Sodium Hydroxide → 3,8-Dibromo-6-hydroxyquinoline

HRID 1244812Notes

Reaction equation

N[C:2]1[CH:3]=[C:4]2[C:9](=[C:10]([Br:12])[CH:11]=1)[N:8]=[CH:7][C:6]([Br:13])=[CH:5]2.[OH-:14].[Na+]>P(=O)(O)(O)O>[Br:13][C:6]1[CH:7]=[N:8][C:9]2[C:4]([CH:5]=1)=[CH:3][C:2]([OH:14])=[CH:11][C:10]=2[Br:12]

Participants

Conditions

Temperature: 180 °C

Procedure

6-Amino-3,8-dibromoquinoline (0.15 g) was suspended in phosphoric acid (75%, 11 ml) and heated in a sealed glass, tube at 180° C. for 72 hours. The mixture was allowed to cool to ambient temperature, diluted with ice (50 ml) and taken to pH 2 with aqueous sodium hydroxide (4M). The brown suspension that formed was extracted with ethyl acetate (twice), dried over magnesium sulphate then evaporated under reduced pressure to give 3,8-dibromo-6-hydroxyquinoline (M+−H 300, 2×Br) as a dark red solid that was used in the next stage without further purification, 1H NMR (d6 DMSO) δ: 7.14(1H, d); 7.60(1H, d); 8.52(1H, d); 8.71(1H, d). In a similar procedure to Step 3, 6-amino-3-bromoquinoline was converted to 3-bromo-6-hydroxyquinoline, brown solid, 1H NMR (d6 DMSO) δ: 7.19(1H, d); 7.40(1H, dd); 7.92(1H, d); 8.66(1H, s); 8.79(1H, s).

Workup

temperatureto cool to ambient temperature
customThe brown suspension that formed
extractionwas extracted with ethyl acetate (twice),
dry with materialdried over magnesium sulphate
customthen evaporated under reduced pressure

Sources & evidence

ORD record: ord-d1d908fb97bc4979a9ddeedd5c70893f
Source dataset: uspto-grants-2006_10
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07122672B2

Reaction notes

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