Butyl bromide → 6-(4-n-Butoxy-3-methoxyphenyl)-3[2H]pyridazinone

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Reaction Steps

11.0 g of 6-(4-hydroxy-3-methoxyphenyl)-4,5-dihydro-3[2H]pyridazinone are heated under reflux together with 8.2 g of 1-bromobutane and 8.3 g of potassium carbonate in 150 ml of anhydrous acetone for 20 hours. Thereafter, the starting compound can no longer be detected by thin-layer chromatography. The suspension is filtered hot, the filter cake is washed out with hot acetone and the filtrates are combined and evaporated in vacuo. The semi-solid residue [6-(4-n-butoxy-3-methoxyphenyl)4,5-dihydro-3[2H]pyridazinone]is taken up in 50 ml of ethanol, 10.0 g of sodium hydroxide in 200 ml of water and 14.6 g of sodium meta-nitrobenzenesulfonate are added and the mixture is heated under reflux for 2 hours. After cooling, it is acidified to pH 1-2 with concentrated hydrochloric acid, the crystalline solid is filtered off with suction and the solution is extracted several times with chloroform. The residue from the chloroform extract is combined with the crystals and the product is recrystallized from ethanol/ethyl acetate. 8.7 g (63.7% of theory) of the title compound of m.p. 193° are obtained.

Provenance & Evidence