p-Toluenesulfonic acid → 5-Nitro-1-(tetrahydro-2H-pyran-2-yl)-1H-indazole

HRID 1269769Notes

Reaction equation

HRID 1269769 reaction equation
[N+:1]([C:4]1[CH:5]=[C:6]2[C:10](=[CH:11][CH:12]=1)[NH:9][N:8]=[CH:7]2)([O-:3])=[O:2].[O:13]1[CH:18]=[CH:17][CH2:16][CH2:15][CH2:14]1.C1(C)C=CC(S(O)(=O)=O)=CC=1>C(Cl)Cl>[N+:1]([C:4]1[CH:5]=[C:6]2[C:10](=[CH:11][CH:12]=1)[N:9]([CH:14]1[CH2:15][CH2:16][CH2:17][CH2:18][O:13]1)[N:8]=[CH:7]2)([O-:3])=[O:2]

Participants

5

Reactant 3

HCID 6101p-Toluenesulfonic acidHCID 80803,4-dihydro-2H-pyranHCID 215015-Nitroindazole

Product 1

HCID 151476265-Nitro-1-(tetrahydro-2H-pyran-2-yl)-1H-indazoleYield 88%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

To a solution of 5-nitroindazole (20.0 g, 123 mmol) in methylene chloride (400 ml) were added 3,4-dihydro-2H-pyran (16.8 ml, 184 mmol) and p-toluenesulfonic acid (4.22 g, 24.5 mmol) at room temperature, and stirred for 2 hours. After the reaction solution was concentrated, a saturated aqueous sodium hydrogencarbonate solution was added thereto, followed by extraction with chloroform. The organic layer was dried over anhydrous magnesium sulfate and distilled under reduced pressure to remove the solvent, and resulting residue was purified by a silica gel column chromatography (eluent: hexane/ethyl acetate=5/1) to obtain 5-nitro-1-tetrahydro-2H-pyran-2-yl-1H-indazole (26.6 g, 88%).

Workup

  1. concentrationAfter the reaction solution was concentrated
  2. additiona saturated aqueous sodium hydrogencarbonate solution was added
  3. extractionfollowed by extraction with chloroform
  4. dry with materialThe organic layer was dried over anhydrous magnesium sulfate
  5. distillationdistilled under reduced pressure
  6. customto remove the solvent
  7. customresulting residue
  8. customwas purified by a silica gel column chromatography (eluent: hexane/ethyl acetate=5/1)

Sources & evidence

ORD record
ord-93b8dfd302174a418a3e598f7c29358a
Source dataset
uspto-grants-2007_04
Patent number
US07199147B2

Reaction notes

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