3-Hydroxyacetophenone → 6-(3-Hydroxyphenyl)pyridazin-3(2H)-one

Participants

Reaction Conditions

Reaction Steps

A 500 ml round bottom flask was equipped with a magnetic stirrer, thermometer, addition funnel, and pH electrode and was charged with 18.4 g (0.2 moles) of glyoxylic acid monohydrate and 75 mls of water. The solution was cooled to 10° C. and 20% aqueous potassium hydroxide was added raise the to pH to 8. A partial solution of 3'-hydroxyacetophenone (27.2 g, 0.2 moles) in KOH solution (20 g, 0.36 moles) was added all at once to the cold sodium glyoxylate solution and the reaction was stirred at room temperature for 2 hours. The dark brown solution was then re-cooled to 10° C., and acetic acid was added to pH 8. The contents were transferred to a separatory funnel, and the aqueous solution was extracted with 4×100 mls of methylene chloride to remove any unreacted 3'-hydroxyacetophenone. The aqueous fraction was again transferred to the reaction flask, cooled to 10° C. and further treated with acetic acid to pH 4.5, then concentrated ammonium hydroxide was added to pH 8. The solution was then heated under reflux with hydrazine monohydrate (10 mls, 0.2 moles) for 2 hours, then cooled to afford a yellow solid which was collected by vacuum filtration, and washed with water. The product was dried overnight under vacuum at 40° C., to yield 25.2 g of 6-(3-hydroxyphenyl)-3(2H)-pyridazinone (90.6% yield).

Provenance & Evidence