Hydrochloric Acid → 6-chloro-3-hydroxy-2-(4-methylphenyl)-4H-1-benzopyran-4-one

Participants

Reaction Steps

A 8.5 g quantity of 5'-chloro-2'-hydroxyacetophenone and 6.0 g of p-tolualdehyde were dissolved in 105 ml of ethanol. Then 17 ml of an aqueous solution containing 10 g of sodium hydroxide was slowly added thereto dropwise and stirred at room temperature for 4 hours. Then 350 ml of ethanol and 17 ml of an aqueous solution containing 3.5 g of sodium hydroxide were added to the reaction mixture, and 8.3 ml of a 30% aqueous hydrogen peroxide solution was further added dropwise slowly and stirred at room temperature for 12 hours. A 10% aqueous HCl solution was added to adjust the reaction mixture to pH 3. The crystals precipitated were collected by filtration and washed serially with 10 ml of water, 5 ml of ethanol and 10 ml of diethyl ether, thus giving 6.0 g of 6-chloro-3-hydroxy-2-(4-methylphenyl)-4H-1-benzopyran-4-one as crystals.

Provenance & Evidence