P-Piperonylacrylic acid

Pinacolone, 349, 351 P-Piperonylacrylic acid, 711,719 Pivalic acid, 350, 351 Platinum catalysts, for dehydrogenation, 948... 

Dissolve 50 g. of piperonal and 75 g. of malonic acid in a mixture of 160 ml. of pyridine and 2-5 ml. of piperidine contained in a 500 ml. round-bottomed flask, and heat under reflux for 1 hour on a water bath. A rapid evolution of carbon dioxide takes place. Complete the reaction by boiling the solution for 5 minutes. Cool, pour into excess of water containing enough hydrochloric acid to combine with the pyridine, filter ofiFthe piperonylacrylic acid, wash with a little water, and dry. The yield is almost quantitative and the acid is practically pure. It may be recrystallised from glacial acetic acid m.p. 238°. 

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