反应详情

To a solution of 3′-chloro-2,3,5,6-tetrahydro-[1,2′]bipyrazinyl-4-carboxylic acid tert-butyl ester (3.7 g, 12.4 mmol, prepared in Example 5a) and dichloromethane (20 mL) was added anhydrous 4M HCl/Dioxane (20 mL). The solution was stirred for 1 h until complete de-protection was evident by LCMS. The solution was concentrated in vacuo, which was then re-dissolved in dichloromethane (50 mL). Triethylamine (3.78 g, 37.4 mmol) was added and the solution was cooled to 0° C. before dropwise addition of 1-isocyanato-3,5-bis-trifluoromethyl-benzene (3.70 g, 14.5 mmol) with stirring. After completion of addition the solution was allowed to warm up to room temperature and stirred for 1 h. The reaction mixture was diluted with EtOAc (150 mL), then washed with saturated sodium bicarbonate, and brine. The organic phase was dried over MgSO4 and concentrated in vacuo to yield 3′-chloro-2,3,5,6-tetrahydro-[1,2′]bipyrazinyl-4-carboxylic acid (3,5-bis-trifluoromethyl-phenyl)-amide (5.6 g, 100%) as a white solid.

1. concentrationThe solution was concentrated in vacuo, which
2. dissolutionwas then re-dissolved in dichloromethane (50 mL)
3. stirringwith stirring
4. additionAfter completion of addition the solution
5. stirringstirred for 1 h
6. washwashed with saturated sodium bicarbonate, and brine
7. dry with materialThe organic phase was dried over MgSO4
8. concentrationconcentrated in vacuo