In a 200-cc. round-bottomed flask, fitted with a reflux condenser, are placed 50 g. (0.33 mole) of m-nitrobenzaldehyde (Note 1), 40 g. (0.48 mole) of freshly fused sodium acetate, and 70 g. (0.68 mole) of acetic anhydride. The contents of the flask are well mixed and the mixture heated in an oil bath held at 180° for about thirteen hours. After the reaction product has been allowed to cool slightly, it is poured into 200–300 cc. of water and then filtered by suction (Note 2). After the solid has been washed several times with water, it is dissolved in a solution of 20 cc. of aqueous ammonia (sp. gr. 0.9) in about 200 cc. of water. The solution of the ammonium salt, after filtering, is poured into a solution of 15 cc. of sulfuric acid (sp. gr. 1.84) in about 200 cc. of water (Note 3). The precipitated m-nitrocinnamic acid is filtered, redissolved in aqueous ammonia, and again precipitated by pouring the solution into dilute sulfuric acid (Note 4).

After the last precipitation, the m-nitrocinnamic acid is washed with a little water and then sucked as dry as possible (Note 5). The product, which still contains considerable water, is dissolved in 250–300 cc. of boiling 95 per cent alcohol from which the nitrocinnamic acid crystallizes on cooling. The yield is 47–49 g. (74–77 per cent of the theoretical amount). The product is pale yellow and melts at 192–194°. If a purer product is desired, it may be recrystallized from benzene or alcohol (Note 6).