Boron tribromide → 3-Chloro-2-(2-fluoro-4-hydroxyphenyl)-4,5,6,7-tetrahydroindazole

HRID 482407Notes

Reaction equation

HRID 482407 reaction equation
B(Br)(Br)Br.[Cl:5][C:6]1[N:7]([C:15]2[CH:20]=[CH:19][C:18]([O:21]C)=[CH:17][C:16]=2[F:23])[N:8]=[C:9]2[C:14]=1[CH2:13][CH2:12][CH2:11][CH2:10]2>C(Cl)Cl>[Cl:5][C:6]1[N:7]([C:15]2[CH:20]=[CH:19][C:18]([OH:21])=[CH:17][C:16]=2[F:23])[N:8]=[C:9]2[C:14]=1[CH2:13][CH2:12][CH2:11][CH2:10]2

Participants

4

Reactant 2

HCID 25134Boron tribromideHCID 189810153-Chloro-2-(2-fluoro-4-methoxyphenyl)-4,5,6,7-tetrahydroindazole

Product 1

HCID 189810483-Chloro-2-(2-fluoro-4-hydroxyphenyl)-4,5,6,7-tetrahydroindazole

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent3×

Procedure

A 1N solution of boron tribromide in methylene chloride (18.0 mL, 0.018 mole) was diluted with 17 mL of methylene chloride and was then cooled to below -10° C. under a nitrogen atmosphere. A solution of 3-chloro-2-(2-fluoro-4-methoxyphenyl)-4,5,6,7-tetrahydroindazole in 25 mL of methylene chloride was added dropwise at a rate to maintain the temperature below -10° C. Upon completion of addition, the reaction mixture was allowed to warm to ambient temperature at which it stirred for sixteen hours. The mixture was then poured into ice-water, and the resulting mixture was stirred for 30 minutes. This mixture was filtered, and the filtrate was passed through a short column of silica gel. The organic phase was separated, dried with anhydrous sodium sulfate, and filtered. The solvent was evaporated from the filtrate under reduced pressure, leaving 0.60 g of 3-chloro-2-(2-fluoro-4-hydroxyphenyl)-4,5,6,7-tetrahydroindazole as a nearly white solid, m.p. 214°-216° C. The NMR and IR spectra were consistent with the proposed structure.

Workup

  1. temperaturewas then cooled to below -10° C. under a nitrogen atmosphere
  2. temperatureto maintain the temperature below -10° C
  3. additionUpon completion of addition
  4. stirringthe resulting mixture was stirred for 30 minutes
  5. filtrationThis mixture was filtered
  6. customThe organic phase was separated
  7. dry with materialdried with anhydrous sodium sulfate
  8. filtrationfiltered
  9. customThe solvent was evaporated from the filtrate under reduced pressure

Sources & evidence

ORD record
ord-9f25c861d4844b2f8d21fd5f02fceb99
Source dataset
uspto-grants-1998_08
Patent number
US05798316

Reaction notes

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