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

HRID 908380Notes

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-hydroxy-phenyl)pyrazine-2-carboxamide (1.6 g) and triphenylphosphine (5.07 g) were dissolved into pyridine (20 ml). The mixture was cooled to −10° C. in a ice-salt bath. Then, 2,2,2-trichloroacetonitrile (2.79 g) was added slowly. The resulting mixture was heated to reflux for 12 hours. The resulting mixture was diluted with ethyl acetate/methanol (4/1, 100 ml). The mixture was filtered by celite (diatomaceous earth), and the mixture was washed with 1M HCl. The organic layer was concentrated and the residue was purified by chromatography on silica gel (hexane/ethyl acetate/Methanol) to yield 3-(6-fluoro-1,3-benzoxazol-2-yl)pyrazin-2-amine (0.3 g). NMR Spectrum: (400 MHz, DMSOd6) 8.23 (s, 1H), 8.00 (s, 1H), 7.85 (m, 1H), 7.80 (m, 4H), 7.30 (m, 1H); Mass spectrum: M+H+ 231.

Workup

temperatureThe resulting mixture was heated
temperatureto reflux for 12 hours
filtrationThe mixture was filtered by celite (diatomaceous earth)
washthe mixture was washed with 1M HCl
concentrationThe organic layer was concentrated
customthe residue was purified by chromatography on silica gel (hexane/ethyl acetate/Methanol)

Sources & evidence

ORD record: ord-bbde67743d5e424abff34f8d5bea2f54
Source dataset: uspto-grants-2011_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08017611B2

Reaction notes

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