved in 1:1 MeOH:DMSO (2 ml) and purified by MDAP (Method C). Evaporation of the product containing fractions gave a residual TFA salt which LCMS indicated had undergone hydrolysis of the 8-methoxy group, presumably on concentration in the presence of TFA. This crude material was dissolved once more in 1:1 MeOH:DMSO (2 ml) and re-purified by MDAP (Method A). Product-containing fractions were evaporated under a stream of nitrogen to give the title compound as a white solid (39 mg).
