Phosphorus oxybromide → 2-Bromo-4-phenyl-1,3-thiazole

HRID 1397365Notes

Reaction equation

[C:1]1([C:7]2[NH:8][C:9](=O)[S:10][CH:11]=2)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.P(Br)(Br)([Br:15])=O>>[Br:15][C:9]1[S:10][CH:11]=[C:7]([C:1]2[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=2)[N:8]=1

Participants

Reactant 2

HCID 24613Phosphorus oxybromide

HCID 6989032-Hydroxy-4-phenylthiazole

Product 1

HCID 99211062-Bromo-4-phenyl-1,3-thiazoleYield 73.5%

Conditions

Temperature: 100 °C

Procedure

A mixture of 4-phenylthiazol-2(3H)-one (300 mg, 1.7 mmol) and POBr3 (4.85 g, 17.0 mmol) was heated to 100° C. in a sealed tube for 10 h. The reaction mixture was poured in ice water and the organic product was extracted with EtOAc. The combined extracts were washed with brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The crude product was purified by column chromatography (silica 60-120 mesh, eluant 1% EtOAc in petroleum ether) to get 2-bromo-4-phenylthiazole (300 mg, yield 73%) as light brown colored liquid. 1H NMR (300 MHz, CDCl3) δ 7.88-7.85 (m, 2H), 7.46-7.35 (m, 4H). MS (ESI) m/z: Calculated for C9H6BrNS: 240.94. found: 242.0 (M+H)+.

Workup

extractionthe organic product was extracted with EtOAc
washThe combined extracts were washed with brine
dry with materialdried over anhydrous sodium sulfate
concentrationconcentrated under reduced pressure
customThe crude product was purified by column chromatography (silica 60-120 mesh, eluant 1% EtOAc in petroleum ether)

Sources & evidence

ORD record: ord-b35b032b6af943d1b1c144db51bba10c
Source dataset: uspto-grants-2014_12
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08901156B2

Reaction notes

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