Toluene → Tert-butyl 4-(3-cyclopropyl-5-methylpyridin-2-yl)piperazine-1-carboxylate

HRID 1803984Notes

Reaction equation

HRID 1803984 reaction equation
[C:1]([O:5][C:6]([N:8]1[CH2:13][CH2:12][N:11]([C:14]2[C:19](Cl)=[CH:18][C:17]([CH3:21])=[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]1(B(O)O)[CH2:32][CH2:31]1.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]([CH:30]3[CH2:32][CH2:31]3)=[CH:18][C:17]([CH3:21])=[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 2760897Cyclopropylboronic acidHCID 673809194-(3-Chloro-5-methylpyridin-2-yl)piperazine-1-carboxylic acid tert-butyl ester

Product 1

HCID 49871665Tert-butyl 4-(3-cyclopropyl-5-methylpyridin-2-yl)piperazine-1-carboxylateYield 98.2%

Reagents, catalysts & solvents 2

HCID 11556747Bis(tricyclohexylphosphine)palladium(II) DichlorideCatalystHCID 962WaterSolvent2×

Procedure

To a mixture of 1-Boc-piperazine (7.2 g), 2,3-dichloro-5-methylpyridine (5 g), palladium (II) acetate (179 mg), rac-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (499 mg) and sodium tert-butoxide (4.1 g) was added toluene (30 mL), and the mixture was refluxed for 5 hr. After cooling, water was added to the reaction mixture, and 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-chloro-5-methylpyridin-2-yl)piperazine-1-carboxylic acid tert-butyl ester (9 g). To a mixture of 4-(3-chloro-5-methylpyridin-2-yl)piperazine-1-carboxylic acid tert-butyl ester (9 g), bis(tricyclohexylphosphine)palladium (II) dichloride (1 g), tripotassium phosphate (30 g) and cyclopropylboronic acid (5.5 g) were added toluene (80 mL) and water (4 mL), and the mixture was refluxed for 8 hr. After cooling, water was added to the reaction mixture, and 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-cyclopropyl-5-methylpyridin-2-yl)piperazine-1-carboxylic acid tert-butyl ester (9 g). 4-(3-Cyclopropyl-5-methylpyridin-2-yl)piperazine-1-carboxylic acid tert-butyl ester (9 g) was dissolved in chloroform (25 mL), 4N hydrogen chloride/ethyl acetate (25 mL) was added, and the mixture was stirred at room temperature overnight. Ethyl acetate (100 mL) was added and the mixture was filtered to give the title compound (4.6 g).

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-19e0cb0d0e1e468daf66dbd79b9fc703
Source dataset
uspto-grants-2013_01
Patent number
US08354401B2

Reaction notes

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