3-Nitroaniline → Tert-butyl 3-nitrophenylcarbamate

To a solution of 3-nitroaniline (15.4 g, 112 mmol) in acetonitrile (220 ml) were added di-tert-butyl bicarbonate (62.2 g, 285 mmol), triethylamine (23.2 mL, 168 mmol) and N,N-dimethylpyridine-4-amine (1.36 g, 11.2 mmol), and the mixture was stirred at room temperature for 42 hr. The reaction mixture was concentrated under reduced pressure. To a solution of the obtained residue in methanol (100 mL)/tetrahydrofuran (100 mL) was added potassium carbonate (30.8 g, 223 mmol), and the mixture was stirred at 60° C. for 1 hr. To the reaction mixture was added water (200 mL), and the mixture was extracted with ethyl acetate (300 mL, 100 mL). The combined organic layer was washed with saturated brine (50 mL), and dried over anhydrous magnesium sulfate. The insoluble material was filtered off, and the filtrate was concentrated under reduced pressure. The obtained residue was purified by silica gel column chromatography (hexane/ethyl acetate=100/0→90/10), and the fractions containing the object product were concentrated under reduced pressure. The obtained residue was recrystallized from ethyl acetate and hexane to give the title compound (18.6 g, 70%) as pale-yellow needle crystals.

1. concentrationThe reaction mixture was concentrated under reduced pressure
2. stirringthe mixture was stirred at 60° C. for 1 hr
3. extractionthe mixture was extracted with ethyl acetate (300 mL, 100 mL)
4. washThe combined organic layer was washed with saturated brine (50 mL)
5. dry with materialdried over anhydrous magnesium sulfate
6. filtrationThe insoluble material was filtered off
7. concentrationthe filtrate was concentrated under reduced pressure
8. customThe obtained residue was purified by silica gel column chromatography (hexane/ethyl acetate=100/0→90/10)
9. additionthe fractions containing the object product
10. concentrationwere concentrated under reduced pressure
11. customThe obtained residue was recrystallized from ethyl acetate and hexane

ORD-Eintrag

ord-e03859147e6d494da55f14376fb36f86

Quelldatensatz

uspto-grants-2013_01

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08344135B2