Dichloromethane → 3-Chloro-6-(4-fluorophenyl)-[1,2,4]triazolo[4,3-b]pyridazine

Participants

Reaction Conditions

Reaction Steps

a mixture of 4.16 g of 4-fluorophenylboronic acid, 9.37 g of barium hydroxide octahydrate, 2.20 g of [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II) in a complex with dichloromethane (1:1) and 5.1 g of commercial 3,6-dichloro[1,2,4]triazolo[4,3-b]pyridazine in 40 cm3 of N,N-dimethylformamide containing 10 cm3 of water is heated in a bath at 80° C. for 1.5 h. The beigey-brown suspension obtained is cooled to 20° C. and then poured into approximately 200 cm3 of water. The insoluble material is spin-filter-dried and washed successively with water and with ether, and then dried under vacuum at 20° C. The resulting beige solid is made into a paste in dichloromethane, spin-filter-dried, and dried under vacuum at 20° C. 1.24 g of 3-chloro-6-(4-fluorophenyl)-1,2,4-triazolo[4,3-b]pyridazine are thus obtained. 30 g of silica are added to the combined mother liquors and the mixture is evaporated to dryness under vacuum. This residue is deposited onto a bed of 10 g of silica in a sintered glass filter and elution is carried out with dichloromethane. An additional 1.60 g of 3-chloro-6-(4-fluorophenyl)-1,2,4-triazolo[4,3-b]pyridazine are thus recovered.

Provenance & Evidence