Glucuronic acid ester

In a study of the relative reactivity of glucuronic acid esters thiodonors, the same authors explored the use of monomeric and dimeric donor building blocks in the synthesis of Steptococcus pneumomiae type 3 oligosaccharide in the presence of activator system NIS/TfOH, as for the synthesis of compound 37 see Scheme 9. ... 

Resin acids are toxic to fish at concentrations of 0.5-1 mg/1, but are not toxic to humans and other mammals. The toxicity of the resin acids is related to their uptake from water and accumulation in the fish [26]. The resin acids are then metabolized in the liver by formation of their glucuronic acid esters, which are excreted through the bile. The glu-curonyltransferase enzyme system in the liver can be overloaded and seriously affect the function of the liver [27]. However, resin acids, as well as fatty acids, are to a large extent removed in modern water treatment plants with mechanical and biological stages [28]. 

Glucuronidation. Complexation of the steroid to glucuronic acid, most predominantiy via the C-3 hydroxyl, leads to a considerable portion of the excreted metabohtes of ah. glucocorticoids. In infants, sulfurylation (formation of a sulfate ester) is also predominant (16). 

Figure 32-13. Structure of bilirubin diglucuronide (conjugated, "direct-reacting" bilirubin). Glucuronic acid is attached via ester linkage to the two propionic acid groups of bilirubin to form an acylglucuronide.

A series of derivatives analogous to those from D-glucuronic acid has been made by Morell and Link.68 An important compound is the crystalline methyl ester of methyl a-D-galacturonoside (XXXII) which on alkaline hydrolysis yields methyl a-D-galacturonoside (XXXIII). Since... 

Figure 3.8(a) Possible ester linkage between an a-OH of lignin and a carboxyl group of a 4-0-methyl-/3-d-glucuronic acid residue on the xylan backbone. 

Metabolism - The metabolic pathway of trospium in humans has not been fully defined. Of the 10% of the dose absorbed, metabolites account for approximately 40% of the excreted dose following oral administration. The major metabolic pathway is hypothesized as ester hydrolysis with subsequent conjugation of benzylic acid to form azoniaspironortropanol with glucuronic acid. Cytochrome P450 is not expected to contribute significantly to the elimination of trospium. 

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