1,2,3-Thiadiazole-4-carboxylic acid, hydrazide → HCID 66599284、化合物

Triethyloxonium tetrafluoroborate (363 mg, 1.908 mmol) was added to a suspension of 4-[(2,4-dichloro-3-fluorophenyl)carbonyl]-2-piperazinone (I37)(505 mg, 1.735 mmol) in dry dichloromethane (DCM) (4.2 ml). The reaction mixture was stirred at room temperature 45 mins—until everything was dissolved. 1,2,3-Thiadiazole-4-carbohydrazide (300 mg, 2.082 mmol, commercially available from e.g. Apollo) was added and the resulting mixture was stirred at room temperature for 3 h. DCM was evaporated and the residue was dissolved into 1-butanol (4.2 ml). The reaction mixture was stirred at reflux for 19 h. The mixture was washed with ethyl acetate and washed with water (2×25 mL) and brine (2×25 mL). The resulting organic layer was dried over MgSO4 and dried under reduced pressure. The crude product was purified by flash chromatography (DCM−10% MeOH in DCM). The residue was triturated with Et2O and then dried under vacuum at 50° C. for 2 days. The resulting solid was triturated with n-hexane and dried at 50° C. under vacuum 20 h to afford the desired product in 4.71 mg, as a white solid.