Cesium carbonate → (S)-tert-Butyl 3-Ethyl-4-(6-nitropyridin-3-yl)piperazine-1-carboxylate

HRID 1411646Notes

Reaction equation

HRID 1411646 reaction equation
Br[C:2]1[CH:3]=[CH:4][C:5]([N+:8]([O-:10])=[O:9])=[N:6][CH:7]=1.[CH2:11]([C@@H:13]1[NH:18][CH2:17][CH2:16][N:15]([C:19]([O:21][C:22]([CH3:25])([CH3:24])[CH3:23])=[O:20])[CH2:14]1)[CH3:12].CC1(C)C2C(=C(P(C3C=CC=CC=3)C3C=CC=CC=3)C=CC=2)OC2C(P(C3C=CC=CC=3)C3C=CC=CC=3)=CC=CC1=2.C(=O)([O-])[O-].[Cs+].[Cs+]>C1C=CC(/C=C/C(/C=C/C2C=CC=CC=2)=O)=CC=1.C1C=CC(/C=C/C(/C=C/C2C=CC=CC=2)=O)=CC=1.C1C=CC(/C=C/C(/C=C/C2C=CC=CC=2)=O)=CC=1.[Pd].[Pd].O1CCOCC1>[CH2:11]([C@@H:13]1[N:18]([C:2]2[CH:7]=[N:6][C:5]([N+:8]([O-:10])=[O:9])=[CH:4][CH:3]=2)[CH2:17][CH2:16][N:15]([C:19]([O:21][C:22]([CH3:23])([CH3:25])[CH3:24])=[O:20])[CH2:14]1)[CH3:12]

Participants

7

Reactant 4

HCID 10796Cesium carbonateHCID 6360441,1'-(9,9-Dimethyl-9H-xanthene-4,5-diyl)bis(1,1-diphenylphosphine)HCID 8176205-Bromo-2-nitropyridineHCID 24820542tert-Butyl (3S)-3-ethylpiperazine-1-carboxylate

Product 1

HCID 86683738(S)-tert-Butyl 3-Ethyl-4-(6-nitropyridin-3-yl)piperazine-1-carboxylateYield 22%

Reagents, catalysts & solvents 2

HCID 9811564Bis(dibenzylideneacetone)palladiumCatalystHCID 312751,4-DioxaneSolvent

Conditions

Temperature
100 °C

Procedure

A 250-mL single-neck round-bottomed flask equipped with a magnetic stirrer and a reflux condenser was charged with 1,4-dioxane (50 mL), 5-bromo-2-nitropyridine (2.02 g, 10 mmol), (S)-tert-butyl 3-ethylpiperazine-1-carboxylate (2.14 g, 10.0 mmol), Pd2(dba)3 (458 mg, 0.50 mmol), XantPhos (576 mg, 1.0 mmol), and cesium carbonate (6.52 g, 20 mmol). After three cycles of vacuum/argon flush, the mixture was heated at 100° C. overnight. After this time the reaction was cooled to room temperature. It was then filtered and the filtrate was evaporated under reduced pressure. The residue was purified by silica-gel column chromatography eluting with 3:1 petroleum ether/ethyl acetate to afford 161a (700 mg, 22%) as a yellow solid. MS: [M+H]+ 336

Workup

  1. customA 250-mL single-neck round-bottomed flask equipped with a magnetic stirrer and a reflux condenser
  2. customAfter three cycles of vacuum/argon flush
  3. temperatureAfter this time the reaction was cooled to room temperature
  4. filtrationIt was then filtered
  5. customthe filtrate was evaporated under reduced pressure
  6. customThe residue was purified by silica-gel column chromatography
  7. washeluting with 3:1 petroleum ether/ethyl acetate

Sources & evidence

ORD record
ord-f038aafc13e94ddca1da76bdff9df967
Source dataset
uspto-grants-2014_12
Patent number
US08921353B2

Reaction notes

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