Claisen by condensing ethoxymethylene aceto-acetic esters and similar compounds with /3-ketonic esters and with 1.3 diketones.
H HN CEH?Chch C(Ch3)N.Cs The ketonic esters under like treatment yield oxypyrimidines, whilst if cyanacetic ester be employed then amino-oxypyrimidines are obtained.
The 2.6-diketo-tetrahydropyrimidines or uracils may be considered as the ureides of /-aldehydo, and 0-ketonic acids.
The carbonyl group is not ketonic in character since it yields neither an oxime nor hydrazone.
Compounds containing an oxy in addition to an aldehydic or ketonic group) undergo both condensation and oxidation when treated with phenylhydrazine, forming compounds known as osozones; these are of great importance in characterizing the sugars (q.v.).