Isothiocyanatotrimethylsilane → 4,4-Dimethyl-4,5-dihydro-pyrazole-1-carbothioic acid amide
Reaction equation
[CH3:1][C:2]1([CH3:7])[CH2:6][N:5]=[N:4][CH2:3]1.C[Si]([N:12]=[C:13]=[S:14])(C)C>C(O)C>[CH3:1][C:2]1([CH3:7])[CH2:6][N:5]([C:13](=[S:14])[NH2:12])[N:4]=[CH:3]1Participants
4
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Procedure
3.0 g (1 mol equiv.) 4,4-Dimethyl-4,5-dihydro-3H-pyrazole (synthesized as described in WO 2008/034863) and 5.6 mL (1.3 mol equiv.) trimethylsilyl isothiocyanate were added to 30 mL ethanol and the reaction mixture was refluxed for 5 hours. Silica gel was added and volatiles were removed under reduced pressure. Purification by flash chromatography on silica gel (Et2O:PA=2:1) afforded 3.91 g (81%) 4,4-dimethyl-4,5-dihydro-pyrazole-1-carbothioic acid amide. 1H NMR (400 MHz, CDCl3) δ 1.27 (s, 6H), 3.94 (s, 2H), 5.82-6.34 (br.s., 1H), 6.50-7.00 (br.s., 1H), 6.80 (s, 1H).