Acetamidine monohydrochloride → t-butyl 2-methyl-4-(trifluoromethyl)-5,8-dihydropyrido[3,4-d]pyrimidin-7(6H)-carboxylate

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Reaction Conditions

Reaction Steps

1.3 mL of sodiumethoxide (21% wt. ethanol solution) was added at room temperature to a solution in which 283 mg (3.0 mmol) of acetamidine hydrochloric acid salt was dissolved in 5 mL of absolute ethanol. After stirring of 15 minutes, to the resulting solution, was added a solution in which 590 mg (2.0 mmol) of t-butyl 3-oxo-4-(trifluoroacetyl)-piperidin-1-carboxylate obtained in PREPARATION 47 was diluted with 5 mL of absolute ethanol. The resulting mixture was heated to 80° C. and stirred for 18 hours. After cooling to room temperature, ethanol was distilled off under reduced pressure, followed by washing with saline which was diluted with ethylacetate. An organic layer was dried over anhydrous magnesium sulfate, the solvent was distilled off under reduced pressure and then the residue was purified by column chromatography (10:1 hexane:ethyl acetate) to give 98 mg of the title compound in a yield of 16%.

Provenance & Evidence