Acetaminoacrylic acid

Pyruvic acid yields mainly a,a-diacetaminopropionic acid, which can be converted into a-acetaminoacrylic acid by hot acetic acid. > Under the optimum conditions " a 23% yield of a-acetaminoacrylic acid is obtained. Phenylpyruvic acid gives mainly a-acetaminocinnamic acid, as would be expected in view of the activating effect of the benzene ring. Benzoylformic acid and a-ketoglutaric acid have been employed as the acid components in this reaction, and benzamide, benzylcarbar mate," and chloroacetamide " as the amide components. The preparation of a-acetaminocinnamic acid by this method is described in the next section. 

In 1930 Bergmann and Grafe 45) observed the formation of a,a-diacetaminopropionic acid (32) and acetaminoacrylic acid (31) on warming a mixture of pyruvic acid and acetamide under reduced pressure. (32) could be converted into (31) by treatment with acetic acid 46, 337) (Scheme 13). The a-hydroxy-a-acylamino acid (30) is almost... 

Hoffmann et al. (114), was reacted with acetaminoacrylic ethyl ester in alkaline medium (115) followed by acid hydrolysis and purification by ion-exchange chromatography (113). 

---