Hydrochloric Acid → 8-(2-(4-isopropyl-1,3-thiazol-2-yl)-ethyl)-4-oxo-4H-pyrido[1,2-a]pyrimidine-3-carbaldehyde

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Reaction Steps

The methyl 8-[2-(4-isopropyl-1,3-thiazol-2-yl)ethyl]-4-oxo-4H-pyrido[1,2-a]-pyrimidin-3-carboxylate (660 mg) obtained in (A) was dissolved in tetrahydrofuran (30 ml), added dropwise with diisopropylaluminum hydride (1 M solution in tetrahydrofuran, 9.2 ml) at −78° C., and then the mixture was stirred for 2 hours at the same temperature. The reaction mixture was added with saturated aqueous ammonium chloride (1 ml), then added with 12% aqueous hydrochloric acid, and stirred at room temperature for 1 hour. After insoluble solids were removed by filtration through a Celite layer, the solvent of the filtrate was evaporated, and the residue was dissolved in methylene chloride. This solution was added with active manganese dioxide (1.2 g) and stirred at room temperature for 16 hours. Then, insoluble matters were removed by filtration to obtain the title compound (390 mg) as yellow powder.

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