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

HRID 1520238Notes

Reaction equation

HRID 1520238 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(=O)(O)[O-].[Na+]>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

6

Reactant 4

HCID 6101p-Toluenesulfonic acidHCID 80803,4-dihydro-2H-pyranHCID 516892Sodium BicarbonateHCID 7619295-bromo-1H-indazole

Product 1

HCID 534338265-bromo-1-(oxan-2-yl)-1H-indazoleYield 100.1%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

To a suspension of 5-bromo-1H-indazole (2.5 g, 12.69 mmol, 1.0 eq) in DCM (10 ml) was added dihydropyran (3.2 g, 38 mmol, 3.0 eq) and a catalytic amount of PTSA (12% in AcOH, 1.8 ml, 0.1 eq). The mixture was stirred overnight and neutralized by addition of sodium bicarbonate. Then the organic layer was sequentially washed with 10% citric acid and brine, dried on Na2SO4 and concentrated under vacuum. The resulting residue was purified by chromatography on silica gel, eluting with DCM to give the expected compound as a colorless liquid (3.57 g, 82%).

Workup

  1. washThen the organic layer was sequentially washed with 10% citric acid and brine
  2. customdried on Na2SO4
  3. concentrationconcentrated under vacuum
  4. customThe resulting residue was purified by chromatography on silica gel
  5. washeluting with DCM

Sources & evidence

ORD record
ord-19862d06b63d4483820d3c569bf6b6e2
Source dataset
uspto-grants-2015_07
Patent number
US09073905B2

Reaction notes

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