Benzyl chloroformate → 1-Benzyl 6-(tert-butyl) 1,6-diazaspiro[3.5]nonane-1,6-dicarboxylate

To a solution of an optically-active compound of 3-amino-3-(2-hydroxyethyl)piperidine-1-carboxylic acid tert-butyl ester (6.46 g), triphenylphosphine (12.5 g) and triethylamine (13.3 ml) in dichloromethane (226 ml) cooled to 0° C. was added carbon tetrabromide (15.8 g). The reaction mixture was stirred at room temperature for 40 minutes and cooled to 0° C. again. Then, thereto were added triethylamine (5.5 ml) and benzyl chloroformate (4.9 ml), and the mixture was stirred for 3.5 hours at room temperature. To the mixture was added water (200 ml), and the mixture was extracted with chloroform (100 ml). The organic layer was washed with saturated aqueous sodium chloride solution, and concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography (eluent: n-hexane/ethyl acetate=5/1) to give the titled compound (5.35 g).

1. temperaturecooled to 0° C. again
2. stirringthe mixture was stirred for 3.5 hours at room temperature
3. extractionthe mixture was extracted with chloroform (100 ml)
4. washThe organic layer was washed with saturated aqueous sodium chloride solution
5. concentrationconcentrated under reduced pressure
6. customThe resulting residue was purified by silica gel column chromatography (eluent: n-hexane/ethyl acetate=5/1)

ORD record

ord-dc0c4a81bcfc485ea2fba4e1a96c98b2

Source dataset

uspto-grants-2013_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08609647B2