Reaction #710581

Reaction equation

2-methyl-quinolin-8-ol

4

8-hydroxy-quinoline-2-carboxaldehyde

NaOAc

hydroxylamine hydrochloride

→

oxime

8-Hydroxy-quinoline-2-carboxaldehyde Oxime

Solvents

dioxane

dioxane

water

Conditions

Workup

1. 1
   Temperaturecooled
2. 2
   Filtrationthe solids filtered off
3. 3
   ConcentrationThe filtrate was concentrated
4. 4
   Otherthe residue purified by column chromatography on silica (dichloromethane/MeOH, 1:0-40:1)
5. 5
   Temperaturewas heated at 100° C. for 15 min
6. 6
   OtherThe precipitate was isolated by filtration

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.

Source