Acetonitrile → 3-Phenylureido-1-(p-sulfophenyl)-5-pyrazolone Triethylamine Salt

Participants

Reaction Steps

Into 30 ml of acetonitrile was dissolved 4 g of ethylβ-amino-β-ethoxy acrylate, and 3 g of phenyl isocyanate was added thereto. The resulting solution was allowed to stand at room temperature for 24 hours. Into a mixed solution of 20 ml of methanol, 6 g of triethylamine and 5 ml of glacial acetic acid there was dissolved 4.7 g of p-sulfophenyl hydrazine, and the above solution, in which the esterification reaction had been completed, was added thereto. The resulting solution was allowed to stand at room temperature for 5 days. The crystals obtained were collected, washed with acetonitrile, and then recrystallized from methanol; thus 7.5 g of crystals of a melting point of 240° to 242° C. was obtained.

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