Water → Tert-butyl 4-(3-fluoro-4-nitrophenyl)piperazine-1-carboxylate

HRID 1641825Notes

Reaction equation

[F:1][C:2]1[CH:7]=[C:6](F)[CH:5]=[CH:4][C:3]=1[N+:9]([O-:11])=[O:10].[C:12]([O:16][C:17]([N:19]1[CH2:24][CH2:23][NH:22][CH2:21][CH2:20]1)=[O:18])([CH3:15])([CH3:14])[CH3:13].C(N(CC)CC)C.O>CN(C=O)C.C(OCC)(=O)C>[C:12]([O:16][C:17]([N:19]1[CH2:24][CH2:23][N:22]([C:6]2[CH:5]=[CH:4][C:3]([N+:9]([O-:11])=[O:10])=[C:2]([F:1])[CH:7]=2)[CH2:21][CH2:20]1)=[O:18])([CH3:15])([CH3:13])[CH3:14]

Participants

Conditions

Temperature: 90 °C

Procedure

A mixture of 2,4-difluoro-nitro-benzene (2.2 mL, 20 mmol), piperazine-1-carboxylic acid tert-butyl ester (3.7 g, 20 mmol), and triethylamine (10 mL) in anhydrous DMF (20 mL) was stirred at 90° C. for 16 hr. After the reaction, the reaction mixture was mixed with water and ethyl acetate, and two layers were separated. The aqueous layer was extracted with ethyl acetate twice. Organic layers were collected, combined, washed with brine, dried over sodium sulfate, filtered, and concentrated. The residue was applied on a silica gel flash column with ethyl acetate and hexanes as eluenting solvents to give 4-(3-fluoro-4-nitro-phenyl)-piperazine-1-carboxylic acid tert-butyl ester (2.1 gm, 32%) as a brown solid. LCMS calcd for C15H20FN3O4 (m/e) 325, obsd 326 (M+H).

Workup

customAfter the reaction
customwere separated
extractionThe aqueous layer was extracted with ethyl acetate twice
customOrganic layers were collected
washwashed with brine
dry with materialdried over sodium sulfate
filtrationfiltered
concentrationconcentrated

Sources & evidence

ORD record: ord-609cb675737645a4b29ecb6d0ba1c2e7
Source dataset: uspto-grants-2012_02
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08115011B2

Reaction notes

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