3-chloro-4-(trifluoromethyl)pyridazine synthesis

Yield:749258-96-6 61%

Reaction Conditions:

with N,N-dimethyl-formamide;trichlorophosphate at 120; for 2 h;

Steps:

Intermediate 49b: 3-chloro-4-(trifluoromethyl)pyridazine

[00514] Intermediate 49b: 3-chloro-4-(trifluoromethyl)pyridazine[00515] To a solution of 5-(trifluoromethyl)-1H-pyridazin-6-one (0.76g, 4.64mmol) in phosphorus oxychloride (4.33mL, 46.44mmol) was added a drop of N,N-dimethylformamide. The mixture washeated to 120 °C for 2 hours. The reaction mixture was allowed to cool to room temperature and concentrated in vacuo. The residue was diluted with EtOAc (lOOmL) and washed with water (lOOmL) and brine (lOOmL). The organic layer was dried over Na2504 and concentrated in vacuoto give 3-chloro-4-(trifluoromethyl)pyridazine (0.51g, 2.82mmol, 61% yield) as a brown oil which was used in the next step without further purification.MS Method 2: RT: 1.29 mi mlz 182.9 [M+H]

References:

WO2016/51193,2016,A1 Location in patent:Paragraph 00511; 00514; 00515