Chlorquinaldol → 5,7-Dichloro-8-hydroxyquinoline-2-carbaldehyde
Reaction equation
[Cl:1][C:2]1[CH:11]=[C:10]([Cl:12])[C:9]([OH:13])=[C:8]2[C:3]=1[CH:4]=[CH:5][C:6]([CH3:14])=[N:7]2.[Se](=O)=[O:16]>O1CCOCC1>[Cl:1][C:2]1[CH:11]=[C:10]([Cl:12])[C:9]([OH:13])=[C:8]2[C:3]=1[CH:4]=[CH:5][C:6]([CH:14]=[O:16])=[N:7]2Participants
4
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Conditions
- Temperature
- 80 °C
Procedure
A solution of 5,7-dichloro-2-methyl-quinolin-8-ol 16 (1.5 g, 6.58 mmol) in 1,4-dioxane (20 mL) was added dropwise over 3 h to a stirred suspension of selenium dioxide (1.3 g, 11.72 mmol) in 1,4-dioxane (60 mL) at 50-55° C. The resulting mixture was then heated at 80° C. overnight, cooled, and the solids filtered off (celite). The filtrate was concentrated and the residue, after washing with diethyl ether (10 mL×3), gave 17 as a yellow solid (quantitative yield). This material was used in the subsequent step without further purification. 1H NMR (CDCl3, 400 MHz): δ 10.26 (s, 1H), 8.69 (d, J=8.8, 1 H), 8.37 (br, 1H), 8.17 (d, J=8.8, 1 H), 7.76 (s, 1H).