反应详情

温度

100 °C

5 parts of monomethyl maleate are added with stirring to 25 parts of water containing 7 parts of p-hydrazinobenzene sulphonate and 4 parts of sodium carbonate and the mixture is heated at 100° C for 6 hours. The pH is then adjusted to 3.8 by addition of hydrochloric acid and the 3-carboxy-1-(4'-sulphophenyl)-5-pyrazolidone thus formed is filtered off and dried between 50°-100° C. The actual weight yield is 12 parts of strength 67% (determined by N.M.R.) which represents a yield of 73% theory.