2-Fluoro-6-nitrobenzaldehyde → 4-fluoro-2-(4-trimethylsilanyl-but-3-ynyl)-2H-indazole

HRID 334669Notes

Reaction equation

HRID 334669 reaction equation
[F:1][C:2]1[CH:9]=[CH:8][CH:7]=[C:6]([N+:10]([O-])=O)[C:3]=1[CH:4]=O.[CH3:13][Si:14]([CH3:21])([CH3:20])[C:15]#[C:16][CH2:17][CH2:18][NH2:19]>C1(C)C=CC=CC=1>[F:1][C:2]1[C:3]2[C:6]([CH:7]=[CH:8][CH:9]=1)=[N:10][N:19]([CH2:18][CH2:17][C:16]#[C:15][Si:14]([CH3:21])([CH3:20])[CH3:13])[CH:4]=2

Participants

4

Reactant 2

HCID 135240432-Fluoro-6-nitrobenzaldehydeHCID 19703099(4-Aminobut-1-yn-1-yl)trimethylsilane

Product 1

HCID 665983684-fluoro-2-(4-trimethylsilanyl-but-3-ynyl)-2H-indazoleYield 55.7%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Procedure

2-Fluoro-6-nitro-benzaldehyde (180 mg, 1.06 mmol) was added to a solution of 4-trimethylsilanyl-but-3-ynylamine (200 mg, 1.40 mmol) in toluene (2 mL) and the reaction mixture was stirred under reflux for 30 min in a Dean-Stark. After evaporation of the solvent, the crude product was dissolved in triethylphosphite (1 mL) and the reaction mixture was stirred at 80° C. for 4 hours. After evaporation, the crude product was purified by flash chromatography (cyclohexane/AcOEt 92.5:7.5) to yield 4-fluoro-2-(4-trimethylsilanyl-but-3-ynyl)-2H-indazole (142 mg, 0.59 mmol, 52%) as a yellow oil.

Workup

  1. temperatureunder reflux for 30 min in a Dean-Stark
  2. customAfter evaporation of the solvent
  3. dissolutionthe crude product was dissolved in triethylphosphite (1 mL)
  4. stirringthe reaction mixture was stirred at 80° C. for 4 hours
  5. customAfter evaporation
  6. customthe crude product was purified by flash chromatography (cyclohexane/AcOEt 92.5:7.5)

Sources & evidence

ORD record
ord-61da16cf79e24d99b283e307cb935c81
Source dataset
uspto-grants-2014_11
Patent number
US08883826B2

Reaction notes

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