Hydrogen Bromide → 3-(4-Chloro-2-fluoro-5-hydroxyphenyl)-1-methyl-6-trifluoromethyl-2-oxo-1,2-dihydropyrazine

HRID 849927Notes

Reaction equation

[Cl:1][C:2]1[C:7]([O:8]C)=[CH:6][C:5]([C:10]2[C:11](=[O:21])[N:12]([CH3:20])[C:13]([C:16]([F:19])([F:18])[F:17])=[CH:14][N:15]=2)=[C:4]([F:22])[CH:3]=1.Br.O>C(O)(=O)C>[Cl:1][C:2]1[C:7]([OH:8])=[CH:6][C:5]([C:10]2[C:11](=[O:21])[N:12]([CH3:20])[C:13]([C:16]([F:19])([F:18])[F:17])=[CH:14][N:15]=2)=[C:4]([F:22])[CH:3]=1

Participants

Conditions

Temperature: 140 °C

Procedure

A mixture of 2.04 g of 3-(4-chloro-2-fluoro-5-methoxyphenyl)-1-methyl-6-trifluoromethyl-2-oxo-1,2-dihydropyrazine (present compound 1-144) and 35 ml of 48% hydrobromic acid was dissolved in 12 ml of acetic acid, and the solution was stirred at 140° C. for 1 hour. After completion of the reaction, the reaction mixture was poured into water, followed by extraction with ethyl acetate. The organic layer was washed with saturated sodium hydrogencarbonate solution, water, and then saturated sodium chloride solution, dried with anhydrous magnesium sulfate, and concentrated. The residue was subjected to silica gel column chromatography, which afforded 1.55 g (yield, 79%) of 3-(4-chloro-2-fluoro-5-hydroxyphenyl)-1-methyl-6-trifluoromethyl-2-oxo-1,2-dihydropyrazine (present compound 1-61; m.p., 188.1° C.).

Workup

customAfter completion of the reaction
extractionfollowed by extraction with ethyl acetate
washThe organic layer was washed with saturated sodium hydrogencarbonate solution, water
dry with materialsaturated sodium chloride solution, dried with anhydrous magnesium sulfate
concentrationconcentrated

Sources & evidence

ORD record: ord-46a410f3c18a4bed81f330043095df15
Source dataset: uspto-grants-2000_01
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06015774

Reaction notes

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