Sulfuric Acid → HCID 178518766, compound

Participants

Reaction Steps

Ethyl [(3-phenyl-1H-pyrazol-5-yl)amino]carbothioylcarbamate (8.4 g, 29 mmol) was dissolved in aqueous sodium hydroxide (100 mL, 2N solution) and the resulting solution was stirred at room temperature overnight. This solution was acidified to pH=1 with concentrated sulfuric acid, resulting in heavy precipitation. This precipitate was collected by filtration and dried to give 7-phenyl-2-thioxo-2,3-dihydropyrazolo-[1,5-a][1,3,5]triazin-4(1H)-one (5.7 g, 80%) as a white solid. 1H-NMR (DMSO-d6): δ 7.97 (m, 2H), 7.48 (m, 3H), 6.41 (s, 1H); MS m/z 245 (M+1).

Provenance & Evidence