Phosphorus oxychloride → Ethyl 3-chloropyridazine-4-carboxylate
Reaction equation
[CH2:1]([O:3][C:4]([C:6]1[C:7](=O)[NH:8][N:9]=[CH:10][CH:11]=1)=[O:5])[CH3:2].O=P(Cl)(Cl)[Cl:15]>>[CH2:1]([O:3][C:4]([C:6]1[CH:11]=[CH:10][N:9]=[N:8][C:7]=1[Cl:15])=[O:5])[CH3:2]Participants
3
Conditions
- Temperature
- 100 °C
Procedure
A mixture of 3-oxo-2,3-dihydro-pyridazine-4-carboxylic acid ethyl ester (355 mg, 2.11 mmol) and POCl3 (6 ml) was heated to 100° C. for 1 h. The volatiles were then removed and the remaining residue was neutralized with sat. NaHCO3-solution. This mixture was extracted three times with Et2O and the combined extracts were dried (Na2SO4) and evaporated to obtain the crude title compound. The remaining brown solid (364 mg, 1.95 mmol, 92%) was used in the next reaction step without further purification. MS: m/e=187.1 [M+H+].