Citric Acid → HCID 178514158, compound

Participants

Reaction Steps

To a stirring solution of 5-amino-3-phenylpyrazole (5 g,31.4 mmol) in dioxane (100 mL) was added MgO (1.27 g, 31.4 mmol) and a saturated aqueous solution of sodium bicarbonate (100 mL). The heterogeneous mixture was stirred for 30 min, then thiophosgene (2.65 mL, 34.6 mmol) was added dropwise, and the reaction mixture was further stirred vigorously for 15 min until completion. Ammonium hydroxide (25 mL) was then added dropwise, and the reaction mixture was stirred for another 20 min. A 10% aqueous solution of citric acid was added to lower the pH to 6, and the mixture was extracted with ethyl acetate (3×). The organic layer was dried over sodium sulfate, filtered, and adsorbed on silica gel. Purification on silica gel with 10-80% ethyl acetate in hexane as eluent provided 6.22 g (91%) of (5-Phenyl-2H-pyrazol-3-yl)-thiourea as a yellow foam.

Provenance & Evidence