2-(3,4-Dimethoxy-5-nitrophenyl)-5-(2-(trifluoromethyl)pyridin-3-yl)-1,3,4-oxadiazole → 3-Nitro-5-[5-(2-trifluoromethyl-pyridin-3-yl)-[1,3,4]oxadiazol-2-yl]-benzene-1,2-diol

HRID 42636Notes

Reaction equation

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

Participants

Conditions

Temperature: 140 °C

Procedure

A suspension of 2-(3,4-dimethoxy-5-nitrophenyl)-5-(2-(trifluoromethyl)pyridin-3-yl)-1,3,4-oxadiazole (0.289 g, 0.73 mmol) in a mixture of 48% hydrobromic acid (5 mL) and 30% hydrogen bromide in acetic acid (5 mL) was heated at 140° C. overnight and then allowed to cool to room temperature. After evaporation to dryness under reduced pressure, toluene (10 mL) was added to the residue and re-evaporated under reduced pressure. The resulting solid was recrystallised from isopropanol to give 3-nitro-5-[5-(2-trifluoromethyl-pyridin-3-yl)-[1,3,4]oxadiazol-2-yl]-benzene-1,2-diol as a yellow solid, 0.183 g, (68%).

Workup

temperatureto cool to room temperature
customAfter evaporation to dryness under reduced pressure, toluene (10 mL)
additionwas added to the residue
customre-evaporated under reduced pressure
customThe resulting solid was recrystallised from isopropanol

Sources & evidence

ORD record: ord-1c2d82341f984df19e3ce887df023deb
Source dataset: uspto-grants-2013_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08536203B2

Reaction notes

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