Bromine → 6-(4-Chlorophenyl)-2,3-dihydropyridazin-3-one

Participants

Reaction Conditions

Reaction Steps

A 47.5 g. portion of 6-(p-chlorophenyl)-4,5-dihydro-3(2H)-pyridazinone (prepared as in Example 1 of U.S. Pat. No. 3,689,652) is dissolved in 250 ml. of glacial acetic acid at 65°-70° C with stirring. Then a solution of 14 ml. (42 g.) of bromine liquid in 50 ml. of acetic acid is added portionwise during a 20 minute period. The reaction mixture is stirred at 65° C. for 3 hours and is cooled to 4° C. The precipitate is collected and washed with 100 ml. of ethyl acetate. The solid is suspended in 500 ml. of water, 25 ml. of concentrated ammonium hydroxide is added and the mixture is stirred at room temperature overnight. the precipitate is collected, washed with 500 ml. of water and dried at 60° C. to afford 6-(p-chlorophenyl)-3(2H)-pyridazinone.

Provenance & Evidence