Water → 3-Bromo-6-propylpyridazine

Participants

Reaction Conditions

Reaction Steps

11.75 g of 6-propyl-3(2H)-pyridazinone were dissolved in 70 ml of absolute toluene while warming in a sulphonation flask under nitrogen, heated to 80° C. and treated dropwise while stirring well within 30 minutes with a solution of 24.4 g of phosphorus oxybromide in 24.4 g of absolute toluene. The mixture was subsequently stirred under reflux for a further 3 hours. After completion of the reaction, the mixture was poured into 200 ml of water and neutralized with solid sodium hydrogen carbonate. The phases were separated and the aqueous phase was back-extracted twice with 100 ml of tert.butyl methyl ether each time. The combined organic phases were washed with 100 ml of water and dried over sodium sulphate. After evaporation of the solvent, the dark brown crystalline residue (14.1 g) was sublimed at 40°-60° C. in a high vacuum, there being obtained 8.2 g (48%) of 3-bromo-6-propylpyridazine as white crystals of melting point 35°-36° C.

Provenance & Evidence