Citra-conic acid

Methyl maleic acid Citra-conic acid... 

Citra-conic and Mesa-conic Acids.—Two such geometrically isomeric acids are known to which the names citra-conic acid and mesa-conic acid have been given. Citra-conic acid melts at 80° and easily yields an anhydride. It must, therefore, be represented by the cis formula and is the methyl derivative of maleic acid. Mesa-conic acid melts at 202° and does not yield an anhydride. It should, therefore, be... 

In the decomposition by heat other acids are also formed, viz., ita-conic and citra-conic acids (p. 293). In this case both carbon di-oxide and water are lost. 

Freri478,480 has reported a very interesting synthesis of 4-oximino-3-methyl-2-pyrazolin-5-one. This consisted in the treatment of citra-conic acid hydrazide with nitrous acid (eq. 211). The physical data which... 

CjfeHjgOe, Mr 446.58, cryst., mp. 59-60°C. Bis-citra-conic acid anhydride derivative and an inhibitor of leucine and cysteine aminopeptidases from cultures of the wood-rotting fungus Tyromyces lacteus (Basidiomy-cetes). T. shows cytostatic activity. 

White crystals m.p. 162-164 C. ll can be prepared by the fermentation of sugar with the mould Aspergillus lerreus or by healing citra-conic anhydride with water at ISO C. Electrolysis of the potassium salt in solution gives allene. Itaconic acid is used as a comonomer in plastics its esters are polymerized to lubricating oils and plasticizers. 

Deacylation of derivatives formed by acid anhydrides (maleic, citra-conic, and 2,3-dimethylmaleic) containing double bonds (cis) occurs at a much faster rate under mild conditions. Several mechanisms have been proposed for deacylating these derivatives formed from the double bond containing anhydrides (9,46,47,48,49). The most important structural factor in the deacylation process is the cis double bond which maintains the terminal carboxyl group in the spatial orientation that makes a nucleophilic attack on the amide carbon much more probable. 

Citra-conic. Mesa-conic and Ita-conic Acids... 

Ita-conic Acid.—There is, however, a third acid known of the same composition as the two preceding. It is called ita-conic acid and like the others is obtained from citric acid by distiUation. More than the two isomers just explained are not possible according to geometric isomerism. The isomerism, therefore, of this new acid with the other two must be explained in some other way and has been shown to be structural isomerism due to the different position of the double bond. We have spoken of the fact that both citra-conic and mesa-conic acids, by the addition of hydrogen, are converted into methyl succinic acid. This same result is obtained with ita-conic acid also as may be explained by the following reactions. 

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