Amino Morgan-Elson reaction

After mild hydrolysis, neomycin has been shown to give a positive Elson-Morgan reaction , a reaction characteristic of amino-sugarsl52 A method involving this reaction has been made the basis of a quantitative assay for neomycinl l which has been used to determine the neomycin content of fermentation broths. ... 

The condensation of amino sugars with /3-keto esters in an alkaline medium results in considerable degradation of the (tetrahydroxybu-tyl)pyrrole produced, giving rise to small yields of 2-methylpyr-role,57,58 which seems to be the main chromophore in the Elson-Morgan reaction. Under these conditions, 3-amino-3-deoxyhexoses yield 2-methylpyrrole-4-carboxylic acid,59 which is, in part, responsible for the coloration produced with p-(dimethylamino)benzaldehyde. 

The most specific and frequently used assay to quantify 2-deoxy-2-amino sugars employs the condensation of the carbohydrate with 2,4-pentanedione in basic solution. The product (a pyrrole derivative) is then reacted with p-dimethylaminobenzaldehyde to form a chromogen that has a maximum absorbance at 530 nm (Fig. 11-2). Although both 6-deoxy-6-amino and 3-deoxy-3-amino sugars can also be analyzed using the Elson-Morgan reaction, the chromogens... 

E Acetyl derivatives of amino sugars (e.g., N-acetyl glucosamine) will undergo an Elson-Morgan reaction in basic solution. Write an equation to describe this reaction and draw the structure of the likely intermediate. 

The Interference Produced by Reducing Sugars and Amino Compounds in the Elson-Morgan Reaction... 

The Elson-Morgan reaction and Morgan-Elson reaction are of great importance for the detection of 2-amino-2-deoxyhexoses and of the 2-acet-amido-2-deoxyhexoses. With their help it is possible to detect these compounds in mixtures which contain nitrogen-free sugars, amino acids, etc. 

The amino sugar gives a reaction similar to that of 2-amino-2-deoxy-D-glucose in the Elson-Morgan test. 

Gottschalkii was able to characterize the split product formed by the action of influenza virus on ovomucin, and on the sialoprotein inhibitor from urine, by its ease of humin formation and its abihty to give the Morgan-Elson color reaction for N-acylated 2-amino-2-deoxyhexoses. Accordingly, he assigned the structure of a AT-substituted D-fructosamine to this product. Odin and Klenk, independently, both suggested that this split product is closely related to a nonulosaminic acid, and noted its ability to give a direct Ehrlich color reaction. Klenk and his coworkers were then able to establish unequivocally that the principal product ... 

A sensitive fluorimetric assay for 2-amino-2-deoxy-D-hexoses with increased sensitivity over the Elson-Morgan and Dische-Borenfreund indole methods has been reported. The 2,5-anhydrohexoses produced by nitrous acid deamination of heparin, heparan sulphate, and 2-amino-2-deoxy-D-hexoses have been treated with 3,5-diaminobenzoic acid to give stable derivatives. Neither neutral sugars nor acetamido sugars interfere in the reaction. In a modification of an earlier procedure, equivalent colour complexes were formed by the interaction of 3-methyl 2-benzothiazoline and the 2,5-anhydrohexoses produced by deamination of 2-amino-2-deoxy-D-glucose and 2-amino-2-deoxy-D-galactose. ... 

Acetylacetone-p-dimethylaminobenzaldehyde for amino sugars (Morgan Elson reaction). 

The Morgan-Elson assay (see Alternate Protocol 2) requires less than 1 hr for the preparation of all the reagents, but a one hour period is required for the reaction of the 2,4-pentadione solution with the amino-sugar samples. In conclusion, without considering the incubation time in the preparation of the reagents, 2 to 4 hrs working time should be enough to determine a sample concentration with any of the procedures. 

The effect of the concentration of tetraborate on the Morgan-Elson reaction for the determination of 2-acetamido-2-deoxy-D-hexoses has been evaluated. Use of optimal concentrations of tetraborate for chromogen formation lower than those previously advocated is suggested. The iV-acetylation of 2-amino-2-deoxy-D-hexoses has been shown to be temperature dependent. Conditions have been chosen for the selective A-acetylation of 2-amino-2-deoxy-D-galactose and not 2-amino-2-deoxy-D-glucose, and have been applied to an assay of mixtures of these two amino-sugars. 

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