Phosphorus oxychloride → 3-Chloro-6-(pyridin-2-yl)pyridazine

Reaction equation

[N:1]1[CH:6]=[CH:5][CH:4]=[CH:3][C:2]=1[C:7]1[CH:8]=[CH:9][C:10](=O)[NH:11][N:12]=1.C([O-])(O)=O.[Na+].P(Cl)(Cl)([Cl:21])=O>>[Cl:21][C:10]1[N:11]=[N:12][C:7]([C:2]2[CH:3]=[CH:4][CH:5]=[CH:6][N:1]=2)=[CH:8][CH:9]=1

Participants

Reactant 3

HCID 24813Phosphorus oxychloride

HCID 516892Sodium Bicarbonate

HCID 49800226-(Pyridin-2-yl)pyridazin-3-ol

Product 1

HCID 64179603-Chloro-6-(pyridin-2-yl)pyridazineYield 95%

Procedure

4 g of pyridinylpyridazinone 7 dissolved in an excess (40 ml) of phosphorus oxychloride are refluxed for 8 hours. After cooling, the reaction mixture is poured into 250 ml of ice-cold water and then neutralized, dropwise, with a saturated aqueous solution of NaHCO3. After extraction with dichloromethane (5×100 ml), the organic phase is dried over MgSO4 and then concentrated under reduced pressure, to give the chlorinated pyridazine 8a with a yield of 95%.