Hexamethylphosphoramide → Methyl-(1-methyl-4-nitro-4-phenyl-butyl)-carbamic acid tert-butyl ester

Temperatur

-15 °C

To a −78° C. solution of 304 mg (2.219 mmol) nitromethyl-benzene (CAS: 622-42-4) in 5 ml tetrahydrofuran over mol-sieve and 1.29 ml HMPA, was added dropwise 2.91 ml (4.654 mmol) n-BuLi (1.6 M in hexane). After 45 minutes at −78° C., a solution of 590.7 mg (2.219 mmol) (3-bromo-1-methyl-propyl)-methyl-carbamic acid tert-butyl ester in 1.5 ml tetrahydrofuran over mol-sieve was added dropwise. After 1 hour at −78° C., the reaction mixture was allowed to warm up slowly, during 2 hours, to −15° C. The mixture was then cooled again to −78° C. and quenched with 0.75 ml of acetic acid, then with 13 ml saturated ammonium chloride. Back to room temperature, the aqueous phase was extracted two times with ethylacetate. The combined organic layers were dried over sodium sulfate, filtered and concentrated in vacuo. The residue was purified on silica (Eluent: heptane/ethyl acetate 0 to 10%) to provide 201 mg (28%) of the title compound as a colorless oil. MS (m/e): 323.3 (M+H).

1. waitAfter 1 hour at −78° C.
2. temperatureThe mixture was then cooled again to −78° C.
3. customquenched with 0.75 ml of acetic acid
4. extractionBack to room temperature, the aqueous phase was extracted two times with ethylacetate
5. dry with materialThe combined organic layers were dried over sodium sulfate
6. filtrationfiltered
7. concentrationconcentrated in vacuo
8. customThe residue was purified on silica (Eluent: heptane/ethyl acetate 0 to 10%)

ORD-Eintrag

ord-c6abea5de68548368a1c6c7042eaea9b

Quelldatensatz

uspto-grants-2015_06

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US09067911B2