In THF (15 mL) were dissolved 4-((3-chloro-4-methoxybenzyl)amino)-2-(methylsulfinyl)-N-(pyrimidin-2-ylmethyl)pyrimidine-5-formamide (134 mg, 0.30 mmol) and 6-azaspiro[2.5]octane (50 mg, 0.45 mmol). Triethylamine (61 mg, 0.60 mmol) was added dropwisely. The reaction was conducted at ambient temperature for 8 h, followed by addition of water and extraction with DCM. The organic phase was dried over sodium sulfate and purified by silica gel column chromatography (DCM/methanol=80/1) to give a white solid (41 mg, 28% yield).
