Boron tribromide → 4-[2-(6-Methyl-pyridin-2-yl)-5,6-dihydro-4H-pyrrolo[1,2-b]pyrazol-3-yl]-phenol

HRID 8275Notes

Reaction equation

HRID 8275 reaction equation
C[O:2][C:3]1[CH:8]=[CH:7][C:6]([C:9]2[C:13]([C:14]3[CH:19]=[CH:18][CH:17]=[C:16]([CH3:20])[N:15]=3)=[N:12][N:11]3[CH2:21][CH2:22][CH2:23][C:10]=23)=[CH:5][CH:4]=1.B(Br)(Br)Br>C(Cl)Cl>[CH3:20][C:16]1[N:15]=[C:14]([C:13]2[C:9]([C:6]3[CH:5]=[CH:4][C:3]([OH:2])=[CH:8][CH:7]=3)=[C:10]3[CH2:23][CH2:22][CH2:21][N:11]3[N:12]=2)[CH:19]=[CH:18][CH:17]=1

Participants

4

Reactant 2

HCID 25134Boron tribromideHCID 219925843-(4-Methoxy-phenyl)-2-(6-methyl-pyridin-2-yl)-5,6-dihydro-4H-pyrrolo[1,2-b]pyrazole

Product 1

HCID 98389794-[2-(6-Methyl-pyridin-2-yl)-5,6-dihydro-4H-pyrrolo[1,2-b]pyrazol-3-yl]-phenolYield 5.8%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

To a solution of 3-(4-methoxy-phenyl)-2-(6-methyl-pyridin-2-yl)-5,6-dihydro-4H-pyrrolo[1,2-b]pyrazole (72 mg, 0.24 mmol) in methylene chloride (1 mL) is added boron tribromide (0.3 mL). The solution is stirred at ambient temperature for 3 h, then quenched with methanol. The mixture is concentrated in vacuo to a reddish solid. The solid is passed through a silica gel cartridge (methylene chloride, ethyl acetate, then acetone). The appropriate methylene chloride fractions are concentrated in vacuo to yield 4 mg (5.8%) of the title compound. The more polar fractions are concentrated in vacuo then treated with aqueous ammonium chloride and methanol. The mixture is concentrated in vacuo and the residue purified on a silica cartridge eluting as above. Appropriate fractions are combined and concentrated in vacuo to yield an additional 49 mg (71%) of the title compound.

Workup

  1. customquenched with methanol
  2. concentrationThe mixture is concentrated in vacuo to a reddish solid
  3. concentrationThe appropriate methylene chloride fractions are concentrated in vacuo

Sources & evidence

ORD record
ord-571984fd63f441349f74f0f050c8655d
Source dataset
uspto-grants-2006_08
Patent number
US07087626B2

Reaction notes

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