Triethylamine → (3-Fluoro-4-nitrophenyl)carbamic acid tert-butyl ester

HRID 722411Notes

Reaction equation

C1(P(N=[N+]=[N-])(C2C=CC=CC=2)=O)C=CC=CC=1.[F:18][C:19]1[CH:20]=[C:21]([CH:25]=[CH:26][C:27]=1[N+:28]([O-:30])=[O:29])C(O)=O.C([N:33]([CH2:36]C)CC)C.[C:38]([OH:42])([CH3:41])([CH3:40])[CH3:39].[O:43]1CCOCC1>C(OCC)(=O)C>[C:38]([O:42][C:36]([NH:33][C:21]1[CH:25]=[CH:26][C:27]([N+:28]([O-:30])=[O:29])=[C:19]([F:18])[CH:20]=1)=[O:43])([CH3:41])([CH3:40])[CH3:39]

Participants

Conditions

Temperature: 95 °C

Procedure

Diphenylphosphorylazide (5.5 mmol, 1.5 g) was added to a solution of 3-fluoro-4-nitrobenzoic acid (5.4 mmol, 1 g) and triethylamine (5.6 mmol, 0.8 mL) in a 1:1 mixture of tert-butyl alcohol/dioxane (60 mL). The reaction mixture was refluxed for 2 days at 95° C. and the solvent was evaporated to give an oily residue. The residue was taken up in ethyl acetate (100 mL) and washed with 10% citric acid, 1N NaOH, brine and H2O. Evaporation of solvent afforded an orange residue that was subsequently purified by flash chromatography eluting with ethyl acetate/hexane to afford (tert-butoxy)-N-(3-fluoro-4-nitrophenyl)carboxamide (1.75 mmol, 0.45 g, yield 32%). 3-Fluoro-4-nitroaniline (0.36 g, 2.3 mmol) was isolated as a byproduct. Treatment of (tert-butoxy)-N-(3-fluoro-4-nitrophenyl)carboxamide with trifluoroacetic acid in methylene chloride afforded additional 3-fluoro-4-nitroaniline.

Workup

customthe solvent was evaporated
customto give an oily residue
washwashed with 10% citric acid, 1N NaOH, brine and H2O
customEvaporation of solvent
customafforded an orange residue that
customwas subsequently purified by flash chromatography
washeluting with ethyl acetate/hexane

Sources & evidence

ORD record: ord-6abd4f6522d741d2ae71ce8cbc060a73
Source dataset: uspto-grants-2006_11
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07138420B2

Reaction notes

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