Phosphorus oxychloride → 4-Chloro-5,7-dimethoxyquinoline
Reaction equation
[CH3:1][O:2][C:3]1[CH:12]=[C:11]([O:13][CH3:14])[CH:10]=[C:9]2[C:4]=1[C:5](O)=[CH:6][CH:7]=[N:8]2.O=P(Cl)(Cl)[Cl:18]>C1(C)C=CC=CC=1>[Cl:18][C:5]1[C:4]2[C:9](=[CH:10][C:11]([O:13][CH3:14])=[CH:12][C:3]=2[O:2][CH3:1])[N:8]=[CH:7][CH:6]=1Participants
4
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Procedure
To a mixture of crude 5,7-dimethoxyquinolin-4-ol (5.36 g, 26 mmol) and Hunig'sBase (9.1 ml, 52 mmol) in toluene, was added POCl3(29 ml, 313 mmol). The mixture was refluxed for 5 h. Excess POCl3 was removed under reduced pressure and the mixture was azeotroped with toluene. The resultant gum was treated with sat. NaHCO3 until no gas generated. The mixture was extracted with EtOAc, the organic extracts were combined and washed with sodium bicarbonate and solvent removed under reduced pressure. The crude product was purified via column chromatography on silica gel (RediSep 120 g column, gradient elution with 0-50% EtOAc/DCM) to afford 4-chloro-5,7-dimethoxyquinoline as a yellow solid. MS: m/z=[M+H]+. 224.2 Calc'd for C11H10ClN: 223.7.