The isolation and identification of 2,4-diketones present in human and animal tissues and in urine.

The chemical isolation of 2,3-diketone fraction from hydrolysates of various mammalian tissues has been accomplished by the use of a modified Girard T procedure. This fraction, which constitutes a new lipid class, has been resolved by gas chromatography into a number of homologous 2,4-diketones, ranging in chain length from C13 to C25. After separation by preparative gas chromatography, the following compounds have been unequivocally identified: 2,4-heptadecanedione, 2,4-nonadecanedione, 2,4-heneicosanedione, 2,4-docosanedione, and delta12-2,4-heneicosenedione. The 2,4-diketones appear to exist in tissues in the free state or in labile combination. They are present also in human urine.