Methylboronic Acid → 4-(3-Methyl-5-trifluoromethylpyridin-2-yl)piperazine-1-carboxylic acid tert-butyl ester

HRID 1803992Notes

Reaction equation

HRID 1803992 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]([C:21]([F:24])([F:23])[F:22])=[CH:16][N:15]=2)[CH2:10][CH2:9]1)=[O:7])([CH3:4])([CH3:3])[CH3:2].[CH:25]1(P(C2CCCCC2)C2C=CC=CC=2C2C(OC)=CC=CC=2OC)CCCCC1.[F-].[K+].CB(O)O>C([O-])(=O)C.[Pd+2].C([O-])(=O)C.O.O1CCCC1>[C:1]([O:5][C:6]([N:8]1[CH2:13][CH2:12][N:11]([C:14]2[C:19]([CH3:25])=[CH:18][C:17]([C:21]([F:24])([F:23])[F:22])=[CH:16][N:15]=2)[CH2:10][CH2:9]1)=[O:7])([CH3:4])([CH3:3])[CH3:2]

Participants

8

Reactant 4

HCID 139377Methylboronic AcidHCID 522689Potassium FluorideHCID 112698722-Dicyclohexylphosphino-2',6'-dimethoxybiphenylHCID 573664161-Tert-butyloxycarbonyl-4-(3-chloro-5-(trifluoromethyl)pyridin-2-YL)piperazine

Product 1

HCID 673808344-(3-Methyl-5-trifluoromethylpyridin-2-yl)piperazine-1-carboxylic acid tert-butyl esterYield 403.6%

Reagents, catalysts & solvents 3

HCID 167845palladium(II) acetateCatalystHCID 962WaterSolventHCID 8028TetrahydrofuranSolvent

Procedure

To 2,3-dichloro-5-trifluoromethylpyridine (25 g) were added 1-BOC-piperazine (23.84 g), potassium carbonate (32.08 g), N,N-dimethylformamide (50 mL) and toluene (50 mL), and the mixture was stirred at 100° C. for 8 hr. Water was added to the reaction mixture, and the mixture was extracted with ethyl acetate. The organic layer was washed with water and saturated brine, and the solvent was evaporated. The residue was purified by column chromatography (hexane:ethyl acetate) to give 4-(3-chloro-5-trifluoromethylpyridin-2-yl)piperazine-1-carboxylic acid tert-butyl ester (45.71 g). To 4-(3-chloro-5-trifluoromethylpyridin-2-yl)piperazine-1-carboxylic acid tert-butyl ester (11 g) were added palladium (II) acetate (0.726 g), 2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl (2.692 g), potassium fluoride (15.06 g), methylboronic acid (7.88 g) and tetrahydrofuran (300 mL), and the mixture was refluxed under a nitrogen stream for 8 hr. Water was added to the reaction mixture, and the mixture was extracted with ethyl acetate. The organic layer was washed with water and saturated brine, and the solvent was evaporated. The residue was purified by column chromatography (hexane:ethyl acetate) to give 4-(3-methyl-5-trifluoromethylpyridin-2-yl)piperazine-1-carboxylic acid tert-butyl ester (9.14 g). To 4-(3-methyl-5-trifluoromethylpyridin-2-yl)piperazine-1-carboxylic acid tert-butyl ester (9.14 g) were added 4N hydrogen chloride/ethyl acetate (26 mL) and chloroform (64 mL), and the mixture was stirred at room temperature overnight. To the reaction mixture were added water and sodium hydrogen carbonate, and the mixture was extracted with chloroform. The solvent was evaporated to give the title compound (6.38 g).

Workup

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

Sources & evidence

ORD record
ord-cb5da3a904244a7eaaf1acdd45d48614
Source dataset
uspto-grants-2013_01
Patent number
US08354401B2

Reaction notes

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