Toluene → 4-(3-Methyl-5-vinylpyridin-2-yl)piperazine-1-carboxylic acid tert-butyl ester

HRID 1803997Notes

Reaction equation

HRID 1803997 reaction equation
[C:1]([O:5][C:6]([N:8]1[CH2:13][CH2:12][N:11]([C:14]2[C:19]([CH3:20])=[CH:18][C:17](Br)=[CH:16][N:15]=2)[CH2:10][CH2:9]1)=[O:7])([CH3:4])([CH3:3])[CH3:2].P([O-])([O-])([O-])=O.[K+].[K+].[K+].[CH:30](B1OC(C)(C)C(C)(C)O1)=[CH2:31].C1(C)C=CC=CC=1>C1CCC(P(C2CCCCC2)C2CCCCC2)CC1.C1CCC(P(C2CCCCC2)C2CCCCC2)CC1.[Cl-].[Cl-].[Pd+2].O>[C:1]([O:5][C:6]([N:8]1[CH2:13][CH2:12][N:11]([C:14]2[C:19]([CH3:20])=[CH:18][C:17]([CH:30]=[CH2:31])=[CH:16][N:15]=2)[CH2:10][CH2:9]1)=[O:7])([CH3:4])([CH3:3])[CH3:2]

Participants

7

Reactant 4

HCID 1140TolueneHCID 62657Potassium Phosphate, TribasicHCID 52330122-Ethenyl-4,4,5,5-tetramethyl-1,3,2-dioxaborolaneHCID 46739269tert-Butyl 4-(5-bromo-3-methylpyridin-2-yl)piperazine-1-carboxylate

Product 1

HCID 673806954-(3-Methyl-5-vinylpyridin-2-yl)piperazine-1-carboxylic acid tert-butyl esterYield 46.3%

Reagents, catalysts & solvents 2

HCID 11556747Bis(tricyclohexylphosphine)palladium(II) DichlorideCatalystHCID 962WaterSolvent

Procedure

To a mixture of 4-(5-bromo-3-methylpyridin-2-yl)piperazine-1-carboxylic acid tert-butyl ester (3.3 g), bis(tricyclohexylphosphine)palladium (II) dichloride (332 mg), tripotassium phosphate (11 g) and vinylboronic acid pinacol ester (3 g) were added toluene (27 mL) and water (1.4 mL), and the mixture was refluxed for 8 hr. After cooling, the mixture was extracted with ethyl acetate. The organic layer was washed with saturated brine, and the solvent was evaporated. The residue was purified by column chromatography (hexane:ethyl acetate) to give 4-(3-methyl-5-vinylpyridin-2-yl)piperazine-1-carboxylic acid tert-butyl ester (1.3 g). 4-(3-Methyl-5-vinylpyridin-2-yl)piperazine-1-carboxylic acid tert-butyl ester (1.3 g) was dissolved in ethanol (20 mL), 5% palladium carbon-ethylenediamine complex (600 mg) was added, and the mixture was stirred under a hydrogen atmosphere for 8 hr at room temperature. After celite filtration, the solvent in the filtrate was evaporated to give 4-(5-ethyl-3-methylpyridin-2-yl)piperazine-1-carboxylic acid tert-butyl ester (870 mg). 4-(5-Ethyl-3-methylpyridin-2-yl)piperazine-1-carboxylic acid tert-butyl ester (870 mg) was dissolved in chloroform (2 mL), 4N hydrogen chloride/ethyl acetate (1.5 mL) was added, and the mixture was stirred at room temperature overnight. 1N Aqueous sodium hydroxide solution (7 mL) was added, and the mixture was extracted with chloroform. The organic layer was washed with saturated brine, and the solvent was evaporated to give the title compound (441 mg).

Workup

  1. temperaturethe mixture was refluxed for 8 hr
  2. temperatureAfter cooling
  3. extractionthe mixture was extracted with ethyl acetate
  4. washThe organic layer was washed with saturated brine
  5. customthe solvent was evaporated
  6. customThe residue was purified by column chromatography (hexane:ethyl acetate)

Sources & evidence

ORD record
ord-fb9ce00806c64947bdb504b06d9c91f2
Source dataset
uspto-grants-2013_01
Patent number
US08354401B2

Reaction notes

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