Pyridine → ethyl 3-methyl-1-(2-naphthyl)-1H-pyrazole-5-carboxylate

HRID 2119436Notes

Reaction equation

HRID 2119436 reaction equation
[CH:1]1[C:10]2[C:5](=[CH:6][CH:7]=[CH:8][CH:9]=2)[CH:4]=[CH:3][C:2]=1B(O)O.[CH3:14][C:15]1[CH:19]=[C:18]([C:20]([O:22][CH2:23][CH3:24])=[O:21])[NH:17][N:16]=1.N1C=CC=CC=1>ClCCl.C([O-])(=O)C.[Cu+2].C([O-])(=O)C>[CH3:14][C:15]1[CH:19]=[C:18]([C:20]([O:22][CH2:23][CH3:24])=[O:21])[N:17]([C:2]2[CH:3]=[CH:4][C:5]3[C:10](=[CH:9][CH:8]=[CH:7][CH:6]=3)[CH:1]=2)[N:16]=1

Participants

6

Reactant 3

HCID 1049PyridineHCID 2734375(Naphthalen-2-yl)boronic acidHCID 178469061HCID 178469061, compound

Product 1

HCID 22728891ethyl 3-methyl-1-(2-naphthyl)-1H-pyrazole-5-carboxylateYield 70%

Reagents, catalysts & solvents 2

HCID 8895Cupric acetateCatalystHCID 6344DichloromethaneSolvent2×

Procedure

To the solutionof 2-naphthylboronic acid (5.00 g, 29.1 mmol) and ethyl 3-methylpyrazole-5-carboxylate (4.48 g, 29.1 mmol) in 100 mL dry dichloromethane (DCM) were added pyridine (4.7 mL, 58.2 mmol) and anhydrous powder of copper(II) acetate (7.94 g, 43.7 mmol). Some activated molecular sieve powder was added afterwards. The resulting slurry was stirred for 2 days under argon. The mixture was diluted with DCM. It was filtered through a celite bed. The blue filtrate was washed with water (×2), dried over MgSO4, concentrated, purified by silica column to yield ethyl 3-methyl-1-(2-naphthyl)-1H-pyrazole-5-carboxylate and its regioisomer in a 1:1 ratio in 70% yield. Rf 0.59 (1:2 EtOAc:hexane), M+H 281; regioisomer, ethyl 5-methyl-1-(2-naphthyl)-1H-pyrazole-3-carboxylate, Rf 0.44 (1:2 EtOAc:hexane). ES-MS: (M+H)+ 281.

Workup

  1. additionSome activated molecular sieve powder was added afterwards
  2. filtrationIt was filtered through a celite bed
  3. washThe blue filtrate was washed with water (×2)
  4. dry with materialdried over MgSO4
  5. concentrationconcentrated
  6. custompurified by silica column

Sources & evidence

ORD record
ord-6529c16faaac4e85a1b701d291a54a9f
Source dataset
uspto-grants-2004_02
Patent number
US06686368B1

Reaction notes

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