Hydrochloric Acid → 5-Oxo-1-(4-sulfophenyl)pyrazolidine-3-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

50 parts of monomethyl maleate are added with stirring to 400 parts of water containing 70 parts of p-hydrazinobenzene sulphonate and 39 parts of sodium carbonate. The mixture is warmed until all reactants are in solution and the pH is adjusted by sodium carbonate to 9.2. The resulting solution is heated at 100° C for 9 hours. On completion of heating, the pH is adjusted to 3.8 by addition of hydrochloric acid and the 3-carboxy-1-(4'-sulphophenyl)-5-pyrazolidone thus formed is recovered and dried between 50°-100° C. The actual weight yield is 140 parts of strength 70% (determined by N.M.R.) which represents a yield of 89% of the theory.

Provenance & Evidence