Boron tribromide → 3-(7-Pyridin-4-yl-pyrazolo[5,1-b]thiazol-6-yl)-phenol

HRID 38101Notes

Reaction equation

C[O:2][C:3]1[CH:4]=[C:5]([C:9]2[C:16]([C:17]3[CH:22]=[CH:21][N:20]=[CH:19][CH:18]=3)=[C:12]3[S:13][CH:14]=[CH:15][N:11]3[N:10]=2)[CH:6]=[CH:7][CH:8]=1.B(Br)(Br)Br.C([O-])(O)=O.[Na+]>C(Cl)Cl>[N:20]1[CH:19]=[CH:18][C:17]([C:16]2[C:9]([C:5]3[CH:4]=[C:3]([OH:2])[CH:8]=[CH:7][CH:6]=3)=[N:10][N:11]3[CH:15]=[CH:14][S:13][C:12]=23)=[CH:22][CH:21]=1

Participants

Conditions

Temperature: 0 °C

Procedure

6-(3-Methoxy-phenyl)-7-pyridin-4-yl-pyrazolo[5,1-b]thiazole (65 mg, 0.212 mmol) was dissolved in dry DCM (2 mL) and cooled to 0° C. A 1 M solution of boron tribromide in DCM (0.850 mL, 0.848 mmol, 4 eq) was added dropwise and the mixture was allowed to warm to room temperature and stirred for 1 hours. Ice was then added to the reaction mixture, followed by saturated aqueous NaHCO3 until pH 6. The aqueous phase was extracted with DCM and the organic layer was dried and evaporated to dryness. An insoluble solid formed during extraction and it was filtered and combined with the organic layer. The crude product was taken up with toluene and concentrated to dryness three times and the same treatment was repeated with DCM. 50 mg of 3-(7-pyridin-4-yl-pyrazolo[5,1-b]thiazol-6-yl)-phenol (80%) were obtained as pale yellow solid.

Workup

temperatureto warm to room temperature
additionIce was then added to the reaction mixture
extractionThe aqueous phase was extracted with DCM
customthe organic layer was dried
customevaporated to dryness
customAn insoluble solid formed during extraction and it
filtrationwas filtered
concentrationconcentrated to dryness three times

Sources & evidence

ORD record: ord-09b308db305d4ac3808ac399b8414822
Source dataset: uspto-grants-2013_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08524707B2

Reaction notes

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