Nitro cinnamic acid

Since most anilines are derived from nitro intermediates the reduction of the aromatic nitro group followed by cyclization of the aniline in situ has offered a direct approach to the synthesis of quinolines. The ort/io-nitro cinnamic acid derivatives 28 undergo cyclization, where R corresponds to R , respectively, when treated with zinc in near-critical water at 250 °C... 

When a large crystal of cyclonite is added to the diphenylamine reagent, a blue color appears slowly on the surface of the crystal. Powdered cyclonite gives within a few seconds a blue color which rapidly becomes more intense. If cinnamic acid is dissolved in concentrated sulfuric acid, and if finely powdered cyclonite is added while the mixture is stirred, gas comes off at a moderate rate, and the mixture, after standing over night and drowning, gives a precipitate which contains a certain amount of p-nitro-cinnamic acid. 

In a 200-cc. round-bottom 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 1800 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 ammonium hydroxide (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-nitro-cinnamic acid is filtered, redissolved in ammonium hydroxide, and again precipitated by pouring the solution into dilute sulfuric acid (Note 4). 

It is necessary to prepare first, o-nitro-phenyl-propiolic acid, which is itself obtained from o-nitro-cinnamic acid. Cinnamic ester (50 gms.) is nitrated by pouring gradually into cooled nitric acid (sp. g. 1-5). 

Baeyer and Emmerling, Indole from ortho-Nitro Cinnamic Acid.—... 

Benzaldehyde, ortho-Nitro Cinnamic Acid, ortho-Nitro Phenyl Propiolic Acid.—Later he started with benzaldehyde and obtained first benzal chloride which by condensation with sodium acetate yielded cinnamic acid salt. 

From the cinnamic acid salt by nitration he obtained ortho-nitro cinnamic acid. This yielded a di-bromide which by loss of two molecules of hydrogen bromide was converted into ortho-nitro phenyl propiolic acid (p. 700). 

From a practical point of view very selective reactions are possible. As already mentioned the CC-double bond of /7-nitro-cinnamic acid can be reduced with enoate reductase and NADH without attacking the nitro group. 

Ito Y, Fujita H (2000) Unusual [2+2] photocycloaddition between tryptamine and 3-nitro-cinnamic acid in the solid state. Chem Lett 288-289... 

This reaction was first reported by Baeyer and Emmerling in 1869. It is the synthesis of indole via the alkaline reduction of o-nitro-cinnamic acid by iron. Although the Fischer Indole Synthesis has been considered as the most versatile approach for the indole derivatives, a few methods similar to Baeyer indole synthesis have also been developed so far. ... 

Hydroxy-3-nitro-cinnamic acid. This compound was prepared according to the procedure described (14) with slight modification. After the acid was obtained by pouring the pyridine solution into cold aqueous HCl solution it was filtered and dried. The acid was then dissolved in NaHC03 solution and was precipitated by treating with cone.HCl. The acid was collected after filtering, washed, dried and recrystallized from ethanol m.p. 224-225 ... 

Hydroxy-4- nitro-cinnamic acid. This acid was prepared according to the procedure used for the 4-hydroxy-3-nitro isomer. It was recrystallized from ethanol with decolorizing carbon to yield a yellow solid (-70% yd) m.p. 256-257°C (lit. m.p. (15) 248°). 

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