Ammonium Chloride → alpha-(1-Methylpyrazol-5-yl)-2,3-dichloro-4,5-dimethoxybenzylalcohol

HRID 1074184Notes

Reaction equation

HRID 1074184 reaction equation
C([Li])CCC.[CH3:6][N:7]1[CH:11]=[CH:10][CH:9]=[N:8]1.[Cl:12][C:13]1[C:20]([Cl:21])=[C:19]([O:22][CH3:23])[C:18]([O:24][CH3:25])=[CH:17][C:14]=1[CH:15]=[O:16].[Cl-].[NH4+]>CCCCCC.O1CCCC1>[CH3:6][N:7]1[C:11]([CH:15]([OH:16])[C:14]2[CH:17]=[C:18]([O:24][CH3:25])[C:19]([O:22][CH3:23])=[C:20]([Cl:21])[C:13]=2[Cl:12])=[CH:10][CH:9]=[N:8]1

Participants

7

Reactant 4

HCID 25517Ammonium ChlorideHCID 702551H-Pyrazole, 1-methyl-HCID 147486342,3-Dichloro-4,5-dimethoxybenzaldehydeHCID 178418339Butyllithium

Product 1

HCID 14748635alpha-(1-Methylpyrazol-5-yl)-2,3-dichloro-4,5-dimethoxybenzylalcoholYield 90.5%

Reagents, catalysts & solvents 2

HCID 8028TetrahydrofuranSolvent2×HCID 8058HexaneSolvent

Procedure

18 ml of 1.6M n-butyl lithium in n-hexane is added dropwise to a solution of 2.26 g of 1-methyl-pyrazole in tetrahydrofuran at -60° C. under argon gas atmosphere and the mixture is stirred at the same temperature for 1 hour. A solution of 5.88 g of 2,3-dichloro-4,5-dimethoxybenzaldehyde in tetrahydrofuran is added dropwise to the mixture at -60° to -50° C. and the mixture is stirred at -50° C. to room temperature for 1 hour. An aqueous ammonium chloride solution is added to the reaction mixture and the mixture is concentarated to remove organic solvent. The residue is extracted with ethyl acetate, and the extract is washed, dried and evaporated to remove solvent. The residue is crystallized from isopropyl ether to give 7.18 g of α-(1-methylpyrazol-5-yl)-2,3-dichloro-4,5-dimethoxybenzylalcohol.

Workup

  1. stirringthe mixture is stirred at -50° C. to room temperature for 1 hour
  2. customto remove organic solvent
  3. extractionThe residue is extracted with ethyl acetate
  4. washthe extract is washed
  5. customdried
  6. customevaporated
  7. customto remove solvent
  8. customThe residue is crystallized from isopropyl ether

Sources & evidence

ORD record
ord-99ab9336973b4769a7797c3a341c197d
Source dataset
uspto-grants-1990_11
Patent number
US04973600

Reaction notes

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