3,4-Dihydro-2H-pyrido[1,2-a]pyrimidin-2-one

Experimental procedure: To a mixture of 2-fluoro-1-methylpyridinium p-toluenesulfonate (1.2 mmol) and 3,4-Dihydro-2H-pyrido[1,2-a]pyrimidin-2-one (4.8 mmol) is added a dichloromethane solution (4 mL) of pentanoic acid (1.0 mmol) and benzyl alcohol (1.0 mmol) at room temperature under argon atmosphere, and the resulting mixture is stirred at room temperature for 46 h. After evaporation of the solvent under reduced pressure, the residue is chromatographed on silica gel, and benzyl pentanoate is isolated (74% yield).