p-Toluenesulfonic acid → 5-bromo-1-(oxan-2-yl)-1H-indazole

HRID 1023187Notes

Reaction equation

HRID 1023187 reaction equation
[Br:1][C:2]1[CH:3]=[C:4]2[C:8](=[CH:9][CH:10]=1)[NH:7][N:6]=[CH:5]2.[O:11]1[CH:16]=[CH:15][CH2:14][CH2:13][CH2:12]1.CC1C=CC(S(O)(=O)=O)=CC=1>C(Cl)Cl>[Br:1][C:2]1[CH:3]=[C:4]2[C:8](=[CH:9][CH:10]=1)[N:7]([CH:12]1[CH2:13][CH2:14][CH2:15][CH2:16][O:11]1)[N:6]=[CH:5]2

Participants

5

Reactant 3

HCID 6101p-Toluenesulfonic acidHCID 80803,4-dihydro-2H-pyranHCID 7619295-bromo-1H-indazole

Product 1

HCID 534338265-bromo-1-(oxan-2-yl)-1H-indazoleYield 97.4%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

To a solution of 5-bromo-1H-indazole (5 g, 25.38 mmol) in DCM (50 mL), 3,4-dihydro-2H-pyran (4.26 g, 50.76 mmol) and PTSA (2.41 g, 12.69 mmol) were added and the reaction was stirred at room temperature for 3 h. Solvent was removed under vacuum. The residue was dissolved in ethyl acetate (150 mL), washed with water (20 mL), brine (20 mL), and dried over sodium sulfate. The organic layer was concentrated under vacuum and the crude product was purified by flash chromatography using hexane/ethyl acetate to give 5-bromo-1-(tetrahydro-2H-pyran-2-yl)-1H-indazole as colorless liquid (6.95 g, 97%). 1HNMR: 400 MHz, DMSO-d6: δ 1.57-1.62 (m, 2H), 1.74-1.76 (m, 1H), 1.96-2.06 (m, 2H), 2.37-2.40 (m, 1H), 3.72-3.78 (m, 1H), 3.87-3.90 (m, 1H), 5.85-5.86 (m, 1H), 7.53-7.54 (m, 1H), 7.74 (d, J=9.20 Hz, 1H), 8.04 (d, J=1.60 Hz, 1H), 8.11 (s, 1H). LCMS: RT 2.033 min; LCMS (ES-API), m/z 283 (M+H).

Workup

  1. customSolvent was removed under vacuum
  2. dissolutionThe residue was dissolved in ethyl acetate (150 mL)
  3. washwashed with water (20 mL), brine (20 mL)
  4. dry with materialdried over sodium sulfate
  5. concentrationThe organic layer was concentrated under vacuum
  6. customthe crude product was purified by flash chromatography

Sources & evidence

ORD record
ord-01ecfa7b1f234cb1bbf1182e98a7b609
Source dataset
uspto-grants-2014_05
Patent number
US08722670B2

Reaction notes

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