Abstract
It is well known that 3-methylbutyrylurea is one of the metabolites of α-bromoisovalerylurea (bromvalerylurea), and the present experiment was carried out in order to find other metabolites of this hypnotic. After the administration of bromovalelrylurea to a rabbit, the urine was collected daily and passed through an anion-exchange resin column. As a result of thin-layer chromatography of the fractions eluted with dil acetic acid, a new Ninhydrin-positive spot was detected much more clearly in the first 24-hr urine than in any other cxcreted urine. From the first 24-hr urine, this substance was obtained as a pure crystalline compound. Mass spectra, infrared spectra, and other chemical analyses suggested that this Ninhydrin-positive spot is a cysteine derivative of bromvalerylurea. Finally, this compound was determined as 2-(2-amino-2-carboxyetylthio)-3-methylbutyrylurea by comparison with a synthetic compound.
