Trifluoroacetic acid → 1-(Piperidin-4-yl)azetidin-2-one

To a solution of 4-(2-methoxycarbonyl-ethylamino)-piperidine-1-carboxylic acid tert-butyl ester (3.4 g, 12.0 mmol) in anhydrous THF (75 mL) was slowly added a solution of methyl magnesium bromide in diethyl ether (3 M, 6 mL, 18 mmol) at 0° C. The reaction mixture was stirred at 0° C. for 3 h, then allowed to warm to RT and stirring was continued for 72 h. The reaction mixture was concentrated in vacuo and the resulting residue was partitioned between EtOAc and an aqueous solution of ammonium chloride. The organic layer was separated and washed with brine, then dried (Na2SO4) and concentrated in vacuo. The resultant residue was purified by column chromatography to give 4-(2-oxo-azetidin-1-yl)-piperidine-1-carboxylic acid tert-butyl ester as a pale yellow oil (598 mg, 20%). To a solution of 4-(2-oxo-azetidin-1-yl)-piperidine-1-carboxylic acid tert-butyl ester (595 mg, 2.34 mmol) in DCM (6 mL) was added TFA (2 mL). The resulting mixture was stirred at RT for 1.5 h, then concentrated in vacuo. The resultant residue was loaded onto an Isolute® SCX-2 cartridge, washed with MeOH then eluted with 2 M NH3 in MeOH to give the title compound as a pale yellow solid (325 mg, 90%).

1. concentrationconcentrated in vacuo
2. washwashed with MeOH
3. washthen eluted with 2 M NH3 in MeOH

ORD record

ord-591334c958f34c4b936c1e3dc873f595

Source dataset

uspto-grants-2012_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08293735B2