Yield: 90.2%

Reaction Conditions:

with triethylamine in acetonitrile at 40; for 4.58333 h;

Steps:

2.1
(1) The preparation of intermediate IV-2 [Show Image] 11.8 g (60 mmol) of piperazine hexahydrate was added to a 150 mL flask with 40 mL acetonitrile, heated to 40 °C, 10.8 g (50 mmol) of 2,3-dichloro-5-(trifluoromethyl)pyridine was added dropwise to the solution in 15 min, then 9 mL triethylamine was added to the mixture and stirred at 40 °C for 4 h. The reaction was monitored by TLC, upon completion, filtrated and washed by a little ethanol to obtain 12 g white solid (90.2% yield).

References:

Sinochem Corporation;Shenyang Research Institute of Chemical Industry Co., Ltd. EP2281810, 2011, A1 Location in patent:Page/Page column 40-41