Water → HCID 68998301, compound

Participants

Reaction Conditions

Reaction Steps

Ethyl 1-[6-tert-butoxycarbonyl-4-(2-chloro-4-fluorobenzylamino)-5,6,7,8-tetrahydropyrido[4,3-d]pyrimidin-2-yl]piperidine-4-carboxylate (9.16 g, 16.1 mmol) prepared according to Process Step 3 was dissolved in ethanol (300 mL), and the solution was mixed with an aqueous sodium hydroxide solution (1 mol/L, 32 mL), followed by stirring at 65° C. for sixteen hours. After checking the completion of the reaction by thin layer chromatography, the reaction mixture was mixed with water and washed with diethyl ether. The aqueous layer was neutralized with diluted hydrochloric acid (1 mol/L, 35 mL), the precipitated crystals were collected by filtration and thereby yielded 1-[6-tert-butoxycarbonyl-4-(2-chloro-4-fluorobenzylamino)-5,6,7,8-tetrahydropyrido[4,3-d]pyrimidin-2-yl]piperidine-4-carboxylic acid (3.94 g). The filtrate was extracted with dichloromethane, the organic layer was washed with brine, was dried over anhydrous magnesium sulfate, and the solvent was distilled off. The residue was mixed with diethyl ether for crystallization. The precipitated crystals were collected by filtration and thereby yielded crystals of the target compound (1.07 g, 5.01 g in total with the above-mentioned crystals, in a yield of 62%).

Provenance & Evidence