Hexamethylphosphoramide → 2-(3-Nitro-3-phenyl-propyl)-pyrrolidine-1-carboxylic acid tert-butyl ester

Temperature

-2 °C

To a −78° C. solution of 200 mg (1.460 mmol) 2-(2-bromo-ethyl)-pyrrolidine-1-car boxylic acid tert-butyl ester (CAS: 958026-65-8) in 4.3 ml tetrahydrofuran over mol-sieves and 851.0 ul HMPA, was added drop-wise 1.92 ml (3.064 mmol) n-BuLi (1.6 M in hexane). After 45 minutes at −78° C., a solution of 406.2 mg (1.460 mmol) nitromethyl-benzene in 0.6 ml tetrahydrofuran over mol-sieves was added drop-wise. After 1 hour at −78° C., the reaction mixture was allowed to warm up slowly (during 5 hours) to −2° C. The mixture was then cooled again to −78° C. and quenched at this temperature with 0.4 ml of acetic acid, then with 8 ml saturated ammonium chloride. Back to room temperature, the aqueous phase was extracted 2 times with ethylacetate. The combined organic layers were washed with brine, dried over sodium sulfate, filtered and concentrated in vacuo. The crude yellow oil (993 mg) was purified with flash column chromatography on silica eluting from n-heptane and ethyl acetate (0 to 15%) to provide 242 mg (y: 49.6%) of the title compound as a colorless oil. MS (m/e): 335.2 (M+H+).

1. waitAfter 1 hour at −78° C.
2. temperatureThe mixture was then cooled again to −78° C.
3. customquenched at this temperature with 0.4 ml of acetic acid
4. extractionBack to room temperature, the aqueous phase was extracted 2 times with ethylacetate
5. washThe combined organic layers were washed with brine
6. dry with materialdried over sodium sulfate
7. filtrationfiltered
8. concentrationconcentrated in vacuo
9. customThe crude yellow oil (993 mg) was purified with flash column chromatography on silica eluting from n-heptane and ethyl acetate (0 to 15%)

ORD record

ord-cf5d6be4c99641e1911a31bd03512c19

Source dataset

uspto-grants-2012_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08143273B2