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

HRID 849952Notes

Reaction equation

[Cl:1][C:2]1[CH:7]=[C:6]([Cl:8])[C:5]([O:9]C)=[CH:4][C:3]=1[C:11]1[C:12](=[O:22])[N:13]([CH3:21])[C:14]([C:17]([F:20])([F:19])[F:18])=[CH:15][N:16]=1.Br.O>C(O)(=O)C>[Cl:1][C:2]1[CH:7]=[C:6]([Cl:8])[C:5]([OH:9])=[CH:4][C:3]=1[C:11]1[C:12](=[O:22])[N:13]([CH3:21])[C:14]([C:17]([F:18])([F:20])[F:19])=[CH:15][N:16]=1

Participants

Conditions

Temperature: 140 °C

Procedure

A mixture of 1.00 g of 3-(2,4-dichloro-5-methoxyphenyl)-1-methyl-6-trifluoromethyl-2-oxo-1,2-dihydropyrazine (present compound 1-358) and 16 ml of 48% hydrobromic acid was dissolved in 5.7 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, 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 0.74 g (yield, 77%) of 3-(2,4-dichloro-5-hydroxyphenyl)-1-methyl-6-trifluoromethyl-2-oxo-1,2-dihydropyrazine (present compound 1-357; m.p., 173.5° C.).

Workup

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

Sources & evidence

ORD record: ord-fdb65215862f46e9891b58de39dce605
Source dataset: uspto-grants-2000_01
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06015774

Reaction notes

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