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 isolation and characterization of 2-methylpyrrole and 3-acetyl-2-methylpyrrole as chromogens in the Elson-Morgan reaction has represented a major advance in our understanding of the reactions involved, but it clearly does not contribute a complete account of the situation. 

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... 

A better knowledge of these reactions will be relevant to an understanding of the Elson-Morgan reaction and interferences therewith, and to an interpretation of the chemical properties of sialic acids. 

Total using values for uronic acid from CO2 liberation, glucosamine by Elson-Morgan reaction, sulphur as SO3. 

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. 

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