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

HRID 1920076Notes

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-c034a38093c3478e863845d039bb3b54
Source dataset: uspto-grants-2012_05
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08168793B2

Reaction notes

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