1-Hydroxybenzotriazole → HCID 23078913, compound

To a solution of the obtained mono-ethyl dimethylmalonate (1 g) in N,N-dimethylformamide (20 mL) were added 1-(benzyloxycarbonyl)piperazine (1.38 g), 1-hydroxybenzotriazole (0.93 g), triethylamine (1.31 mL) and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (2.4 g), and the mixture was stirred at room temperature for 2 days. The reaction mixture was poured into water, and the resulting mixture was extracted with diethyl ether. The extract was washed with a saturated aqueous sodium hydrogen carbonate solution, water and brine, and dried over anhydrous magnesium sulfate. The solvent was removed under reduced pressure, and the residue was purified by column chromatography on silica gel (eluent: n-hexane/ethyl acetate=4/1-2/1) to give 1-benzyloxycarbonyl-4-[2-ethoxycarbonyl-2-(methyl)propionyl]piperazine (1.77 g). This material was dissolved in ethanol (5 mL). To the solution was added 2 mol/L aqueous sodium hydroxide solution (2.93 mL), and the mixture was stirred at 55° C. overnight. The reaction mixture was poured into water, and the resulting mixture was washed with diethyl ether. The aqueous layer was acidified by addition of 2 mol/L hydrochloric acid, and the mixture was extracted with diethyl ether. The extract was washed with brine, and dried over anhydrous magnesium sulfate. The solvent was removed under reduced pressure to give the title compound (0.28 g).

1. extractionthe resulting mixture was extracted with diethyl ether
2. washThe extract was washed with a saturated aqueous sodium hydrogen carbonate solution, water and brine
3. dry with materialdried over anhydrous magnesium sulfate
4. customThe solvent was removed under reduced pressure
5. customthe residue was purified by column chromatography on silica gel (eluent: n-hexane/ethyl acetate=4/1-2/1)

ORD record

ord-8d820aa75f894ecc9c311e7cb6ef5369

Source dataset

uspto-grants-2012_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08324176B2