Amino sugars reaction with

During the processing of foods, several chemical reactions affect the structure of some amino acids reactions with reducing sugars and polyphenols, interaction of the side chains of the amino acids, oxidation, etc. In some cases, these chemical modifications do not seem to change the nutritional availability of the amino acids involved, while in other cases, they do. In all cases, the presence of the newly formed molecules induces biochemical and physiological changes. 

The reaction of 1-amino-l-deoxy-D-fructose with /3-dicarbonyl compounds in aqueous acetone at neutral pH has also been studied. The acetate of this amino sugar affords, with ethyl acetoacetate, ethyl 2-methyl-4-(D-om6wo-tetrahydroxybutyl)pyrrole-3-carboxylate (17). As in previous... 

Several approaches based on nitro-aldol for the synthesis of amino sugars have been reported Alumina-catalyzed reaction of methyl 3- nitropropanoate with O-benzyl-o-lactaldehyde gives the o-ribo-nitro-aldol fanti, and isomeri in 63% yield, which is converted into L-dannosamine fsee Secdon 3 3 Jager and coworkers have reported a short synthesis of L-acosamine based on the stereoselective nitro-aldol reaction of 2-O-benzyl-L-lactaldehyde with 3-nitropropanal dimethyl acetal as shovm in Scheme 3 10 The stereoselecdve nitro-aldol reacdon is carried ont by the silyl nitronate approach as discussed in Secdon 3 3... 

Preparation of the TMS derivative Add 0.5 ml of TRI-SIL Z reagent (trimethylsilylimidazole in pyridine) to 1-5 mg of the sample. (This derivatizing preparation does not react with amino groups and tolerates the presence of water.) Heat in a sealed vial at 60° until the sample is dissolved. An alternate method is to let the reaction mixture stand at room temperature for at least 30 minutes (or overnight). This procedure is not appropriate for amino sugars. 

In a less straightforward way, D-glucose (393) underwent a Maillard-type reaction with an excess of glycine (394) under microwave irradiation to afford 5-hydroxy-l,3-dimethyl-2(l/f)-quinoxahnone (395) as a major product, Repetition with labeled reactants suggested that the product contained six carbon atoms from the sugar and four from the amino acid on this evidence, a detailed mechanism has been postulated. 

In a total synthesis of inhibitors of this kind, the following methods have so far been employed successfully (a) reaction of a cyclohexenyl halide with an amine, (b) coupling of an amine with an epoxide, and (c) condensation of an amine with ketone and reduction of the resulting Schiff base (reductive alkylation of an amino sugar). 

A second main subject of research by Garci a Gonzalez, mainly with the collaboration of A. Gomez-Sanchez, was the reaction of amino sugars with... 

Nitroacetaldehyde diethyl acetal is prepared by the reaction of nitromethane with triethyl orthoformate in the presence of ZnCl2 (Eq. 5.8).17 Jager and coworkers have used this reagent for the synthesis of amino sugars via nitro-aldol reaction.18 Preparation of this useful reagent is now described in volume 74 of Organic Synthesis.19... 

The death on October 8, 2009 of Antonio Gomez Sanchez is noted with regret. He was one of the successors of the Seville carbohydrate school built up by Francisco Garcia Gonzalez, with whom he coauthored in Volume 20 a chapter on the reaction of amino sugars with 1,3-dicarbonyl compounds, a subject that was a major theme of Gomez Sanchez s research. 

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