2-Methyl-8-hydroxyquinoline → 2-(Hydroxyiminomethyl)quinolin-8-ol

HRID 623399

Reaction equation

[CH3:1][C:2]1[CH:11]=[CH:10][C:9]2[C:4](=[C:5]([OH:12])[CH:6]=[CH:7][CH:8]=2)[N:3]=1.OC1C=CC=C2C=1N=C(C=O)C=C2.CC([O-])=O.[Na+].Cl.[NH2:32][OH:33]>O1CCOCC1.O>[OH:12][C:5]1[CH:6]=[CH:7][CH:8]=[C:9]2[C:4]=1[N:3]=[C:2]([CH:1]=[N:32][OH:33])[CH:11]=[CH:10]2

Participants

Conditions

Temperature: 80 °C

Procedure

A solution of 2-methyl-quinolin-8-ol (536 mg, 3.37 mmol) in dioxane (8 mL) was added dropwise over 3 h into a stirred mixture of SeO2 (665 mg, 5.99 mmol) in dioxane (25 mL) at 50-55° C. The resulting mixture was then heated at 80° C. for 16 h, cooled, and the solids filtered off. The filtrate was concentrated and the residue purified by column chromatography on silica (dichloromethane/MeOH, 1:0-40:1). This afforded 8-hydroxy-quinoline-2-carboxaldehyde 4 as a straw-coloured solid (358 mg, 61%). 4: 1H NMR (CDCl3): δ 10.24 (s, 1H), 8.34 (d, J=8.6, 1H), 8.22 (br, 1H), 8.07 (d, J=8.6, 1H), 7.64 (dd, J=7.5 and 8.0, 1H), 7.44 (d, J=8.0, 1H), 7.30 (d, J=7.5, 1H). The mixture of 4 (100 mg, 0.578 mmol), NaOAc (63 mg, mmol), hydroxylamine hydrochloride (60 mg, 0.863 mmol) and water (5 mL) was heated at 100° C. for 15 min. The precipitate was isolated by filtration. This provided the title oxime (ID 969) D1 as an off-white solid (87 mg, 80%); spectral data of this compound are shown in Table 2.

Workup

temperaturecooled
filtrationthe solids filtered off
concentrationThe filtrate was concentrated
customthe residue purified by column chromatography on silica (dichloromethane/MeOH, 1:0-40:1)
temperaturewas heated at 100° C. for 15 min
customThe precipitate was isolated by filtration

Sources & evidence

ORD record: ord-75aab6ae20004150b700cec79767a5e5
Source dataset: uspto-grants-2016_04
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09302993B2

Linked notes

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