反应详情

A solution of N-[(1H-pyrazol-3-ylamino)carbonothioyl]benzamide (22 g, 0.089 mol) in 10% NaOH solution (200 ml) is stirred at 80° C. for 45 min. The reaction mixture is cooled down to rt and the solvents are removed under vacuum. The residue is acidified with 2M HCl to pH=1 and then basified with ammonium hydroxide. The product is extracted with dichloromethane (4×100 ml). The combined extracts are dried and evaporated. The solid residue is purified by flash chromatography using chloroform/methanol (9/1) as eluent. N-1H-Pyrazol-3-ylthiourea is isolated as a solid (9 g; 75%). 1H NMR (DMSO-d6, 300 MHz): δ 5.88 (br s, 1H), 7.64 (s, 1H), 8.44 (br s, 1H), 9.02 (br s, 1H), 10.30 (br s, 1H), 12.47 (br s, 1H). HPLC (Method B), Rt: 3.88 min (purity: 99.4%). TLC: Chloroform/methanol (9/1): Rf−0.2. Mp: 130-132° C.

1. customthe solvents are removed under vacuum
2. extractionThe product is extracted with dichloromethane (4×100 ml)
3. customThe combined extracts are dried
4. customevaporated
5. customThe solid residue is purified by flash chromatography