Boron tribromide → 3-(5-(3,4-Dihydroxy-5-nitrophenyl)-1,2,4-triazin-3-yl)-2-(trifluoromethyl)pyridine 1-oxide

HRID 1401300Notes

Reaction equation

C[O:2][C:3]1[CH:4]=[C:5]([C:14]2[N:15]=[C:16]([C:20]3[C:21]([C:27]([F:30])([F:29])[F:28])=[N+:22]([O-:26])[CH:23]=[CH:24][CH:25]=3)[N:17]=[N:18][CH:19]=2)[CH:6]=[C:7]([N+:11]([O-:13])=[O:12])[C:8]=1[O:9]C.B(Br)(Br)Br>ClCCl>[OH:2][C:3]1[CH:4]=[C:5]([C:14]2[N:15]=[C:16]([C:20]3[C:21]([C:27]([F:28])([F:30])[F:29])=[N+:22]([O-:26])[CH:23]=[CH:24][CH:25]=3)[N:17]=[N:18][CH:19]=2)[CH:6]=[C:7]([N+:11]([O-:13])=[O:12])[C:8]=1[OH:9]

Participants

Conditions

Temperature: -78 °C

Procedure

3-(5-(3,4-dimethoxy-5-nitrophenyl)-1,2,4-triazin-3-yl)-2-(trifluoromethyl)pyridine 1-oxide (1.27 g, 3 mmol) was taken up in dichloromethane (25 mL). The yellowish solution was cooled to −78° C. under argon and boron tribromide (2.55 mL, 27 mmol) was added dropwise. The red reaction mixture was allowed to warm to room temperature and stirred for 18 hours. It was then carefully poured into ice-water (100 mL) and stirred for 1 hour. The yellow precipitate was filtered off, washed with water and dried over P2O5 under vacuum. The solid was recrystallised from dichloromethane-ethanol to give 3-(5-(3,4-dihydroxy-5-nitrophenyl)-1,2,4-triazin-3-yl)-2-(trifluoromethyl)pyridine 1-oxide as a yellow solid, 0.84 g (71%).

Workup

customThe red reaction mixture
temperatureto warm to room temperature
stirringstirred for 1 hour
filtrationThe yellow precipitate was filtered off
washwashed with water
dry with materialdried over P2O5 under vacuum
customThe solid was recrystallised from dichloromethane-ethanol

Sources & evidence

ORD record: ord-561cf75fa8f44ea3a85aeff1b791fb6d
Source dataset: uspto-grants-2014_12
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08907099B2

Reaction notes

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