Glucose complexing with chromium

Metabolic Functions. Chromium (ITT) potentiates the action of insulin and may be considered a cofactor for insulin (137,138). In in vitro tests of epididymal fat tissue of chromium-deficient rats, Cr(III) increases the uptake of glucose only in the presence of insulin (137). The interaction of Cr(III) and insulin also is demonstrated by experimental results indicating an effect of Cr(III) in translocation of sugars into ceUs at the first step of sugar metaboHsm. Chromium is thought to form a complex with insulin and insulin receptors (136). 

Chromium(III) compounds are essential to normal glucose, protein, and fat metabolism. In addition, chromium(III) is capable of forming complexes with nucleic acids and proteins. Chromium(VI) is... 

In humans and animals, chromium(III) is an essential nutrient that plays a role in glucose, fat, and protein metabolism by potentiating action of insulin. Chromium picolinate, a trivalent form of chromium complexed with picolinic acid, is used as a dietary supplement, because it is claimed to speed metabolism... 

Finally, it should be noted that this chemistry may have biological relevance. Several metalloenzymes are believed to contain more than one metal ion bound at the active site. One relevant example is the glucose tolerance factor (GTF) which is important for the metabolic degradation of glucose (398-401). GTF is a low-molecular-weight protein which contains chromium(III). Its structure is not known, but it has been suggested that the active site contains a dinuclear chromium(III) complex (401). The fact that hydroxo-bridged dinuclear chromium(III) complexes exhibit reactions which are often very fast compared with those observed for the parent mononuclear species seems to support such a proposal. 

Chromium was proposed as an essential element after the observation that rats fed with Torula yeast developed impaired glucose tolerance.1085 The active ingredient in other yeasts was suggested to be a chromium complex, named the glucose-tolerance factor . Brewers yeast contains chromium in the range 0.35-5.4 xgg-1.1086... 

As an example of 1 2-chromation by the dichromate-glucose method [20], the azo dye obtained by coupling of diazotized l-amino-2-hydroxy-5-nitrobenzene with l-methylsulfonylamino-7-hydroxynaphthalene is dissolved in dilute NaOH and boiled after addition of K2Cr20r2H20 and glucose. Chromation is complete after a few minutes. The resulting 1 2 chromium complex 12 [83748-22-5] is precipitated with NaCl to give a black powder that imparts bluish olive dyeings on wool in a weakly acidic dyebath. 

Chromium(III) is an essential nutrient required for normal energy metabolism. The National Research Council (NRC) recommends a dietary intake of 50-200 ig/day (NRC 1989). The biologically active form of an organic chromium(ni) complex, often referred to as GTF, is believed to function by facilitating the interaction of insulin with its cellular receptor sites. The exact mechanism of this interaction is not known (Anderson 1981 Evans 1989). Studies have shown that chromium supplementation in deficient and marginally deficient subjects can result in improved glucose, protein, and lipid metabolism. 

Chung et al. [179] demonstrated that carbohydrate auxiliaries can also be employed for the preparation of chiral (arene)tricarbonyl complexes, which are useful intermediates in organic synthesis. The D-glucose-derived benzylidene acetal 284 was reacted with hexacarbonyl chromium... 

The n-octylaminocarbene complex derived from glucose is synthesized from penta-acetylated gluconic acid chloride 326 addition of potassium pentacarbonyl chromate 251 followed by methylation gives chromium methoxycarbene 327 that undergoes low-temperature aminolysis with u-octylamine and 0-deprotection under basic conditions to afford chromium n-octylaminocarbene 328 (Scheme 11.68) [127]. 

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