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

HRID 1615970Notes

Reaction equation

HRID 1615970 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.CC1C=CC(S(O)(=O)=O)=CC=1.N1C=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 161440Pyridine 4-methylbenzene-1-sulfonateHCID 516892Sodium BicarbonateHCID 247280596-bromo-4-nitro-1H-indazole

Product 1

HCID 582558186-Bromo-4-nitro-2-(tetrahydro-2H-pyran-2-yl)-2H-indazoleYield 96.5%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

A mixture of 6-bromo-4-nitro-1H-indazole (available from Sinova, 10 g, 0.041 mol), 3,4-dihydro-2H-pyran (7.85 g, 8.52 ml, 0.093 mol) and pyridine 4-methylbenzenesulfonate (0.125 g, 0.496 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) and dried over magnesium sulphate. Solvent was removed in vacuo to give the title compound (12.9 g) as a dark orange solid.

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 materialdried over magnesium sulphate
  7. customSolvent was removed in vacuo

Sources & evidence

ORD record
ord-9cc57ac3080b443eb604f0ff28a58cf7
Source dataset
uspto-grants-2014_07
Patent number
US08765743B2

Reaction notes

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