3,4-dihydro-2H-pyran → 6-Bromo-4-nitro-2-(tetrahydro-2H-pyran-2-yl)-2H-indazole

HRID 42235Notes

Reaction equation

HRID 42235 reaction equation
[Br:1][C:2]1[CH:10]=[C:9]2[C:5]([CH:6]=[N:7][NH:8]2)=[C:4]([N+:11]([O-:13])=[O:12])[CH:3]=1.[O:14]1[CH:19]=[CH:18][CH2:17][CH2:16][CH2:15]1.C1(C)C=CC(S([O-])(=O)=O)=CC=1.[NH+]1C=CC=CC=1.C(=O)(O)[O-].[Na+]>ClCCl>[Br:1][C:2]1[CH:3]=[C:4]([N+:11]([O-:13])=[O:12])[C:5]2[C:9]([CH:10]=1)=[N:8][N:7]([CH:15]1[CH2:16][CH2:17][CH2:18][CH2:19][O:14]1)[CH:6]=2

Participants

6

Reactant 4

HCID 80803,4-dihydro-2H-pyranHCID 466102Benzenesulfonic acid, 4-methyl-, compd. with pyridine (1:1)HCID 516892Sodium BicarbonateHCID 247280596-bromo-4-nitro-1H-indazole

Product 1

HCID 582558186-Bromo-4-nitro-2-(tetrahydro-2H-pyran-2-yl)-2H-indazole

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

A mixture of 6-bromo-4-nitro-1H-indazole (10.0 g, 0.041 mol), 3,4-dihydropyran (8.52 ml, 0.09 mol) and pyridinium para-toluene sulfonate (125 mg, 0.50 mol) in dichloromethane (150 ml) was heated at reflux for 4.5 hours. The reaction was allowed to cool to room temperature and was poured onto saturated aqueous sodium bicarbonate (200 ml). The layers were separated and the aqueous layer extracted with dichloromethane (2×100 ml). The combined organic layers were washed with 5% aqueous citric acid (w/v, 100 ml) and brine (100 ml) then dried over magnesium sulphate. Solvent was removed in vacuo to give the title compound which was used in subsequent reactions without further purification (12.89 g).

Workup

  1. temperaturewas heated
  2. temperatureat reflux for 4.5 hours
  3. customThe layers were separated
  4. extractionthe aqueous layer extracted with dichloromethane (2×100 ml)
  5. washThe combined organic layers were washed with 5% aqueous citric acid (w/v, 100 ml) and brine (100 ml)
  6. dry with materialthen dried over magnesium sulphate
  7. customSolvent was removed in vacuo

Sources & evidence

ORD record
ord-97ec8250b6ce4c9e9eb79df6beba4bf8
Source dataset
uspto-grants-2013_09
Patent number
US08536169B2

Reaction notes

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