3-Bromo-4-hydroxy-6-methoxyquinoline synthesis

Yield:724788-41-4 80%

Reaction Conditions:

with bromine in diethyl ether;dichloromethane;

Steps:

12 3-Bromo-6-methoxy-4-quinolone

Preparation 12 3-Bromo-6-methoxy-4-quinolone To a solution of 6-methoxy-4-chromanone (35 g) in ethyl ether (1.6 liters) at 5-10° C. was added dropwise over 30 minutes 10.6 ml of bromine. The mixture was stirred at 5-10° C. for 30 minutes and then allowed to warm to room temperature. After 2 hours tlc (CH₂ Cl₂) indicated formation of less polar products and only a trace of starting material remaining. The reaction mixture was washed with water (1 liter), saturated NaHCO₃ (500 ml), and brine (500 ml), dried over MgSO₄, and concentrated in vacuo to a yellow solid. The crude product was purified by silica gel flash column chromatography on 2.4 Kg fine silica gel, eluding with a gradient system consisting of 3:1 hexanes/dichloromethane followed by 2:1 hexanes/dichloromethane and finally 30% hexanes/dichloromethane. This afforded title product as a yellow solid in 80% yield.

References:

US6166031,2000,A