Sodium Hydroxide → 6-(2,4-Difluorophenyl)imidazo[2,1-b]oxazole

HRID 1929972Notes

Reaction equation

Br.[F:2][C:3]1[CH:8]=[C:7]([F:9])[CH:6]=[CH:5][C:4]=1[C:10](=O)[CH2:11][N:12]1[CH:16]=[CH:15][O:14][C:13]1=[NH:17].[OH-].[Na+]>O>[F:2][C:3]1[CH:8]=[C:7]([F:9])[CH:6]=[CH:5][C:4]=1[C:10]1[N:17]=[C:13]2[N:12]([CH:11]=1)[CH:16]=[CH:15][O:14]2

Participants

Conditions

Temperature: 80 °C

Procedure

Polyphosphoric acid (124.4 g) was charged to a flask and heated to about 80° C. 1-(2,4-Difluorophenyl)-2-(2-iminooxazol-3(2H)-yl)ethanone hydrobromide salt (19.8 g, 62.0 mmol, Preparation #B.1 intermediate) was transferred to the flask in approximately 3 g portions over about 2 h. The thick solution was mixed and heated at about 80-90° C. for about 22 h. The reaction mixture was slowly transferred to a flask containing water (150 mL) and 30% aqueous NaOH (150 mL) that had been cooled to about 5-10° C. The pH of the resulting slurry was adjusted to about 5.4 by addition of 30% aqueous NaOH and the product was isolated by filtration. The wet cake was rinsed with warm water (3×150 mL) and dried under vacuum to give the title compound (9.5 g, 69%): MS m/z 221.1 (M+H)+ FIA (APCI)

Workup

additionThe thick solution was mixed
temperatureheated at about 80-90° C. for about 22 h
customThe reaction mixture was slowly transferred to a flask
temperaturehad been cooled to about 5-10° C
customthe product was isolated by filtration
washThe wet cake was rinsed with warm water (3×150 mL)
customdried under vacuum

Sources & evidence

ORD record: ord-6ceeca2dbee04a0487d4a9585f519fc7
Source dataset: uspto-grants-2012_05
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08188083B2

Reaction notes

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