Sodium ethoxide → tert-Butyl 4-(trifluoromethyl)-5,6-dihydropyrido[3,4-d]pyrimidine-7(8H)-carboxylate

Participants

Reaction Steps

0.52 mL of sodium ethoxide (21% wt. ethanol solution) was added at room temperature to a solution in which 95 mg (1.18 mmol) of formamidine hydrochloric acid salt was dissolved in 2 mL of anhydrous ethanol at room temperature. After stirring at room temperature for 10 minutes, to the resulting solution, was added a solution in which 232 mg (0.786 mmol) of tert-butyl-3-oxo-4-(trifluoroacetyl)-piperidine-1-carboxylate (product of PREPARATION 47) was diluted with 2 mL of anhydrous ethanol. Thereafter, the temperature of the solution was raised to 80° C., followed by stirring for about 18 hours. After cooling to room temperature, ethanol was removed under reduced pressure, and the reaction solution was diluted with ethylacetate, then washed in sequence aqueous NaCl. An organic layer was dried over anhydrous magnesium sulfate and filtered off. The filtrated solution was distilled off under reduced pressure and then, the residue was isolated and purified by prep-TLC (ethylacetate 20% normal hexane in solvent) to give 30 mg of the title compound in a yield of 13%

Provenance & Evidence