Synthesis and absolute stereochemistry of 5-alkyl-5-(3'-hydroxy-1'-methylbutyl)barbituric acid and 5-alkyl-5-(3'-hydroxy-1'-methylbutyl)-2-thiobarbituric acids.

5-Alkyl-5-(3-hydroxy-1-methylbutyl) barbituric acid (2) and 5-alkyl-5-(3-hydroxy-1-methylbutyl)-2-thiobarbituric acids (3) are matabolites of 5-alkyl-5-(2-pentyl) barbituric acid and 5-alkyl-5-(2-pantyl)-2-thiobarbituric acid, respectively. We have synthesized the four possible optical isomers of 2 and 3 by a procedure which established the absolute stereochemistry of each isomer. The two racemic pairs in each case were also prepared. The properties of these synthetic samples of 2 and 3 of known stereochemistry are compared to the properties of 2 and 3 which have been isolated from metabolism studies.