反应详情

A solution of 3.2 mL (1 mol equiv.) 2,2,2-trifluoro-ethylamine in 60 mL acetonitrile was added to a stirred solution of 7.4 g (2.1 mol equiv.) 1,1′-thiocarbonyldiimidazole in 100 mL acetonitrile at room temperature. The reaction mixture was stirred overnight, and 1.96 g (1 mol equiv.) 4-Ethyl-4,5-dihydro-1H-pyrazole (synthesized as described in WO 2008/034863) was added to the reaction mixture. After 1 hour volatiles were removed under reduced pressure and the residue was purified by flash chromatography on silica gel (Et2O:PA=1:3) to afford 2.85 g (60%) 4-ethyl-4,5-dihydro-pyrazole-1-carbothioic acid (2,2,2-trifluoro-ethyl)-amide. 1H NMR (400 MHz, CDCl3) δ 1.01 (t, J=7.5 Hz, 3H), 1.50-1.74 (m, 2H), 3.13-3.23 (m, 1H), 3.86 (dd, J=11.6, 7.1 Hz, 1H), 4.27 (t, J=11.6 Hz, 1H), 4.44 (m, 2H) 6.99 (d, J=1.5 Hz, 1H), 7.32-7.40 (br.s., 1H).

1. customAfter 1 hour volatiles were removed under reduced pressure
2. customthe residue was purified by flash chromatography on silica gel (Et2O:PA=1:3)