Derivatives of Glucuronic Acid I. the Preparation of Glucuronic Acid from Glucuron and a Comparison of Their Reducing Values by Walther F. Goebel and Frank H. Babers

The presence of glucuronic acid in the complex molecules of specific bacterial polysaccharides (1) has stimulated a study of certain derivatives of this important substance and its lactone, glucuron. These investigations have entailed the necessity of elaborating a satisfactory method for preparing both the acid and its lactone, and at the same time they have embraced a study of the comparative reducing values of these two substances. The present communication presents the results of this work. Preparation of Source Material-A considers&on of the various available sources and methods for the preparation of glucuronic acid has led us to the adoption of the excellent method of Quick (2) for securing large quantities of this compound in the form of the zinc salt of the borneolglycoside of glucuronic acid. Although the method of Weinmann (3), who prepared glucuronic acid from an acidic gum (4) derived from gum arabic, as well as the method of Fischer (5), offers available sources of the material, both of these methods have certain drawbacks. The method of Quick, on the other hand, proved to us to be of utmost value, for not only is it simple, but it provides a source material of high purity without elaborate chemical procedure. Thus, eight dogs weighing 7 to 12 kilos each were housed in clean metabolism cages. They were fed a daily diet of 2 pound of ground raw horse meat mixed with a little bread, salt, and 7 gm. of pulverized d-borneol, during 4 consecutive days. During the succeeding 3 days of the week, the animals were maintained on a borneol-free diet. When these conditions were followed the