Pyridine → 3-(6-Fluoro-1,3-benzoxazol-2-yl)pyrazin-2-amine

HRID 908459Notes

Reaction equation

[NH2:1][C:2]1[C:3]([C:8]([NH:10][C:11]2[CH:16]=[CH:15][C:14]([F:17])=[CH:13][C:12]=2[OH:18])=O)=[N:4][CH:5]=[CH:6][N:7]=1.C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.N1C=CC=CC=1.ClC(Cl)(Cl)C#N>C(OCC)(=O)C.CO>[F:17][C:14]1[CH:15]=[CH:16][C:11]2[N:10]=[C:8]([C:3]3[C:2]([NH2:1])=[N:7][CH:6]=[CH:5][N:4]=3)[O:18][C:12]=2[CH:13]=1

Participants

Conditions

Temperature: 10 °C

Procedure

3-Amino-N-(4-fluoro-2-hydroxyphenyl)pyrazine-2-carboxamide (1.6 g) and triphenylphosphine (5.1 g) were dissolved into pyridine (20 ml). The mixture was cooled to 10° C. in a salt-ice bath. 2,2,2-Trichloroacetonitrile (2.79 g) was added slowly to the mixture. The mixture was warmed up to room temperature, and then heated to 130° C. for 13 hours. The resulting mixture was diluted with ethyl acetate/methanol (4/1, 100 ml). The mixture was filtered through Celite (diatomaceous earth), and the mixture was washed to pH 6 with 1 M hydrochloric acid. The organic layer was concentrated, and the residue was purified by chromatography on silica gel to give 3-(6-fluoro-1,3-benzoxazol-2-yl)pyrazin-2-amine (0.3 g). NMR Spectrum: (DMSOd6, 400 MHz) 7.30 (m, 1H), 7.80 (m, 4H), 7.85 (m, 1H), 8.00 (s, 1H), 8.23 (s, 1H); Mass spectrum: M+H+ 231

Workup

temperatureThe mixture was warmed up to room temperature
temperatureheated to 130° C. for 13 hours
filtrationThe mixture was filtered through Celite (diatomaceous earth)
washthe mixture was washed to pH 6 with 1 M hydrochloric acid
concentrationThe organic layer was concentrated
customthe residue was purified by chromatography on silica gel

Sources & evidence

ORD record: ord-974ba73935da42848d9fa689d5a541be
Source dataset: uspto-grants-2011_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08017611B2

Reaction notes

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