Aceto acetic acid Constitution

From Acetic and Formic Acids.—A fourth method of synthesis from acetic and formic acid esters will be explained in detail in connection with the next acid. All of these syntheses prove the constitution of pyro-racemic acid as an a//>/fa-ketone acid as given. It may be considered as aceto formic acid which is in accord with the fourth method of synthesis. As an acid it forms all acid derivatives and as a ketone it undergoes the characteristic ketone reactions, e.g.y with phenyl hydrazine and hydroxyl amine. On heating to 150° with dilute sulphuric acid in a sealed tube it loses carbon dioxide and yields acet aldehyde. 

The product here is an acid and the reaction is termed the acid hydrolysis. Both of these hydrolyses are more easily explained by the keto constitution for the ethyl aceto acetate. 

Synthesis from Glycerol.--Citric acid is related to the two preceding acids and its constitution has been established by two syntheses, one from glycerol and the other from aceto-acetic ester. 

It is similar in its constitution to a dipeptide except that one acid constituent has no amino group. A compound exactly analogous to it is aceto amino acetic acid, CH3—CO—NH—CH2—COOH. Such semi-peptides result when an amino acid is treated with the acid chloride of a non-amino acid analogous to the second method of preparing poly-... 

The constitution of the iso-dialuric acid was established by its synthesis from aceto-acetic ester and urea. 

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