反应详情

2.68 g (1 mol equiv.) 4-Ethyl-4,5-dihydro-1H-pyrazole (synthesized as described in WO 2008/034863) and 3.11 mL (1.3 mol equiv.) ethyl isothiocyanate were added to 20 mL ethanol. The reaction mixture was refluxed overnight, silica gel was added and volatiles were removed under reduced pressure. Purification by flash chromatography on silica gel (Et2O:PA=1:3) afforded 1.80 g (36%) 4-ethyl-4,5-dihydro-pyrazole-1-carbothioic acid ethylamide. 1H NMR (400 MHz, CDCl3) δ 0.99 (t, J=7.5 Hz, 3H), 1.25 (t, J=7.2 Hz, 3H), 1.47-1.71 (m, 2H), 3.08-3.18 (m, 1H), 3.63-3.72 (m, 2H), 3.86 (dd, J=11.5, 7.1 Hz, 1H), 4.25 (t, J=11.5 Hz, 1H), 6.90 (d, J=1.5 Hz, 1H), 7.12 (br.s., 1H).

1. temperatureThe reaction mixture was refluxed overnight
2. additionsilica gel was added
3. customvolatiles were removed under reduced pressure
4. customPurification by flash chromatography on silica gel (Et2O:PA=1:3)