To a solution of 8-(1-Benzyl-1H-pyrazol-4-yl)-2-chloro-1-propyl-1,7-dihydro-purin-6-one (0.05 g, 0.136 mmol) in THF (5 ml) under argon was added Diisopropyl ethyl amine (0.05 g, 0.407 mmol) and 1M methyl amine in THF (0.042 g, 1.36 mmol). The reaction mixture was heated at 50° C. for overnight. The reaction mixture concentrated under reduced pressure. The residue obtained was purified by column chromatography to obtain 8-(1-Benzyl-1H-pyrazol-4-yl)-2-methylamino-1-propyl-1,7-dihydro-purin-6-one (0.025 g, 51%) as a white solid.
