Sodium Hydroxide → 3-Chloro-6-propylpyridazine

Participants

Reaction Conditions

Reaction Steps

46.0 g of phosphorus oxychloride were heated to 60° C. in a sulphonation flask under nitrogen and treated within 1 hour with 27.6 g of 6-propyl-3(2H)-pyridazinone (prepared according to Example 3) in small portions. The mixture was subsequently heated slowly to 100° C. and stirred at this temperature until the reaction was complete according to thin-layer chromatography (about 2 hours). After cooling to room temperature, the dark brown solution was poured into 1 l of water and neutralized with solid sodium hydroxide and sodium hydrogen carbonate. The aqueous phase was subsequently extracted once with 500 ml of tert.butyl methyl ether and then twice with 250 ml of tert.butyl methyl ether each time. The organic phases were washed with 500 ml of water and the aqueous phase was back-extracted twice with 100 ml of tert.butyl methyl ether each time. The combined organic phases were dried over sodium sulphate and freed from solvent on a rotary evaporator. Distillation of the resulting dark brown oil in a high vacuum gave in the main run 22.9 g (73.1%) of 3-chloro-6-propylpyridazine as a colourless liquid; b.p. 72°-74° C./0.4 Torr.

Provenance & Evidence