5-Decynedioic acid, an acetylenic compound in human urine.

An acetylenic dicarboxylic acid, 5-decynedioic acid, has been isolated from human urine. The structure was determined by mass spectrometry of several derivatives, and by infrared spectroscopy. On osmium tetroxide oxidation, a vic-diketone was formed, the mass spectrum of which established the position of the triple bond between carbon atoms 5 and 6. Mass spectrometric evidence for the presence of a small amount of the isomeric 4-decynedioic acid was also obtained. The 24-h excretion of these acids is 0.01-0.1 mmol for healthy adults on a regular diet.